Motor controller system and method for maximizing energy savings

Abstract
A motor controller (4) and method for maximizing the energy savings in an AC induction motor (3) at every load wherein the motor is calibrated at two or more load points to establish a control line (6), which is then programmed into a non-volatile memory (30) of the motor controller. A DSP-based closed-loop motor controller observes the motor parameters of the motor such as firing angle/duty cycles (23), voltage (37), current (9) and phase angles to arrive at a minimum voltage necessary to operate the motor at any load along the control line. The motor controller performs closed-loop control to keep the motor running at a computed target control point, such that maximum energy savings are realized by reducing voltage through pulse width modulation.
Description
BACKGROUND OF THE INVENTION

This invention relates to a system and method for maximizing the energy savings in AC induction motors at every load, more particularly one that uses a digital signal processor that calibrates control lines to determine the most efficient operational characteristics of the motors.


In prior systems and methods related to energy saving motor controllers using control lines of a motor, constant phase angle and/or constant power factor control were used to determine the control lines. This meant that the control lines were horizontal and the motor controllers were not able to control the motor to specific calibrated operating point at every load to maximize energy savings.


Thus, a need exists for a method and system for AC induction motors which controls the motor to a specific calibrated operating point at every load. Operating points taken across all loads will define a control line or a control curve. Furthermore, a need exists for a method and system for AC induction motors which is capable of recognizing when a motor begins to slip and is about to stall and uses that information to determine calibrated control line so as to maximize energy savings at every load.


The relevant patents of prior art includes the following references:

















Patent/Ser. No.
Inventor
Issue/Publication Date









2008/0100245
Turner
May 01, 2008



7,288,911
MacKay
Oct. 30, 2007



7,279,860
MacKay
Oct. 09, 2007



7,256,564
MacKay
Aug. 14, 2007



7,211,982
Chang et al.
May 01, 2007



7,081,729
Chang et al.
Jul. 25, 2006



6,643,149
Arnet et al.
Nov. 04, 2003



6,489,742
Lumsden
Dec. 03, 2002



5,506,484
Munro et al.
Apr. 09, 1996



5,350,988
Le
Sep. 27, 1994










SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a system and method of maximizing energy savings in AC induction motors at every load.


Another object of the present invention is to provide a system and method which recognizes when a motor begins to slip and when the motor is about to stall.


A further object of the present invention is to provide a system and method which controls the motor to a specific calibrated operating point at every load.


Another object of the present invention is to provide a motor controller that is capable of observing the operational characteristics of AC induction motors.


A further object of the present invention is to provide a motor controller capable of making corrections to the RMS motor voltage as an AC induction motor is running and under closed loop control.


Another object of the present invention is to provide a motor controller capable of responding to changes in the load of an AC induction motor in real-time.


The present invention fulfills the above and other objects by providing a motor controller system and method for maximizing the energy savings in the motor at every load wherein a motor is calibrated at one or more load points, establishing a control line or curve, which is then programmed into a non-volatile memory of the motor controller. A digital signal processor (DSP) a part of a closed loop architecture of the motor controller possesses the capability to observe the motor parameters such as current, phase angles and motor voltage. This DSP based motor controller is further capable of controlling the firing angle/duty cycle in open-loop mode as part of a semi-automatic calibration procedure. In normal operation, the DSP based motor controller performs closed-loop control to keep the motor running at a computed target control point, such that maximum energy savings are realized. The method described here works equally well for single phase and three phase motors.


The preferred implementation of this method uses a DSP to sample the current and voltage in a motor at discrete times by utilizing analog to digital converters. From these signals, the DSP can compute key motor parameters, including RMS motor voltage, RMS current and phase angle. Furthermore, the DSP based motor controller can use timers and pulse width modulation (PWM) techniques to precisely control the RMS motor voltage. Typically the PWM is accomplished by using power control devices such as TRIACs, SCRs, IGBTs and MOSFETs.


The above and other objects, features and advantages of the present invention should become even more readily apparent to those skilled in the art upon a reading of the following detailed description in conjunction with the drawings wherein there is shown and described illustrative embodiments of the invention.





BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed description, reference will be made to the attached drawings in which:



FIG. 1 is a block diagram of a digital signal processor (DSP) with hardware inputs and outputs of the present invention showing hardware inputs and outputs;



FIG. 2 is a block diagram of a DSP-based motor controller of the present invention;



FIG. 3 is a diagram showing a phase rotation detection method of the present invention;



FIG. 4 is a flow chart showing a phase rotation detection method of the present invention;



FIG. 5 is a graph showing power control device outputs for positive phase rotation;



FIG. 6 is a graph showing power control device outputs for negative phase rotation;



FIG. 7 is a block diagram of a window comparator;



FIG. 8 is a schematic of the window comparator;



FIG. 9 is a graph of a current waveform and zero-cross signals;



FIG. 10 is a schematic of a virtual neutral circuit;



FIG. 11 is a graph showing power control device outputs for single phase applications;



FIG. 12 is a three-dimensional graph showing a three-dimensional control line of the present invention;



FIG. 13 is a three-dimensional graph showing a control line projected onto one plane;



FIG. 14 is a graph showing a two-dimensional plotted control line;



FIG. 15 is a graph showing a sweeping firing angle/duty cycle in a semi-automatic calibration;



FIG. 16 is a graph showing a directed sweep of a firing angle/duty cycle;



FIG. 17 is a graph showing plotted semi-automatic calibration data;



FIG. 18 is a graph showing plotted semi-automatic calibration data;



FIG. 19 is a graph showing plotted semi-automatic calibration data;



FIG. 20 is a flow chart of a semi-automatic high level calibration;



FIG. 21 is a flow chart of a semi-automatic high level calibration;



FIG. 22 is a flow chart of a manual calibration;



FIG. 23 is a flow chart of a fixed voltage clamp:



FIG. 24 is a graph showing a RMS motor voltage clamp;



FIG. 25 is a graph showing a RMS motor voltage clamp;



FIG. 26 is a flow chart of a stall mitigation technique; and



FIG. 27 is a graph showing the stall mitigation technique.





DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of describing the preferred embodiment, the terminology used in reference to the numbered components in the drawings is as follows:

  • 1. digital system processor (DSP)
  • 2. hardware inputs
  • 3. motor
  • 4. motor controller
  • 5. observed phase angle
  • 6. control line
  • 7. observed calibration data curve from sweep ofconlrol space
  • 8. supply divider resistors
  • 9. current
  • 10. target phase angle
  • 11. phase error signal
  • 12. proportional integral derivative (PID) controller
  • 13. root square mean (RMS) motor voltage
  • 14. power control device outputs
  • 15. phase A line voltage zero crossing
  • 16. phase B line voltage zero crossing
  • 17. phase C line voltage zero crossing
  • 18. positive phase rotation
  • 19. negative phase rotation
  • 20. powcr-on-rcsct (POR)
  • 21. stall point
  • 22. a.c.b phase turn on times
  • 23. firing angle/duty cycle
  • 24. percent load
  • 25. paramctrical control line
  • 26. operating point
  • 27. low output impedance amplifier
  • 28. phase error
  • 29. control voltage
  • 30. point b
  • 31. knee
  • 32. calibration bullon
  • 33. power control device
  • 34. point c
  • 35. voltage minimum (Vmin)
  • 36. phase zero crossing inputs
  • 37. phase line voltage
  • 38. phase motor voltage
  • 39. lime is measured
  • 40. is time greater or less than 90°
  • 41. ABC rotation
  • 42. ACB rotation
  • 43. point d
  • 44. place in loaded configuration
  • 45. place in unloaded configuration
  • 46. run calibration
  • 47. control line ends calibrated
  • 48. calculate control line
  • 49. saves control line
  • 50. line voltages
  • 51. set firing angle/duly cycle to 90°
  • 52. measure motor parameters
  • 53. detects knee
  • 54. decrease firing angle/duly cycle by 2°
  • 55. save phase angle and motor voltage
  • 56. repeat four times
  • 57. compute average values
  • 58. firing angle/duly cycle is increased
  • 59. measure next step
  • 60. fixed voltage clamp
  • 61. synthesize control segment
  • 62. analog to digital converter
  • 63. phase computation
  • 64. phase error is computed
  • 65. voltage error is computed
  • 66. RMS molor voltage is compared to fixed voltage threshold
  • 67. is control target positive
  • 68. voltage loop is run
  • 69. control line loop is run
  • 70. motor placed on dynamometer
  • 71. molor is connected to computer
  • 72. firing angle/duty cycle is increased and voltage decreased
  • 73. record calibration point
  • 74. stari motor
  • 75. firing angle/duty cycle is adjusted
  • 76. form control line
  • 77. differential-lo-single-ended amplifiers
  • 78. input resistors
  • 79. attenuator
  • 80. feedback resistor
  • 81. ground reference resistor
  • 82. protection diodes
  • 83. summing amplifier
  • 84. DC blocking capacitors
  • 85. summing resistors
  • 86. neutral
  • 87. juniper block for alternate neutral connection
  • 88. window comparator
  • 89. motor current is provided
  • 90. positive voltage is provided
  • 91. negative voltage is provided
  • 92. voltage passes through two comparators
  • 93. voltage passes through operation (OR) gale
  • 94. zero-cross digital signal is created
  • 95. current waveform
  • 96. positive voltage half cycle
  • 97. negative voltage half cycle
  • 98. OR function
  • 99. DSP monitors for increase in current
  • 100. increase is observed
  • 101. motor voltage is turned to full on
  • 102. motor voltage is reduced to control line
  • 103. load on the motor
  • 104. power applied to motor
  • 105. point a
  • 106. count sweeps


With reference to FIG. 1, a block diagram of a digital signal processor (DSP) 1 and hardware inputs and outputs of the present invention is shown. The DSP 1 can observe the operational characteristics of a motor and make corrections to root mean square (RMS) voltage for the motor that is running and under closed loop control. Hardware inputs 2 capture phase zero crossing inputs 36, phase line voltage 37, phase motor voltage 38 and current 9 and passed through the DSP 1 for processing and then onto power control devices through the power control device outputs 14.


