JP2020043672A - Inverter controller - Google Patents

Abstract

To provide an inverter controller capable of properly determining an abnormality of a current sensor without an abnormality determination section being affected by current ripples in an inverter controller in which a current control section and the abnormality determination section share a processing.SOLUTION: A current control microcomputer 30 of an inverter controller 20 controls an operation of an inverter 60 on the basis of a current sensor value obtained from current sensors 71, 72 and 73 for detecting a phase current flowing between an inverter 60 and a motor 80. An abnormality determination microcomputer 40 determines abnormality of one or more current sensors on the basis of the current sensor value. A carrier wave generator 50 as "a timing instruction section" is provided inside the current control microcomputer 30, and instructs timing for detecting the current sensor value used for abnormality determination by use of the abnormality determination microcomputer 40. The abnormality determination microcomputer 40 determines abnormality of the current sensors 71, 72 and 73 on the basis of the current sensor value at the timing instructed by the carrier wave generator 50.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an inverter control device that determines an abnormality of a current sensor.

  2. Description of the Related Art Conventionally, there has been known a device that detects an abnormality of a current sensor that detects a phase current flowing between an inverter and a multi-phase rotating electric machine. For example, the current detection device disclosed in Patent Document 1 detects an abnormality based on the fact that the three-phase sum of the respective phase current values supplied to the load from the AC three-phase power supply deviates from zero.

JP-A-3-155322

  The simplest configuration for realizing the abnormality determination is to execute the abnormality determination using the same arithmetic device as the arithmetic device that performs the current control of the inverter. However, in recent years, various functions have tended to be included in the inverter control device, and it has become difficult for a single arithmetic device to cover the processing due to an increase in processing load. As a solution to this problem, a method is adopted in which a plurality of arithmetic devices are arranged in the control device of the inverter to share processing. Particularly, in recent years, from the viewpoint of safety design requirements such as avoiding abnormal high torque and cost reduction, a current control unit having a current control function and an abnormality determination unit having an abnormality determination function are arranged in separate arithmetic units. It has been known.

  Here, the fact that the failure detection capability of the arithmetic device itself is high is expressed as “high safety requirement”, and the fact that the failure detection capability of the arithmetic device itself is low is expressed as “low safety requirement”. In this technical trend, a current control unit with a low safety requirement is arranged in an inexpensive arithmetic unit without a safety mechanism, and an abnormality detection unit with a high safety requirement is arranged in an expensive arithmetic unit with a safety mechanism. As a result, it is possible to ensure both failure detection performance and cost reduction.

  By the way, in the voltage-type inverter, current ripple occurs with ON / OFF of each switching element of the inverter. However, if the peak or bottom of the current ripple is sampled and used for abnormality determination, the abnormality determination threshold must be set large, and the accuracy of abnormality detection is reduced. Therefore, from the viewpoint of improving the accuracy of abnormality detection, it is desired to sample an effective current at the peak and bottom timings of a carrier wave in, for example, PWM control.

  However, in a configuration in which the current control unit and the abnormality determination unit share processing, the abnormality determination unit cannot recognize the timing of the carrier managed by the current control unit, and thus cannot sample an effective current value. Therefore, the current value used by the abnormality determination unit for the abnormality determination may be affected by the current ripple.

  The present invention has been made in view of such a point, and a purpose of the present invention is to provide an inverter control device in which a current control unit and an abnormality determination unit share processing. It is an object of the present invention to provide an inverter control device capable of appropriately determining an abnormality of a current sensor without detecting the abnormality.

  The present invention relates to an inverter control device that is provided between a DC power supply (10) and a multi-phase rotating electric machine (80) and controls the operation of an inverter (60) that converts power mutually. An inverter control device according to a first aspect of the present invention includes a current control unit (30, 35), an abnormality determination unit (40, 45), and a timing instruction unit (50).

  The current control unit controls the operation of the inverter based on current sensor values obtained from a plurality of current sensors (71, 72, 73) that detect a phase current flowing between the inverter and the multi-phase rotating electric machine. The abnormality determination unit determines an abnormality of one or more current sensors among the plurality of current sensors based on the current sensor value. The timing instruction unit is provided inside the current control unit or the abnormality determination unit, or outside the current control unit and the abnormality determination unit, and indicates a timing at which a current sensor value used for abnormality determination by the abnormality determination unit is detected. . Then, the abnormality determination unit determines an abnormality of the current sensor based on the current sensor value at the timing instructed by the timing instruction unit.

  In the first aspect, since the timing of the current sensor value used for the abnormality determination is instructed by the timing instruction unit, the abnormality determination unit can appropriately determine the abnormality of the current sensor without being affected by the current ripple. Can be.

