JP2015106930A - Motor control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor control device that is able to store data sufficient for malfunction analysis even when the rotating speed of a motor is low.SOLUTION: When the rotating speed of a motor is relatively low, a data group is stored in the malfunction analysis data storage area of a RAM 35 even at timing between the crest and trough parts of a triangular wave signal in addition to the respective timings of the crest and trough parts of it. Specifically, the data group is sampled at frequency higher than the frequency of change in triangular wave signal, and is stored in the malfunction analysis data storage area. Accordingly, in a case where an abnormal state arises in a motor control device 21, a sufficient data group for malfunction analysis can be obtained regardless of the rotating speed of the motor.

Description

  The present invention relates to a motor control device that controls a rotation state of a motor using a PWM signal generated according to a comparison result between a command signal and a triangular wave carrier signal.

  For example, as described in Patent Document 1, when a failure occurs in a device including a motor, sensor data and control for controlling the motor are used as failure analysis data for analyzing the cause of the failure. Data that stores data necessary for processing, data indicating processing results, and the like are known.

  In the apparatus of Patent Document 1, when the control is normally performed, the above-described sensor data and the like are temporarily stored using the first memory area of the RAM and used for data transfer. When a failure is detected, the data temporary storage area is switched from the first memory area to the second memory area. As a result, data such as sensor data at the time of failure detection is stored in the first memory area.

JP 2009-269458 A

  In the apparatus disclosed in Patent Document 1 described above, various data used for controlling the motor are temporarily stored in the first memory area of the RAM. Therefore, the update cycle of various data temporarily stored in the first memory area of the RAM is the same as the cycle of sampling sensor data or the like for motor control.

  Here, generally, the sampling period of the sensor data for motor control changes according to the rotational speed of the motor. For example, when the rotation speed of the motor is low, the switching cycle of energization to the stator coil of each phase of the motor becomes long. Therefore, when sampling the current flowing through each phase as sensor data, the sampling cycle is set to be longer as the motor rotational speed is lower.

  On the other hand, when a failure occurs, for example, the current value supplied to each phase of the motor may change suddenly. Therefore, in the apparatus of Patent Document 1, particularly when the rotational speed of the motor is low, the update period of data stored in the RAM becomes too long, and the failure analysis data may become insufficient.

  The present invention has been made in view of the above points, and provides a motor control device capable of storing sufficient data for failure analysis even when the rotational speed of the motor is low. With the goal.

In order to achieve the above object, the motor control device (21) according to the present invention uses each PWM signal generated in accordance with the comparison result between the command signal and the triangular wave carrier signal to switch each inverter circuit (19). By driving the element (20), the rotational state of the motor is controlled,
The frequency of the triangular wave carrier signal changes according to the rotational speed of the motor, and acquisition means (S100, S120) that acquires at least one control parameter used for motor control at a timing synchronized with the change of the triangular wave carrier signal. , S300 to S320),
Storage means (35) for storing the control parameters acquired by the acquisition means;
When an abnormality occurs in the motor control device, an abnormality detecting means (S200) for detecting the abnormality,
Storage means (S150) for saving the control parameter stored in the storage means when an abnormality is detected by the abnormality detection means,
The acquisition unit is characterized in that when the frequency of the triangular wave carrier signal is lower than a predetermined frequency, the acquisition unit acquires the control parameter at a frequency higher than the frequency at which the triangular wave carrier signal changes and stores the control parameter in the storage unit.

  As described above, in the present invention, the rotation state of the motor is controlled using the PWM signal generated according to the comparison result between the command signal and the triangular wave carrier signal. The frequency of the triangular wave carrier signal is adjusted so as to change according to the rotational speed of the motor. The acquisition unit acquires at least one control parameter used for controlling the motor at a timing synchronized with the change of the triangular wave carrier signal, and stores it in the storage unit. Therefore, when the rotational speed of the motor is relatively high, the frequency of the triangular wave carrier signal also increases, so that the acquisition unit can acquire the control parameter at a relatively short period and store it in the storage unit.

  However, when the rotational speed of the motor becomes relatively low, the frequency of the triangular carrier signal also decreases. For this reason, the acquisition unit acquires the control parameter and stores it in the storage unit. In this case, the control parameters stored in the storage means may be insufficient as data for failure analysis.