Referring now to FIG. 2, a block diagram of a system and method of the DSP-based motor controller 4 of the present invention is shown. First, the motor controller 4 reads the voltages 37 of each phase A, B and C and current 9 to capture the zero-crossing inputs 36. At this point voltage 13 and current 9 may be converted from analog to digital using converters 62. Next, computations 63 of motor phase angle for each phase are calculated to yield an observed phase angle 5. Next, a target phase angle 10 which has been derived from a preprogrammed control line 6 is compared to the observed phase angle 5. The difference between the target phase angle 10 and observed phase angle 5 yields a resulting phase error signal 11 which is processed by a digital filter called a proportional integral derivative (PID) controller 12 which has proportional, integral and differential components. The output from the PID controller 12 is the new control voltage 13 to the motor 3, which can be obtained through the use of power control devices 33, such as TRIACs, SCRs, IGBTs or MOSFETS, to yield power control device outputs 14 of RMS motor voltage 13 supplied with line voltages 50 for each phase for maximum energy savings.


In this closed loop system, the voltage 13 of each phase of the motor 3 and the current are continually monitored. The motor controller 4 will drive the observed phase angle 5 to the point on the calibrated control line 6 corresponding to the load that is on the motor. At this point, maximum energy savings will be realized because the control line 6 is based on known calibration data from the motor 3. The motor controller 4 can control the motor 3 just as if a technician set the voltage 13 by hand. The difference is that the DSP 1 can dynamically respond to changes in the load in real-time and make these adjustments on a cycle by cycle basis.


Referring now to FIG. 3, in a three-phase system, the motor controller 4 is used to automatically determine the phase rotation. Zero-crossing detectors on the line voltages provide an accurate measurement of the angle between the phase A line voltage zero crossings 15 and the phase B line voltage zero crossings 16. For positive phase rotation 18, the angle is nominally 120° and for negative phase rotation 19, the angle is nominally 60°.


Referring to FIG. 4, a flow chart for phase rotation detection is shown. After a power-on-reset (POR) 20, it is easy for the motor controller 4 to determine positive phase rotation 18 and the negative phase rotation 19. First, the time is measured from phase A line voltage zero crossings to phase B line voltage zero crossings 39. Next it is determined if the time is greater than or less than 90 degrees 40. If it greater than 90 degrees, than it is an ACB rotation 42. If the time is less than 90 degrees, than it is an ABC rotation 41. The motor controller 4 of the present invention can control three-phase or single-phase motors with the same basic software and hardware architecture. For the three-phase case, depending on the phase rotation, the motor controller 4 can drive power control device outputs 14.


Referring now to FIG. 5 which shows power control device outputs for positive drive rotation, the motor controller drives phase A power control device outputs 14 and phase B power control device outputs 14 together during the phase A line voltage zero crossings 15 turn-on time as indicated by the oval 22a. Similarly, the motor controller drives power control devices which drive phase B 16 and phase C power control device outputs 14 together during the phase B turn-on time as indicated by the oval 22b. Finally, the motor controller 4 drives phase C 17 and phase A power control device outputs 14 together during the phase C power control device outputs 14 turn-on time as indicated by the oval 22c. Note that the example shown in FIGS. 5 and 6 depicts a firing angle/duty cycle 23 of 90°.


Referring now to FIG. 6 which shows the TRIAC drive outputs for negative phase rotation, the motor controller 4 drives phase A power control device outputs 14 and phase C power control device outputs 14 together during the phase A line voltage zero crossings 15 turn-on time as indicated by the oval 22c. Similarly, the motor controller 4 drives phase B 16 and phase A power control device outputs 14 together during the phase B line voltage zero crossings 16 turn-on time, as indicated by oval 22a. Finally, the motor controller drives phase C power control device outputs 14 and phase B power control device outputs 14 together during the phase C line voltage zero crossings 17 turn-on time, as indicated by oval 22b.


Now referring to FIG. 7, a block diagram of a window comparator is shown. The DSP based motor controller of the present invention uses the window comparator 88 to detect zero-crossings of both positive and negative halves of a current wave form. When RMS motor voltage is reduced by the motor controller, it if difficult to detect zero crossings of current waveform because the current is zero for a significant portion of both half cycles. First, motor current is provided 89, a positive voltage is provided 90 as a reference for a positive half cycle and a negative voltage is provided 91 as a reference. Next, the current, positive voltage and negative voltage are presented to two comparators 92 and are then passed through an operation (OR) gate 93 to create a composite zero-cross digital signal 94.


As further illustrated in FIG. 8, a schematic of the window comparator 88 is shown. The motor current is provided 89, a positive voltage is provided 90 as a reference for a positive half cycle and a negative voltage is provided 91 as a reference. Next, the current, represented as a positive voltage and negative voltage, is processed by two comparators 92 and are then passed to an OR gate 93 to create a composite zero-cross digital signal 94.


Further, FIG. 9 shows graphs of a current waveform 95, a positive voltage half cycle 96, a negative voltage half cycle 97 and an OR function 98.


Now referring to FIG. 10, a schematic of a virtual neutral circuit is shown. A virtual neutral circuit may be used as a reference in situations where three phase power is available only in delta mode and there is no neutral present for use as a reference. The virtual neutral circuit comprises three differential-to-single-ended amplifiers 77. Because phase to phase voltages are high, input resistors 78 are used to form a suitable attenuator 79 together with feedback resistors 80 and ground reference resistors 81. Because the danger exists of a loss of phase, protection diodes 82 are used to protect the differential-to-single-ended amplifiers 77. The differential-to-single-ended amplifiers 77 are coupled to a summing amplifier 83 through DC blocking capacitors 84 and summing resistors 85 together with the feedback resistor 80. The output of of the summing amplifier 83 is boosted by amplifier 27 thereby providing a low impedance output which is at neutral potential. Additional resistors divide a supply rail thereby allowing the summing amplifier 83 to handle alternating positive and negative signals. An alternate connection is available in the event that a neutral 86 is available along with a jumper block for alternate neutral connection 87.


Referring now to FIG. 11 showing a power control device output 14 for a single-phase application, the output 14 for phase A is turned on each half-cycle based on a power control device output 14 derived from the voltage zero-crossing input 15. The power control device output 14 for phase B line voltage zero crossings and phase C line voltage zero crossings are disabled in the DSP 1 and the hardware may not be present. The power control device outputs 14 are not paired as they were in the three-phase case.


Referring now to FIG. 12 which illustrates a three-dimensional control line for the motor operating space of a motor bounded by an observed phase angle 5 on the y-axis. A controlled firing angle/duty cycle 23 showing the decrease in voltage is shown on the x-axis and the percent load 24 on a motor is shown on the z-axis.


Every motor operates along a parametrical control line 25 within its operating space. For example, when a given motor is 50% loaded and the firing angle/duty cycle 23 is set to 100°, a phase angle 5 of approximately 55° is observed.


The parametrical control line 25 shown in FIG. 12 is defined by five parametric operating points 26 ranging from a loaded case 44 in the upper left corner, to an unloaded case 45 in the lower right corner. Furthermore, the parametrical control line 25 has special meaning because it is the line where a motor is using the least energy possible. If the firing angle/duty cycle 23 is increased and the motor voltage 13 decreased then a motor would slow down and possibly stall. Similar results would be seen if the load on the motor 3 is increased.


As illustrated in FIG. 13, the parametric control line 25 may be parameterized and projected onto one plane described by phase angle 5 in the vertical direction and the firing angle/duty cycle 23 in the horizontal direction.


Further, as shown in FIG. 14, the parametrical control line 25 may be displayed on a two-dimensional graph. On the x-axis, increasing firing angle/duty cycle 23 may be equated with a decreasing motor voltage. This is because small firing angle/duty cycles result in high voltage and large firing angle/duty cycles result in low voltage. The motor controller will drive the observed phase angle 5 to the point on the control line 25 that corresponds to the load presently on a motor. To accomplish this, a DSP computes the phase angle 5 between the voltage and current.