  Further, an inverter control device according to a second aspect of the present invention includes a current control unit (30, 35) and an abnormality determination unit (40, 45) similar to those of the inverter control device according to the first aspect. The abnormality determination unit determines abnormality of the current sensor based on a current sensor value at a timing determined based on ON / OFF timing of a switching element of a specific phase of the inverter.

  In the second aspect, since the timing of the current sensor value used for the abnormality determination is determined based on the ON / OFF timing of the switching element of the specific phase, the abnormality determination unit can control the current without being affected by the current ripple. An abnormality in the sensor can be appropriately determined.

1 is an overall configuration diagram of a motor drive system to which an inverter control device according to each embodiment is applied. The figure explaining the relationship between the current ripple of the current sensor value and the "effective current". FIG. 1 is a configuration diagram of an inverter control device according to a first embodiment. 5 is a flowchart showing the operation of the abnormality determination microcomputer. 5 is a time chart illustrating processing of the microcomputer according to the first embodiment. (A) A three-phase sum waveform diagram in a normal state, (b) a three-phase sum waveform diagram in an abnormal case, and (c) a waveform diagram of a filter value of the three-phase sum absolute value in an abnormal case. 9 is a flowchart of an abnormality determination process. 9 is a time chart showing processing of the microcomputer according to the second embodiment. (A) The 3rd, (b) The block diagram of the inverter control apparatus of 4th Embodiment. (A) The block diagram of the inverter control apparatus of 5th, (b) 6th Embodiment. The block diagram of the inverter control device of 7th Embodiment. (A) The block diagram of the inverter control apparatus of 8th, (b) 9th Embodiment. The figure explaining the synchronization of the current control part and abnormality determination part by 10th Embodiment. The figure explaining the timing of the current sample by 11th Embodiment. The block diagram of the inverter control device of 12th Embodiment. FIG. 4 is a conceptual diagram of a reference embodiment in which a filtered current value is used for abnormality determination.

  Hereinafter, a plurality of embodiments of an inverter control device will be described with reference to the drawings. In a plurality of embodiments, substantially the same configuration is denoted by the same reference numeral, and description thereof is omitted. The first to twelfth embodiments are collectively referred to as “the present embodiment”. The inverter control device according to the present embodiment is mounted on a hybrid vehicle or an electric vehicle having a motor as a “polyphase rotating electric machine” as a power source.

[System configuration]
First, the overall configuration of a motor drive system to which the inverter control device of each embodiment is applied will be described with reference to FIG. In the motor drive system 90, a battery 10 as a “DC power supply” and a motor 80 as a “polyphase rotating electric machine” are electrically connected via an inverter 60. The battery 10 of the present embodiment is a chargeable / dischargeable secondary battery such as a lithium ion battery. The positive electrode of battery 10 is connected to DC bus Lp, and the negative electrode of battery 10 is connected to ground line Ln.

  The motor 80 is, for example, a permanent magnet type synchronous three-phase AC motor. The motor 80 according to the present embodiment has both a function as an electric motor that generates torque for driving the drive wheels of the hybrid vehicle and a function as a generator that recovers the torque transmitted from the engine and the drive wheels by generating electricity. It is a motor generator. In general, a motor control is provided with a rotation angle sensor for detecting a rotation angle used for coordinate conversion calculation or the like, but illustration in FIG. 1 and reference in the specification are omitted.

  Inverter 60 is provided between battery 10 and motor 80, and converts DC power and AC power mutually. That is, the inverter 60 converts the DC power of the battery 10 into AC power and supplies it to the motor 80 during the power running operation, and converts the AC power generated by the motor 80 into DC power and regenerates the battery 10 into the battery 10 during the regenerative operation. I do.

  In the inverter 60, six switching elements 61-66 of the upper and lower arms are bridge-connected. The switching elements 61, 62, and 63 are upper-arm switching elements of U-phase, V-phase, and W-phase, respectively, and the switching elements 64, 65, and 66 are lower-arm switching elements of U-phase, V-phase, and W-phase, respectively. Element. Each of the switching elements 61 to 66 is formed of, for example, an IGBT, and is connected in parallel with a return diode that allows a current flowing from a low potential side to a high potential side. Smoothing capacitor 15 is connected between DC bus Lp and ground line Ln, and smoothes a DC voltage input to inverter 60.

  Current paths 81, 82, and 83 between the inverter 60 and each phase winding of the motor 80 are provided with current sensors 71, 72, and 73 for detecting phase currents flowing through the respective phases. Here, the configuration in which the three-phase current sensors 71, 72, 73 are provided corresponds to the first to eleventh embodiments, and only the twelfth embodiment differs in the arrangement configuration of the current sensors.

