The invention relates generally to the field of motor drives and similar devices comprising a number of power electronic circuits. More particularly, the invention relates to techniques for verifying proper selection, installation, and operability of components in such devices.
A wide range of power electronic devices are know and currently available, particularly in automation context. For example, many electric motors and other loads in industrial, commercial, automation, process, transportation, and other contexts are powered by electronic circuits that control and regulate the characteristics of electrical power based upon the application and load characteristics. In a particularly important range of products, variable frequency, multi-phase output is provided for regulating the speed, torque, and other characteristics of driven motors. Motor drives used in such applications have become increasingly complex, with multiple layers of control, monitoring, drive, and power circuitry interconnected for generating the desired output signals.
A typical motor drive used for automation applications includes a converter that transforms alternating current (AC) power to direct current (DC) power that is applied to a DC bus. Power from the DC bus is then converted via an inverter to controlled frequency AC power for application to the load. The converter may be passive (non-switched) or active (switched), while the inverter circuitry typically includes sets of power electronic switches that are switched between conducting and non-conducting states to provide the desired output waveform. Such circuits are available in single and multi-phase configurations.
As load requirements and circuitry become increasingly complex, significant modularity has been developed for circuit topologies of the type described above. For example, smaller loads may be driven by a single converter coupled to a single inverter via a single DC bus. Increasingly, however, larger loads may be powered by parallel inverters or entire paralleled drives, the output signals of which are joined to provide a single, higher powered output.
In all of these topologies, challenges arise at multiple stages in the life of the equipment, including manufacturing, operation, and servicing. In particular, the equipment may employ multiple separate, modular components that may be interconnected to provide the desired functionality. Such components may include control circuitry, interface circuitry, power layer circuitry, switching modules, feedback and monitoring components, and so forth. When the equipment is initially manufactured and commissioned, if erroneous components have been used, this can lead to malfunction and even failure of the overall system or of certain components of the system. Similarly, during operation, the failure of certain devices or certain signal communications can lead to disabling or failure of the system or of components. During servicing, where certain components are factory or field replaceable, or reparable, the erroneous selection or connection of such components can similarly lead to system or component failure.
There is a need in the field, therefore, for techniques that will reduce the risk or avoid the potential for improper component selection and installation, and that can monitor operation of components during their service life.
The present invention provides systems and methods for verifying proper component selection and installation designed to respond to such needs. The techniques can be used during manufacturing and commissioning stages, as well as during operation and subsequent serving. In accordance with one aspect of the invention, a motor control system comprises a plurality of monitored circuit components configured to cooperate to generate output signals for powering an electric motor, and memory circuitry configured to store reference identification data representative of circuit components that should be present, correct, communicating and operative in the system. Processing circuitry is coupled to the memory circuitry and configured to receive data from each of the monitored circuit components, to generate component identification data, and to compare the component identification data to the reference data to determine whether all monitored circuit components are present, correct, communicating and operative.
In accordance with another aspect of the invention, a motor control system comprises a plurality of motor drives coupled in parallel to produce a combined multi-phase output. Each motor drive comprises a plurality of monitored circuit components configured to cooperate to generate output signals for powering an electric motor, memory circuitry configured to store reference identification data representative of the monitored circuit components, and processing circuitry coupled to the memory circuitry and configured to receive data from each of the monitored circuit components, to generate component identification data, and to compare the component identification data to the reference data to determine whether all monitored circuit components are present, correct, communicating and operative. Common control circuitry is coupled to the processing circuitry of each inverter drive and configured to receive data indicative of results of the comparison and to control operation of the inverter drives based upon the received data.
The invention also provides a motor control method comprising coupling a plurality of monitored circuit components in a motor drive, the circuit components being configured to cooperate to generate output signals for powering an electric motor. Identification data is communicated from each of the monitored circuit components to processing circuitry. In the processing circuitry, composite identification data is generated based upon the communicated identification data, and the composite identification data is compared to reference identification data representative of circuit components that should be present, correct, communicating and operative in the motor drive. Various actions may then be taken, including storing data representative of the results of the comparison, disabling the drive, and so forth.
