JP2010063239A - Controller and control system of multiple phase rotating machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration of detection precision of current when a V0 vector period becomes short at the time of detecting current flowing in an inverter IV by using shunt resistors SRu, SRv and SRw. <P>SOLUTION: A microcomputer 30 takes in a voltage drop amount in shunt resistors SRu, SRv and SRw as actual currents iu, iv and iw through a current detecting circuit DC. The inverter IV is operated in accordance with command voltage with respect to an electric motor 10 based on it. Command voltages vur, vvr and vwr are offset to a positive electrode potential side being an electrode potential of a battery 12 on a side to which the shunt resistors SRu, SRv and SRw are not connected. Thus, the V0 vector period is expanded and detection precision of current is improved. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention provides a switching element that selectively connects each of a positive electrode and a negative electrode of a DC power supply to each terminal of a multi-phase rotating machine, at least one electrode of the DC power supply, and each switching that connects the electrode to each terminal. A control device for a multi-phase rotating machine that controls a control amount of the multi-phase rotating machine by operating a power conversion circuit including shunt resistors connected to each of the elements according to a command voltage, and multi-phase rotation The present invention relates to a machine control system.

  As this type of control device, for example, a device that includes a shunt resistor for each phase of the lower arm of the inverter and detects a current flowing through each phase of the motor based on a voltage drop amount in the shunt resistor of each phase has been proposed. ing. However, in such a case, if the V0 vector period in which all the switching elements of the lower arm are turned on is excessively short, the current flowing through the motor cannot be detected.

Therefore, conventionally, as can be seen, for example, in Patent Document 1 below, when the V0 vector period becomes excessively short, the on-time of the switching element of the lower arm flows through one phase that is excessively short based on Kirchhoff's law. It has also been proposed to estimate the current based on the detected values of the remaining two-phase currents.
JP 2005-143153 A

  By the way, when Kirchhoff's law is used as described above, an error in the detected values of the remaining two-phase currents is accumulated in the estimated value of the current flowing through one phase where the on-time of the switching element of the lower arm is excessively short. As a result, the error may increase as compared with the case of detecting a three-phase current. In this case, the controllability of the electric motor may be reduced.

  For example, when one phase of the electric motor is grounded, the current flowing through the remaining two phases is substantially zero. For this reason, the current of the ground fault phase cannot be estimated with high accuracy by the current flowing through the remaining two phases.

  The present invention has been made to solve the above-mentioned problems, and its purpose is to detect the current flowing through the power conversion circuit using a shunt resistor, and to detect the current flowing through the power conversion circuit with higher accuracy. It is an object of the present invention to provide a control device and a control system for a possible multiphase rotating machine.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

  According to the first aspect of the present invention, there is provided a switching element that selectively connects each of a positive electrode and a negative electrode of a DC power supply to each terminal of a multiphase rotating machine, at least one electrode of the DC power supply, and the electrode connected to each terminal. In a control device for a multiphase rotating machine that controls a control amount of the multiphase rotating machine by operating a power conversion circuit including a shunt resistor connected to each switching element to be connected according to a command voltage An offset means for offsetting the command voltage is provided on a potential side that does not correspond to a shunt resistor used for detecting a current of each phase of the multiphase rotating machine among a pair of electrode potentials of the DC power supply. And

  In the said invention, the period when the switching element connected to the shunt resistance used for an electric current detection will be in an all-phase ON state is expanded. For this reason, it can be avoided that the current detection period becomes excessively short, and as a result, current detection can be performed with higher accuracy.

  In addition, when the signal used for the process of generating the operation signal of the power conversion circuit is a signal obtained by performing the two-phase modulation process on the sinusoidal command voltage, the sinusoidal command voltage may be an offset target. desirable.

  According to a second aspect of the present invention, in the first aspect of the invention, the offset means sets the offset amount of the command voltage to a value that does not depend on the electrical angle of the multiphase rotating machine.

  According to a third aspect of the present invention, in the first or second aspect of the invention, an abnormality in the current flowing through at least one of the power conversion circuit and the multiphase rotating machine based on the current detected in the current detection possible period. It is further characterized by further comprising a judging means for judging the presence or absence.

  In the above invention, since the current can be detected with high accuracy by the offset means, the abnormality determination by the determination means can be performed with high accuracy.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the shunt resistor is connected to a negative electrode side of the DC power supply, and is a terminal of the multiphase rotating machine. The apparatus further comprises means for determining the presence or absence of overcurrent due to a ground fault, and the means is constituted by the determination means.