Referring back to the block diagram of FIG. 2, the DSP 1 then computes the next target phase angle 5 based on the present value of the RMS voltage 13, or equivalently the present value of the firing angle/duty cycle. The difference between the observed phase angle and the target phase angle 10 results in a phase angle error, which is processed through a proportional-integral-differential (PID) controller 12 or similar device to generate a new control target. This control target changes the voltage in such a way as to minimize the phase angle error. The target phase angle 10 is dynamic and it changes as a function of the firing angle/duty cycle.


As stated above, the motor controller 4 will drive the observed phase angle 5 to the point on the control line 25 that corresponds to the load presently on the motor 3. This operating point 26 provides the maximum energy savings possible because the control line 25 is calibrated directly from the motor 3 that is being controlled.


This preferred method for calibration is called semi-automatic calibration. The semi-automatic calibration is based on the DSP 1 sweeping the control space of the motor. As shown in FIG. 15, sweeping the control space means that the DSP increases the firing angle/duty cycle 23 and records the current 9 and firing angle/duty cycle 23 of each phase at discrete points along the way. Thus, in this manner it is possible to see the beginning of the stall point 21 of the motor. A well-defined linear portion of observed calibration data curve obtained from sweeping the control space 7, which is used to determine points on the control line 6, has a constant negative slope at lower firing angle/duty cycles 23. Then, as the firing angle/duty cycle 23 continues to increase, the current 9 begins to flatten out and actually begins to increase as the motor 3 begins to slip and starts to stall, called the “knee” 31.


As shown in FIG. 16, subsequent sweeps can be directed at smaller ranges of motor voltages to “zoom in” on the knee. The motor controller 4 requires multiple sweeps in order to get data that is statistically accurate. There is a tradeoff between the number of sweeps and the time required to calibrate the control line 25. A measure of the quality of the calibration can be maintained by the DSP 1 using well known statistical processes and additional sweeps can be made if necessary. This is true because the DSP 1 has learned the approximate location of knee 31 from the first sweep.


There is little danger of stalling during the semi-automatic sweep because of the controlled environment of the setup. A technician or operator helps to insure that no sudden loads are applied to the motor 3 under test while a semi-automatic calibration is in progress.


The process of sweeping the control space can be performed at any fixed load. For example, it can be performed once with the motor 3 fully loaded and once with the motor 3 unloaded. These two points become the two points that define the control line 25. It is not necessary to perform the calibration at exactly these two points. The DSP 1 will extend the control line 25 beyond both these two points if required.


There are many numerical methods that can be applied to find the stall point 21 in the plot of the current motor voltage 23. As shown in FIG. 17, the preferred method is to use the “least squares” method to calculate a straight line that best fits the accumulated data tabulated from the first five motor voltages 23.


The continuation of this method is shown in FIG. 18. Using the previous data points the value of the current 9 may be predicted. Graphically, the DSP 1 is checking for one or more points that deviate in the positive direction from the predicted straight line.


As shown in FIG. 19, the DSP 1 is looking for the beginning of the knee in the curve. The first point that deviates from the predicted control line may or may not be the beginning of the knee 31. The first point with a positive error may simply be a noisy data point. The only way to verify that the observed calibration data curve obtained from sweeping the control space 7 is turning is to observe data obtained from additional sweeps.


Semi-automatic calibration may be performed in the field. Referring now to FIG. 20, a flow chart showing how semi-automatic calibration is performed is shown. First the motor 3 is placed in a heavily loaded configuration 44. Ideally this configuration is greater than 50% of the fully rated load. Next a calibration button 32 on the motor controller 4 is pressed to tell the DSP 1 to perform a fully-loaded measurement. The DSP 1 runs a calibration 46 which requires several seconds to explore the operating space of the motor 3 to determine the fully-loaded point. The motor controller 4 indicates that it has finished this step by turning on an LED.


Next the motor 3 is placed in an unloaded configuration 45. Ideally this configuration is less than 25% of the rated load. Then a calibration button 32 on the motor controller 4 is pressed 47 to tell the DSP 1 to perform an unloaded measurement. The DSP 1 runs the calibration 46 to determine the unloaded point. The motor controller 4 indicates that it has finished calibrating both ends 47 of the control line 25 by turning on a light emitting diode (LED). The DSP 1 then determines the control line 48 using the two measurements and applies this control line when it is managing the motor 3. The values of the control line 25 are stored in non-volatile memory 49.



FIG. 21 shows a more detailed flow chart of the semi-automatic calibration. First a first calibration sweep is run 46 with the motor voltage set at a certain degree 51, depending on if it is a first sweep or previous sweeps have been run 106, in which the motor controller measures the motor 52 until the motor controller detects a knee 53. If a knee 53 is detected the firing angle/duty cycle is decreased by two degrees 54 and the phase angle and the motor voltage are recorded to the memory 55. This process is repeated to obtain at least four sweeps 56 to get a computed average value 57 of the phase angle and the firing angle/duty cycle. If during any step along the calibration sweep, the knee is not detected, then the firing angle/duty cycle is increased by at least one degree 58 and the nest step is measured 59.


An alternative method for calibration is called manual calibration. FIG. 22 shows a flow chart of manual calibration. First a motor is placed on a dynamometer 70. Next the motor is connected to a computer for manual control 71 which allows the motor to be run in a open-loop mode and the firing angle/duty cycle of the AC induction motor to be manually set to any operating point. Then the motor is placed in a fully unloaded configuration 45. Next the firing angle/duty cycle is increased and the RMS motor voltage is reduced 72 until the motor is just about to stall. The firing angle/duty cycle and phase angle are recorded and this becomes a calibrated point which is recorded 73. Then the motor is started with drive elements fully on 74. Then the motor is placed in a fully loaded configuration 44. Next the firing angle/duty cycle is increased or decreased until the RMS motor voltage is chopped by the motor controller 75 until the motor is just about to stall. The firing angle/duty cycle are recorded and this becomes another calibrated point which is recorded 73. Finally the two calibrated points are used to form a control line 76.


When the RMS line voltage is greater than a programmed fixed-voltage, the DSP controller clamps the RMS motor voltage at that fixed voltage so energy savings are possible even at full load. For example, if the mains voltage is above the motor nameplate voltage of 115V in the case of a single phase motor then the motor voltage is clamped at 115V. This operation of clamping the motor voltage, allows the motor controller to save energy even when the motor is fully loaded in single-phase or three-phase applications.



FIG. 23 shows a flow chart of the fixed voltage clamp. First a phase error is computed 64. Next a voltage error is computed 65. Then the RMS motor voltage of the AC induction motor is determined and compared to a fixed voltage threshold 66. If the RMS motor voltage is greater than the fixed voltage threshold then it is determined whether or not control target is positive 67. If the control target is positive then a voltage control loop is run 68. If the RMS motor voltage of the AC induction motor is less than a fixed-voltage threshold, then the a control line closed loop is run 69 and the entire process is repeated. If the control target is determined not to be positive then a control line loop is run 69 and the entire process is repeated again.


In some cases, it may not be possible to fully load the motor 3 during the calibration process. Perhaps 50% is the greatest load that can be achieved while the motor is installed in the field. Conversely, it may not be possible to fully unload the motor; it may be that only 40% is the lightest load that can be achieved. FIG. 24 shows an example of both load points being near the middle of the operating range. On the unloaded end 45 at the right of the control line 25, the DSP 1 will set the fixed voltage clamp 60 of the voltage at minimum voltage 35. When the load on the motor increases, the DSP 1 will follow the control line moving to the left and up the control segment 61. This implementation is a conservative approach and protects the motor 3 from running in un-calibrated space.


As further shown in FIG. 25, on the fully loaded end 44 at the left, the DSP 1 will synthesize a control segment 61 with a large negative slope. This implementation is a conservative approach and drives the voltage to full-on.


Referring now to FIG. 26, the DSP-based motor controller uses a special technique to protect a motor from stalling. First, the DSP actively monitors for a significant increase in current 99 which indicates that load on the motor has increased. Next, if a significant increase is observed 100 then the DSP turns motor voltage to full on 101. Next, the DSP will attempt to reduce motor voltage to return to the control 102 and the DSP returns to actively monitoring for a significant increase in current 99. This technique is a conservative and safe alternative to the DSP attempting to track power requirements that are unknown at that time.


As further shown in FIG. 27, a graph of the stall mitigation technique, the load on the motor is represented on an x-axis and time is represented on a y-axis. The bottom line represents the load on the motor 103 and the top line represents the power applied to the motor by the DSP 104. Prior to point a 105, the DSP is dynamically controlling the motor at a fixed load. In between point a 105 and point b 30, the load on the motor is suddenly increased and the DSP turns the motor voltage to full on. At point c 34, the DSP reduces the motor voltage to point d 43.


Although a preferred embodiment of a motor controller method and system for maximizing energy savings has been disclosed, it should be understood, it is not to be limited to the specific form or arrangement of parts herein described and shown. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not be considered limited to what is shown and described in the specification and drawings.

