JP2005151664A - Switched reluctance motor drive controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detects a fault that short-circuits a direct-current power supply and prevent the expansion of the faulty part. <P>SOLUTION: The switching elements 2a to 2f in respective phases of an inverter 2 are switched according to a plurality of switching patterns. Then, any fault is located in the inverter 2 and SRMs 1a to 1c and the causes of the fault are diagnosed based on winding currents detected by current detectors 4a to 4c and a rate of direct-current supply voltage change detected by a voltage detector 5c. At this time, the occurrence of any fault that short-circuits a direct-current power supply 3 is determined based on either or both of the values of winding currents detected by the current detectors 4a to 4c and the value of rate of direct-current supply voltage change detected by the voltage detector 5c. If it is determined that a fault has occurred, the switching elements 2a to 2f are immediately turned off. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a drive control device for a switched reluctance motor (hereinafter referred to as SRM), and more particularly to a motor and device failure diagnosis method.

  The peak hold circuit detects peak values Ip1 to Ip3 of the coil current flowing in the stator winding of the SRM, and if any of the coil current peak values is abnormal compared to the other coil current peak values, motor drive control There is known an SRM drive control device that is determined to be a device failure (see, for example, Patent Document 1).

Prior art documents related to the invention of this application include the following.
JP 2002-010681 A

  However, since the conventional SRM drive control device simply detects and compares the peak value of the coil current flowing in the stator winding of the SRM, any part of the SRM drive control device fails. It is not possible to identify the cause of the failure and the cause of the failure, and it takes a long time to diagnose the failure, and the operation of the apparatus is continued to cause damage to a non-failed part.

  The switching elements of each phase of the inverter are switched according to a plurality of switching patterns, and based on the winding current detected by the current detector and the DC power supply voltage change rate detected by the voltage detector, the inverter and When diagnosing the location of the SRM failure and the cause of the failure, a failure of short-circuiting the DC power supply based on the winding current detected by the current detector and the DC power supply voltage change rate detected by the voltage detector When the occurrence of a failure is determined, the switching element is immediately turned off.

  ADVANTAGE OF THE INVENTION According to this invention, the failure which short-circuits DC power supply can be detected, and the expansion of a failure part can be prevented.

  FIG. 1 shows the configuration of the first embodiment. The SRM drive control apparatus according to the first embodiment includes a U-phase winding 1a, a V-phase winding 1b, and a W-phase winding that are stator windings of a switched reluctance motor (SRM) having three-phase windings. SRM drive inverter 2 for applying a rectangular wave voltage to 1c, SRM control unit 5 for controlling SRM drive inverter 2, DC power supply 3 for supplying DC power to inverter 2, and a DC link of inverter 2 And the condenser 6.

  A switched reluctance motor (SRM) is a motor that does not use a permanent magnet, and has a salient pole structure rotor and stator, and the magnetic reluctance (reluctance) between these rotors and stator is minimal. Rotational power is generated by switching the excitation phases of the windings 1a to 1c so that. This SRM has a robust structure, can be used even in a high temperature environment, and is suitable for high-speed driving, and is expected to be applied to electric vehicles and high-speed motors. In FIG. 1, only the windings 1a to 1c of the SRM are illustrated, and the mechanical and structural parts of the SRM are not directly related to the present invention and are not illustrated.

  The SRM driving inverter 2 converts the DC voltage of the DC power source 3 into a rectangular wave voltage by using six switching elements 2a to 2f and six diodes 2g to 2l, and converts them into three-phase windings 1a, 1b and 1c of the SRM. Apply. The connection line between the inverter 2 and the DC power source 3 is called a DC link, and a capacitor 6 is connected between the positive side (P side) and the negative side (N side) of the DC power source 3 of this DC link. Yes.

  In this embodiment, the six switching elements 2a to 2f are divided into a U-phase upper stage (P side) switching element 2a, a V phase upper stage (P side) switching element 2b, a W phase upper stage (P side) switching element 2c, They are referred to as a U-phase lower stage (N side) switching element 2d, a V-phase lower stage (N side) switching element 2e, and a W-phase lower stage (N side) switching element 2f. Further, the six diodes 2g to 2l are composed of a U-phase upper stage (P side) diode 2g, a V phase upper stage (P side) diode 2h, a W phase upper stage (P side) diode 2i, and a U phase lower stage (N side) diode 2j. , V phase lower stage (N side) diode 2k and W phase lower stage (N side) diode 2l.