  When one specific phase of the multiphase rotating machine has a ground fault, a large current may flow in a portion corresponding to this specific phase in the power conversion circuit. In this case, even when all the switching elements connected to the negative electrode side of the DC power supply are turned on, the current continues to flow due to the inductance component of the power conversion circuit, etc. Can be detected. For this reason, it is possible to determine the presence or absence of a ground fault based on the current detected by the shunt resistor without depending on other means by extending the detectable period by the offset means.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the offset means always offsets the command voltage regardless of a rotation state of the multiphase rotating machine. Features.

  In the above-described invention, the offset process can be performed simply by performing the offset process constantly as compared with the case where the process of offsetting the command voltage is performed only under a specific condition.

  According to a sixth aspect of the present invention, in the first aspect of the present invention, the temporary abnormality for detecting a temporary abnormality of the current flowing through the multiphase rotating machine based on a voltage drop amount in the shunt resistor. The apparatus further comprises a detecting means, wherein the offset means offsets the command voltage based on the provisional abnormality detected by the abnormality detecting means.

  Immediately after the switching state is switched and the current detection possible period is reached, there is a possibility that noise is mixed in the current detection due to the effect of switching the switching state. For this reason, when the current is detectable based on the amount of voltage drop in the shunt resistor when the current detectable period is short, the current detection accuracy may be lowered, and thus the reliability of abnormality detection may be lowered. In this regard, in the above invention, a temporary abnormality is first detected based on the voltage drop amount. Then, when a temporary abnormality is detected, the current detection possible period is extended by offsetting the command voltage by the offset means. This makes it possible to detect the presence or absence of abnormality with high accuracy.

  The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the maximum value of the command voltage due to the offset is equal to or less than the positive electrode potential of the DC power supply and the minimum value of the command voltage. Is set to be equal to or higher than the negative electrode potential of the DC power supply.

  The output voltage of the power conversion circuit is limited by the voltage of the DC power supply. For this reason, when the maximum value and the minimum value of the command voltage deviate from between the positive electrode potential and the negative electrode potential of the DC power supply, the output voltage of the power conversion circuit deviates from the command voltage. Decreases. In the above invention, in view of this point, an offset process is performed so that the maximum value and the minimum value fall within the positive electrode potential and the negative electrode potential of the DC power supply, thereby avoiding a decrease in controllability of the multiphase rotating machine. Processing can be performed.

  The invention according to claim 8 is a control system for a multi-phase rotating machine comprising the control device for a multi-phase rotating machine according to any one of claims 1 to 7 and the power conversion circuit. is there.

(First embodiment)
Hereinafter, a first embodiment in which a control device for a multiphase rotating machine according to the present invention is applied to an in-vehicle electric steering device will be described with reference to the drawings.

  FIG. 1 shows an overall configuration of a control system according to the present embodiment.

  The illustrated electric motor 10 is a three-phase surface magnet synchronous rotating machine. The electric motor 10 is mounted on an in-vehicle electric steering device that assists a steering operation of the vehicle. Specifically, in the present embodiment, a gear ratio variable device (VGS) that changes the rotation amount ratio between the input shaft connected to the steering wheel and the output shaft connected to the electric motor 10 is employed as the steering device. .

  The electric motor 10 is connected to the battery 12 via the inverter IV. Inverter IV includes a switching element for selectively connecting each phase of electric motor 10 to each of a positive terminal and a negative terminal of battery 12. That is, a serial connection body of switching elements Sup and Sun, a serial connection body of switching elements Svp and Svn, and a serial connection body of switching elements Swp and Swn are connected in parallel. A connection point between the switching elements to be configured is connected to each of the U, V, and W phases of the electric motor 10. Note that free wheel diodes Dup, Dun, Dvp, Dvn, Dwp, Dwn are connected in parallel to the switching elements Sup, Sun, Svp, Svn, Swp, Swn, respectively.

  One specific phase (here, V phase is illustrated) of the electric motor 10 is pulled up. Specifically, the connection point and the positive terminal of the battery 12 are connected via a resistor 29 in order to pull up the connection point between the specific one phase and the inverter IV. Further, the U phase of the inverter IV is grounded via a series connection body of the resistors 18 and 20, the V phase is grounded via a series connection body of the resistors 22 and 24, and the W phase is composed of the resistance bodies 26 and 28. Grounded through a series connection. Specifically, each of the pair of switching elements (between the switching elements Sup and Sun, between the switching elements Svp and Svn, between the switching elements Swp and Swn) connected to each phase of the electric motor 10 includes the resistors 18 to 28. Is grounded.

