Patent Application
20100329894
The present application relates to providing control signals to internal components of hermetic compressors, and more specifically to the controlling of internal components in a hermetic compressor by the use of control signals transmitted on the power lines of the motor of the hermetic compressor.
The operation of hermetic compressors can be controlled through the use of control devices, e.g., solenoids, that are located inside of the housing of the hermetic compressor. By way of example, without limitation, capacity modulation can be controlled in some compressors by a solenoid-actuated valve. Also, an internal bleed valve controlled by an electromagnetic solenoid actuator may be used for pressure equalization on the start-up of the compressor. A controller positioned outside of the hermetic compressor can be used to operate and control the internal control devices of the hermetic compressor.
At least two control wires can be needed to provide actuation control signals from the controller or control panel to a solenoid actuator. To provide the control signals from the controller to the internal control devices of the hermetic compressor, hermetically sealed terminals, one for each control wire, can be used to provide a connection through the housing. The use of the hermetically sealed terminals to provide control signals inside the housing of the hermetic compressor is in addition to the use of a set of hermetically sealed terminals to provide the main supply voltage, e.g., an AC (alternating current) voltage, to the motor inside the housing of the hermetic compressor. The use of additional hermetically sealed terminals for the control wires adds to the manufacturing cost of the compressor, and increases the chances that the hermetic seal of the compressor may be compromised.
Therefore, what is needed is a simple and inexpensive technique to provide control signals to the internal devices in a compressor without the use of dedicated terminals.
The present application is directed to a system for transmitting control signals to internal devices of a compressor. The compressor includes a housing, a sealed power terminal, and a motor for powering the compressor. The system includes a first signal converter disposed externally of the compressor housing. The first signal converter is configured to receive a control signal and convert the control signal to a modulated signal. A second signal converter is disposed internally of the compressor housing. The second signal converter is configured to decode the modulated signal. A plurality of power transmission lines is connected to an AC input power source. The plurality of power transmission lines is connected to the sealed power terminal. The first signal converter is electrically coupled to at least one of the power transmission lines to transmit the modulated signal to the second signal converter. The second signal converter is coupled to at least one power transmission line. The second signal converter is configured to receive the modulated signal and generate a driver signal in response to the modulated signal for operating at least one of the internal devices of the compressor.
In another embodiment, the application is directed to a refrigeration system. The refrigeration system includes a compressor, a condenser, and an evaporator connected in a closed refrigerant loop. The compressor has a motor to power the compressor. The compressor includes a housing and a hermetic power terminal A frequency converter is disposed externally of the compressor housing. The frequency converter is configured to receive a control signal and convert the control signal to a high-frequency signal. A frequency decoder is disposed internally of the compressor housing. The frequency decoder is configured to decode the high-frequency signal and convert the high-frequency signal to a driver signal. A plurality of power transmission lines is connected to the hermetic power terminal. The frequency converter is electrically coupled to at least one power transmission line of the plurality of transmission lines to transmit the high-frequency signal to the frequency decoder. The frequency decoder is coupled to at least one power transmission line and configured to receive the high-frequency signal and generate a driver signal in response to the high-frequency signal for operating at least one of the internal devices of the compressor.
In another embodiment, the application is directed to a method for controlling internal devices of a hermetic compressor wherein the compressor includes a housing, a hermetic power terminal and a motor for powering the compressor. The method includes generating a control signal, converting the control signal to a high-frequency signal, transmitting the high-frequency signal on an AC input power line of the compressor, decoding the high-frequency signal, generating a driver signal in response to the decoded high-frequency signal, and controlling an internal device with the generated driver signal.
A further embodiment of the application is directed to a system for transmitting control signals to internal components of a compressor. The compressor includes a hermetically sealed housing and a motor positioned inside the hermetically sealed housing. The system includes a first signal converter located external to the hermetically sealed housing and a second signal converter located internal to the hermetically sealed housing. The first signal converter is configured to receive a control signal and convert the control signal to an output signal. The second signal converter is configured to decode the output signal and generate a control signal for an internal component of the compressor. The system also includes a power terminal configured and positioned to provide a hermetically sealed electrical connection through the housing, a plurality of power lines connectable to a power source to provide an operating voltage to the motor, and a plurality of motor leads positioned inside the hermetically sealed housing. The plurality of power lines are connected to the power terminal external to the hermetically sealed housing and the plurality of motor leads are connected to the power terminal at one end and to the motor at an opposite end. The first signal converter is electrically coupled to at least one power line of the plurality of power lines to transmit the output signal through the at least one power line and the power terminal to the plurality of motor leads. The second signal converter is electrically coupled to at least one motor lead of the plurality of motor leads to receive the output signal and the at least one motor lead is connected to the power terminal at a location corresponding to the connection of the at least one power line of the plurality of power lines to the power terminal.
