JP5664928B2 - Rotating electrical machine control device - Google Patents

Description

  The present invention is directed to a rotating electrical machine driving device that includes an inverter that converts power between DC power and three-phase AC power and drives an AC rotating electrical machine, and detects an actual current flowing through the rotating electrical machine to detect current. The present invention relates to a rotating electrical machine control apparatus that performs feedback control.

  In many cases, a rotary electric machine is driven and controlled by current feedback control based on a deviation between a current flowing through the rotary electric machine and a target current. For this reason, it is necessary to measure the electric current which flows into a rotary electric machine. For example, in the case of a three-phase AC type rotating electrical machine, the current flowing through the stator coil of each phase is measured by a current sensor provided corresponding to each phase. Japanese Patent Laid-Open No. 2002-233160 (Patent Document 1) discloses an inverter control device that performs power conversion between direct current power and alternating current power to control an inverter that drives the rotating electrical machine and performs current feedback control of the rotating electrical machine. It is disclosed. This inverter control device identifies the phase in which the current sensor provided corresponding to each phase has become abnormal, and uses the measurement result of the other phase instead of the measurement result of the current sensor. An estimated value is obtained, and current feedback control of the rotating electrical machine is continued even if an abnormality occurs in one of the current sensors (6th, 18-20 paragraphs, summary, etc.).

  By the way, as a control method for the rotating electrical machine, there is a control method suitable for the target torque and the rotational speed of the rotating electrical machine. For example, pulse width modulation control for outputting a pulse by comparing the amplitude of a voltage command based on a sine wave and a carrier, or outputting one rectangular wave corresponding to one cycle of an electrical angle in synchronization with the rotation of a rotating electrical machine There is a rectangular wave control. Here, for example, when the control method is switched between the pulse width modulation control and the rectangular wave control, the voltage applied to the inverter varies, and a transient current may occur along with the variation. . Such a transient current may be outside the guaranteed range that guarantees the current measurement accuracy of the current sensor. By measuring the transient current, it is determined that the current sensor is abnormal. There is a case. Alternatively, the operation of the rotating electrical machine may be limited by detecting the occurrence of excessive current. However, the current sensor is not always abnormal, and transient currents are also temporarily generated. Therefore, it is not preferable to limit the operation of the rotating electrical machine excessively, and it is not preferable to restrict the use of the current sensor determined to be abnormal more than necessary.

JP 2002-233160 A

  In view of the above background, efficient operation without excessively limiting the operation of the rotating electrical machine or excessively limiting the use of the current sensor due to the transient current that occurs when the control method for controlling the inverter is switched. It is desirable to detect the current of the rotating electrical machine and perform current feedback control on the rotating electrical machine.

In view of the above problems, the characteristic configuration of the rotating electrical machine control device according to the present invention is:
A rotating electrical machine drive device that includes an inverter that converts power between DC power and 3-phase AC power to drive an AC rotating electrical machine, and that performs current feedback control by detecting an actual current flowing through the rotating electrical machine. An electric control device,
A current detection unit configured to detect the actual current of each phase based on a measurement result of a current sensor provided corresponding to each of the three phases and measuring a current flowing in each phase;
The phase corresponding to the current sensor equal to or higher than the overcurrent determination threshold value set to a value within a predetermined measurement accuracy guarantee range of the current sensor is an overcurrent phase in an overcurrent state. An overcurrent determination unit for determining
Based on the determination result of the overcurrent determination unit, an output limit determination unit that determines whether or not the output of the rotating electrical machine needs to be limited is necessary.
When one execution control method is determined from at least two different control methods according to the target torque and the rotation speed of the rotating electrical machine and the inverter is switched, and when it is determined that the restriction state is required, An inverter control unit for stopping the operation state of the inverter;
A determination grace period setting unit for setting a determination grace period for a predetermined period from the control method switching time when the inverter control unit switches the execution control method,
When the overcurrent determination unit determines that two or more of the three phases are the overcurrent phases, the output restriction determination unit is in the required restriction state regardless of the determination grace period. And
When it is determined by the overcurrent determination unit that any one of the three phases is the overcurrent phase, the output restriction determination unit holds the determination until the determination grace period elapses, The current detection unit calculates a current value of the overcurrent phase based on a measurement result of the current sensor corresponding to two phases different from the overcurrent phase at least during the determination grace period, and calculates all three phases. The actual current is detected at the point.

  According to this characteristic configuration, the determination grace period is set from the control method switching time when the inverter control unit switches the execution control method. Therefore, even if a transient current occurs due to the switching of the control method and the measurement result by the current sensor in one of the three phases exceeds the overcurrent determination threshold value, a state where the output of the rotating electrical machine is immediately limited is required. It is not judged. That is, the operation of the rotating electrical machine is not unnecessarily restricted. In addition, the current sensor corresponding to the phase whose measurement result is equal to or greater than the overcurrent threshold is not determined as a failure during the determination grace period. That is, use of the current sensor is not unnecessarily restricted. On the other hand, when it is determined that two or more of the three phases are overcurrent phases, the output limit determination unit determines that the required state is limited even within the determination grace period, and Output is limited. Therefore, it is possible to appropriately cope with the occurrence of an overcurrent that needs to limit the operation of the rotating electrical machine or the failure of the current sensor. As described above, according to this characteristic configuration, the operation of the rotating electrical machine is excessively restricted by the transient current generated when the control method for controlling the inverter is switched, or the use of the current sensor is restricted more than necessary. Therefore, it is possible to efficiently detect the current of the rotating electrical machine and perform current feedback control on the rotating electrical machine.

  In some cases, the measurement result of the plurality of phases simultaneously exceeds the overcurrent threshold due to the generation of the transient current, and in such a case, the inverter is controlled to be stopped. Since the generation of the transient current is temporary, there may be a case where the event that has been determined to be in the restricted state is required after the inverter is stopped. In such a case, it is preferable to quickly restart the switching control of the inverter. As one aspect, the inverter control unit of the rotating electrical machine control device according to the present invention resumes the inverter switching control after a predetermined standby period has elapsed since the operation state of the inverter is set to the stop state. It is preferable.