  On the other hand, between the switching elements Sun, Svn, Swn of the lower arm of the inverter IV and the ground, resistors (shunt resistors SRu) as linear elements for detecting currents flowing through the respective phases of the motor 10 are respectively provided. , SRv, SRw) are connected. The amount of voltage drop in each of the shunt resistors SRu, SRv, SRw is taken into the current detection circuit DC. The current detection circuit DC is configured to include a differential amplifier circuit and an inverting amplifier circuit, as exemplified by the circuit configuration for the U phase in the drawing. The output of the current detection circuit DC is taken into the microcomputer (microcomputer 30) as currents iu, iv, iw flowing through the phases of the electric motor 10.

  The microcomputer 30 operates the inverter IV via the driver 32 based on the currents iu, iv, iw flowing through the motor 10 and the voltage of the battery 12 detected as the divided voltage values of the resistors 14, 16. 10 is controlled. That is, the inverter IV is operated by outputting the operation signals gup, ung, gvp, gvn, gwp, gwn to the switching elements Sup, Sun, Svp, Svn, Swp, Swn of the inverter IV via the driver 32, respectively. . Further, the microcomputer 30 determines each phase of the motor 10 and the inverter IV based on the potentials of the connection points of the resistors 18 and 22, the connection points of the resistors 22 and 24, and the connection points of the resistors 26 and 28. The disconnection abnormality of an electric path provided with the part connected to each of these phases and the wiring which connects these is detected. Since this is well known, its description is omitted.

  FIG. 2 shows a block diagram of processing relating to generation of the operation signal of the inverter IV.

  The currents iu, iv, iw flowing through the phases of the electric motor 10 are converted into the actual current id on the d-axis and the actual current iq on the q-axis, which are the actual currents of the rotating two-phase coordinate system, in the dq converter 40. The On the other hand, the command current setting unit 42 sets the command current idr on the d axis and the command current iqr on the q axis, which are command values of the current in the rotating two-phase coordinate system, based on the required torque Tr. Here, for example, the command currents idr and iqr may be set so as to realize the maximum torque control. The deviation calculating unit 44 calculates a difference between the command current idr and the actual current id, and the deviation calculating unit 46 calculates a difference between the command current iqr and the actual current iq. The command voltage setting unit 48 sets the command voltage vdr on the d axis and commands the actual current iq on the q axis based on the operation amount for feedback control of the actual current id on the d axis to the command current idr. A command voltage vqr on the q axis is set based on an operation amount for feedback control to the current iqr.

  The three-phase conversion unit 50 converts the command voltages vdr and vqr in the rotating two-phase coordinate system into three-phase command voltages vur, vvr and vwr. The harmonic superimposing unit 52 superimposes the third harmonic on the sinusoidal command voltage output from the three-phase conversion unit 50. The duty generation unit 54 generates a duty signal by normalizing the output of the harmonic superposition unit 52 with the voltage of the battery 12. The PWM signal generation unit 62 uses a signal corresponding to the output of the duty generation unit 62 as a signal wave, and generates PWM signals gu, gv, and gw based on the magnitude of the signal wave. The operation signal generation unit 64 generates operation signals gup, gun, gvp, gvn, gwp, and gwn that are complementary to each other in the upper and lower arms based on the PWM signals gu, gv, and gw in consideration of dead time and the like.

  On the other hand, the abnormality detection unit 66 detects an abnormality in which an overcurrent flows in the motor 10 or the inverter IV based on the currents iu, iv, and iw flowing through the phases of the motor 10 during the control of the motor 10. Is.

  FIG. 3 shows the procedure of the overcurrent detection process. This process is repeatedly executed by the microcomputer 30 at a predetermined cycle, for example.