Still another embodiment of the application is directed to a system including a compressor having a hermetically sealed housing, a motor positioned in the hermetically sealed housing, and a hermetic power terminal configured and positioned to provide a sealed electrical connection through the hermetically sealed housing. The system also includes a plurality of first power lines connectable to an AC power source at one end and connected to the hermetic power terminal at an opposite end, an encoder located external to the hermetically sealed housing, a plurality of second power lines positioned inside the hermetically sealed housing, and a decoder located internal to the hermetically sealed housing. The AC power source is configured to provide a voltage greater than 100 volts. The encoder is configured to receive a first signal and convert the first signal to a second signal. The encoder is connected to at least one first power line of the plurality of first power lines to transmit the second signal on the at least one first power line. The plurality of second power lines is connected to the hermetic power terminal. The decoder is connected to at least one second power line of the plurality of second power lines to receive the second signal from the at least one second power line. The decoder is configured to receive the second signal and generate a third signal from the second signal. The third signal corresponds to the first signal. The system also includes a component located internal to the hermetically sealed housing and controlled by the third signal from the decoder. The connection of the at least one first power line to the power terminal corresponds to the connection of the at least one second power line to the power terminal.
Yet another embodiment of the application is directed to a method for controlling an internal device of a hermetic compressor. The compressor includes a housing, a hermetic power terminal providing an electric connection through the housing and a motor positioned in the housing. The method includes receiving a control signal for an internal device of a hermetic compressor, converting the control signal to an output signal at a location external to a housing of the hermetic compressor, and transmitting the output signal on an AC power line through a hermetic power terminal into the interior of the housing. The output signal has a frequency in the range between about 10 KHz and about 100 MHz. The method also includes receiving the output signal at a location internal to the housing, generating a driver signal based on the received output signal, and controlling the internal device of the hermetic compressor using the generated driver signal.
An advantage of the present application is that a dual capacity compressor may be controlled without the use of external starting devices by unloading the high pressure side of the compressor to lower the required motor starting torque.
Another advantage of the present application is that a modulated capacity compressor may be modulated without additional hermetic terminals.
A further advantage of the present application is that by using the motor leads and input AC power lines to transmit the control signal inside the compressor, it is not necessary to create additional hermetic terminals in the compressor for control signal wiring, thereby avoiding the expense of the additional hermetic terminals that would otherwise be required.
Other features and advantages of the present application will be apparent from the following more detailed description of the exemplary embodiments, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the application.
Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
As shown in
Referring back to the operation of the system 100, whether operated as a heat pump or as an air conditioner, a compression device 36 of the compressor 34 is driven by a motor 22 that can be powered by a motor drive 114 or directly from an AC power source 102. A control panel or controller 108 can be used to control the operation of the motor drive 114 (if used), the motor 22 and/or the compressor 34. In another exemplary embodiment, the control panel or controller 108 can be used to control other components of system 100, e.g., reversing valve 150. The control panel 108 can include a variety of different components such as an analog to digital (A/D) converter, a microprocessor, a non-volatile memory, and an interface board.
The motor drive 114 can be a variable speed drive (VSD) or variable frequency drive (VFD) that receives AC power having a particular fixed line voltage and fixed line frequency from the AC power source 102 and that provides power to the motor 22 at a desired voltage and desired frequency (including providing a desired voltage greater than the fixed line voltage and/or providing a desired frequency greater than the fixed line frequency), both of which can be varied to satisfy particular requirements. Alternatively, the motor drive 114 can be a “stepped” frequency drive that can provide a predetermined number of discrete output frequencies and voltages, i.e., two or more, to the motor 22.