  By the way, the determination grace period does not need to be a fixed value. For example, when the inverter control unit can determine the execution control method from three or more different methods, there are at least two combinations of control methods before and after switching. Further, the magnitude and duration of the excessive current generated when the execution control method is switched vary depending on the combination of control methods before and after switching, and have characteristics that can be predicted to some extent by the combination. Therefore, it is preferable that the determination grace period is set to a different value depending on the combination of control methods before and after switching. As one aspect, the inverter control unit of the rotating electrical machine control device according to the present invention can determine the execution control method from at least three different methods, and the determination grace period is a combination of the control methods before and after switching. It is preferable to set a different value depending on.

  Further, as one aspect, the rotating electrical machine control device according to the present invention requires that the inverter control unit be constrained by the synchronous control method in which switching is performed in synchronization with the rotation of the rotating electrical machine and the rotation of the rotating electrical machine. The execution control method can be switched between an asynchronous control method that performs switching according to a set control cycle, and each of the synchronous control method and the asynchronous control method has a different switching pattern. The execution control method can be switched between at least two control methods, and the determination grace period is longer than the period when the execution control method is switched between the synchronous control method and the asynchronous control method. The period for switching the execution control method between the control method and the asynchronous control method is set longer. It is preferable to have. According to the inventors' experiments and analysis, the magnitude and duration of the transient current that occurs when the execution control method is switched are more synchronized than when the execution control method is switched between the synchronous control method and the asynchronous control method. It was found that switching the execution control method between the method and the asynchronous control method is larger. Therefore, by setting the determination grace period as in the above configuration, it is possible to more appropriately detect the current of the rotating electrical machine and perform current feedback control on the rotating electrical machine.

  Even if it is determined that an overcurrent phase exists outside the determination grace period, such as after the determination grace period, if the other two phases are still alive, the measurement results of the two phases are used to determine the three phases. It is possible to detect the actual current. That is, it is possible to detect the current of the rotating electrical machine and perform current feedback control on the rotating electrical machine without excessively limiting the operation of the rotating electrical machine. As one aspect, the output restriction determination unit of the rotating electrical machine control device according to the present invention determines that one of the three phases is the overcurrent phase by the overcurrent determination unit after the determination delay period has elapsed. If it is determined that the current sensor corresponding to the overcurrent phase is a fault current sensor in which the current sensor has failed, the current detection unit detects two current sensors different from the fault current sensor. It is preferable to calculate the current value of the overcurrent phase based on the measurement result to detect the three-phase actual current.

  In the situation where the current of the overcurrent phase is calculated based on the measurement result of the two-phase current sensor, if it is determined that the other phase is the overcurrent phase, the actual current of the three phases may be detected. become unable. In such a case, since current feedback control cannot be performed, it is preferable to quickly limit the operation of the rotating electrical machine. As one aspect, the output restriction determination unit of the rotating electrical machine control device according to the present invention may further include the restriction state when the at least one phase is determined to be the overcurrent phase by the overcurrent determination unit. It is preferable to determine that

Block diagram schematically showing a configuration example of a rotating electrical machine control device The figure which shows the data structure of flag and counter The flowchart which shows an example of the process sequence of an inverter control part First partial diagram of a flowchart showing an example of a processing procedure of the rotating electrical machine control device Timing chart showing an example of the procedure for setting the judgment grace period The 2nd partial figure of the flowchart which shows an example of the process sequence of a rotary electric machine control apparatus The 3rd partial figure of the flowchart which shows an example of the process sequence of a rotary electric machine control apparatus

  Embodiments of the present invention will be described below with reference to the drawings, taking as an example a rotating electrical machine control device that controls a rotating electrical machine drive device that drives a three-phase AC type rotating electrical machine having an embedded magnet structure as the rotating electrical machine. . This rotating electrical machine operates as both a motor (motor) and a generator (generator) as necessary. Hereinafter, the rotating electric machine will be described as a motor.

  As shown in FIG. 1, the motor MG (rotary electric machine) is connected to the battery 3 via a drive device 1 (rotary electric machine drive device) that drives the motor MG. The control device 10 (rotary electric machine control device) drives and controls the motor MG via the drive device 1. The battery 3 includes, for example, various secondary batteries such as nickel hydride secondary batteries and lithium ion secondary batteries, capacitors, or combinations thereof. The battery 3 is configured to be able to supply electric power to the motor MG via the driving device 1 and to be able to store electric power obtained by the motor MG generating power. The drive device 1 includes an inverter 5 that converts power between DC power and three-phase AC power. The drive device 1 may include a voltage conversion device (converter) for converting a DC voltage between a system voltage (DC voltage) that is a voltage on the DC side of the inverter 5 and the voltage of the battery 3. The battery 3 and the converter correspond to the DC power source 2.

  Inverter 5 performs power conversion between DC power having a system voltage and three-phase AC power of motor MG. The inverter 5 is configured by a bridge circuit including a plurality of sets of switching elements. In the present embodiment, an IGBT (insulated gate bipolar transistor) is used as the switching element. The inverter 5 includes a pair of switching elements for each leg corresponding to each phase (three phases of U phase, V phase, and W phase) of the motor MG. Each leg is composed of an upper arm element and a lower arm element connected in series. Each switching element is provided with a free wheel diode connected in parallel (reversely connected in parallel) so as to be in a direction opposite to the flow direction when the switching element is in the ON state.

  Each of the switching elements operates in accordance with a switching control signal SI (here, a gate drive signal for driving the gate of the IGBT) output from the control device 10. A drive signal input to the gate of an IGBT or MOSFET that switches a high voltage requires a voltage higher than the power supply voltage of an electronic circuit (such as a microcomputer as described later) constituting the control device 10. For this reason, the switching control signal SI generated by the control device 10 is voltage-converted (for example, boosted) via a driver circuit (not shown) and then input to the inverter 5.

  Inverter 5 converts DC power of system voltage Vdc into AC power and supplies it to motor MG, and causes motor MG to output a torque corresponding to target torque TM provided from another control device (not shown). At this time, each switching element performs a switching operation based on a switching control signal SI generated according to a control method such as pulse width modulation control or rectangular wave control described later. Further, when the motor MG functions as a generator, the inverter 5 converts AC power obtained by power generation into DC power and regenerates it to the battery 3.