  The inverter control device 20 is configured by a microcomputer or the like, and internally includes a CPU, a ROM, an I / O (not shown), a bus line connecting these components, and the like. The microcomputer executes control by software processing by executing a program stored in advance by the CPU and hardware processing by a dedicated electronic circuit.

  The inverter control device 20 acquires the current sensor values detected by the current sensors 71, 72, 73, outputs a drive signal calculated based on the current values to the inverter 60, and controls the operation of the inverter 60. That is, the inverter control device 20 has a function of “current control” as a basic function.

  More specifically, the inverter control device 20 acquires the rotation angle of the motor 80 and the like in addition to the current sensor value, and calculates a drive signal so that the motor 80 outputs torque according to a torque command input from a higher-level control circuit. . However, since such general motor control is a well-known technique, detailed description will be omitted. In addition, the motor control of the present embodiment executes PWM control for generating a voltage pulse signal by comparing a voltage command value with a carrier wave.

  In addition, the inverter control device 20 has a function of detecting that an abnormality has occurred in any of the current sensors based on the current sensor values detected by the current sensors 71, 72, and 73. That is, the inverter control device 20 has a function of “abnormality determination” in addition to a function of “current control”.

Here, the relationship between the current ripple of the current sensor value and the “effective current” will be described with reference to FIG. While the effective current is indicated by a sine wave, the actually detected current includes a ripple component that varies according to the ON / OFF operation of each phase switching element of the voltage-type inverter 60. In FIG. 2, the amplitude of the ripple component is represented as I _rip .

  Then, at the timing of sampling the current values detected by the current sensors 71, 72, 73, an effective current is obtained when sampling a substantially intermediate current value of the ripple, but the peak or bottom current of the ripple is obtained. When sampling the value, an effective current will not be obtained. In the PWM control, when sampling is performed at the peak or bottom timing of the carrier, a current value approximately at the middle of the ripple can be sampled. In the (* 1) part of FIG. 2, the current value sampled at the peak timing of the carrier is indicated by a white circle.

  Then, in the abnormality detection of the current sensors 71, 72, 73 by the inverter control device 20, from the viewpoint of increasing the accuracy of the abnormality detection, it is preferable that the current sensor value used for abnormality determination is an effective current. That is, it is not preferable to sample the peak or bottom current value of the ripple and use it for abnormality determination. In the (* 2) part of FIG. 2, the current value corresponding to the peak of the ripple is indicated by a hatched circle. Next, the reason will be described.

  Conventionally, as disclosed in Patent Document 1 (Japanese Unexamined Patent Application Publication No. 3-155322), a technique for detecting an abnormality of a current sensor based on the fact that the three-phase sum of current deviates from 0 is known. I have. Incidentally, a gain error and an offset error occur in the current sensor due to manufacturing variations and the like. When these errors are multiplied by the sensor values, the three-phase sum deviates from zero even if no failure has occurred in the sensor. Therefore, the abnormality determination threshold must be set to a value other than 0 in consideration of these errors. Hereinafter, a value that is not 0, that is, a value whose absolute value is larger than 0 is referred to as a “non-zero value”.

If the effective current can be sampled, the current ripple I _rip in FIG. 2 does not affect the sensor value. Therefore, the sensor acquisition value and the three-phase sum (X) when the gain error and the offset error are superimposed on the current sensor value of each phase are expressed by Expression 1. Here, _assuming that * = u, v, w, for the * phase, I _{* _sens} is a sensor acquired value, I _{* 0} is an effective current, g _* is a gain error, and ofs _* is an offset error.

As described above, when the effective current can be sampled, the abnormality determination threshold is set by accumulating the terms of the gain error g _* and the offset error ofs _* included in the three-phase sum X of Expression 1.

On the other hand, if the effective current cannot be sampled, the current ripple I _rip in FIG. 2 is included in the sensor value. Accordingly, the sensor acquisition value and the three-phase sum (X) when the gain error and the offset error are superimposed on the current sensor value of each phase are expressed by Expression 2. I _{* rip} represents the current ripple for the * phase.

As described above, when the effective current cannot be sampled, an underlined term derived from the current ripple I _rip is added to the three-phase sum X of Expression 1 with respect to the three-phase sum X of Expression 1. Since the number of terms to be stacked increases, the abnormality determination threshold value must be set large, and the sensitivity of abnormality detection decreases. That is, in order to improve the sensitivity of abnormality detection, it is necessary to sample an effective current as a current value used for abnormality determination.