Claims
  • 1. A system for controlling an AC induction motor to conserve energy, the system comprising: a processor that communicates with a computer-readable non-volatile memory having instructions stored thereon that, when executed by the processor, cause the processor to:sweep a control space of said AC induction motor;obtain operating parameters of said AC induction motor;establish a control line from said measurements;receive said control line at said motor controller;perform a closed-loop control of said AC induction motor in accordance with said control line to observe an operating parameter;drive the observed operating parameter of said AC induction motor relative to said control line, the observed operating parameter comprising a current;detect zero-crossings of positive and negative halves of a current waveform of said AC induction motor every cycle by: obtaining a positive voltage as a reference for a positive half cycle;obtaining a negative voltage as a reference for a negative half cycle; andtransmitting signals through an OR gate to create composite current zero-cross digital signals.
  • 2. The system of claim 1, wherein the processor is configured to drive the observed operating parameter of said AC induction motor to correspond to a fully loaded configuration.
  • 3. The system of claim 1, wherein the processor is configured to drive the observed operating parameter of said AC induction motor to correspond to a fully unloaded configuration.
  • 4. The system of claim 1, wherein the processor is further configured to obtain the current of said AC induction motor.
  • 5. The system of claim 4 wherein the processor obtains the current measurement of said AC induction motor in substantially real-time.
  • 6. The system of claim 1 wherein the processor is further configured to obtain phase angles of said AC induction motor.
  • 7. The system of claim 6 wherein the processor obtains the phase angles of said AC induction motor in substantially real-time.
  • 8. The system of claim 1, wherein said observed operating parameter is a phase angle and wherein the processor is further configured to control a firing angle of said AC induction motor.
  • 9. The system of claim 8 wherein the processor controls said firing angle of said AC induction motor in substantially real-time.
  • 10. The system of claim 1 wherein the processor is further configured to sweep the control space of said AC induction motor and measure said operating parameters by automatically varying a root square means motor voltage of said AC induction motor.
  • 11. The system of claim 10, wherein the processor varies the root square means motor voltage of the AC induction motor in substantially real-time.
  • 12. The system of claim 1, wherein the processor establishes said control line from said measurements in substantially real-time.
  • 13. The system of claim 1, wherein the processor receives said control line in said motor controller is from the non-volatile memory.
  • 14. The system of claim 1, wherein the processor performs said closed-loop control of said AC induction motor in substantially real-time.
  • 15. The system of claim 1, wherein the processor is further configured to perform said closed-loop control of said AC induction motor using pulse width modulation.
  • 16. The system of claim 15 wherein: said pulse width modulation is performed using at least one TRIAC driver.
  • 17. The system of claim 15 wherein: said pulse width modulation is performed using at least one SCR driver.
  • 18. The system of claim 15 wherein: said pulse width modulation is performed using at least one IGBT driver.
  • 19. The system of claim 15 wherein: said pulse width modulation is performed using at least one MOSFET driver.
  • 20. The system of claim 1, wherein the processor is further configured to clamp an operating motor voltage of said AC induction motor at a maximum voltage.
  • 21. The system of claim 1, wherein the processor is further configured to prevent said AC induction motor from running at a voltage below a minimum voltage when monitoring said AC induction motor for a stall point.
  • 22. A system for controlling an AC induction motor to conserve energy, the system comprising: a processor that communicates with a computer-readable non-volatile memory having instructions stored thereon that, when executed by the processor, cause the processor to: sweep a control space of said AC induction motor and measuring operating parameters of said AC induction motor;establish a control line from said measurements;receive said control line in said motor controller:perform a closed-loop control of said AC induction motor in accordance with said control line to observe an operating parameter;drive the observed operating parameter of said AC induction motor relative to said control line;protect against stalling of said AC induction motor by: actively controlling said AC induction motor while constantly monitoring said AC induction motor for increases in a motor current;turning a motor voltage to full on when an increase in said motor current is detected; andreducing said motor voltage to follow said control line after said motor current decreases.
  • 23. A method for controlling an AC induction motor to conserve energy, the method comprising the steps of: sweeping a control space of said AC induction motor and measuring operating parameters of said AC induction motor;establishing a control line for said AC induction motor from said measured operating parameters;receiving said control line at said motor controller;performing a closed-loop control of said AC induction motor in accordance with said control line to observe an operating parameter of said AC induction motor after the step of establishing said control line;driving the observed operating parameter of said AC induction motor relative to said control line;detecting zero-crossings of positive and negative halves of a current waveform in said AC induction motor every cycle;obtaining a positive voltage at a window comparator as a reference for a positive half cycle;obtaining a negative voltage at the window comparator as a reference for a negative half cycle; andtransmitting signals from said window comparator through an OR gate to create composite current zero-cross digital signals.
  • 24. The method of claim 23, wherein the step of sweeping comprises the steps of: placing the operating parameters of said AC induction motor in a fully loaded configuration;determining a fully loaded point of said AC induction motor;placing the operating parameters of said AC induction motor in a fully unloaded configuration; anddetermining a fully unloaded point of said AC induction motor.
  • 25. The method of claim 24, further comprising the step of: connecting the fully loaded point and the fully unloaded point to establish said control line of said AC induction motor.
  • 26. The method of claim 23, further comprising the step of: automatically recording a motor current and an observed phase angle along said control line.
  • 27. The method of claim 23, further comprising the step of: controlling a voltage along said control line using pulse width modulation.
  • 28. The method of claim 27 wherein: said pulse width modulation is performed using at least one TRIAC driver.
  • 29. The method of claim 27 wherein: said pulse width modulation is performed using at least one SCR driver.
  • 30. The method of claim 27 wherein: said pulse width modulation is performed using at least one IGBT driver.
  • 31. The method of claim 27 wherein: said pulse width modulation is performed using at least one MOSFET driver.
  • 32. The method of claim 23, wherein the step of controlling further comprises the step of: clamping a voltage of said AC induction motor at a minimum voltage to prevent said AC induction motor from running at a voltage below said minimum voltage.
  • 33. A method for controlling an AC induction motor to conserve energy, the method comprising the steps of: sweeping a control space of said AC induction motor and measuring operating parameters of said AC induction motor;establishing a control line for said AC induction motor from said measured operating parameters;receiving said control line at said motor controller;performing a closed-loop control of said AC induction motor in accordance with said control line to observe an operating parameter of said AC induction motor after the step of establishing said control line;driving the observed operating parameter of said AC induction motor relative to said control line;increasing a firing angle/duty cycle of said AC induction motor from eighty degrees to one-hundred-fifty degrees; andrecording a motor current and a phase angle along said control line.
  • 34. A method for controlling an AC induction motor to conserve energy, the method comprising the steps of: sweeping a control space of said AC induction motor and measuring operating parameters of said AC induction motor;establishing a control line for said AC induction motor from said measured operating parameters;receiving said control line at said motor controller;performing a closed-loop control of said AC induction motor in accordance with said control line to observe an operating parameter of said AC induction motor after the step of establishing said control line;driving the observed operating parameter of said AC induction motor relative to said control line; andprotecting against stalling of said AC induction motor by: actively controlling said AC induction motor while constantly monitoring said AC induction motor for increases in a motor current;turning a motor voltage to full on when an increase in said motor current is detected; andreducing said motor voltage to follow said control line after said motor current decreases.
  • 35. A motor controller for controlling an AC induction motor to conserve energy, the motor controller comprising: a processor that communicates with a computer-readable non-volatile memory having instructions stored thereon that, when executed by the processor, cause the processor to: compute a control line from measured operating parameters;perform a closed-loop control of the AC induction motor in accordance with said computed control line to observe an operating parameter of the AC induction motor;drive the observed operating parameter of the AC induction motor relative to said computed control line;detect zero-crossings of positive and negative halves of a current waveform in the AC induction motor by:obtaining a positive voltage as a reference for a positive half cycle;obtaining a negative voltage as a reference for a negative half cycle; andtransmitting signals through an OR gate to create composite current zero-cross digital signals.
  • 36. The motor controller of claim 35 wherein the processor is configured to obtain a current of the AC induction motor.
  • 37. The motor controller of claim 35 wherein the processor is configured to obtain a phase angle of the AC induction motor.
  • 38. The motor controller of claim 35 wherein said observed operating parameter is a phase angle.
  • 39. The motor controller of claim 35, wherein the processor is configured to obtain said operating parameters by varying a root square means motor voltage of the AC induction motor.
  • 40. The motor controller of claim 35, wherein the processor is configured to perform said closed-loop control of the AC induction motor in substantially real-time.
  • 41. The motor controller of claim 35, wherein the processor is further configured to protect against stalling of the AC induction motor.
  • 42. The motor controller of claim 41, wherein the processor is further configured to actively control the AC induction motor while monitoring the AC induction motor for increases in a motor current; turn a motor voltage to full on when an increase in the motor current is detected; andreduce the motor voltage to follow said control line after the motor current decreases.
CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application Nos. 60/993,706 filed Sep. 14, 2007; and 61/135,402 filed Jul. 21, 2008.