  The current (actual currents Iu, Iv, Iw (detected current)) flowing between the inverter 5 and the coils of the respective phases of the motor MG is the current measured by the current sensor 7 (measured current Mi (Mu, Mv, Mw)). ) Is detected by the current detection unit 11 of the control device 10. In the present embodiment, a configuration in which all three phases are measured by the non-contact type current sensor 7 is illustrated. Further, the magnetic pole position θ (rotor rotation angle) and the rotation speed ω at each time point of the rotor of the motor MG are detected by the rotation sensor 9, and the detection result is acquired by the control device 10. The rotation sensor 9 is composed of, for example, a resolver.

  In this embodiment, each functional unit of the control device 10 that controls the drive device 1 is controlled by the cooperation of hardware such as a microcomputer, a DSP (digital signal processor) and a memory, and software such as a program and parameters. Realized. The microcomputer that is the core of the control device 10 includes a CPU core, a program memory, a parameter memory, a work memory, an A / D converter, a timer (counter), and the like. Of course, it is not necessary for all to be configured in one integrated circuit. For example, a part such as a program memory may be an element different from the CPU core. The CPU core is configured to include an ALU (arithmetic logic unit) serving as an execution subject of various operations, an instruction register, an instruction decoder, a flag register, a general-purpose register, an interrupt controller, and the like. The A / D converter that converts an analog electric signal into digital data receives the measurement current Mi measured by the current sensor 7 and converts it into digital data. Since these details are publicly known, detailed explanations are omitted.

  As described above, in the present embodiment, the current flowing through all the three-phase stator coils of the motor MG is measured by the non-contact type current sensor 7 and is used for current feedback control by the control device 10. By the way, since the three-phase current is balanced, the sum of the three-phase current is zero. Therefore, the control device 10 is different when one of the three current sensors 7 provided corresponding to each of the three phases breaks down or when it is determined that the reliability of the measurement result is low. It is possible to detect all three-phase currents based on the measurement results of the two current sensors 7. Hereinafter, a functional configuration of such a control device 10 and a specific mode of execution of the function will be described.

  As shown in FIG. 1, the control device 10 includes a current detection unit 11, an overcurrent determination unit 12, an output restriction determination unit 13, a determination grace period setting unit 14, and an inverter control unit 15. ing. The current detection unit 11 is provided corresponding to each of the three phases, and based on the measurement results (measurement currents Mu, Mv, Mw) of the current sensor 7 that measures the current flowing in each phase, the actual current Iu of each phase. , Iv, Iw. The overcurrent determination unit 12 determines, for each phase, whether each phase is an overcurrent phase in an overcurrent state based on the measurement results (measurement currents Mu, Mv, Mw) of the current sensor 7 (for each phase). It is a functional part. Specifically, the overcurrent determination unit 12 has a phase (current sensor 7) corresponding to the current sensor 7 whose measurement result (measurement currents Mu, Mv, Mw) is equal to or greater than the overcurrent determination threshold (THOC). Is the overcurrent phase in the overcurrent state. The overcurrent determination threshold value (THOC) is set in advance, for example, to a value within the measurement accuracy guarantee range of the current sensor 7.

  The measurement accuracy guarantee range of the current sensor 7 is, for example, a current range in which the output of the current sensor 7 can be output while maintaining linearity, a current range in which output can be performed while maintaining a correlation defined by a function such as logarithm, The current range within which the measurement error falls within the allowable error range is a value defined in advance according to the type of the current sensor 7. In the present embodiment, the measurement accuracy guarantee range is a linearity guarantee range in which the output of the current sensor 7 can be output while maintaining linearity. The overcurrent determination threshold value (THOC) is further set within the range of the maximum allowable current value of the drive device 1 such as the inverter 5. Further, the overcurrent determination threshold value (THOC) does not have to be a fixed value, and may be a value that varies according to a control method described later.

  The output restriction determination unit 13 is a functional unit that determines whether or not the output state of the motor MG needs to be limited based on the determination result of the overcurrent determination unit 12. For example, when it is determined by the overcurrent determination unit 12 that there is an overcurrent phase, the output restriction determination unit 13 determines that it is in a restricted state. As will be described later, the inverter control unit 15 sets the operation state of the inverter 5 to the stop state when the output restriction determination unit 13 determines that the restriction state is required.

  However, even if the measured currents Mu, Mv, and Mw are equal to or higher than the overcurrent threshold (THOC), it may not actually be a problem. As will be described later, the inverter control unit 15 has a plurality of control methods for switching control of the inverter 5. When the control method executed by the inverter control unit 15 is switched, the applied voltage to the inverter 5 may fluctuate transiently to generate a transient current. Such a transient current is temporary. Therefore, there is no need to limit the output of the motor MG. For this reason, the determination grace period setting unit 14 sets a determination grace period for suspending the determination by the output restriction determination unit 13. Specifically, the determination grace period setting unit 14 sets a determination grace period for a predetermined period from when the control method (execution control method) executed by the inverter control unit 15 is switched.

  The inverter control unit 15 is a functional unit that performs switching control of the inverter 5 by determining one execution control method from at least two different control methods according to the target torque TM and the rotational speed ω of the motor MG. Moreover, the inverter control part 15 makes the operation state of the inverter 5 a stop state, when the output restriction | limiting determination part 13 determines with it being a restriction | limiting required state. In the present embodiment, the inverter control unit 15 controls the motor MG by executing current feedback control using a current vector control method in a two-axis orthogonal vector space that rotates in synchronization with the rotation of the motor MG. In the current vector control method, for example, current feedback is performed in a two-axis orthogonal vector space of a d-axis along the direction of the field magnetic flux by a permanent magnet and a q-axis that is electrically advanced by π / 2 with respect to the d-axis. Take control.

  The inverter control unit 15 determines d-axis and q-axis current commands based on the target torque TM (torque command) of the motor MG to be controlled. Then, the inverter control unit 15 obtains a deviation between the actual current in the vector space obtained based on the actual currents Iu, Iv, and Iw flowing through the coils of the respective phases of the motor MG and the current command, and performs a proportional integral control calculation ( PI control calculation) and proportional-integral-derivative control calculation (PID control calculation) are performed to finally determine a three-phase voltage command. Based on this voltage command, a switching control signal SI is generated. Mutual coordinate conversion between the actual three-phase space of the motor MG and the biaxial orthogonal vector space is performed based on the magnetic pole position θ detected by the rotation sensor 9. The rotational speed ω (angular speed) of the motor MG is derived from the detection result of the rotation sensor 9.