  Further, the upper side (P side) switching elements 2a, 2b, and 2c of the U, V, and W phases are collectively referred to as "upper stage switching elements" or "P side switching elements", and the lower side of the U, V, and W phases ( N-side) switching elements 2d, 2e, and 2f are collectively referred to as “lower switching elements” or “N-side switching elements”. Furthermore, the upper stage (P side) diodes 2g, 2h, and 2i of the U, V, and W phases are collectively referred to as "upper stage diode" or "P side diode", and the lower stage side (N side) of the U, V, and W phases. The diodes 2j, 2k, and 2l are collectively referred to as “lower diodes” or “N-side diodes”.

  The SRM driving inverter 2 also includes a U-phase winding current sensor 4a that detects a current flowing in the U-phase winding 1a of the SRM, a V-phase winding current sensor 4b that detects a current flowing in the V-phase winding 1b, And a W-phase winding current sensor 4c for detecting a current flowing through the W-phase winding 1c.

  The SRM control unit 5 includes an inverter drive signal generation unit 5a that supplies drive signals to the inverter switching elements 2a to 2f, a winding current detection unit 5b that detects a winding current from output values of the winding current sensors 4a to 4c, One or both of a DC voltage change rate detection unit 5c for detecting a time change rate of DC voltage in the DC link of the inverter 2, a detection value by the winding current detection unit 5b, and a detection value by the DC voltage change rate detection unit 5c The failure detection unit 5d that identifies the failure part and the failure cause of the SRM or its drive control device based on the above, and the failure location / cause storage unit 5e that stores the failure location and the failure cause.

  Next, three types of switching patterns given to the switching elements 2a to 2f at the time of failure diagnosis will be described. FIG. 2 shows an upper switching element driving signal and a lower switching element driving signal for one phase when three types of switching patterns 1 to 3 are sequentially executed.

  In the switching pattern 1, only the upper switching element of the phase for failure diagnosis is turned on, while the lower switching element is turned off. When a failure is detected during the execution of the switching pattern 1, the upper switching element is immediately turned off. When no failure is detected, the upper switching element is turned off after a predetermined time t1.

  In the switching pattern 2, only the lower switching element of the phase for failure diagnosis is turned on, while the upper switching element is turned off. When a failure is detected during the execution of the switching pattern 2, the lower switching element is immediately turned off. When no failure is detected, the lower switching element is turned off after a predetermined time t2.

  In switching pattern 3, the upper and lower switching elements of the phase for failure diagnosis are simultaneously turned on. If a failure is detected during execution of the switching pattern 3, the upper and lower switching elements are immediately turned off. If no failure is detected, the upper and lower switching elements are turned off after a predetermined time t3.

  Next, regarding the U-phase winding current, the U-phase winding voltage, and the DC voltage of the DC link of the inverter 2 when the switching patterns are given to the switching elements 2a and 2d above and below the U-phase in the order of 1, 2, and 3, Each failure mode will be described with reference to FIGS. 3 to 7, in order from the top, the driving signal for the upper switching element 2a, the driving signal for the lower switching element 2d, the operating state of the upper switching element 2a, the operating state of the lower switching element 2d, and the U phase of the SRM in each failure mode. The waveform of the winding current of winding 1a and the DC voltage of the inverter DC link is shown.

FIG. 3 shows operation waveforms of each part of the U phase of the inverter 2 at the normal time. In switching patterns 1 and 2, both the winding voltage and winding current of the SRM U-phase winding 1a remain zero. In switching pattern 3, at time t3 when both upper and lower switching elements 2a and 2d are on, current iu expressed by the following equation flows through U-phase winding 1a of the SRM.
iu = (1 / L) ∫Edt (1)
In equation (1), L is the inductance of the U-phase winding 1a of the SRM, E is the DC link voltage of the inverter 2, and t is the elapsed time since both the upper switching element 2a and the lower switching element 2d are turned on. . When the time t3 elapses and the upper and lower switching elements 2a and 2d are turned off, the winding current is regenerated to the DC power source 3 via the diodes 2g and 2j, and the winding current is attenuated.

  FIG. 4 shows an operation waveform of each part of the U phase when the upper diode 2g is short-circuited. In this failure mode, no winding current flows in all the switching patterns 1 to 3. The DC voltage of the inverter DC link shows the same value in the switching pattern 1 as in the normal state. In the switching pattern 2, the DC voltage is substantially zero during the time t2 when the lower switching element 2d is on. During the time t3 when both of the switching elements 2a and 2d are turned on, the switching elements 2a and 2d become substantially zero.