US Referenced Citations (347)
Number Name Date Kind
2276353 Vickers Mar 1942 A
2276358 Vickers Mar 1942 A
2345933 Green et al. Apr 1944 A
3440512 Hubby Apr 1969 A
3470443 Nola et al. Sep 1969 A
3470446 Nola et al. Sep 1969 A
3523228 Nola et al. Aug 1970 A
3541361 Nola Nov 1970 A
3582774 Forgacs Jun 1971 A
3671849 Kingston Jun 1972 A
3718846 Bejach Feb 1973 A
3740629 Kohlhagen Jun 1973 A
3753472 Dwbwad et al. Aug 1973 A
3851995 Mills Dec 1974 A
3860858 Nola Jan 1975 A
3953777 McKee Apr 1976 A
3959719 Espelage May 1976 A
3976987 Anger Aug 1976 A
4039946 Nola Aug 1977 A
4052648 Nola Oct 1977 A
4096436 Cook et al. Jun 1978 A
4145161 Skinner Mar 1979 A
4168491 Phillips et al. Sep 1979 A
4220440 Taylor Sep 1980 A
4266177 Nola May 1981 A
4324987 Sullivan, II et al. Apr 1982 A
4333046 Lee Jun 1982 A
4346339 Lewandowski Aug 1982 A
4353025 Dobkin Oct 1982 A
4363605 Mills Dec 1982 A
4388585 Nola Jun 1983 A
4391155 Bender Jul 1983 A
4392100 Stanton Jul 1983 A
4400657 Nola Aug 1983 A
4404511 Nola Sep 1983 A
4412167 Green et al. Oct 1983 A
4413676 Kervin Nov 1983 A
4417190 Nola Nov 1983 A
4420787 Tibbits Dec 1983 A
4426614 Nola Jan 1984 A
4429269 Brown Jan 1984 A
4429578 Darrel et al. Feb 1984 A
4433276 Nola Feb 1984 A
4439718 Nola Mar 1984 A
4454462 Spann Jun 1984 A
4456871 Stich Jun 1984 A
4459528 Nola Jul 1984 A
4469998 Nola Sep 1984 A
4489243 Nola Dec 1984 A
4490094 Gibbs Dec 1984 A
4513240 Putman Apr 1985 A
4513274 Halder Apr 1985 A
4513361 Rensink Apr 1985 A
4551812 Gurr et al. Nov 1985 A
4561299 Orlando et al. Dec 1985 A
4616174 Jorgensen Oct 1986 A
4644234 Nola Feb 1987 A
4649287 Nola Mar 1987 A
4659981 Lumsden Apr 1987 A
4679133 Moscovici Jul 1987 A
4689548 Mechlenburg Aug 1987 A
4706017 Wilson Nov 1987 A
4716357 Cooper Dec 1987 A
4819180 Hedman et al. Apr 1989 A
4841404 Marshall Jun 1989 A
4859926 Wolze Aug 1989 A
4876468 Libert Oct 1989 A
4971522 Butlin Nov 1990 A
4997346 Bohon Mar 1991 A
5003192 Beigel Mar 1991 A
5010287 Mukai et al. Apr 1991 A
5044888 Hester, II Sep 1991 A
5066896 Bertenshaw et al. Nov 1991 A
5134356 El-Sharkawl et al. Jul 1992 A
5136216 Wills et al. Aug 1992 A
5180970 Ross Jan 1993 A
5202621 Reischer Apr 1993 A
5204595 Opal et al. Apr 1993 A
5214621 Maggelet et al. May 1993 A
5222867 Walker, Sr. Jun 1993 A
5227735 Lumsden Jul 1993 A
5239255 Schanin et al. Aug 1993 A
5259034 Lumsden Nov 1993 A
5281100 Diederich Jan 1994 A
5299266 Lumsden Mar 1994 A
5332965 Wolf et al. Jul 1994 A
350988 Le Sep 1994 A
5350988 Le Sep 1994 A
5362206 Westerman et al. Nov 1994 A
5425623 London Jun 1995 A
5442335 Cantin et al. Aug 1995 A
5481140 Maruyama et al. Jan 1996 A
5481225 Lumsden et al. Jan 1996 A
5500562 Kelley Mar 1996 A
5506484 Munro et al. Apr 1996 A
5543667 Shavit et al. Aug 1996 A
5559685 Lauw et al. Sep 1996 A
5572438 Ehlers et al. Nov 1996 A
5600549 Cross Feb 1997 A
5602462 Stich Feb 1997 A
5602689 Kadlec et al. Feb 1997 A
5614811 Sagalovich et al. Mar 1997 A
5615097 Cross Mar 1997 A
5625236 Lefebvre et al. Apr 1997 A
5635826 Sugawara Jun 1997 A
5637975 Pummer et al. Jun 1997 A
5652504 Bangerter Jul 1997 A
5699276 Roos Dec 1997 A
5732109 Takahashi Mar 1998 A
5747972 Baretich et al. May 1998 A
5754036 Walker May 1998 A
5821726 Anderson Oct 1998 A
5828200 Ligman et al. Oct 1998 A
5828671 Vela et al. Oct 1998 A
5856916 Bennet Jan 1999 A
5880578 Oliveira et al. Mar 1999 A
5909138 Stendahl Jun 1999 A
5936855 Salmon Aug 1999 A
5942895 Popovic et al. Aug 1999 A
5945746 Tracewell et al. Aug 1999 A
5946203 Jiang et al. Aug 1999 A
5994898 DiMarzio et al. Nov 1999 A
6005367 Rohde Dec 1999 A
6013999 Nola et al. Jan 2000 A
6055171 Ishii et al. Apr 2000 A
6104737 Mahmoudi Aug 2000 A
6118239 Kadah Sep 2000 A
6178362 Woolard et al. Jan 2001 B1
6184672 Berkcan Feb 2001 B1
6191568 Poletti Feb 2001 B1
6198312 Floyd Mar 2001 B1
6225759 Bogdan et al. May 2001 B1
6259610 Karl et al. Jul 2001 B1
6265881 Meliopoulos et al. Jul 2001 B1
6274999 Fujii et al. Aug 2001 B1
6297610 Bauer et al. Oct 2001 B1
6325142 Bosley et al. Dec 2001 B1
6326773 Okuma et al. Dec 2001 B1
6346778 Mason et al. Feb 2002 B1
6351400 Lumsden Feb 2002 B1
6400098 Pun Jun 2002 B1
6411155 Pezzani Jun 2002 B2
6414455 Watson Jul 2002 B1
6414475 Dames et al. Jul 2002 B1
6426632 Clunn Jul 2002 B1
6449567 Desai et al. Sep 2002 B1
6459606 Jadric Oct 2002 B1
6483247 Edwards et al. Nov 2002 B2
6486641 Scoggins et al. Nov 2002 B2
6489742 Lumsden Dec 2002 B2
6490872 Beck et al. Dec 2002 B1
6495929 Bosley et al. Dec 2002 B2
6528957 Luchaco Mar 2003 B1
6534947 Johnson et al. Mar 2003 B2
6548988 Duff, Jr. Apr 2003 B2
6548989 Duff, Jr. Apr 2003 B2
6553353 Littlejohn Apr 2003 B1
6592332 Stoker Jul 2003 B1
6599095 Takada et al. Jul 2003 B1
6618031 Bohn, Jr. et al. Sep 2003 B1
6643149 Arnet et al. Nov 2003 B2
6650554 Darshan Nov 2003 B2
6657404 Clark et al. Dec 2003 B1
6662821 Jacobsen et al. Dec 2003 B2
6664771 Scoggins et al. Dec 2003 B2
6678176 Lumsden Jan 2004 B2
6690594 Amarillas et al. Feb 2004 B2
6690704 Fallon et al. Feb 2004 B2
6718213 Enberg Apr 2004 B1
6724043 Ekkanath Madathil Apr 2004 B1
6747368 Jarrett, Jr. Jun 2004 B2
6770984 Pai et al. Aug 2004 B2
6774610 Orozco Aug 2004 B2
6781423 Knoedgen Aug 2004 B1
6801022 Fa Oct 2004 B2
6809678 Vera et al. Oct 2004 B2
6836099 Amarillas et al. Dec 2004 B1
6849834 Smolenski et al. Feb 2005 B2
6891478 Gardner May 2005 B2
6912911 Oh et al. Jul 2005 B2
6952355 Riggio et al. Oct 2005 B2
6963195 Berkcan Nov 2005 B1
6963773 Waltman et al. Nov 2005 B2
7010363 Donnelly et al. Mar 2006 B2
7019474 Rice et al. Mar 2006 B2
7019498 Pippin et al. Mar 2006 B2
7019992 Weber Mar 2006 B1
7019995 Niemand et al. Mar 2006 B2
7045913 Ebrahim et al. May 2006 B2
7049758 Weyhrauch et al. May 2006 B2
7049976 Hunt et al. May 2006 B2
7061189 Newman, Jr. et al. Jun 2006 B2
7062361 Lane Jun 2006 B1
7068184 Yee et al. Jun 2006 B2
7069161 Gristina et al. Jun 2006 B2
7081729 Chang et al. Jul 2006 B2
7091559 Fragapane et al. Aug 2006 B2
7106031 Hayakawa et al. Sep 2006 B2
7119576 Langhammer et al. Oct 2006 B1
7123491 Kusumi Oct 2006 B1
7136724 Enberg Nov 2006 B2
7136725 Paciorek et al. Nov 2006 B1
7157898 Hastings et al. Jan 2007 B2
7164238 Kazanov et al. Jan 2007 B2
7168924 Beck et al. Jan 2007 B2
7188260 Shaffer et al. Mar 2007 B1
7205822 Torres et al. Apr 2007 B2
7211982 Chang et a May 2007 B1
7227330 Swamy et al. Jun 2007 B2
7245100 Takahashi Jul 2007 B2
7250748 Hastings et al. Jul 2007 B2
7256564 MacKay Aug 2007 B2
7259546 Hastings et al. Aug 2007 B1
7263450 Hunter Aug 2007 B2
7279860 MacKay Oct 2007 B2
7288911 MacKay Oct 2007 B2
7298132 Woolsey et al. Nov 2007 B2
7298133 Hastings et al. Nov 2007 B2
7301308 Aker et al. Nov 2007 B2
7309973 Garza Dec 2007 B2
7330366 Lee Feb 2008 B2
7336463 Russell et al. Feb 2008 B2
7336514 Amarillas et al. Feb 2008 B2
7349765 Reaume et al. Mar 2008 B2
7355865 Royak et al. Apr 2008 B2
7358724 Taylor et al. Apr 2008 B2
7378821 Simpson, III May 2008 B2
7386713 Madter et al. Jun 2008 B2
7394397 Nguyen et al. Jul 2008 B2
7397212 Turner Jul 2008 B2
7397225 Schulz Jul 2008 B2
7412185 Hall et al. Aug 2008 B2
7417410 Clark, III et al. Aug 2008 B2
7417420 Shuey Aug 2008 B2
7436233 Yee et al. Oct 2008 B2
7446514 Li et al. Nov 2008 B1
7525296 Billig et al. Apr 2009 B2
7528503 Rognli et al. May 2009 B2
7561977 Horst et al. Jul 2009 B2