  The inverter control unit 15 includes at least pulse width modulation (PWM) control and rectangular wave control (one pulse control) as a switching pattern method (voltage waveform control method) of the switching elements constituting the inverter 5. There are two control methods. In the pulse width modulation control, a pulse width modulation waveform that is an output voltage waveform of the inverter 5 of each phase of U, V, and W is in a high level period in which the upper arm element is turned on, and the lower arm element is turned on. This is a control in which the duty of each pulse is set so that the fundamental wave component becomes a substantially sine wave shape in a certain period as well as a set of pulses composed of a low level period. In pulse width modulation, a pulse is generated based on the magnitude relationship between the amplitude of an AC voltage waveform (voltage command) and the amplitude of a triangular wave (including sawtooth) carrier waveform. In some cases, the PWM waveform is directly generated by digital calculation without being compared with the carrier, but even in this case, the AC voltage waveform and the amplitude of the virtual carrier waveform have a correlation.

  For pulse width modulation control, well-known sinusoidal pulse width modulation (SPWM) control, space vector pulse width modulation (SVPWM) control, discontinuous pulse width modulation (DPWM) control, etc. Is included. Space vector pulse width modulation is a modulation method in which a pulse is generated based on a voltage command in which a neutral point bias voltage is applied to a sinusoidal fundamental wave. Sine wave pulse width modulation and space vector pulse width modulation are modulation methods in which the amplitude of the fundamental wave component is less than or equal to the carrier amplitude, but discontinuous pulse width modulation is a pulse width modulation in which the amplitude of the voltage command exceeds the amplitude of the carrier waveform. It is. For this reason, sinusoidal pulse width modulation and space vector pulse width modulation may be referred to as normal pulse width modulation, and discontinuous pulse width modulation may be referred to as overmodulation pulse width modulation. In discontinuous pulse width modulation, the waveform of the fundamental component of the output voltage waveform of the inverter 5 is distorted by making the duty ratio of each pulse larger on the peak side of the fundamental component and smaller on the valley side, and the amplitude is normally pulse width modulated. Control to be larger than For example, in discontinuous pulse width modulation, two-phase modulation is performed in which one of the three phases is fixed to high or low and the other two phases are pulse-width modulated.

  These sinusoidal pulse width modulation, space vector pulse width modulation, and discontinuous pulse width modulation have a correlation with the carrier. This carrier is determined in accordance with the control cycle of the control device 10 such as the calculation cycle of the microcomputer constituting the control device 10 and the operation cycle of the electronic circuit constituting the control device 10. In other words, the carrier has a period that is not constrained by the rotation speed or rotation angle (electrical angle) of the motor MG. Therefore, neither the carrier nor each pulse generated based on the carrier is synchronized with the rotation of the motor MG. In addition, since the change point of each pulse is determined by comparing the carrier and the voltage command, the relationship between each pulse and the carrier is not in a synchronous relationship. Therefore, in the present embodiment, the control method when the inverter 5 is switching-controlled by sinusoidal pulse width modulation control, space vector pulse width modulation control, and discontinuous pulse width modulation control is referred to as “asynchronous control method”.

  By the way, as an index indicating the conversion rate from DC voltage to AC voltage, there is a modulation rate indicating the ratio of the effective value of the line voltage of the multiphase AC voltage to the DC voltage. In general, the maximum modulation rate of sine wave pulse width modulation control is about 0.61, and the maximum modulation rate of space vector pulse width modulation control is about 0.71. The voltage command in the sinusoidal pulse width modulation control is almost sinusoidal. The voltage command of the space vector pulse width modulation control has a slight distortion because the voltage command is partially shifted up and down as described above so that the interphase voltage of the three-phase voltage can be used effectively. It is almost sinusoidal. Therefore, in general, modulation by space vector pulse width modulation control up to a maximum modulation rate of about 0.71 is treated as “normal pulse width modulation”. On the other hand, a modulation method having a modulation rate exceeding about 0.71, which is the maximum modulation rate of space vector pulse width modulation control, is called “overmodulation pulse width modulation” as a modulation method having a higher modulation rate than usual. The In the discontinuous pulse width modulation control, this overmodulation pulse width modulation is possible, and the maximum modulation rate is about 0.78. This modulation factor 0.78 is a physical limit value. When the modulation rate reaches 0.78 in the discontinuous pulse width modulation control, rectangular wave control (one pulse control) is performed in which one pulse is output in one cycle of the electrical angle. In the rectangular wave control, the modulation rate is fixed to about 0.78 which is a physical limit value.

  In this embodiment, in the pulse width modulation control, an armature current that is a combined vector of a field current (d-axis current) and a drive current (q-axis current) along each axis of the dq-axis vector space is calculated. To control the drive of the inverter 5. That is, the inverter control unit 15 controls the drive of the inverter 5 by controlling the current phase angle of the armature current in the dq axis vector space (the angle formed by the q axis current vector and the armature current vector). Therefore, the pulse width modulation control is also referred to as current phase control.

  On the other hand, the rectangular wave control is a method of controlling the inverter 5 by controlling the voltage phase of the three-phase AC power. The voltage phase of the three-phase AC power corresponds to the phase of a three-phase voltage command. In the present embodiment, in the rectangular wave control, each switching element of the inverter 5 is turned on and off once per electrical angle cycle of the motor MG, and one pulse is output per electrical angle cycle for each phase. Rotation synchronization control. As described above, in the present embodiment, the control method when the inverter 5 is switching-controlled by sine wave pulse width modulation control or the like is referred to as an “asynchronous control method”. On the other hand, a control method in which the inverter 5 is switching-controlled in synchronization with the rotation of the motor MG as in the rectangular wave control is referred to as “synchronous control method” in the present embodiment. Since the rectangular wave control drives the inverter 5 by controlling the voltage phase of the three-phase voltage, it can also be called voltage phase control.

  By the way, in the above description, a modulation method having a modulation rate exceeding about 0.71 is called “overmodulation pulse width modulation”, and it has been described that discontinuous pulse width modulation can perform this overmodulation pulse width modulation. Further, it has been described that the modulation rate can reach 0.78 in the discontinuous pulse width modulation. However, in this modulatable region, it is also possible to apply multi-pulse control that outputs several pulses in synchronization with the rotation of the motor MG, instead of discontinuous pulse width modulation that is an asynchronous control method. For multi-pulse control, 5-pulse control, 7-pulse control, etc. can be employed. This multi-pulse control belongs to the “synchronous control method” because a pulse is output in synchronization with the rotation of the motor MG.