  Therefore, in the present invention, when the frequency of the triangular wave carrier signal is lower than the predetermined frequency, the acquisition unit acquires the control parameter at a frequency higher than the frequency at which the triangular wave carrier signal changes, and stores the control parameter in the storage unit. did. As a result, when an abnormality occurs in the motor control device, it is possible to save sufficient data for failure analysis regardless of the motor rotation speed by saving the control parameters stored in the storage means. It becomes.

  Note that the reference numerals in the parentheses merely show an example of a correspondence relationship with a specific configuration in an embodiment described later in order to facilitate understanding of the present invention, and limit the scope of the present invention. It is not intended.

  Further, the technical features described in the claims of the claims other than the features described above will become apparent from the description of embodiments and the accompanying drawings described later.

1 is a block diagram illustrating an overall configuration of a motor control device according to an embodiment. It is the figure which showed a mode that a PWM signal was produced | generated by the comparison with a command value and a triangular wave signal. It is a figure which shows an example of the storage area of the data for failure analysis in RAM. When the frequency of the triangular wave signal is relatively high, the sensor detection signal for motor control is sampled at the timing when the peaks and valleys of the triangular wave signal are generated, stored in the RAM as control data, and at the same timing 5 is a waveform diagram when failure analysis data is stored in each block of the failure analysis data storage area of the RAM. FIG. 5 is a waveform diagram of the same type as that in FIG. 4 for explaining a problem when the frequency of the triangular wave signal is relatively low. It is a wave form chart for explaining the feature of processing which memorizes data for failure analysis in the motor control device concerning this embodiment. 6 is a flowchart showing a process of storing failure analysis data in the motor control device according to the present embodiment. It is a flowchart for demonstrating abnormality detection processing. It is a flowchart which shows the process for setting the sampling timing of the data for failure analysis. It is a flowchart which shows an overcurrent detection process.

  Hereinafter, a motor control device according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of the motor control device according to the present embodiment. The motor control device according to the present embodiment is mounted on, for example, a vehicle and used to drive a motor of a fuel pump that pumps up fuel stored in a fuel tank and provides it to a fuel injection system, or In a so-called air conditioner, it is used to drive a blower fan motor for adjusting the amount of air blown into the passenger compartment. However, the application of the motor that is driven and controlled by the motor control device of the present embodiment is not limited to these.

  As a motor (not shown) to be controlled by the motor control device according to the present embodiment, for example, a three-phase brushless motor having a permanent magnet in the rotor and a stator coil for three phases in the stator can be used. . However, the motor to be controlled by the motor control device according to the present embodiment is not limited to a three-phase brushless motor, and may be a brushed motor or an induction motor. Further, it may be a multiphase motor having two phases or three phases.

  In the motor control device 21 of the present embodiment, the power supply voltage sensor 10, the inverter input voltage sensor 11, and the like are used for motor control and / or when an abnormality occurs in the motor control device. Detection signals from various sensors such as the temperature sensor 12, the V-phase current sensor 13, and the W-phase current sensor 14 are input.

  The power supply voltage sensor 10 detects a power supply voltage supplied to the motor control device 21. The inverter input voltage sensor 11 detects a voltage input to the inverter circuit 19. The temperature sensor 12 detects the temperature of each switching element 20 in the inverter circuit 19. V-phase current sensor 13 and W-phase current sensor 14 detect currents flowing through the V-phase stator coil and the W-phase stator coil of the motor, respectively.

  An example in which detection values from the various sensors described above are used for motor control will be described. For example, in the motor control device 21 according to the present embodiment, a target value (command value) of the current flowing in each phase of the motor is determined, and the actual current detected by the V-phase current sensor 13 and the W-phase current sensor 14 is Current feedback control is executed so as to approach the predetermined target value. In this current feedback control, a command value is determined based on the current flowing in each phase, the motor rotation speed, the required torque given from the outside, and the like, and each switching of the inverter circuit 19 is compared by comparing this command value with the triangular wave carrier signal. This is done by generating a PWM signal for driving the element.

  The input voltage of the inverter circuit 19 is applied to the motor when the switching element 20 is turned on. Further, when the temperature of the switching element 20 of the inverter circuit 19 exceeds the predetermined temperature and becomes high, it is desired to shorten the ON time of the switching element in order to prevent the switching element 20 from being damaged. For this reason, the motor control device 21 according to the present embodiment calculates the command value in consideration of the inverter input voltage and the switching element temperature when executing the current feedback control.