  Therefore, it is desired that the inverter control device 20 use the effective current sampled at the timing of the peak or bottom of the carrier for the abnormality determination. As a means for realizing this, in a configuration having the functions of “current control” and “abnormality judgment” in one microcomputer, the current value is sampled at the peak and bottom timings of the carrier controlled by current control, and the current control and It can be commonly used for abnormality determination.

  By the way, as described in the column of [Problems to be Solved by the Invention], in recent years, from the viewpoint of safety design requirements and cost reduction, a current control unit having a current control function and an abnormality determination unit having an abnormality determination function have been recently developed. A configuration is adopted in which the processing of FIG. In such a configuration, in order for the abnormality determination unit to obtain an effective current, information on the current value may be transmitted from the current control unit to the abnormality determination unit via communication. However, in this case, a safety mechanism is originally required for the current sampling function and the communication function of the current control unit, which may have low safety requirements, so that the cost of the current control unit increases.

  Further, it is conceivable that the current value is sampled on the abnormality determination unit side separately from the current control unit and used for abnormality determination. However, in this case, since the timing of the peak and bottom of the carrier managed by the current control unit is not known by the abnormality determination unit, an effective current value cannot be sampled.

  Therefore, in the present embodiment, in the inverter control device 20 having a configuration in which the current control unit and the abnormality determination unit share processing, the abnormality determination unit obtains an effective current, and the current sensor is not affected by the current ripple. An attempt is made to be able to appropriately determine an abnormality. The specific configuration for that will be described in detail below for each embodiment.

(1st Embodiment)
FIG. 3 shows the configuration of the inverter control device 20 according to the first embodiment. The inverter control device 20 includes a current control microcomputer 30, an abnormality determination microcomputer 40, and a carrier generator 50. In the current control microcomputer 30 and the abnormality determination microcomputer 40, the “current control unit” and the “abnormality determination unit” are each configured by one microcomputer. Further, the carrier generator 50 as a “timing instruction unit” is provided inside the current control unit 30 in the first embodiment.

  The current control microcomputer 30 outputs a drive signal to the inverter 60 based on the three-phase current sensor values Iu, Iv, Iw acquired from the current sensors 71, 72, 73, and outputs a drive signal to each of the switching elements 61-66 of the inverter 60. Control behavior. Thereby, the inverter 60 converts the DC power of the battery 10 into AC power and supplies it to the motor 80 during the power running operation, and converts the AC power generated by the motor 80 into DC power and regenerates the battery 10 into the battery 10 during the regenerative operation. I do. The abnormality determination microcomputer 40 determines an abnormality of any one or more of the current sensors 71, 72, 73 based on the current sensor values Iu, Iv, Iw.

  The carrier generator 50 as a “timing instructing unit” instructs a timing at which a current sensor value used for abnormality determination by the abnormality determination microcomputer 40 is detected. The abnormality determination microcomputer 40 determines an abnormality of the current sensors 71, 72, 73 based on the current sensor values at the timing instructed by the carrier generator 50. Specifically, the carrier generator 50 indicates the peak or bottom timing of the carrier wave in the PWM control as the “timing at which the current sensor value used for abnormality determination is detected”. Hereinafter, the peak or bottom timing of a carrier is simply referred to as “carrier timing”. Note that “carrier” may be appropriately read as “carrier”, but in this specification, “carrier” is unified and described.

  The current control microcomputer 30 and the abnormality determination microcomputer 40 include AD converters (“ADC” in the figure) 31 and 41, respectively. The analog current signals of the current sensors 71, 72, 73 are A / D converted by the A / D converters 31, 41 and acquired by the current control microcomputer 30 and the abnormality determination microcomputer 40, respectively.

  In the first embodiment, an interrupt notification signal line 28 for notifying the occurrence of an interrupt from the current control microcomputer 30 to the abnormality determination microcomputer 40 is provided. The signal line 28 may be a dedicated line or a data communication line between microcomputers such as a UART. When a communication line is used, the wiring cost can be reduced as compared with a case where a dedicated line is provided.

  The current control microcomputer 30 obtains the AD-converted current value in accordance with the carrier wave timing, and controls the operation of the inverter 60. When an interrupt timing occurs, the current control microcomputer 30 notifies the abnormality determination microcomputer 40 of the occurrence of the interrupt via the signal line 28. Upon receiving the notification of the occurrence of the interrupt, the abnormality determination microcomputer 40 obtains the AD-converted current value and uses it for abnormality determination.

  The operation of the abnormality determination microcomputer 40 is shown in the flowchart of FIG. In the following flowcharts, the symbol S represents “step”. The abnormality determination microcomputer 40 receives the interrupt notification signal from the current control microcomputer 30 in S10. Next, in S20, the abnormality determination microcomputer 40 converts the analog current signals acquired from the current sensors 71, 72, 73 from analog to digital and stores them in the RAM. Then, in S30, the abnormality determination microcomputer 40 reads out the current value stored in the RAM and uses it for abnormality determination.