  In this embodiment, the inverter control unit 15 can execute at least two control methods, an “asynchronous control method” and a “synchronous control method”, as a plurality of control methods, and the target torque TM and rotation of the motor MG. The execution control method is determined according to the speed ω. In the present embodiment, the inverter control unit 15 has at least two control methods having different switching patterns as “asynchronous control methods”, and at least two controls having different switching patterns as “synchronous control methods”. Has a method. Specifically, the inverter control unit 15 has three control methods, namely, a sine wave pulse width modulation control, a space vector pulse width modulation control, and a discontinuous pulse width modulation control as an “asynchronous control method”. Further, the inverter control unit 15 has two control methods of rectangular wave control and multi-pulse control as “synchronous control methods”.

  As described above, when the execution control method is switched, the applied voltage to the inverter 5 may fluctuate transiently and a transient current may occur. In order to prevent the output of the motor MG from being limited by such a temporary transient current, the control device 10 sets a determination grace period for suspending the determination of the output restriction. Hereinafter, the control procedure by the control device 10 will be described in detail using a flowchart and a timing chart.

  First, various flags and counter values (timer values) used for control by the control device 10 will be described with reference to FIG. Such various flags and counter values (timer values) are realized by the flag register and counter (timer) of the CPU core as described above. The control method switching flag SW is a 1-bit flag. As shown in the timing chart of FIG. 5, the control method switching flag SW is set to “1” at the time of control method switching (time t1) when the inverter control unit 15 switches the control method of the inverter 5. When the determination grace period setting unit 14 sets the determination grace period MT based on the control method switching flag SW, it is set (reset) to “0”. The output restriction flag SD is also a 1-bit flag. This flag is set to “0” or “1” by the output restriction determination unit 13. The initial value of the output restriction flag SD is “0”. When the value of the flag is “0”, the inverter control unit 15 performs normal switching control on the inverter 5, and when it is “1”. Limits the output of the inverter 5.

  The overcurrent phase flag C is a 3-bit flag and includes “Cu” corresponding to the U phase, “Cv” corresponding to the V phase, and “Cw” corresponding to the W phase. The initial value of each flag is “0”, and the flag corresponding to the phase in which the measured currents Mu, Mv, Mw measured by the current sensor 7 are equal to or higher than the overcurrent threshold (THOC) is set to “1” by the overcurrent determination unit 12. Is set. The failure phase flag F is a flag indicating a phase in which it is determined that the current sensor 7 has failed. The failure phase flag F is also a 3-bit flag corresponding to each phase, and includes “Fu”, “Fv”, and “Fw” corresponding to the U, V, and W phases. The exclusion phase flag E is an exclusion phase that does not use the measured values (measurement currents Mu, Mv, Mw) when the current detection unit 11 detects the actual currents Iu, Iv, Iw based on the measurement currents Mu, Mv, Mw. It is a flag to show. The excluded phase flag E is also a 3-bit flag corresponding to each of the three phases, and the initial value is “0”, indicating that all phases are not excluded. The exclusion phase flag E is set by a bit logical sum of the overcurrent phase flag C and the failure phase flag F. Specifically, “Eu” corresponding to the U phase is the logical sum of “Cu” and “Fu”, “Ev” corresponding to the V phase is the logical sum of “Cv” and “Fv”, U “Ew” corresponding to the phase is determined by the logical sum of “Cw” and “Fw”. That is, the phase in which “1” is set in either the overcurrent phase flag C or the failure phase flag F is an excluded phase in which the measured value of the current sensor 7 is not used for current detection.

  The standby period counter WC is a counter (timer) that measures an elapsed time after the output restriction flag SD is set to “1”. The inverter control unit 15 resumes the switching control of the inverter 5 after a predetermined standby period or more has elapsed since the operation state of the inverter 5 is stopped. A value corresponding to this waiting period is set in the waiting period counter WC. In this embodiment, the initial value is “0”, and the preset value set at the start of counting is “300”. That is, the standby period counter WC indicates the count value (timer value) of a counter (timer) that is preset to “300” and performs a down-count (decrement) operation to an initial value “0”.

  The grace period counter MC is a counter (timer) for defining the determination grace period MT after the execution control method is switched. The determination grace period setting unit 14 sets a determination grace period MT for a predetermined period from the control method switching time (time t1 shown in FIG. 5) when the inverter control unit 15 switches the execution control method. In the grace period counter MC, a value corresponding to the determination grace period MT is set. In this embodiment, the initial value is “0”, and the preset value set at the start of counting is “3”. The grace period counter MC is preset to “3” when the control method switching flag SW is “1”, and then the counter value (counter) of the counter (timer) that performs the down-count (decrement) operation to the initial value “0” ( Timer value).

  Note that the preset value of the grace period counter MC does not have to be a fixed value. For example, when the inverter control unit 15 can determine the execution control method from at least three different methods, the determination grace period MT may be set to a different value depending on the combination of control methods before and after switching. For example, if the execution control method can be switched in the order of space vector pulse width modulation control, discontinuous pulse width modulation control, and rectangular wave control, switching between space vector pulse width modulation control and discontinuous pulse width modulation control The determination grace period MT at this time and the determination grace period MT at the time of switching between the discontinuous pulse width modulation control and the rectangular wave control may be different values.

  Further, as described above, the inverter control unit 15 performs switching in accordance with the synchronous control method in which switching is performed in synchronization with the rotation of the motor MG and the control cycle set without being restricted by the rotation of the motor MG. The execution control method can be switched between the asynchronous control method and the execution control method can be switched between at least two control methods having different switching patterns in each of the synchronous control method and the asynchronous control method. There can be. In such a case, the determination grace period MT is greater when the execution control method is switched between the synchronous control method and the asynchronous control method than when the execution control method is switched between the synchronous control method and the asynchronous control method. It is preferable that the period is set longer. This is because when the execution control method is switched between asynchronous control and synchronous control, a transient current is more likely to occur than when switching the execution control method within asynchronous control and synchronous control. Because it is easy to continue.