7602136 Garza Oct 2009 B2
7605495 Achart Oct 2009 B2
7615989 Kojori Nov 2009 B2
7622910 Kojori Nov 2009 B2
7667411 Kim Feb 2010 B2
7693610 Ying Apr 2010 B2
7719214 Leehey May 2010 B2
7746003 Verfuerth et al. Jun 2010 B2
7768221 Boyadjieff et al. Aug 2010 B2
7788189 Budike, Jr. Aug 2010 B2
7791326 Dahlman et al. Sep 2010 B2
7797084 Miwa Sep 2010 B2
7848897 Williams, Jr. Dec 2010 B2
7882383 May et al. Feb 2011 B2
7902788 Garza Mar 2011 B2
7911173 Boyadjieff Mar 2011 B2
7919958 Oettinger et al. Apr 2011 B2
7977842 Lin Jul 2011 B2
8004255 Lumsden Aug 2011 B2
8085009 Lumsden Dec 2011 B2
8085010 Lumsden Dec 2011 B2
8120307 Lumsden Feb 2012 B2
8333265 Kang et al. Dec 2012 B2
8374729 Chapel et al. Feb 2013 B2
20010010032 Ehlers et al. Jul 2001 A1
20020071405 Kelley et al. Jun 2002 A1
20020079859 Lumsden Jun 2002 A1
20020109477 Ikezawa Aug 2002 A1
20030090362 Hardwick May 2003 A1
20030181288 Phillippe Sep 2003 A1
20040010350 Lof et al. Jan 2004 A1
20040047166 Lopez-Santillana et al. Mar 2004 A1
20040095237 Chen et al. May 2004 A1
20040153170 Santacatterina et al. Aug 2004 A1
20040181698 Williams Sep 2004 A1
20040189265 Rice et al. Sep 2004 A1
20040239335 McClelland et al. Dec 2004 A1
20050033951 Madter et al. Feb 2005 A1
20050068013 Scoggins Mar 2005 A1
20050073295 Hastings et al. Apr 2005 A1
20060038530 Holling Feb 2006 A1
20060049694 Kates Mar 2006 A1
20060103365 Ben-Yaacov May 2006 A1
20060103549 Hunt et al. May 2006 A1
20060125422 Costa Jun 2006 A1
20060175674 Taylor et al. Aug 2006 A1
20060276938 Miller Dec 2006 A1
20070024250 Simpson, III Feb 2007 A1
20070024264 Lestician Feb 2007 A1
20070037567 Ungless et al. Feb 2007 A1
20070069668 Mackay Mar 2007 A1
20070071047 Huang et al. Mar 2007 A1
20070211400 Weiher et al. Sep 2007 A1
20070213776 Brink Sep 2007 A1
20070244603 Level Oct 2007 A1
20070279053 Taylor et al. Dec 2007 A1
20070283175 Marinkovic et al. Dec 2007 A1
20070290645 Boyadjieff et al. Dec 2007 A1
20070300084 Goodrum et al. Dec 2007 A1
20070300085 Goodrum et al. Dec 2007 A1
20080005044 Benya et al. Jan 2008 A1
20080043506 Ozaki et al. Feb 2008 A1
20080049452 Van Bodegraven Feb 2008 A1
20080100245 Turner May 2008 A1
20080104430 Malone et al. May 2008 A1
20080116825 Descarries et al. May 2008 A1
20080121448 Betz et al. May 2008 A1
20080177678 Di Martini et al. Jul 2008 A1
20080221737 Josephson et al. Sep 2008 A1
20080272934 Wang et al. Nov 2008 A1
20080281473 Pitt Nov 2008 A1
20080290731 Cassidy Nov 2008 A1
20080291607 Braunstein et al. Nov 2008 A1
20090018706 Wittner Jan 2009 A1
20090045804 Durling et al. Feb 2009 A1
20090046490 Lumsden Feb 2009 A1
20090051344 Lumsden Feb 2009 A1
20090062970 Forbes, Jr. et al. Mar 2009 A1
20090063228 Forbes, Jr. Mar 2009 A1
20090083167 Subbloie Mar 2009 A1
20090085545 Shen et al. Apr 2009 A1
20090088907 Lewis et al. Apr 2009 A1
20090094173 Smith et al. Apr 2009 A1
20090105888 Flohr et al. Apr 2009 A1
20090154206 Fouquet et al. Jun 2009 A1
20090160267 Kates Jun 2009 A1
20090189581 Lawson et al. Jul 2009 A1
20090200981 Lumsden Aug 2009 A1
20100001704 Williams Jan 2010 A1
20100013427 Kelley Jan 2010 A1
20100014989 Tsuruta et al. Jan 2010 A1
20100033155 Lumsden Feb 2010 A1
20100054001 Dyer Mar 2010 A1
20100117588 Kelley May 2010 A9
20100138066 Kong Jun 2010 A1
20100145542 Chapel et al. Jun 2010 A1
20100148866 Lee et al. Jun 2010 A1
20100191385 Goodnow et al. Jul 2010 A1
20100228398 Powers et al. Sep 2010 A1
20100250590 Galvin Sep 2010 A1
20100277955 Duan Nov 2010 A1
20100283423 Boyadjieff Nov 2010 A1
20100305771 Rodgers Dec 2010 A1
20100320956 Lumsden et al. Dec 2010 A1
20110080130 Venkataraman Apr 2011 A1
20110121775 Garza May 2011 A1
20110182094 Lumsden et al. Jul 2011 A1
20120213645 Lumsden et al. Aug 2012 A1
Foreign Referenced Citations (35)
Number Date Country
0330477 Aug 1989 EP
1650860 Aug 2008 EP
2183849 May 2010 EP
06-261594 Sep 1994 JP
11-007328 Jan 1999 JP
2011-007328 Jan 1999 JP
11-241687 Sep 1999 JP
11-241687 Sep 1999 JP
2001-245496 Sep 2001 JP
2001-245496 Sep 2001 JP
2009535013 Sep 2009 JP
2010-502533 Jan 2010 JP
2010-502533 Jan 2010 JP
10-2001-0006838 Jan 2001 KR
10-2001-0006838 Jan 2001 KR
10-2009-0009872 Jan 2009 KR
10-2009-0009872 Jan 2009 KR
298359 Feb 2009 MX
303414 May 2010 MX
WO-80002895 Dec 1980 WO
WO-9103093 Mar 1991 WO
WO-9216041 Sep 1992 WO
WO 00-66892 Nov 2000 WO
WO 0066892 Nov 2000 WO
WO-00-66892 Nov 2000 WO
WO0066892 Nov 2000 WO
WO 20060021079 Mar 2006 WO
WO 20080008745 Jan 2008 WO
WO-2008-051386 May 2008 WO
WO-2008-150458 Dec 2008 WO
WO 20100114916 Oct 2010 WO
WO2011031603 Mar 2011 WO
WO 20120030403 Mar 2012 WO
WO 20120044289 Apr 2012 WO
WO 20120050635 Apr 2012 WO
Non-Patent Literature Citations (79)
Entry
International Search Report for International Application No. PCT/US2008/009482, dated Nov. 6, 2008 (2 pages).
Written Opinion of the International Search Authority for International Application No. PCT/US2008/009482, dated Nov. 6, 2008 (11 pages).
International Search Report for International Application No. PCT/US2008/009483, dated Nov. 18, 2008 (2 pages).
Written Opinion of the International Search Authority for International Application No. PCT/US2008/009483, dated Nov. 18, 2008 (6 pages).
International Search Report for International Application No. PCT/US2008/009533, dated Oct. 6, 2008 (2 pages).
Written Opinion of the International Search Authority for International Application No. PCT/US2008/009533, dated Oct. 6, 2008 (5 pages).
International Search Report for International Application No. PCT/US2008/010720, dated Nov. 25, 2008 (2 pages).
Written Opinion of the International Search Authority for International Application No. PCT/US2008/010720, dated Nov. 25, 2008 (4 pages).
International Search Report for International Application No. PCT/US2008/009393, dated Oct. 6, 2008 (3 pages).
Written Opinion of the International Search Authority for International Application No. PCT/US2008/009393, dated Oct. 6, 2008 (13 pages).
Frick, Vincent, et al., “CMOS Microsystem for AC Current Measurement with Galvanic Isolation,” IEEE Sensors Journal, vol. 3, No. 6, pp. 752-760, 2003 IEEE (9 pages).
Official Action of the Eurasian Patent Office, Application No. 201070369, date Apr. 26, 2011 (2 pages).
PCT Notification of Transmittal of the International Search Report and the Written Opinion of the International Searching Authority, or the Declaration, from the International Searching Authority Korea (ISA/KR) Korean Intellectual Property Office mailed Sep. 7, 2011; corresponding to U.S. Appl. No. 12/967,128, now Publication No. US2011/0080130 A1 (our file No. 133) (9 pages).
Extended European Search Report, European Patent Office, for Application No. 108795029.1-1242/2183849 PCT/US2008009393 dated Aug. 1, 2011; corresponding U.S. Appl. No. 12/185,442, now Publication No. US2009/0046490 A1 (10 pages).
PCT Notification of Transmittal of the International Search Report and the Written Opinion of the International Searching Authority, or the Declaration, from the International Searching Authority Korea (ISA/KR) Korean Intellectual Property Office mailed Jun. 29, 2011 corresponding to U.S. Appl. No. 12/893,539 (not yet published) (our file No. 113) (8 pages).
English language translation of Japanese Patent JP-11-007328 A above (13 pages).