  In this series of processing, first, in step S10, it is determined whether or not it is a predetermined timing in the V0 vector period in which the lower arm is in the all-phase ON state. This process is for determining whether it is the detection timing of the actual currents iu, iv, iw based on the voltage drop amounts in the shunt resistors SRu, SRv, SRw. Here, in the present embodiment, the predetermined timing is a timing slightly delayed from the center of the V0 vector period. If an affirmative determination is made in step S10, actual currents iu, iv, and iw are detected in step S12. In subsequent step S14, the absolute value of the actual current iu is greater than or equal to the threshold value α, the absolute value of the actual current iv is greater than or equal to the threshold value α, and the absolute value of the actual current iw is greater than or equal to the threshold value α. It is determined whether or not the logical sum condition is satisfied. This process is for determining whether or not an abnormality in which an overcurrent flows in at least one phase of the electric motor 10 or the inverter IV has occurred. Here, the threshold value α is set based on an upper limit value that can maintain the reliability of the inverter IV and the like.

  If it is determined that the logical sum condition is satisfied, it is determined in step S16 that there is an overcurrent abnormality. If a negative determination is made in steps S10 and S14, or if the process of step S16 is completed, this series of processes is temporarily terminated.

  By the way, the detection accuracy of the overcurrent abnormality depends on the detection accuracy of the currents iu, iv, and iw. Here, immediately after the operation state of the inverter IV is switched to the V0 vector, the influence of noise accompanying the switching may be superimposed on the detected values of the currents iu, iv, and iw. For this reason, it is desirable that the detection timing of the currents iu, iv, iw be after a predetermined time has elapsed after switching to the V0 vector period. However, when the V0 vector period itself is short, the predetermined time may not be sufficiently secured.

  Therefore, in this embodiment, as shown in FIG. 2, the correction units 56, 58, and 60 offset the Duty signals Du, Dv, and Dw by the offset amount Δ to the high potential side. Specifically, as shown in FIG. 4, the duty signals Du, Dv, and Dw are offset to the high potential side by “5%”. In FIG. 4, the lower limits of the duty signals Du, Dv, and Dw are “10%”, and the upper limit is “95%”. Here, the upper limit is set to “95%” in order to enable dead time generation.

  According to such setting, as shown in FIG. 5, the detection timing of the currents iu, iv, iw can be sufficiently separated from the timing at which the operation state of the inverter IV is switched to the V0 vector. Here, FIG. 5 (a1) shows the transition of the operating state of the switching elements Sun, Svn, Swn of the lower arm, FIG. 5 (b1) shows the transition of the current detection timing, and FIG. 5 (c1) The transition of the voltage drop amount in the shunt resistors SRu, SRv, SRw is shown. On the other hand, FIGS. 5 (a2) to 5 (c2) show a case where the correction by the offset amount Δ is not performed. Each of FIGS. 5A2 to 5C2 corresponds to FIGS. 5A1 to 5C1.

  As shown in the figure, by expanding the V0 vector period, the currents iu, iv, iw can be detected at the timing when the noise accompanying the switching to the V0 vector is sufficiently attenuated. For this reason, in this embodiment, it is possible to detect an abnormality in which a specific phase of the inverter IV, the electric motor 10, and their connection lines is grounded using the voltage drop amount in the shunt resistors SRu, SRV, SRw. Become.

  That is, when a ground fault occurs, almost no current flows in the remaining two phases. Therefore, based on the voltage drop in the shunt resistance for these two phases, the current flowing through a specific phase is calculated using Kirchhoff's law. It cannot be estimated. For this reason, it is desired to detect the current using the V0 vector period. However, when the V0 vector period becomes excessively short, it cannot be detected with high accuracy due to the influence of the noise. For this reason, conventionally, a shunt resistor is provided between the inverter IV and the positive electrode of the battery 12, and a ground fault abnormality is detected based on the amount of voltage drop. However, in this case, not only the shunt resistor but also the number of current detection circuits DC is increased, and further, the number of input terminals of the microcomputer 30 is increased in order to capture a signal from the current detection circuit DC. .

  On the other hand, according to the offset process, the currents iu, iv, and iw of all phases can be detected with high accuracy in the V0 vector period. Therefore, the shunt connected between the positive electrode of the battery 12 and the inverter IV. Resistance can be omitted.

  Incidentally, when a ground fault occurs, a large current flows through the switching element of the corresponding phase of the upper arm, but by switching the switching element to the OFF state, parasitics such as wiring in the inverter IV are caused. Due to the counter electromotive force due to the inductance, a current flows through the switching element (or diode) of the corresponding phase in the lower arm. As a result, the absolute value of the voltage drop amount of any one of the shunt resistors SRu, SRv, SRw becomes excessively large. Therefore, based on this, an overcurrent abnormality can be detected by the process shown in FIG.