The motor drive 114 can be located or positioned outside of the compressor 34 (see
The AC power source 102 can provide single phase or multi-phase (e.g., three phase), fixed voltage, and fixed frequency AC power to the motor drive 114. The motor drive 114 can accommodate virtually any AC power source 102, such as an AC power source 102 that can supply an AC voltage or line voltage in the range between 100 and 600 volts AC (VAC), for example, 187 VAC, 208 VAC, 230 VAC, 380 VAC, 460 VAC, or 600 VAC, at a line frequency of 50 Hz or 60 Hz. In another exemplary embodiment, the AC power source 102 can provide power directly to the motor 22. In still another exemplary embodiment, the power source can be a DC (direct current) power source that can supply a DC voltage in the range between 12 and 600 volts DC (VDC) to the motor.
The motor 22 used in the system 100 can be any suitable type of motor that can be powered by a motor drive 114 or directly from the AC power source 102 (or a DC power source). The motor 22 can be any suitable motor type including an induction motor, a switched reluctance (SR) motor, or an electronically commutated permanent magnet motor (ECM).
Referring back to
The liquid refrigerant delivered to the evaporator 106 enters into a heat exchange relationship with a fluid, e.g., air or water, and undergoes a phase change to a refrigerant vapor as a result of the heat exchange relationship with the fluid. The vapor refrigerant in the evaporator 106 exits the evaporator 106 and returns to the compressor 34 by a suction line to complete the cycle (and the reversing valve 150 if operated as a heat pump). It is to be understood that any suitable configuration of the condenser 104 and the evaporator 106 can be used in the system 100, provided that the appropriate phase change of the refrigerant in the condenser 104 and evaporator 106 is obtained.
In one exemplary embodiment, as shown in
In addition to the compression device 36 and motor 22, other components 110 can be included in the housing 20 that are used in the operation of compressor 34. Components 110 can include protection devices for the motor 22 and/or compression device 36, an electromechanical capacity modulating device, e.g., a solenoid, or an internal oil sump heater. Each of the components 110 located inside of the housing 20 require control signals from a control panel or controller for proper operation and control. In another exemplary embodiment, a motor drive 114 located inside of the housing 20 can require the providing of control algorithms or signals, similar to components 110, to ensure that motor drive 114 provides the appropriate voltage to control the motor 22.
In
A control signal S, e.g., a capacity modulation signal or a solenoid energizing signal, for an internal component is input to a converter or encoder 12. The signal S provided to the converter 12 can be a predetermined control voltage, in the range of 24 VAC to 230 VAC. The signal S can be generated by the control panel 108 either automatically or manually depending on the control scheme or algorithm used for compressor 34. In one embodiment, the converter 12 can be configured to convert the control signal S to an output signal having a frequency greater than the line frequency of the AC power supply 102 and a voltage in the range from a few millivolts to 20 volts. The output 14 of the converter 12 can be connected to an input AC power line 16 extending from the AC power supply 102 to the compressor 34. The output 14 can be connected across a power conductor and a neutral conductor, or across two power conductors. In another exemplary embodiment, the output 14 of the converter 12 can be connected between two phases of a three-phase power supply on input AC power line 16. In a further embodiment, the output 14 of the converter 12 can be connected to any one of the power terminal inputs and a conductor connected to the compressor housing that serves as a signal return path, i.e., ground. In addition, if required, additional lugs for grounding and neutral connections may also be provided. The various arrangements described here for connecting the converter to the input conductors are exemplary and not intended as limiting. Those skilled in the art will appreciate that other coupling arrangements for connecting the converter 12 to the input AC power lines may be employed within the spirit and scope of the present application.
In
Inside the compressor housing 20, a decoder or driver 28 is connected to motor leads 24 via control lines 32 using the same conductors or phases of the AC input power lines 16 as the output 14 of the converter 12. The decoder 28 can receive the output signal or instruction from the converter 12 on the AC power line 16 and convert the output signal to a control signal understood by the internal component(s) of the compressor 34.