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
A controller 22 is coupled to the circuitry of each drive and is configured to control operation of the circuitry as described more fully below. In a presently contemplated embodiment, the controller may be housed in one of the drives or in a separate enclosure. Appropriate cabling (e.g., fiber optic cabling) is provided to communicate control and feedback signals between the controller and the circuitry of the individual drives. The controller will coordinate operation of the drives to ensure that the provision of power is shared and that operation of the drives is synchronized sufficiently to provide the desired power output to the motor. In the embodiment illustrated in
The power bus 26 distributes three phases of AC power between the individual drives. Downstream of this bus, each drive includes converter circuitry 28 that converts the three phases of AC power to DC power that is applied to a DC bus 30. The converter circuitry 28 may be passive or active. That is, in a presently contemplated embodiment non-switched circuitry alone is used to define a full wave rectifier that converts the incoming AC power to DC power that is applied to the bus. In other embodiments the converter circuitry 28 may be active, including controlled power electronic switches that are switched between conducting and non-conducting states to control the characteristics of the DC power applied to the bus.
Continuing with the components of each drive, bus filtration circuitry 34 may be provided that conditions the DC power conveyed along the DC busses 30. Such filtration circuitry may include, for example, capacitors, inductors (e.g., chokes), braking resistors, and so forth. In some embodiments common devices may be provided on the DC busses, which may be coupled to one another by links illustrated by reference numeral 32.
Each drive further includes inverter circuitry 36. As will be appreciated by those skilled in the art, such circuitry will typically include sets of power electronic switches, such as insulated gate bipolar transistors (IGBTs) and diodes arranged to allow for converting the DC power from the bus to controlled frequency AC output waveforms. The inverters thus create three phases of controlled frequency output, with each phase being shorted or combined along an output bus 38. The combined power may be applied to output filtration circuitry 40, which may include magnetic components that couple the output power between the phases. Such circuitry may also be provided along the load-side bus 38.
The controller 22 will typically include control circuitry 42 that is configured to implement various control regimes by properly signaling the inverter circuitry (and, where appropriate, the converter circuitry) to control the power electronic switches within these circuits. The control circuitry 42 may, for example, include any suitable processor, such as a microprocessor, field programmable gate array (FPGA), memory circuitry, supporting power supplies, and so forth. In motor drive applications, the control circuitry may be configured to implement various desired control regimes, such as for speed regulation, torque control, vector control, start-up regimes, and so forth. In the embodiment illustrated in
The controller will typically allow for connection to an operator interface, which may be local at the controller and/or remote from it. In a presently contemplated embodiment, for example, an operator interface 46 may be physically positioned on the controller but removable for hand-held interfacing. The interface circuitry (e.g., portable computers) may also be coupled permanently or occasionally to the controller, such as via Internet cabling, or other network protocols, including standard industrial control protocols. Finally, the controller may be coupled to various remote monitoring and control circuitry as indicated by reference numeral 48. Such circuitry may include monitoring stations, control stations, control rooms, remote programming stations, and so forth. It should be noted that such circuitry may also include other drives, such that the operation of the system 10 may be coordinated, where desired, with that of other equipment. Such coordination is particularly useful in automation settings where a large number of operations are performed in a coordinated manner. Thus, the control circuitry 42 may form its control in coordination with logic implemented by automation controllers, separate computers, and so forth.
The structure and operation of the control circuitry may be substantially similar to those described in U.S. published patent application no. 20100123422, entitled “Motor Controller with Deterministic Synchronous Interrupt having Multiple Serial Interface Backplane,” filed by Campbell et al. on Nov. 17, 2008, which is hereby incorporated into the present disclosure by reference.
As noted above, the control processing circuitry 58 may include its own memory circuitry or separate memory circuitry may be provided. In the illustration of
The power layer processing circuitry 70 is also associated with memory circuitry as indicated by reference numeral 82. This memory circuitry, again, may be provided as a dedicated part of the processing circuitry, or separate memory may be provided. In a presently contemplated embodiment, the memory circuitry 82 comprises an electrically erasable programmable read-only memory that is mounted separately on a common substrate or board with the processing circuitry, and that will remain resident on the board even if the processing circuitry is changed for service reasons. As discussed below, this allows for the functionality described herein to continue despite changes in components, including the power layer processing circuitry. The memory circuitry 82 stores, among other things, a frame rating identification 84 which is substantial identical to the particular component identification 80 from the frame rating table for the particular product configuration. That is, when the device is initially specified, built and commissioned, an entry is made in memory circuitry 82 that includes an identification (e.g., a multi-bit word or value) substantially identical to or derived from the component identification 80. The frame rating identification 84 at the power layer, then, allows for later verification of components provided in or connected to the power layer as described below.