English language translation of Japanese Patent JP 11241687 above (16 pages).
English language translation of Japanese Patent JP 2001-245496 above (14 pages).
English language translation of Japanese Patent JP 2010-502533 A above (16 pages).
PCT Notification of Transmittal of the International Search Report and the Written Opinion of the International Searching Authority, or the Declaration, from the International Searching Authority USA (ISA/US) mailed Oct. 6, 2008; corresponding to U.S. Appl. No. 12/185,442, now Publication No. US2009/0046490 A1 (our file No. 113) (15 pages).
Frick, Vincent, Member, IEEE; Hebrard, Luc, Member, IEEE; Poure, Phillippe; Anstotz, Freddy; Braun, Francis; “CMOS Microsystem for AC Current Measurement with Galvanic Isolation”; IEEE Sensors Journal, vol. 3, No. 6, Dec. 2003; see NPL-H (our file 113) where considered a “Y” reference (9 pages).
PCT Notification Concerning Transmittal of International Preliminary Report on Patentability mailed Feb. 20, 2010 from the International Bureau of WIPO; corresponding to U.S. Appl. No. 12/185,442, now Publication No. US2009/0046490 A1 (our file No. 113) (14 pages).
PCT Notification of Transmittal of the International Search Report and the Written Opinion of the International Searching Authority, or the Declaration, from the International Searching Authority USA (ISA/US) mailed Nov. 6, 2008; corresponding to U.S. Appl. No. 12/187,136, now Publication No. US2009/0051344 A1 (our file No. 114) (15 pages).
PCT Notification of Transmittal of the International Search Report and the Written Opinion of the International Searching Authority, or the Declaration, from the International Searching Authority USA (ISA/US) mailed Nov. 18, 2008; corresponding to U.S. Appl. No. 12/187,186, now Publication No. US2009/0200981 A1 (our file No. 115) (9 pages).
PCT Notification of Transmittal of the International Search Report and the Written Opinion of the International Searching Authority, or the Declaration, from the International Searching Authority USA (ISA/US) mailed Oct. 6, 2008; corresponding to U.S. Appl. No. 12/187,805, now Publication No. US2010/0033155 A1 (our file No. 116) (7 pages).
PCT Notification Concerning Transmittal of International Preliminary Report on Patentability mailed Feb. 17, 2011 from the International Bureau of WIPO; International Application No. PCT/US2008/009533 corresponding to U.S. Appl. No. 12/187,805, now Publication No. US2010/0033155 A1 (our file No. 116) (6 pages).
PCT Notification of Transmittal of the International Search Report and the Written Opinion of the International Searching Authority, or the Declaration, from the International Searching Authority USA (ISA/US) mailed Nov. 25, 2008; corresponding to International Application No. PCT/US 08/10720 and U.S. Appl. No. 12/207,913, now Publication No. US2010/0013427 A1 (our file No. 117) (8 pages).
PCT Notification Concerning Transmittal of International Preliminary Report on Patentability mailed Mar. 25, 2010 from the International Bureau of WIPO; corresponding to International Application No. PCT/US2008/1010720 and U.S. Appl. No. 12/207,913, now Publication No. US2010/0013427 A1 (our file No. 117) (7 pages).
English language translation of Offcial Action from the Eurasian Patenet Office pertaining to Application No. 201070369/(OFE/1004/0111) and original Office Action both corresponding to PCT Application No. US 2008/010720 dated Apr. 26, 2011 and U.S. Appl. No. 12/207,913, now Publication No. US2010/0013427 A1 (our file No. 117) (2 pages).
PCT Notification of Transmittal of The International Search Report and the Written Opinion of the International Searching Authority, or the Declaration, from the International Searching Authority USA (ISA/US), mailed Oct. 15, 2010; corresponding to U.S. Appl. No. 12/873,510, now Publication No. US2010/0320956 A1 (our file No. 123) (11 pages).
International Search Report and Written Opinion for International Application No. PCT/US2012/035844 dated Nov. 16, 2012 corresponding to US2012/0213645 A1 (our matter 135) (8 pages).
First Non-Final Office Action mailed Feb. 3, 2011, U.S. Appl. No. 12/187,186, filed Aug. 6, 2008, (19 pages).
Response and Amendment to First Non-Final Office Action mailed Apr. 8, 2011, U.S. Appl. No. 12/187,186, filed Aug. 6, 2008, (32 pages).
Final Office Action mailed Jun. 13, 2011, U.S. Appl. No. 12/187,186, filed Aug. 6, 2008, (23 pages).
Notification of the First Office Action dated Dec. 23, 2011, State Intellectual Property Office of People's Republic of China; Chinese National Phase of PCT Application No. 200880111387.0, with English translation (19 pages).
Response to NPL PP above dated Jan. 13, 2012 adding new claims of U.S. Appl. No. 13/331,757 (16 pages).
Response and Amendment to Aug. 3, 2011 Non-Final Office Action filed Oct. 31, 2011, U.S. Appl. No. 12/207,913 (23 pages).
Final Office Action in U.S. Appl. No. 12/207,913 mailed from the USPTO on Mar. 14, 2012 relying on US 6,274,999 to Fuji and US 6,489,742 to Lumsden (17 pages).
Extended European Search Report from the European Patent Office in Application No. 08830045.4 dated Aug. 22, 2012 (8 pages).
Notice of Reasons for Refusal of Patent Application No. 2010-524881 mailed from the Japanese Patent Office on Aug. 28, 2012 relying on Japanese Unexamined Patent Publication HEI6-261594 with English translation (6 pages).
Response to final Office Action of NPL 3A for U.S. Appl. No. 12/207,913, filed with the USPTO on Sep. 13, 2012 (32 pages).
Sul, S K and Park, M H: “A novel Technique for Optimal Efficiency Control of a Current-Source Inverter-Fed Induction Motor”, IEEE Transactions on Power Electronics, vol. 3, No. 2, Apr. 1, 1988, pp. 192-199, XP002063874, ISSN: 0885-8993, DOI: 10.1109/63.4349, p. 2, left-hand column, line 9—p. 4, left-hand column, line 29; Figs. 4-8 (8 pages); clean copy retrieved from IEEE databank attached, considered to be particularly relevant if taken alone, see NPL 3B (8 pages).
Flemming Abraham Sen, et al.: “On the Energy Optimized Control of Standard and High-Efficiency Induction Motors in CT and HVAC Applications”, IEEE Transactions on Industry Applications, IEEE Service Center, Piscataway, NJ, US, vol. 34, No. 4, Aug. 1, 1998, XP011022398, ISSN: 0093-9994, p. 4, right-hand column, line 11—p. 5, left-hand column, line 5; Fig. 9 (10 pages); ); clean copy retrieved from IEEE databank attached, considered to be particularly relevant if taken alone, see NPL 3B (10 pages).
Office Action issued by the State Intellectual Property Office (SIPO) on Apr. 28, 2012 for Chinese Application No. 200880115946 (PCT/US2008/010720) relying on US 6,274,999 B1 to Fuji, with English translation (21 pages).
Office Action issued by the Colombian Patent Office in Application No. 10.042.683 (PCT/US2008/010720) relying on US 6,274,999 B1 to Fuji and US 6,489,742 to Lumsden, with English translation (24 pages).
Office Action from Eurasian Patent Office dated Aug. 16, 2012 signed by Official Patent Examiner A.M. Komarov for Application No. 201070369/31 with English translation (4 pages).
European Patent Office grant of patent dated Jun. 4, 2012, European Patent Application No. 08795029.1-1242 (61 pages).