In one exemplary embodiment, the signal S is input to the encoder or converter 12 from the control panel 108, to control a component of the compressor 34. Signal S is provided to the AC power lines 16 via converter 12 through output lines 14. The encoder or converter 12 converts signal S from a low frequency signal, e.g., 50 Hz or 60 Hz, to a high frequency signal, e.g., 10 KHz-100 MHz. In one embodiment, the higher the frequency of the output signal from the encoder 12, the smaller the coupling capacitors that are required by the encoder 12 and decoder 28 to isolate the output of the converter 12 from the AC power supply. Those skilled in the art will appreciate that there are many known methods of modulating the high frequency signal, for example, frequency modulation (FM), amplitude modulation (AM), burst or digital encoding, and other methods of modulation may be employed. Signal S can be a low power level signal relative to the power level provided to the motor 22.
The output signal from the encoder 12, which corresponds to signal S, is transmitted on AC power lines 16 through the hermetic power terminals 18 or 19, and into the housing 20 on motor leads 24. The decoder or driver 28 receives the output signal from the converter 12 and generates a driver signal D or suitable control signal to the component, e.g., solenoid valve 26, in response to the output signal from the converter 12, which corresponds to signal S, being detected by decoder or driver 28.
In the embodiments shown in
In another embodiment, the control system may be used to operate other internal control devices of the compressor 34, such as a bleed valve for pressure equalization.
The bleed valve 37 of the pressure equalization system is positioned within a discharge muffler housing 44. The bleed valve 37, which can be a solenoid valve, is shown schematically at aperture 40. Aperture 40 provides a pressure bleed port between the high-pressure side of the compressor at muffler 44 and the low pressure side of the compressor at inlet 42. Various solenoid valve arrangements for use with the present application are described in commonly owned U.S. Pat. No. 6,584,791 and No. 6,823,686, both of which patents are hereby incorporated by reference.
In an exemplary embodiment shown in
In an alternate embodiment, the valve 26 can be configured in the normally closed or “off” position to provide a substantially fluid tight seal to prevent the flow of high pressure fluid from the high pressure side 52 to the low pressure side 54. In the normally closed configuration, the valve 26 is pulsed open by a signal from the decoder/driver 28 for a short interval when the compressor is started. Once the valve 26 opens, high-pressure fluid from the high-pressure side 52 of the compressor flows to the low-pressure side 54, the valve 26 being sufficiently sized to permit a rapid change in pressure toward equalization. After this change in pressure occurs, the motor 22 can then accelerate to its operating speed requiring substantially reduced starting torque. After a time delay in which the motor may reach its operating speed, the valve 26 closes in response to a driver signal D from the decoder/driver 28. The housing 20 must be sufficiently sized, along with other considerations, such as valve actuation delay, to ensure the housing 20 does not become overly pressurized before the motor has reached its operating speed.
In one exemplary embodiment, the control system can use an encoder/decoder device that can both send and receive signals on the AC power lines 16. By using an encoder/decoder device, information from within the compressor, e.g., sensor measurements such as temperature, pressure, voltage, current, speed, resistance, or rotor position, can be sent back to the control panel to enhance the operation of the compressor.
In another exemplary embodiment where the motor drive 114 is located inside the compressor housing 20, the decoder 28 can be incorporated into the motor drive and directly decode the signals from the converter 12 on the AC power lines 16. The output signals from the converter 12 can be decoded and used to control the output power provided by the motor drive 114 to the motor 22.
In one exemplary embodiment, the encoder 12 and decoder 28 can be configured to control multiple components inside the compressor housing 20. To be able to identify the different components inside the compressor housing 20 to be controlled, each component can have a unique identifier that can be incorporated into the output signal from the encoder 12 and included in control signal S. The decoder 28, upon receiving the output signal from the encoder 12, can determine the unique identifier and then distribute the control signal to the appropriate component.
It should be understood that the application is not limited to the details or methodology set forth in the following description or shown in the figures. It should also be understood that the phraseology and terminology employed herein is for the purpose of description only and should not be regarded as limiting.
While only certain features and embodiments of the invention have been shown and described, many modifications and changes may occur to those skilled in the art (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters (e.g., temperatures, pressures, etc.), mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited in the claims. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention. Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not have been described (i.e., those unrelated to the presently contemplated best mode of carrying out the invention, or those unrelated to enabling the claimed invention). It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, without undue experimentation.
This application is a continuation-in-part of U.S. application Ser. No. 11/428,942 filed Jul. 6, 2006, which is incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11428942 | Jul 2006 | US |
| Child | 12878982 | US |