  Next, an example in which detection values obtained by the various sensors described above are used for abnormality detection will be described. In the motor control device 21 according to the present embodiment, a normal fluctuation range is predetermined for the detection values detected by the various sensors described above. When the motor control device 21 operates normally and performs motor control, the detection values of various sensors fall within the normal fluctuation range. However, if any abnormality occurs in the motor control device 21, the detection values of the various sensors may deviate from the normal fluctuation range. Therefore, in this embodiment, when the detection values of the various sensors deviate from their normal fluctuation ranges, it is considered that an abnormality has occurred in the motor control device 21.

  Moreover, as an example of abnormality of the motor control apparatus 21, it is mentioned that an excessive electric current flows into the stator coil of each phase of a motor. This overcurrent state may be determined when the current detected by the V-phase current sensor 13 and the W-phase current sensor 14 exceeds the upper limit of the normal fluctuation range. However, in the present embodiment, a dedicated overcurrent detection circuit 24 is provided in order to reduce erroneous detection due to noise and prevent delay in detection of an overcurrent state. The overcurrent detection circuit 24 outputs an overcurrent signal when the current detected by the V-phase current sensor 13 and the W-phase current sensor 14 exceeds a predetermined upper limit value. When the output of the overcurrent signal continues for a predetermined time (several tens of ms), it is detected that an overcurrent state is reached in which an excessive current flows through the stator coil of each phase of the motor.

  The detection signals of the various sensors described above are sequentially output to the A / D converter 23 via the multiplexer 22 at a predetermined sampling period. The sampling period will be described later in detail. The A / D converter 23 converts the input analog detection signal into a digital detection signal. The converted detection signal is output to the bus 26 via the input port 25. Thus, the CPU 37 can perform processing for motor control based on detection signals from various sensors, or can store the data in the RAM 35 at a temporary point.

  The motor control device 21 also receives a signal from the IG signal sensor 15 that outputs a signal corresponding to the state of the ignition switch. When the signal from the IG signal sensor 15 is taken in via the input circuit 27 and the input / output port 30, the motor control device 21 starts or stops operating in conjunction with the ON / OFF of the ignition switch. It becomes possible to do.

  The motor is provided with a resolver sensor 16 as a position detection device that detects and outputs position information related to the rotation angle of the motor. The detection signal of the resolver sensor 16 is also taken into the motor control device 21 via the input circuit 28 and the input / output port 30. As is well known, the resolver sensor 16 has coils respectively provided on a rotor and a stator of a motor. When the rotor rotates with an AC voltage applied to the rotor-side coil, the distance from the stator-side coil changes, so that an AC voltage whose amplitude changes is generated in the stator-side coil. From this voltage change, the rotational angle position and rotational speed of the motor can be detected.

  Alternatively, as the position detection device, three Hall elements that detect the current phases of the U-phase, V-phase, and W-phase currents, which are pseudo alternating currents (pseudo sine wave currents) applied to each of the three phases, are used. Also good. Each of these Hall elements detects a current change in a specific stator coil as a change in magnetic flux. In the three-phase brushless motor, the phases of the U-phase current, the V-phase current, and the W-phase current, which are three-phase pseudo alternating currents, are shifted by 120 degrees. Therefore, by combining the detection signals of the three Hall elements, the rotational position can be detected every time the motor (rotor) rotates 60 degrees. The number of rotations of the motor per unit time (that is, the rotation speed) can be calculated from the time required for the motor to rotate 60 degrees.

  Further, as the position detection device, the rotational position and the rotational speed of the motor may be calculated from the induced voltage of each phase of the motor without providing the resolver sensor 16 and the Hall element as described above.

  The failure diagnosis device 17 is connected to the motor control device 21 by a dealer or the like when an abnormality occurs in the motor control device 21, and reads out the failure analysis data stored in the RAM 35. Are diagnosed. The failure diagnosis device 17 is connected to the communication circuit 29 of the motor control device 21 and exchanges various information with the communication circuit 29. For example, a failure analysis device 17 transmits a failure analysis data read request to the communication circuit 29. In response to this read request, the CPU 37 reads out the failure analysis data from the RAM 35 and transmits it to the failure diagnosis device 17 through the communication circuit 29.