  FIG. 5 shows an operation waveform of each part of the U phase when the lower diode 2j is short-circuited. In this failure mode, no winding current flows in all the switching patterns 1 to 3. The DC voltage of the inverter DC link shows the same value in the switching pattern 2 as in the normal state. In the switching pattern 1, the DC voltage is substantially 0 during the time t1 when the upper switching element 2a is on. During the time t3 when both of the switching elements 2a and 2d are turned on, the switching elements 2a and 2d become substantially zero.

  FIG. 6 shows an operation waveform of each part of the U phase when the SRM U phase winding 1a is short-circuited. In this failure mode, the same winding current waveform is obtained in the switching patterns 1 and 2 as in the normal state, but in the switching pattern 3, during the time t3 when both the upper and lower switching elements 2a and 2d are on, a large winding is obtained. Current flows. Further, the DC voltage of the inverter DC link can be obtained in the switching patterns 1 and 2 in the same voltage waveform as in the normal state, but in the switching pattern 3, during the time t3 when both the upper and lower switching elements 2a and 2d are on. It becomes almost zero.

  FIG. 7 shows an operation waveform of each part of the U phase when the positive side (P side) terminal of the U phase winding of the SRM is grounded. In this failure mode, the same winding current waveform is obtained in the switching pattern 2 as in the normal state, but in the switching patterns 1 and 3, a large winding current is generated during the times t1 and t3 when the upper switching element 2a is on. Flowing. Further, the DC voltage of the inverter DC link has a voltage waveform similar to that in the normal state in the switching pattern 2, but in the switching patterns 1 and 3, it is almost 0 during the times t 1 and t 3 when the upper switching element 2 a is on. become.

  Next, a failure detection method will be described. For detecting the failure, either or both of the winding current detected by the winding current detection unit 5b and the DC voltage change rate of the inverter DC link detected by the DC voltage change rate detection unit 5c are used. . In this embodiment, a failure detection method using both the winding current and the DC voltage change rate will be described.

  When an SRM winding short circuit or a winding positive side (P side) terminal ground fault occurs, a large current flows through the winding during failure diagnosis. Therefore, when a predetermined current threshold value ioc [A] is set and the winding current i detected by the winding current detection unit 5b exceeds the threshold value ioc, the SRM winding short-circuit or the positive winding side ( P side) It is determined that a terminal ground fault has occurred.

Further, when a short circuit failure of the DC power supply 3 occurs, a large short circuit current flows. At this time, the current is flowing from the DC link capacitor 6 is expressed by the following equation.
is = C · dv / dt (2)
In the equation (2), the direction of the current is flowing into the capacitor 6 is positive, C is the capacitance of the capacitor 6, and v is the voltage across the capacitor 6. If a short circuit failure of the DC power supply 3 has occurred, a short circuit current of current is << 0 is generated, and dv / dt << 0 from equation (2). That is, the DC voltage of the inverter DC link is rapidly reduced. Therefore, when a negative voltage change rate threshold value vod [V / sec] is set and the DC voltage change rate dv / dt detected by the DC voltage change rate detection unit 5c falls below the threshold value vod, It is determined that a short circuit failure of the DC power supply 3 has occurred.

  In the failure mode shown in FIGS. 4 to 7, when the DC voltage change rate dv / dt of the inverter DC link falls below the threshold value vod in the switching pattern 2 (dv / dt <vod), the upper stage ( It is determined that a short circuit fault has occurred in the diode (2g, 2h, 2i) on the P side.

  Further, when the winding current i of the SRM is smaller than the threshold value ioc and the DC voltage change rate dv / dt is lower than the threshold value vod in the switching pattern 1 (i <ioc, dv / dt <vod). Then, it is determined that a short-circuit failure has occurred in the diode (2j, 2k, 2l) on the lower stage (N side) of the diagnostic phase.

  When the winding current i is smaller than the threshold value ioc (i <ioc) in the switching pattern 1 and the winding current i is larger than the threshold value ioc (i> ioc) in the switching pattern 3, the SRM Judge that winding short-circuit has occurred.