  FIG. 3 partially shows an example of a processing procedure by the inverter control unit 15. The inverter control unit 15 determines whether or not the execution control method is switched in each control cycle (substantially equivalent to “T1” shown in FIG. 5) (# 101). When the execution control method is switched, the control method switching flag SW is set to “1” (# 102). In the timing chart of FIG. 5, at time t1, the execution control method is switched from space vector pulse width modulation (SVPWM) control to discontinuous pulse width modulation (DPWM) control, and the control method switching flag SW is set to “1”. An example is shown. When the execution control method is not switched, the value of the control method switching flag SW is maintained as it is. Next, the state of the output restriction flag SD is determined (# 103). If “1”, the output restriction of the inverter 5 is executed. Specifically, the inverter controller 15 controls each IGBT of the inverter 5 to be in an off state, and the inverter 5 is controlled to be in a stopped state (# 104). On the other hand, when the state of the output restriction flag SD is “0”, the inverter control unit 15 performs switching control of the inverter 5 according to the execution control method (# 105).

  Hereinafter, with reference to FIGS. 4 to 7 as well, an example of a processing procedure centering on the current detection unit 11, the overcurrent determination unit 12, the output restriction determination unit 13, and the determination grace period setting unit 14 will be described. A series of processing from FIG. 4 to FIG. 6 to FIG. 7 is executed at every predetermined control cycle T1 (see FIG. 5). The process of the flowchart shown in FIG. 4 is executed at the head of each control cycle T1. First, it is determined whether or not the value of the standby period counter WC is “0” (# 01). When the value of the standby period counter WC is not “0”, the output restriction flag SD becomes “1” and the inverter 5 is controlled to be in a stopped state, and then a predetermined standby period (here, the control cycle T1 × 300) has not passed. Therefore, if the value of the standby period counter WC is not “0”, the process proceeds to step # 43 in FIG. 7 via $ 3, and the counter value is decremented by one. Note that the result is the same even if it passes through $ 1 or $ 2.

  If it is determined in step # 01 that the value of the standby period counter WC is “0”, the determination grace period setting unit 14 then determines whether or not the control method switching flag SW is “1”. (# 02). If the control method switching flag SW is not “1”, the execution control method by the inverter control unit 15 is not changed, and it is not necessary to set the determination grace period MT. The process proceeds to step # 05 where currents Mu, Mv, Mw) are acquired. On the other hand, when the control method switching flag SW is “1”, the determination grace period setting unit 14 activates a counter (timer) to set the determination grace period MT, and sets a preset value in the grace period counter MC. “3” is set (# 03). The preset value “3” is set based on the determination result of step # 02 executed after the control method switching flag SW becomes “1”. As shown in FIG. 5, when the grace period counter MC sets the preset value “3”, the determination grace period setting unit 14 resets the control method switching flag SW to “0” (# 04).

  As shown in FIG. 5, the value of the grace period counter MC is decremented by one for each control cycle T1. The period in which the value of the grace period counter MC is not “0” is the determination grace period MT. When the execution control method is switched again within the determination grace period MT and the control method switching flag SW is set to “1”, the value of the grace period counter MC is preset again, and again from “3”. Is decremented, and the determination grace period MT is substantially extended. When the series of processes of Steps # 02 to # 04 with the determination grace period setting unit 14 as the execution subject is completed, the current detection unit 11 acquires the current measurement values (measurement currents Mu, Mv, Mw) from the current sensor 7. (# 05). In the present embodiment, a series of processes (FIGS. 6 and 7) using the acquired measurement currents Mu, Mv, and Mw are executed in the calculation period T2 in FIG. That is, after the grace period counter MC is appropriately set and the determination grace period MT is appropriately set, a series of processes shown in FIGS. 6 and 7 are executed.

  As shown in steps # 11 to # 16 of FIG. 6, when the measurement currents Mu, Mv, and Mw are acquired, the overcurrent determination unit 12 determines whether each measurement current Mi is equal to or greater than the overcurrent determination threshold value THOC. Is determined, and an overcurrent phase flag C is set based on the determination result. Steps # 11 to # 12 are processing for the U phase, steps # 13 to # 14 are processing for the V phase, and steps # 15 to # 16 are processing for the W phase, but the processing order for the U, V, and W phases is arbitrary. . In steps # 11, # 13, and # 15, it is determined whether or not the measured currents Mu, Mv, and Mw are equal to or greater than the overcurrent determination threshold value THOC. When the measured currents Mu, Mv, Mw are equal to or greater than the overcurrent determination threshold value THOC, the overcurrent phase flags Cu, Cv, Cw of each phase are set to “1” (# 12a, # 14a, # 16a). ). On the other hand, when the measured currents Mu, Mv, and Mw are less than the overcurrent determination threshold value THOC, the overcurrent phase flags Cu, Cv, and Cw of each phase are set to “0” (# 12b, # 14b, # 16b).

  When the setting of the overcurrent phase flag C is completed, the overcurrent determination unit 12 determines whether or not it is during the determination grace period MT. In the present embodiment, it is determined whether or not it is during the determination grace period MT based on whether or not the value of the grace period counter MC is “0” (# 21). When the value of the grace period counter MC is “0”, it is not during the determination grace period MT, so the value of the overcurrent phase flag C is highly reliable. Accordingly, when any bit of the overcurrent phase flag C is “1”, there is a high possibility that the current sensor 7 of the phase corresponding to the bit has failed or an overcurrent has actually occurred. . Accordingly, for the phase in which the value of the overcurrent phase flag C is “1”, the value of the failure phase flag F is also set to “1”. Further, for the phase whose failure phase flag F is already “1”, it is necessary to hold the value “1” as it is. Therefore, the overcurrent determination unit 12 updates the value of the failure phase flag F by taking the bit OR of the failure phase flag F and the overcurrent phase flag C (# 23). Subsequently, the value of the failure phase flag F is set in the excluded phase flag E in order to distinguish the phase that uses the measurement result of the current sensor 7 in the current detection calculation by the current detection unit 11 from the phase that is not used ( # 25a).