  FIG. 5 shows the flow of tasks and signals as processing of the abnormality determination microcomputer 40. The tasks of the abnormality determination microcomputer 40 include a carrier wave timing process and an abnormality determination process. The cycle of the carrier timing processing is faster than the cycle of the abnormality determination processing. In the carrier wave timing process, the abnormality determination microcomputer 40 acquires the three-phase current sensor values Iu, Iv, Iw, and stores the AD-converted values in the RAM. In the abnormality determination processing having a cycle that is slower than the carrier wave timing processing, the abnormality determination microcomputer 40 reads a current value from the RAM at each processing timing and uses the current value for abnormality determination.

  An abnormality determination process in a configuration in which the current sensors 71, 72, and 73 are provided in three phases will be described with reference to a current waveform diagram of FIG. 6 and a flowchart of FIG. In the abnormality determination processing, first, the sum of the three-phase current sensor values Iu, Iv, and Iw is calculated, and the three-phase sum (Iu + Iv + Iw) is obtained. When all the current sensors 71, 72, and 73 can detect a correct current value, the three-phase sum is constant at 0 according to Kirchhoff's law, as shown in FIG. However, when an abnormality occurs in any of the current sensors 71, 72, and 73 and a correct current value cannot be detected, the three-phase sum is not constant at 0 and fluctuates as shown in FIG. 6B.

  The three-phase sum waveform in FIG. 6B is an AC waveform, and it is difficult to use it as it is for abnormality determination. Therefore, the absolute value of the three-phase sum is filtered to calculate the “filter value of the three-phase sum absolute value”. As shown in FIG. 6C, the “filter value of the absolute value of the three-phase sum” at the time of an abnormality is a non-zero, substantially constant value. When the “non-zero substantially constant value” is larger than the abnormality determination threshold, one of the current sensors is determined to be abnormal.

  Here, the abnormality determination threshold value is set so as to prevent erroneous determination in consideration of characteristic variations such as gain errors and offset errors of the current sensors 71, 72, and 73 and calculation errors of the abnormality determination microcomputer 40. Is preferred.

  FIG. 7 shows a detailed flowchart of the abnormality detection process in S30 of FIG. The abnormality determination microcomputer 40 calculates the three-phase sum of the current in S31, and calculates the filter value of the three-phase sum absolute value in S32. Subsequently, the abnormality determination microcomputer 40 compares the filter value of the three-phase sum absolute value with the abnormality determination threshold in S33. If the filter value of the three-phase sum absolute value is larger than the abnormality determination threshold, one of the current sensors is determined to be abnormal in S34. If the filter value of the three-phase sum absolute value is equal to or smaller than the abnormality determination threshold, it is determined in S35 that all the current sensors 71, 72, and 73 are normal.

  As described above, in the first embodiment, from the current control microcomputer 30 having the carrier generator 50 to the abnormality determination microcomputer 40, the timing managed for the ripple timing is used as the timing of the current sensor value used for the abnormality determination. Be instructed. Thus, the abnormality determination microcomputer 40 can appropriately determine the abnormality of the current sensors 71, 72, 73 without being affected by the current ripple.

(2nd Embodiment)
Next, a second embodiment in which the processing method of the abnormality determination microcomputer 40 is different from the first embodiment will be described with reference to FIG. In the second embodiment, in the carrier wave timing process, not only AD acquisition but also a filter value of a three-phase sum absolute value is calculated and stored in the RAM. In the second embodiment, it is possible to suppress aliasing that occurs when the abnormality determination processing cycle and the vibration cycle of the three-phase sum, that is, the electrical cycle, are close.

(Third and fourth embodiments)
Next, third and fourth embodiments will be described with reference to FIG. In the third and fourth embodiments, the carrier generator 50 is provided outside the current control microcomputer 30 and the abnormality determination microcomputer 40. The carrier signal from the carrier generator 50 is transmitted to both the current control microcomputer 30 and the abnormality determination microcomputer 40. Thereby, it is possible to avoid a sample delay due to a communication delay of a notification signal from the current control microcomputer 30 to the abnormality determination microcomputer 40 in the first embodiment.

  In the third embodiment shown in FIG. 9A, analog current signals from the current sensors 71, 72, and 73 are A / D converted by A / D converters 31 and 41, and acquired by the current control microcomputer 30 and the abnormality determination microcomputer 40, respectively. You.