  When the winding current i is larger than the threshold value ioc and the DC voltage change rate dv / dt is lower than the threshold value vod (i> ioc, dv / dt <vod) in the switching pattern 1, the winding of the SRM It is determined that a ground fault has occurred at the line positive side (P side) terminal.

  If a failure is detected during the failure diagnosis based on the switching pattern, the drive signals of the upper and lower switching elements 2a to 2f are immediately turned off, and the failure diagnosis based on the subsequent switching pattern is also stopped. Subsequently, the location and cause of the failure are recorded in the failure location / cause storage unit 5e, and the recorded information is read before the next failure inspection so that the switching element of the phase in which the failure has occurred is not turned on.

  As described above, according to the embodiment, the switching elements 2a to 2f of the respective phases of the inverter 2 are switched according to a plurality of switching patterns, and the winding currents detected by the winding current sensors 4a to 4c are detected. When diagnosing the location and cause of the failure of the inverter 2 and the SRM based on i and the DC power supply voltage change rate dv / dt detected by the DC voltage change rate detector 5c, the winding current sensor 4a The DC power supply 3 is short-circuited based on one or both of the winding current i detected from .about.4c and the DC power supply voltage change rate dv / dt detected by the DC voltage change rate detector 5c. The occurrence of a failure is determined, and the switching elements 2a to 2f are immediately turned off when the failure occurrence is determined. Thereby, the failure which short-circuits DC power supply 3 can be detected, and expansion of a failure part can be prevented. Furthermore, since a short circuit failure can be detected without using an inverter having a self-protection function, a system can be configured at low cost.

  In addition, according to the embodiment, the switching pattern 1 in which the P-side switching element in the failure diagnosis phase is turned on for a predetermined time t1, and the N-side switching element in the same phase is kept off; The switching element 2 that turns on the switching element for a predetermined time t2 and keeps the P-side switching element in the same phase off, and the P-side switching element and the N-side switching element in the fault diagnosis phase are simultaneously turned on for a predetermined time t3. When a switching pattern consisting of the switching pattern 3 is used and when the switching patterns 1 to 3 are executed, the winding current i detected by the winding current sensors 4a to 4c exceeds a preset threshold value ioc Is determined as the occurrence of a short-circuit fault in the SRM windings 1a to 1c or a ground fault in the SRM winding P-side terminal. To turn off the switching element 2a~2f. Thereby, the failure which short-circuits DC power supply 3 can be detected, and expansion of a failure part can be prevented.

  Furthermore, according to one embodiment, the switching pattern 1 in which the P-side switching element in the failure diagnosis phase is turned on for a predetermined time t1, and the N-side switching element in the same phase is kept off; The switching element 2 that turns on the switching element for a predetermined time t2 and keeps the P-side switching element in the same phase off, and the P-side switching element and the N-side switching element in the fault diagnosis phase are simultaneously turned on for a predetermined time t3. The DC power supply voltage change rate dv / dt detected by the DC voltage change rate detection unit 5c when the switching patterns 1 to 3 are executed using the switching pattern consisting of the switching pattern 3 exceeds a preset threshold value vod. The SRM windings 1a to 1c, or the ground fault of the SRM winding P side terminal, Determining the occurrence of short-circuit failure of the inverter 2 diodes 2G～2l, turns off the switching element 2a to 2f. Thereby, the failure which short-circuits DC power supply 3 can be detected, and expansion of a failure part can be prevented.

  Furthermore, according to the embodiment, the failure location and the cause of the failure diagnosis result are stored, the short-circuit failure of the SRM windings 1a to 1c, the ground fault failure of the SRM winding P side terminal, and the inverter 2 If any occurrence of a diode short-circuit fault is stored, the fault diagnosis of the phase where the fault is detected is prohibited and the switching element of that phase is left off. It is possible to avoid performing failure diagnosis again for a certain phase, and to prevent expansion of the failure site.

  The correspondence between the constituent elements of the claims and the constituent elements of the embodiment is as follows. That is, the winding current sensors 4a to 4c are current detectors, the DC voltage change rate detection unit 5c is a voltage detector, the failure detection unit 5d is a failure diagnosis circuit and a drive inhibition circuit, and a failure location / cause storage unit 5e is Each memory circuit is configured. In addition, unless the characteristic function of this invention is impaired, each component is not limited to the said structure.

  In the above-described embodiment, the three-phase SRM has been described as an example. However, the SRM is not limited to the three-phase, and the present invention can be applied to SRMs other than the three-phase. .