  On the other hand, if it is determined in step 21 that the value of the grace period counter MC is not “0”, the value of the grace period counter MC is decremented by one (# 22). In this case, since the determination grace period MT is in progress, the value of the overcurrent phase flag C is not highly reliable, and the value of the failure phase flag F is updated based on the value of the overcurrent phase flag C. Is not done. However, in the current detection calculation by the current detector 11, both the phase in which the overcurrent phase flag C is “1” and the phase in which the failure phase flag F is “1” cannot be used. Accordingly, the bit OR of the value of the overcurrent phase flag C and the value of the failure phase flag F is calculated, and the value of the overcurrent phase flag C is updated (# 24). Then, the updated overcurrent phase flag C value is set in the excluded phase flag E in order to exclude the phase in which the measurement result by the current sensor 7 cannot be used in the current detection calculation by the current detection unit 11 (# 25b).

  Note that steps # 23 and # 25a and steps # 24 and # 25b in the series of processes from step # 21 to # 25a and the series of processes from step # 21 to # 25b are the current detection by the current detection unit 11. This is a process of selecting a phase that uses the measurement result of the current sensor 7 for calculation. Accordingly, steps # 23 and # 25a and steps # 24 and # 25b may be referred to as excluded phase setting step # 25.

  As shown in FIG. 6, when a phase not using (excluding) the measurement result of the current sensor 7 is set in the current detection calculation by the current detection unit 11, the process proceeds to the current detection calculation by the current detection unit 11 after $ 2. To do. As shown in FIG. 7, the current detection unit 11 (or the output restriction determination unit 13) first determines whether or not the values of the exclusion phase flag E are all “000”. When the value of the exclusion phase flag E is “000”, the current sensor 7 has neither the influence of the transient current due to the switching of the control method nor the failure. Accordingly, the output restriction determination unit 13 sets the value of the output restriction flag SD to “0” (# 35a). The current detector 11 calculates the U-phase actual current Iu based on the U-phase measured current Mu, calculates the V-phase actual current Iv based on the V-phase measured current Mv, and obtains the W-phase measured current Mw. Based on this, the W-phase actual current Iw is calculated (# 37a (# 37)).

  If it is determined in step # 31 that the value of the excluded phase flag E is not “000”, whether one bit of the excluded phase flag E is “1” and the other two bits are “0”. Are sequentially determined (# 32 to # 34). When the value of the excluded phase flag E is any one of “001”, “010”, and “100”, all three phases are measured using the two-phase measurement current Mi whose value of the excluded phase flag E is “0”. Real currents Iu, Iv, and Iw can be calculated. Therefore, the output restriction determination unit 13 sets the value of the output restriction flag SD to “0” (# 35u, # 35v, # 35w). In addition, the current detection unit 11 calculates the actual current of the phase whose excluded phase flag E is “1” based on the measured currents of the other two phases, and the value of the excluded phase flag E is “0”. The phase actual current is calculated based on the measured current of the phase, and the three-phase actual currents Iu, Iv, Iw are detected (# 37u, # 37v, # 37w).

  Specifically, when only the U-phase excluded phase flag Eu is “1”, the current detection unit 11 calculates the U-phase actual current Iu based on the V-phase measured current Mv and the W-phase measured current Mw. Then, the V-phase actual current Iu is calculated based on the V-phase measured current Mv, and the W-phase actual current Iw is calculated based on the W-phase measured current Mw to detect all the three-phase actual currents (# 37u). Similarly, when only the V-phase excluded phase flag Ev is “1”, the current detector 11 calculates the V-phase actual current Iv based on the U-phase measured current Mu and the W-phase measured current Mw, The U-phase actual current Iu is calculated based on the U-phase measured current Mu, and the W-phase actual current Iw is calculated based on the W-phase measured current Mw to detect all three-phase actual currents (# 37v). . When only the W-phase excluded phase flag Ew is “1”, the current detection unit 11 calculates the W-phase actual current Iw based on the U-phase measured current Mu and the V-phase measured current Mv, and U The U-phase actual current Iu is calculated based on the phase measurement current Mu, and the V-phase actual current Iv is calculated based on the V-phase measurement current Mv to detect all three-phase actual currents (# 37w).

  When none of the conditions of steps # 31 to # 34 is satisfied, at least two bits of the exclusion phase flag E are “1”. That is, any two bits of the exclusion phase flag E are “1” or all the bits are “1”. In this case, since it is impossible to calculate the remaining one-phase actual current using the two-phase measurement current Mi, the current detection unit 11 does not perform the current detection calculation, and the output restriction determination unit 13 The value of the output restriction flag SD is set to “1” (# 35z). Steps # 35a, # 35u, # 35v, # 35w, and # 35z described above can be collectively referred to as an output restriction flag setting step # 35 by the output restriction determination unit 13. Further, the above-described steps # 37a, # 37u, # 37v, and # 37w can be collectively referred to as an actual current detection step (actual current calculation step) by the current detector 11.

  The output restriction determination unit 13 determines whether or not the value of the standby period counter WC is “0” after setting the value of the output restriction flag SD to “1” in Step # 35z (# 41). If the value of the standby period counter WC is “0”, the output restriction determination unit 13 activates the counter (timer) and presets the value of the standby period counter WC to “300” (# 42). If the value of the waiting period counter WC is other than “0”, the counter (timer) has already been started, and thus the value of the waiting period counter WC is decremented by one (# 43). With the above processing, a series of processing in one control cycle T1 is completed, and a series of processing from step # 01 shown in FIG. 4 is executed again in the next control cycle T1.

  As described above, when the overcurrent determination unit 12 determines that two or more of the three phases are overcurrent phases (step # 34: No in FIG. 7), the output restriction determination unit 13 Determines that the state is in a required restriction state regardless of the determination grace period MT, and sets the value of the output restriction flag SD to “1”. That is, regardless of whether or not it is the determination grace period MT (regardless of the branch direction in step # 21 in FIG. 6), when two or more of the three phases are overcurrent phases, the output restriction determination The unit 13 sets the value of the output restriction flag SD to “1”. On the other hand, when it is determined by the overcurrent determination unit 12 that one of the three phases is an overcurrent phase, the output restriction determination unit 13 is in a restricted state until the determination grace period MT elapses. Judgment that it exists is suspended (steps # 31- # 34 and these Yes branches). Further, if the determination grace period MT is in progress (step # 21: No in FIG. 6), the value of the failure phase flag F is not updated (# 24), so that the failure phase may be recognized during the determination grace period MT. In addition, the determination of the failure phase is also suspended.