  According to the embodiment described in detail above, the following effects can be obtained.

  (1) The command voltages vur, vvr, vwr (Duty signals Du, Dv, Dw) for the motor 10 are offset to the positive potential side of the battery 12, which is the side to which the shunt resistors SRu, SRv, SRw are not connected. As a result, the current detection period can be prevented from becoming excessively short, and as a result, current detection can be performed with higher accuracy.

  (2) Based on the current detected in the current detection possible period (V0 vector period), the presence or absence of abnormality of the current flowing through at least one of the inverter IV and the electric motor 10 was determined. Thereby, abnormality determination can be performed with high accuracy.

  (3) The presence / absence of overcurrent due to the grounding of the terminal of the electric motor 10 was determined using the shunt resistors SRu, SRv, SRw. Thereby, it is possible to avoid adding new hardware means for detecting the presence or absence of the ground fault abnormality.

  (4) Regardless of the rotation state of the motor 10, the command voltages vur, vvr, vwr (Duty signals Du, Dv, Dw) are always offset. As a result, the process of offsetting the command voltages vur, vvr, and vwr can be easily performed as compared with the case where the process is performed only under specific conditions.

  (5) The maximum value of the command voltage after the offset is set to be smaller than the positive potential of the battery 12 and the minimum value of the command voltage is set to be larger than the negative potential of the battery 12. Thereby, the controllability of the electric motor 10 can be maintained high.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  In the present embodiment, a temporary abnormality is detected based on the currents iu, iv, iw detected using the shunt resistors SRu, SRv, SRw in a state where the correction by the offset amount Δ is not performed. In addition, the presence or absence of an overcurrent abnormality is determined in the manner of the first embodiment.

  FIG. 6 shows a procedure of overcurrent temporary abnormality detection processing according to the present embodiment. This process is repeatedly executed by the microcomputer 30 at a predetermined cycle, for example.

  In this series of processing, first, in step S20, it is determined whether or not it is a predetermined timing within the V0 vector period, as in step S10 of FIG. In subsequent step S22, actual currents iu, iv, and iw are detected as in step S12 of FIG. In step S24, the absolute value of the actual current iu is greater than or equal to the threshold A, the absolute value of the actual current iv is greater than or equal to the threshold A, and the absolute value of the actual current iw is greater than or equal to the threshold A. It is determined whether or not the logical sum condition is satisfied. This process is for tentative determination as to whether or not an abnormality in which an overcurrent flows in at least one phase of the electric motor 10 or the inverter IV has occurred. Here, the threshold value A is set to a value larger than the threshold value α shown in step S14 of FIG. This is in view of the fact that when the V0 vector period is short, noise may be superimposed on the currents iu, iv, and iw and the current value may be recognized as being larger than the actual value.

  If the logical sum condition is satisfied, an overcurrent temporary abnormality determination is performed in step S26. In the subsequent step S28, the command voltage offset process is performed in the manner of the first embodiment, and the process of detecting the overcurrent abnormality shown in FIG. 3 is performed. The process of step S28 is completed when the process of detecting the overcurrent abnormality shown in FIG. 3 is performed for a predetermined period.

  When the process of step S28 is completed or when a negative determination is made in steps S20 and S24, this series of processes is temporarily terminated.

  According to the present embodiment described above, the following effects can be obtained in addition to the effects (1) to (3) and (5) of the first embodiment.

  (6) Temporary abnormality detection is performed based on the currents iu, iv, iw detected using the shunt resistors SRu, SRv, SRw in a state where correction by the offset amount Δ is not performed. Correction by the offset amount Δ was performed. This makes it possible to detect the presence or absence of abnormality with high accuracy.

(Other embodiments)
Each of the above embodiments may be modified as follows.

  As the abnormality detection of the current flowing through the electric motor 10 or the inverter IV, as illustrated in the first and second embodiments, it is determined whether or not the absolute value of at least one phase current is greater than or equal to the threshold value α. Not limited to things. For example, the abnormality may be detected based on whether or not the absolute value of the sum of the actual currents of all phases is equal to or greater than the threshold value β. Moreover, you may use together the abnormality detection method described in the said patent document 1. FIG.

  In the second embodiment, the difference in the conditions between the provisional abnormality determination and the overcurrent abnormality determination is only the magnitude of the threshold, but the present invention is not limited to this. For example, in addition to the provisional abnormality detection process by the process shown in FIG. 6, the provisional abnormality detection may be performed when an abnormality is detected by the abnormality detection method described in Patent Document 1.