It is a circuit block diagram of one embodiment. It is a figure which shows the switching pattern signal used for a failure diagnosis. It is a figure which shows the operation waveform of each part of the U phase at the time of normality when the failure diagnosis by the switching patterns 1-3 is performed by the U phase of the SRM drive control apparatus. It is a figure which shows the operation waveform of each part of U phase when a short circuit fault generate | occur | produces in the upper stage diode 2g at the time of performing failure diagnosis by the switching patterns 1-3 in the U phase of the SRM drive control apparatus. It is a figure which shows the operation | movement waveform of each part of U phase when a short circuit fault generate | occur | produces in the lower diode 2j at the time of performing fault diagnosis by the switching patterns 1-3 in the U phase of the SRM drive control apparatus. It is a figure which shows the operation | movement waveform of each part of U-phase when a short circuit fault generate | occur | produces in a SRM winding at the time of performing failure diagnosis by the switching patterns 1-3 in the U-phase of an SRM drive control apparatus. The figure which shows the operation | movement waveform of each part of U phase when a ground fault occurs in the SRM winding positive side (P side) terminal at the time of performing fault diagnosis by switching patterns 1 to 3 in the U phase of the SRM drive control device It is.

Explanation of symbols

1a to 1c SRM windings 2a to 2f Switching elements 2g to 2l Diode 3 DC power sources 4a to 4c Winding current sensor 5 SRM control unit 5a Inverter drive signal generation unit 5b Winding current detection unit 5c DC voltage change rate detection unit 5d Failure Detection unit 5e Failure location / cause storage unit 5f Failure threshold determination unit 6 Capacitor

Claims (5)

Each phase is composed of P-side and N-side switching elements and P-side and N-side diodes, and converts a DC voltage of a DC power source into a rectangular wave voltage to convert a multi-phase switched reluctance motor (hereinafter referred to as SRM). An inverter to be applied),
A current detector for detecting a current flowing in each phase winding of the SRM;
A voltage detector for detecting a rate of change of the DC power supply voltage of the inverter;
The switching elements of each phase of the inverter are switched according to a plurality of switching patterns, and based on the winding current detected by the current detector and the DC power supply voltage change rate detected by the voltage detector. A failure diagnosis circuit for diagnosing the failure part and the cause of the failure of the inverter and the SRM,
The fault diagnosis circuit short-circuits the DC power supply based on one or both of a winding current detected by the current detector and a DC power supply voltage change rate detected by the voltage detector. An SRM drive control device characterized in that the occurrence of a failure to be determined is determined and the switching element is immediately turned off when the failure is determined. The SRM drive control device according to claim 1,
The plurality of switching patterns include a switching pattern 1 in which the P-side switching element in the failure diagnosis phase is turned on for a predetermined time t1, and the N-side switching element in the same phase is kept off;
A switching pattern 2 that turns on the N-side switching element of the fault diagnosis phase for a predetermined time t2, and keeps the P-side switching element of the same phase off;
An SRM drive control device comprising: a switching pattern 3 for simultaneously turning on a P-side switching element and an N-side switching element in a failure diagnosis phase for a predetermined time t3. The SRM drive control device according to claim 2,
If the winding current detected by the current detector exceeds the preset threshold when the switching patterns 1 to 3 are executed, the fault diagnosis circuit detects a short circuit fault in the SRM winding or An SRM drive control apparatus characterized in that it is determined that a ground fault has occurred in the SRM winding P-side terminal, and the switching element is immediately turned off. The SRM drive control device according to claim 2,
If the DC power supply voltage change rate detected by the voltage detector is less than a preset threshold when the switching patterns 1 to 3 are executed, the fault diagnosis circuit short-circuits the SRM winding. An SRM drive control device characterized in that it determines that a failure, a ground fault in the SRM winding P-side terminal, or a short-circuit failure in the inverter diode occurs, and turns off the switching element. In the SRM drive control device according to any one of claims 1 to 4,
A storage circuit for storing a failure location and a failure cause of a failure diagnosis result by the failure diagnosis circuit;
If the storage circuit stores any one of the short circuit fault of the SRM winding, the ground fault of the SRM winding P side terminal, and the diode short circuit fault of the inverter, the phase of the phase in which the fault is detected is stored. An SRM drive control device comprising: a drive inhibition circuit that inhibits failure diagnosis and keeps the switching element of the phase off.

Images