  In addition, when the overcurrent determination unit 12 determines that one of the three phases is an overcurrent phase, the current detection unit 11 determines that the overcurrent phase is at least during the determination grace period MT. Based on the measurement result of the current sensor 7 corresponding to another two phases, the current value of the overcurrent phase is calculated to detect the actual currents Iu, Iv, Iw of all three phases (step # 21 in FIG. 6: via No) Step # 37 in FIG. In this embodiment, even after the determination grace period MT elapses, the current sensor 7 corresponding to only one of the three phases is broken by the output restriction determination unit 13 even outside the determination grace period MT. If it is determined that the fault current sensor is a fault current sensor, the current detection unit 11 corresponds to the fault current sensor based on the measurement results (measurement current Mi) of two current sensors 7 different from the fault current sensor. The phase current values are calculated to detect the three-phase actual currents Iu, Iv, Iw (FIG. 6 # 21: Yes, step # 37 in FIG. 7 via # 23).

  As one aspect, when the overcurrent determination unit 12 determines that one of the three phases is an overcurrent phase after the determination grace period MT has elapsed, the output restriction determination unit 13 performs the overcurrent phase. Is determined to be a fault current sensor, and the value of the fault phase flag F of the relevant phase is set to “1” (# 23 in FIG. 6). The current detection unit 11 calculates the current value of the overcurrent phase based on the measurement result (measurement current Mi) of the two current sensors 7 different from the fault current sensor, and obtains the three-phase actual currents Iu, Iv, and Iw. To detect. However, if at least one other phase is determined to be an overcurrent phase by the overcurrent determination unit 12, the output limit determination unit 13 determines that the output limit flag SD is required and determines the value of the output limit flag SD. Is set to “1” (# 35z in FIG. 7).

  In the above description, for ease of explanation, the flowchart shown in FIG. 3 has been described independently. However, it may be included in a series of procedures combined with FIGS. 4, 6, and 7. For example, steps # 101 and # 102 in FIG. 3 are executed before step # 01 in FIG. 4 (after the start), and steps # 103 to # 105 in FIG. 3 are performed in steps # 37, # 42, # in FIG. It may be executed after 43 (before return).

  The present invention is directed to a rotating electrical machine driving device that includes an inverter that converts power between DC power and three-phase AC power and drives an AC rotating electrical machine, and detects an actual current flowing through the rotating electrical machine to detect current. The present invention can be applied to a rotating electrical machine control device that performs feedback control.

ω: Rotational speed 1: Drive device (rotary electric machine drive device)
5: Inverter 7: Current sensor 10: Control device (rotary electric machine control device)
11: current detection unit 12: overcurrent determination unit 13: output restriction determination unit 14: determination delay period setting unit 15: inverter control unit Iu: actual current Iv: actual current Iw: actual current MG: motor (rotating electric machine)
MT: Determination grace period M: Measurement current Mu: U-phase measurement current Mv: V-phase measurement current Mw: W-phase measurement current SD: Output restriction flag (output restriction)
TM: Target torque

Claims (6)

A rotating electrical machine drive device that includes an inverter that converts power between DC power and 3-phase AC power to drive an AC rotating electrical machine, and that performs current feedback control by detecting an actual current flowing through the rotating electrical machine. An electric control device,
A current detection unit configured to detect the actual current of each phase based on a measurement result of a current sensor provided corresponding to each of the three phases and measuring a current flowing in each phase;
The phase corresponding to the current sensor equal to or higher than the overcurrent determination threshold value set to a value within a predetermined measurement accuracy guarantee range of the current sensor is an overcurrent phase in an overcurrent state. An overcurrent determination unit for determining
Based on the determination result of the overcurrent determination unit, an output limit determination unit that determines whether or not the output of the rotating electrical machine needs to be limited is necessary.
When one execution control method is determined from at least two different control methods according to the target torque and the rotation speed of the rotating electrical machine and the inverter is switched, and when it is determined that the restriction state is required, An inverter control unit for stopping the operation state of the inverter;
A determination grace period setting unit for setting a determination grace period for a predetermined period from the control method switching time when the inverter control unit switches the execution control method,
When the overcurrent determination unit determines that two or more of the three phases are the overcurrent phases, the output restriction determination unit is in the required restriction state regardless of the determination grace period. And
When it is determined by the overcurrent determination unit that any one of the three phases is the overcurrent phase, the output restriction determination unit holds the determination until the determination grace period elapses, The current detection unit calculates a current value of the overcurrent phase based on a measurement result of the current sensor corresponding to two phases different from the overcurrent phase at least during the determination grace period, and calculates all three phases. The rotating electrical machine control apparatus which detects the said actual electric current.   2. The rotating electrical machine control device according to claim 1, wherein the inverter control unit restarts the switching control of the inverter after a predetermined standby period or more has elapsed after setting the operation state of the inverter to the stopped state.   The said inverter control part can determine the said execution control system from at least 3 different systems, and the said determination grace period is set to a different value according to the combination of the said control systems before and behind switching. The rotating electrical machine control device according to 1. The inverter control unit includes a synchronous control system that performs switching in synchronization with the rotation of the rotating electrical machine, and an asynchronous control system that performs switching according to a control cycle that is set without being restricted by the rotation of the rotating electrical machine. The execution control method can be switched between, and the execution control method can be switched between at least two control methods having different switching patterns in each of the synchronous control method and the asynchronous control method. ,
The determination grace period is when the execution control method is switched between the synchronous control method and the asynchronous control method, compared to a period when the execution control method is switched between the synchronous control method and the asynchronous control method. The rotating electrical machine control device according to claim 3, wherein the period is set longer. The output restriction determination unit, when the overcurrent determination unit determines that one of the three phases is the overcurrent phase after the determination grace period has elapsed, the corresponding to the overcurrent phase The current sensor is determined to be a failed current sensor,
5. The current detection unit calculates a current value of the overcurrent phase based on measurement results of two current sensors different from the fault current sensor, and detects the three-phase actual current. The rotary electric machine control apparatus as described in any one of these.   6. The rotating electrical machine control according to claim 5, wherein the output restriction determination unit determines that the at least one phase is in the restricted state when the overcurrent determination unit determines that the at least one phase is the overcurrent phase. apparatus.

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