  The fourth embodiment shown in FIG. 9B is a modified example of the third embodiment, and uses the current value after AD conversion obtained by the abnormality determination microcomputer 40 as a digital signal from the abnormality determination microcomputer 40 to the current control microcomputer 30. Send to In this configuration, the AD converter 31 on the side of the current control microcomputer 30 can be eliminated, which leads to cost reduction.

(Fifth and sixth embodiments)
Next, referring to FIG. 10, fifth and sixth embodiments will be described. In the fifth and sixth embodiments, the carrier generator 50 is provided inside the abnormality determination microcomputer 40. The abnormality determination microcomputer 40 notifies the input circuit (“INT” in the figure) 32 of the current control microcomputer 30 of the generation of the carrier by the carrier generator 50.

  As a notification method, a notification using a dedicated line, a notification using a communication line, a method using synchronization of CPU time described in a tenth embodiment described later, or the like can be used. The current control microcomputer 30 synchronizes the carrier used by the current control microcomputer 30 with the carrier of the abnormality determination microcomputer 40 based on the notification from the abnormality determination microcomputer 40. As a method of synchronizing a carrier wave, a phase synchronization method of a signal using a PLL (phase synchronization circuit) is known.

  The carrier generator 50 is an acquisition source of a signal to be used for abnormality determination, and requires high reliability. Therefore, when the carrier generator 50 is provided inside the current control microcomputer 30 as in the first embodiment, it is necessary to increase the cost of the current control microcomputer 30 in order to improve the reliability of the carrier generator 50, and to reduce the cost. Contrary to the purpose of Therefore, in the fifth and sixth embodiments, by providing the carrier generator 50 inside the abnormality determination microcomputer 40 which is originally highly reliable, the cost increase of the entire inverter control device can be suppressed.

  In the fifth embodiment shown in FIG. 10A, analog current signals from the current sensors 71, 72, and 73 are A / D converted by A / D converters 31 and 41, and acquired by the current control microcomputer 30 and the abnormality determination microcomputer 40, respectively. You.

  The sixth embodiment shown in FIG. 10B is a modification of the fifth embodiment, and uses the current value after AD conversion obtained by the abnormality determination microcomputer 40 as a digital signal from the abnormality determination microcomputer 40 to the current control microcomputer 30. Send to In this configuration, the AD converter 31 on the side of the current control microcomputer 30 can be eliminated, which leads to cost reduction.

(Seventh, eighth, and ninth embodiments)
Next, seventh to ninth embodiments will be described with reference to FIGS. In the seventh to ninth embodiments, the current control core 35 as the “current control unit”, the abnormality determination core 45 as the “abnormality determination unit”, and the carrier generator 50 are provided in one microcomputer 25. In this configuration, one microcomputer 25 functions as an “inverter control device”. By using one microcomputer, the cost can be reduced as compared with the first to sixth embodiments including two microcomputers. Further, the cost can be reduced by dividing the high reliability part and the low cost part inside the microcomputer.

  In the seventh embodiment shown in FIG. 11, a carrier generator 50 is attached to the current control core 35. Analog current signals from the current sensors 71, 72, and 73 are AD-converted by AD converters 36 and 46, and are acquired by the current control core 35 and the abnormality determination core 45, respectively. Further, the generation of the carrier is notified from the current control core 35 to the abnormality determination core 45.

  In the eighth embodiment shown in FIG. 12A, a carrier generator 50 is provided outside the current control core 35 and the abnormality determination core 45. With this configuration, it is possible to prevent a delay in the timing at which current is acquired by the abnormality determination core 45, as compared with the seventh embodiment.

  The ninth embodiment shown in FIG. 12B is a modification of the eighth embodiment, in which the current value acquired by the abnormality determination core 45 is transmitted from the abnormality determination core 45 to the current control core 35 via the RAM 26. . That is, the abnormality determination core 45 writes the obtained current value to the RAM 26, and the current control core 35 reads the current value written to the RAM 26. In this configuration, the AD converter 36 on the current control core 35 side can be eliminated. It is preferable that the abnormality determination core 45 requiring high reliability is configured by, for example, a lock step core or the like.

(Tenth embodiment)
In each of the above embodiments, the carrier wave timing signal is notified from the carrier generator 50 to the current control units 30 and 35 and the abnormality determination units 40 and 45, or between the current control units 30 and 35 and the abnormality determination units 40 and 45. Is done. That is, when a carrier is actually generated, a common timing between the current control units 30 and 35 and the abnormality determination units 40 and 45 is determined. On the other hand, in the tenth embodiment, the current control units 30 and 35 and the abnormality determination units 40 and 45 are adjusted to execute their respective processes in synchronization, and the abnormality determination units 40 and 45 perform the abnormality determination. The timing at which the current sensor value used for the detection is detected is notified in advance.