  In each of the above embodiments, the shunt resistors SRu, SRv, SRw are provided on the lower arm, but not limited thereto, they may be provided on the upper arm. In this case, the current detectable period can be extended by offsetting the command voltage to the low potential side. Moreover, you may provide shunt resistance in both an upper arm and a lower arm. In this case, the command voltage may be offset to the potential side of the battery 12 connected to the shunt resistor that is not used for current detection.

  In each of the above embodiments, the signal wave in the PWM processing is obtained by superimposing the third harmonic on the sinusoidal command voltage. However, the present invention is not limited to this. For example, a signal wave may be obtained by two-phase modulating a sinusoidal command voltage. Even in this case, the current detectable period can be extended by offset correcting the sinusoidal command voltage prior to the two-phase modulation process.

  In each of the above embodiments, the maximum value of the command voltage due to the offset is set to be equal to or less than the positive potential of the DC power supply, and the minimum value of the command voltage is set to be equal to or higher than the negative potential of the DC power supply. For example, the maximum value of the command voltage after offset may exceed the positive potential of the DC power supply.

  The vehicle-mounted electric steering device that assists the steering operation by the user is not limited to the gear ratio variable device (VGS). For example, it may be an electric power steering in which the gear ratio is not variable.

  -As a multiphase rotating machine, it is not restricted to what is mounted in a vehicle-mounted electric steering device. For example, it may be mounted on an in-vehicle air conditioner.

1 is a system configuration diagram according to a first embodiment. FIG. The block diagram which shows a part of process of the control apparatus concerning the embodiment. The flowchart which shows the procedure of the abnormality detection process concerning the embodiment. The time chart which shows the offset process of the command voltage concerning the embodiment. The time chart which shows the effect of the embodiment. The flowchart which shows the procedure of the abnormality detection process concerning 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Electric motor, 12 ... Battery, 30 ... Microcomputer (one embodiment of a control apparatus), IV ... Inverter (one embodiment of a power converter circuit), SRu, SRv, SRw ... Shunt resistance.

Claims (8)

A switching element that selectively connects each of a positive electrode and a negative electrode of a DC power supply to each terminal of the multiphase rotating machine, and at least one electrode of the DC power supply and each switching element that connects the electrode to each terminal. In a control device for a multi-phase rotating machine that controls a control amount of the multi-phase rotating machine by operating a power conversion circuit including a shunt resistor connected to the control circuit according to a command voltage,
An offset means for offsetting the command voltage is provided on a potential side that does not correspond to a shunt resistor used for current detection of each phase of the multiphase rotating machine among a pair of electrode potentials of the DC power supply. Control device for multi-phase rotating machines.   The control device for a multi-phase rotating machine according to claim 1, wherein the offset means sets the offset amount of the command voltage to a value that does not depend on an electrical angle of the multi-phase rotating machine.   2. The apparatus according to claim 1, further comprising: a determination unit configured to determine whether there is an abnormality in a current flowing through at least one of the power conversion circuit and the multiphase rotating machine based on a current detected during the current detection possible period. Or the control apparatus of the multiphase rotary machine of 2. The shunt resistor is connected to the negative electrode side of the DC power source,
4. The method according to claim 1, further comprising means for determining whether or not there is an overcurrent due to a ground fault in a terminal of the multiphase rotating machine, and the means is constituted by the determination means. The control apparatus of the multiphase rotary machine of Claim 1.   The control device for a multi-phase rotating machine according to any one of claims 1 to 4, wherein the offset means always offsets the command voltage regardless of a rotation state of the multi-phase rotating machine. Provisional abnormality detecting means for detecting a provisional abnormality of the current flowing through the multiphase rotating machine based on the amount of voltage drop in the shunt resistor;
The multi-phase rotating machine according to any one of claims 1 to 5, wherein the offset means offsets the command voltage based on detection of a temporary abnormality by the abnormality detection means. Control device.   2. The maximum value of the command voltage due to the offset is set to be equal to or lower than the positive potential of the DC power supply, and the minimum value of the command voltage is set to be equal to or higher than the negative potential of the DC power supply. The control apparatus of the multiphase rotating machine of any one of -6. A control device for a multi-phase rotating machine according to any one of claims 1 to 7,
A control system for a multi-phase rotating machine comprising the power conversion circuit.

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