Response to NPL 3J above requesting deletion of text added to claims 1 and 10 by Examiner dated Sep. 19, 2012, European Patent Application No. 08795029.1-1242 (2 pages).
Office Action from the Eurasian Patent Office dated May 28, 2012, signed by Official Patent Examiner A.M, Komarov, Eurasian Patent Application No. 201070276/31 (English translation, 2 pages).
Industry and Commerce Superintendency, Republic of Colombia, Resolution No. 71361, denying the Colombian patent application corresponding to US2010/0117588 (U.S. Appl. No. 12/207,913) (our matter 117), dated Nov. 26, 2012, executed by Pablo Felipe Robledo Del Castillo (6 pages), with English translation (6 pages) (Total 12 pages).
Patent Cooperation Treaty Notification Concerning Transmittal of International Preliminary Report on Patentability (Chapter 1 of the Patent Cooperation Treaty) (PCT Rule 44bis.1(c) mailed Mar. 14, 2013 for PCT Application corresponding to International Application No. PCT/US2011/020326, filed on Jan. 6, 2011, and published as WO2012/030403 on Mar. 2, 2012, corresponding to U.S. Appl. No. 12/967,128 published as US-2011/0080130 A1 (our matter 0133) (6 pages).
Office Action from the U.S. Patent and Trademark Office mailed Feb. 22, 2013 corresponding to U.S. Appl. No. 12/207,913, republished as US-2010/0117588 A1 (our matter 0017US) (48 pages).
Office Action from the U.S. Patent and Trademark Office mailed Mar. 29, 2013 for Chinese Application No. 200880115946.5 with English translation corresponding to U.S. Appl. No. 12/207,913, republished as US-2010/0117588 A1 (19 pages).
Response to Office Action from the State Intellectual Property Office dated Mar. 29, 2013 (NPL 3R) for Chinese Application No. 200880115946.5 corresponding to U.S. Appl. No. 12/207,913, republished as US-2010/0117588 A1 (13 pages).
Notice of Allowance form the U.S Patent and Trademark Office mailed Jun. 11, 2013 for U.S. Appl. No. 13/451,041, published as US-2012/0213645 A1 (our matter 0135US) (49 pages)
Response to Office Action from the Colombian Patent Office dated Dec. 27, 2012 for Colombian Application No. 10.042.683 with English translation corresponding to U.S. Appl. No. 12/207,913, republished as US-2010/0117588 A1 (55 pages).
Response to Office Action from Eurasian Patent Office dated Dec. 17, 2012 for Application No. 201070369/31 corresponding to U.S. Appl. No. 12/207,913, republished as US-2010/0117588 A1 (15 pages).
Notification of the necessity to Submit Additional Materials from the Eurasian Patent Office dated Apr. 1, 2013 for Application No. 201070369/31 with English translation corresponding to U.S. Appl. No. 12/207,913, republished US-2010/0117588 A1 (4 pages).
Response to Supplementary European Search Report from the European Patent Office mailed on Aug. 22, 2012 filed on Mar. 18, 2013 regarding European Application No. 08830045.4 corresponding to U.S. Appl. No. 12/207,913, republished as US-2010-0117588 A1 (21 pages).
Notice of Reasons for Refusal of Patent Application No. 2010-524881 mailed from the Japanese Patent Office on Aug. 28, 2012 with English translation, relying on Japanese Unexamined Patent Publication HEI6-261594; See NPL 4R (6 pages).
Response to 2 nd Office Action for Chinese Patent Application No. 200880111387.0 filed on Jan. 8, 2013 corresponding to U.S. Appl. No. 12/185,442, issued as US Patent No. 8085009B2 (25 pages).
Voluntary Amendment filed on Mar. 21, 2013 for Chinese Patent Application No. 200880111387.0 filed on Jan. 8, 2013 corresponding to U.S. Appl. No. 12/185,442, issued as US Patent Number 8085009B2 (22 pages).
Notification on Grant of Patent Right for Invention mailed on Apr. 9, 2013 for Chinese Patent Application No. 200880111387.0 filed on Jan. 8. 2013 with English translation corresponding to U.S. Appl. No. 12/185,442, issued as US Patent No. 8085009132 (4 pages).
Response to Office Action for Colombian Patent Application No. 10.029.658 filed on Feb. 20, 2013 corresponding to U.S. Appl. No. 12/185,442, issued as US Patent No. 8085009B2 (42 pages).
Office Action from the U.S. Patent and Trademark Office mailed Mar. 13, 2013 corresponding to U.S. Appl. No. 12/873,510, published as US-2010/0320956 A1 on Dec. 23, 2010, which is a continuation-in-part of U.S. Appl. No. 12/207,913, republished as US-2010/0117588 A1 (15 pages).
International Search Report for International Application No. PCT/US2010/047477 mailed Mar. 22, 2012 corresponding to U.S. Appl. No. 12/873,510, published as US-2010/0320956 A1 (9 pages).
Voluntary Amendment filed on Nov. 9, 2012 for Chinese Patent Application No. 201080039849.X corresponding to U.S. Appl. No. 12/873,510, republised as US-2010/0320956 A1 (8 pages).
Office Action from U.S. Patent and Trademark Office mailed Feb. 26, 2013 corresponding to U.S. Appl. No. 12/893,539, published as US-2012/0075896 A1 (7 pages).
International Search Report for International Application No. PCT/US2010/050714 mailed Apr. 11, 2013 corresponding to U.S. Appl. No. 12/893,539, published as US-2012/0075896 A1 (5 pages).
Office Action from the U.S. Patent and Trademark Office mailed Apr. 10, 2013 corresponding to U.S. Appl. No. 13/026,931 (11 pages).
Notice of Allowance from the U.S. Patent and Trademark Office mailed Julie 11, 2013 corresponding to U.S. Appl. No. 12/967,128 (11 pages).
Office Action from the U.S. Patent and Trademark Office mailed Aug. 17, 2012 corresponding to U.S. Appl. No. 13/331,757 (14 pages).
Response to Office Action from the U.S, Patent and Trademark Office mailed Aug. 17, 2012, filed on Nov. 15, 2012 corresponding to U.S. Appl. No. 13/331,757 (26 pages).
Final Office Action from the U.S. Patent and Trademark Office mailed Feb. 27, 2013 corresponding to U.S. Appl. No. 13/331,757 (45 pages).
Response to Office Action from the Eurasian Patent Office filed on Apr. 19, 2013 corresponding to U.S. Appl. No, 13/331,757 (13 pages).
Sul, S K and Park, M H; “A novel Technique for Optimal Efficiency Control of a Current-Source Inverter-Fed Induction Motor”, IEEE Transactions on Power Electronics, vol. 3, No. 2, Apr. 1, 1988, pp. 192-199, XP002083874, ISSN: 0885-8993, DOI: 10.1109/63.4349, p. 2, left-hand column, line 9—p. 4, left-hand column, line 29; Figs. 4-8 (8 pages); clean copy retrieved from IEEE databank attached, considered to be particularly relevant if taken alone, see NPL 3X (16 pages).
Flemming Abrahamsen, et al.: “On the Energy Optimized Control of Standard and High-Efficiency Induction Motors in CT and HVAC Applications”, IEEE Transactions on Industry Applications, IEEE Service Center, Piscataway, NJ, US, vol. 34, No. 4, Jul./Aug. 1998, XP011022398, ISSN: 0093-9994, p. 4, right-hand column, line 11—p. 5, left-hand column, line 5; Fig. 9 (10 pages): ); clean copy retrieved from IEEE databank attached, considered to be particularly relevant if taken alone, see NPL 3X (20 pages).
International Search Report for International Application No. PCT/US2011/032840, mailed Apr. 11, 2013 corresponding to U.S. Appl. No. 13/026,931, published as US 2011-0182094 A1 (6 pages).
English language Abstract and English language translation of Japanese Unexamined Patent Publication HEI6-261594; See NPL 3Y (9 pages).
Related Publications (1)
Number Date Country
20100117588 A9 May 2010 US
Provisional Applications (2)
Number Date Country
61135402 Jul 2008 US
60993706 Sep 2007 US