  For example, in the configuration in which the carrier generator 50 is provided inside the current control microcomputer 30, the current control microcomputer 30 and the abnormality determination microcomputer 40 send the carrier wave to the abnormality determination microcomputer 40 in a state where the CPU times of the current control microcomputer 30 and the abnormality determination microcomputer 40 are synchronized. The scheduled occurrence time is notified. Upon receiving the notification, the abnormality determination microcomputer 40 performs the abnormality determination based on the current sensor value detected at the scheduled timing.

  The CPU time is, for example, a time after the start of the microcomputer or a counter value for counting an elapsed time from the synchronization signal. As a method of synchronization, the power may be simultaneously applied to both microcomputers 30 and 40, or a synchronization signal may be transmitted from one of the microcomputers to the other as shown in FIG. In the illustrated example, after the activation of the current control unit and the abnormality determination unit, a synchronization signal is transmitted from the current control unit to the abnormality determination unit. Alternatively, a synchronization signal may be transmitted from outside of both microcomputers. In addition, even when the operating conditions such as the number of revolutions are changed during the driving of the motor 80 in addition to the start-up, the synchronization signal may be transmitted to keep the synchronization state properly.

  Compared with the other embodiments in which the carrier timing signal is notified, in the tenth embodiment, the shift of the sample timing due to the communication delay can be eliminated.

(Eleventh embodiment)
In the eleventh embodiment, the abnormality determination units 40 and 45 determine abnormality of the current sensors 71, 72, and 73 based on current sensor values at timings determined based on ON / OFF timings of the switching elements 61-66. . For example, the abnormality determination units 40 and 45 recognize the switching timing of a specific phase, and recognize the intermediate timing of the ON / OFF timing as the timing at which the current should be sampled, as shown in FIG. For example, assuming that a specific phase is a U-phase, currents Iu, Iv, Iw of each phase are sampled simultaneously at a timing determined based on the switching timing of the U-phase, and abnormality is determined based on a sum of the three phases.

  Here, the upper arm element is ON when the duty ratio obtained by converting the voltage command value exceeds the carrier, and is OFF when the duty ratio is lower than the carrier. The intermediate timing of the ON timing of the upper arm element corresponds to the timing of the bottom (valley) of the carrier, and the intermediate timing of the OFF timing corresponds to the timing of the peak (peak) of the carrier. The opposite is true for the lower arm element.

  As a method for the abnormality determination units 40 and 45 to recognize the switch timing, a switching signal instructed by the current control units 30 and 35 may be fetched, or the switch timing may be estimated from the peak and bottom of the current. Also in the method, the current can be sampled at high speed, the measured value can be stored in a buffer, and the intermediate value can be determined as the sample value after the switch timing is determined.

  In the eleventh embodiment, since the timing of the current sensor value used for the abnormality determination is determined based on the ON / OFF timing of the switching element of a specific phase, the abnormality determination units 40 and 45 are affected by the current ripple. The abnormality of the current sensor can be appropriately determined without any problem. Further, in the eleventh embodiment, there is no need to provide a timing instruction unit, and the configuration of the inverter control device can be simplified. It should be noted that “no need for the timing instructing unit” does not mean that the carrier generator itself in the PWM control becomes unnecessary, for example. Even if the carrier generator itself is present, there is no need to provide a configuration for notifying the abnormality determination units 40, 45, etc., of the carrier wave timing, which means that there is no need to function at least as a timing instruction unit.

(Twelfth embodiment)
The twelfth embodiment shown in FIG. 15 differs from the first embodiment shown in FIG. 3 in the arrangement of current sensors. In the configuration of FIG. 3, the current sensors 71, 72, and 73 are provided in three phases, whereas in the configuration of FIG. 15, no current sensor is provided in one phase (for example, U phase), and the remaining two phases (for example, Two current sensors 72, 75 and 73, 76 are redundantly provided for the (V-phase and W-phase). Note that three or more current sensors may be redundantly provided in the remaining two phases.

  In this configuration, the abnormality determination of the current sensor is performed based on the deviation between the redundant V-phase current sensors 72 and 75 and the deviation between the redundant W-phase current sensors 73 and 76. Further, similarly to the first embodiment, in addition to the configuration in which the carrier generator 50 transmits an interrupt notification signal from the current control unit 30 provided inside to the abnormality determination unit 40, the configuration of the timing instruction according to each of the above embodiments is also described. Can be applied.