The power layer processing circuitry may interface with a number of devices as illustrated in
Further circuitry communicating with the processing circuitry 70 may include a power supply 90. In a currently contemplated embodiment, this power supply is a separate board that is supported in the power layer support along with a power layer interface board that supports the processing circuitry 70. Here again, multiple such power supplies may be available and the particular power supply selected for the particular application may be important to the proper operation of the power layer interface circuitry.
In addition to these components, in the embodiment illustrated in
In operation, each of the components coupled to the processing circuitry provide, in addition to the signals and data they normally provide for operation of the drive, identification data that uniquely identifies itself Based upon the information received, then, the processing circuitry 70 computes or compiles an identification 106. In a present embodiment, the identification comprises a 32-bit word or value with separate fields populated based upon the data received from the various components. Other protocols for establishing such coded identification may, of course, be employed. The identification 106 may then be compared to the frame rating identification 84 stored in the memory circuitry (which, again is equivalent to the component identification 80 for the particular product as referenced in the frame rating table 78). If the comparison indicates the same code, the processing circuitry recognizes that all components are proper, properly installed, and properly functional, and operation may proceed. If a mismatch occurs, on the other hand, this may result in various prescribed actions, including disabling of the drive, reporting of faults to the control circuitry, and so forth.
The identification and comparison process may occur at specific points in the operation of the drive, particularly at startup, or as in a presently contemplated embodiment, may occur repeatedly and cyclically during operation. Such cyclic application of the process allows for evaluation of the proper functional state of the components during operation of the system. Moreover, the identification compiled by the processing circuitry at the inverter level may be reported back to the control circuitry, which may evaluate the operation of the components and compile a log indicating times, operating state, and so forth. This also permits the control circuitry to recognize which component may have malfunctioned, and at what time. Such evaluation may be used for diagnostics, route cause analysis, and so forth. It should also be noted that the comparison made between the compiled identification and the frame rating identification may be performed at the power layer level or in the control circuitry, or both.
At step 110, then, the system is built and assembled as specified in the system design. This will include selection and identification of all of the various components discussed above, including the power layer circuitry, the current sensing devices, the power supply, the output phase gate driver circuits, and so forth. Following assembly of the drive, then, the drive is commissioned as indicated at step 114. As discussed above, similar processes after this step may be performed upon subsequent maintenance or servicing. Commissioning the drive typically includes starting the drive, carrying out certain tests procedures, quality control, documentation, and so forth. As part of this commissioning, the processing circuits of each power layer poll the components and build the component identification as discussed above and as summarized at step 116. Again, in a present embodiment, the identification data has fields that are populated based upon the data reported by each component. If a component is absent, is disconnected, or as otherwise non-communitative, the corresponding portion of the identification may remain at a default level (e.g., all 0's).
At step 118, then, a comparison is made to determine whether the compiled component identification based upon the reported data matches the frame rating identification. If the two do not match, this may be taken to indicate that either a component was mis-selected, a component was improperly installed or connected, or that a component is not properly functioning (or communicating). In such cases, it will generally be desirable to disable the drive as indicated at step 120 and to provide a notification to the control circuitry (and ultimately to a human operator) as indicated at step 122. If, on the other hand, the information matches, the verification process is successful and the drive may be placed into operation.
Subsequently, then, the drive may be run in normal operation as indicated at step 124. Such operation may comprise any range of functionality that is programmed into and permitted for the drive and its components. In a presently contemplated embodiment, the process of identification and verification continues throughout this operation with the components being periodically polled, component identification data being compiled, and the comparison made as indicated at step 126 in
As discussed above, the same process may be carried out at the time of servicing, or just subsequent to servicing, particularly where any components are removed, replaced, disconnected, or repaired. The process may be assumed to be recommenced, then, at step 114 in
While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. 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.
This application is a Continuation Application of U.S. patent application Ser. No. 12/838,190 entitled “Motor Drive Component Verification System and Method,” filed Jul. 16, 2010, which is herein incorporated by reference.
Number | Date | Country | |
---|---|---|---|
Parent | 12838190 | Jul 2010 | US |
Child | 13767763 | US |