(Reference form)
FIG. 16 shows another configuration in which the abnormality determination units 40 and 45 use the current value for avoiding the influence of the ripple in the abnormality determination, as a reference form. In this embodiment, the current sensor values from which the ripple components have been removed by the filtering process are acquired by the abnormality determination units 40 and 45. In the first place, the occurrence of the ripple is caused by the ripple component being put on the signal line input to the AD port of the microcomputer. The frequency component of the ripple is generally higher than the frequency component of the effective current. Therefore, it is effective to provide a filter between the current sensor and the abnormality determination units 40 and 45 to remove a ripple component.

  As a method of realizing this, there are a method of configuring an analog filter up to an AD port, and a method of configuring a digital filter after AD acquisition to remove ripples. By removing the ripples by the filter processing, an effective current value can be obtained regardless of the sampling timing. Therefore, the timing instructing unit is not required, and the configuration is simplified.

(Other embodiments)
(A) In the above embodiment (excluding the eleventh embodiment), the “timing instructing unit” is configured by the carrier generator 50, assuming the configuration of PWM control generally used in motor control. However, for example, in the case of a motor control configuration that does not use a PWM carrier such as pulse pattern control, a “timing instructing unit” for instructing a timing different from the carrier timing may be provided.

  (B) The “multi-phase rotating electric machine” in the present invention is not limited to a three-phase AC motor, but may be a four-phase or more multi-phase AC motor. Even in the case of four or more N-phases, when all the current sensors are normal, an abnormality determination process can be performed using the fact that the N-phase sum becomes 0 based on Kirchhoff's law. Further, according to the twelfth embodiment, two or more current sensors may be redundantly provided for the (N-1) phase.

  (C) The inverter control device according to the present invention is not limited to an inverter that supplies power to a motor of a vehicle, and may be applied to an inverter that supplies power to a rotating electric machine for any purpose.

  As described above, the present invention is not limited to the above embodiment, and can be implemented in various forms without departing from the spirit of the present invention.

10 ... battery (DC power supply),
20: inverter control device, 25: microcomputer (inverter control device),
30 ... current control microcomputer (current control unit),
35 ... current control core (current control unit)
40... Abnormality determination microcomputer (abnormality determination unit)
45... Abnormality determination core (abnormality determination unit)
50 ... Carrier generator (timing instructing unit)
60 ... inverter,
71, 72, 73 ... current sensor, 80 ... motor (polyphase rotating electric machine).

Claims (8)

An inverter control device provided between a DC power supply (10) and a multi-phase rotating electric machine (80) for controlling an operation of an inverter (60) for mutually converting power,
A current control unit that controls the operation of the inverter based on current sensor values obtained from a plurality of current sensors (71, 72, 73) that detect a phase current flowing between the inverter and the multi-phase rotating electric machine; 30, 35),
An abnormality determination unit (40, 45) for determining an abnormality of one or more of the plurality of current sensors based on the current sensor value;
The current control unit or the abnormality determination unit, or provided outside the current control unit and the abnormality determination unit, and indicates a timing at which the current sensor value used for abnormality determination by the abnormality determination unit is detected. A timing instructing unit (50) for performing
With
The inverter control device, wherein the abnormality determination unit determines an abnormality of the current sensor based on the current sensor value at a timing instructed by the timing instruction unit.   The inverter control device according to claim 1, wherein the timing instruction unit is provided outside the current control unit and the abnormality determination unit.   The inverter control device according to claim 1, wherein the timing instruction unit is provided inside the current control unit.   The inverter control device according to claim 1, wherein the timing instruction unit is provided inside the abnormality determination unit.   The timing notification signal instructed by the timing instruction unit is communicated from the timing instruction unit to the current control unit and the abnormality determination unit, or between the current control unit and the abnormality determination unit. The inverter control device according to any one of claims 1 to 4.   The current control unit and the abnormality determination unit are adjusted so as to execute respective processes in synchronization, and the abnormality determination unit notifies a timing at which the current sensor value used for abnormality determination is detected in advance. The inverter control device according to any one of claims 1 to 4, wherein: The timing instruction unit is configured by a carrier generator,
The inverter control device according to any one of claims 1 to 6, wherein a timing of a peak or a bottom of a carrier wave is designated as a timing at which the current sensor value used for abnormality determination is detected. An inverter control device provided between a DC power supply (10) and a multi-phase rotating electric machine (80) for controlling an operation of an inverter (60) for mutually converting power,
A current control unit that controls the operation of the inverter based on current sensor values obtained from a plurality of current sensors (71, 72, 73) that detect a phase current flowing between the inverter and the multi-phase rotating electric machine; 30, 35),
An abnormality determination unit (40, 45) for determining an abnormality of one or more of the plurality of current sensors based on the current sensor value;
With
The inverter control device, wherein the abnormality determination unit determines abnormality of the current sensor based on the current sensor value at a timing determined based on ON / OFF timing of a switching element of a specific phase of the inverter.

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