  When an abnormality occurs in the motor control device 21, a drive signal for driving an abnormality warning unit such as a warning lamp is output via the output port 32 and the drive circuit 31. With this abnormality warning, the user of the vehicle can recognize the occurrence of the abnormality, and can be urged to bring the vehicle to a dealer or the like.

  In the motor control device 21, the motor control is executed mainly by the CPU 37 executing various processes according to the control program stored in the ROM 36. For example, as shown in FIG. 2, the CPU 37 uses command values (U-phase command value, V-phase command value, W-phase command value) corresponding to each phase based on the required torque applied from the outside or the actual rotational speed of the motor. ) Is calculated. The calculation of the command value is executed every time the motor advances by a predetermined angle, for example. The calculated command value is compared with a triangular wave signal generated in the motor control device 21. And CPU37 produces | generates the PWM signal for generating the pseudo alternating current which supplies with electricity to the stator coil of each phase from the comparison result of a command value and a triangular wave signal.

  The PWM signal generated corresponding to each phase is output to the inverter circuit 19 via the output port 34 and the drive circuit 33. The inverter circuit 19 includes three pairs of switching elements 20 that are bridge-connected so as to correspond to the U phase, V phase, and W phase of the motor. The PWM signals are supplied to the gates of the switching elements 20, and each switching element 20 is turned on / off according to the corresponding PWM signal. Thereby, the pseudo alternating current according to the command value is energized to the stator coil of each phase of the motor.

  Here, as shown in FIG. 2, the command value is calculated so as to have a sine wave shape, and the frequency of the sine wave is determined so as to increase (the cycle becomes shorter) as the rotation speed of the motor increases. On the other hand, the triangular wave signal is generated using, for example, an up / down counter that alternately repeats counting up and counting down. This up / down counter may be hardware or software. The frequency and period of this triangular wave signal change with the same tendency as the frequency and period of the command value, for example, the clock that counts up and down, or the clock that counts up and down is changed at the same timing. The frequency is changed. Thereby, the period of the generated PWM signal can be adjusted appropriately.

  The oscillation circuit 38 has, for example, a crystal resonator and generates a clock signal having a constant frequency. When the motor control device 21 operates according to the clock signal, the constant frequency clock signal generated by the oscillation circuit 38 is used to generate a PWM signal including calculation of a command value even when the motor rotates at the maximum rotation speed. It is set so that necessary processing can be completed.

  The RAM 35 temporarily stores sensor detection signals necessary for motor control, data calculated in the control process by the CPU 37, and the like. Further, the RAM 35 has a failure analysis data storage area for storing failure analysis data.

  FIG. 3 shows an example of a failure analysis data storage area in the RAM 35. In this failure analysis data storage area, as shown in FIG. 3, a data group composed of a plurality of data detected by various sensors such as a power supply voltage value, a V-phase current value, a W-phase current value, and an element temperature is stored. Remembered. Note that the stored data group may include a calculation processing result by the CPU 37. The failure analysis data storage area is divided into n blocks. Therefore, when each data is sampled and stored periodically, a data group for n cycles can be held in the failure analysis data storage area. After the number of data groups periodically sampled and stored reaches n, the block storing the oldest data group is rewritten with the newly acquired data group.

  Further, the failure analysis data storage area of the RAM 35 is provided with an area for storing an abnormality code indicating the type of abnormality when an abnormality occurs. When the CPU 37 detects that an abnormality has occurred in the motor control device 21 and writes an abnormality code indicating the type of the abnormality in the abnormality code storage area, the data group in the subsequent failure analysis data storage area Rewriting is prohibited and the stored data group is frozen. The failure analysis data storage area of the RAM 35 is also provided with an area for storing the number of blocks in which the data group is stored when the data group is frozen.

  Next, the failure analysis data storage process related to the characteristic part of the motor control device 21 of the present embodiment will be described in detail.

  As described above, in the motor control device 21 of the present embodiment, the rotational state of the motor is controlled using the PWM signal generated according to the comparison result between the command value and the triangular wave signal. At that time, the frequency and period of the triangular wave signal are adjusted so as to change according to the rotational speed of the motor.

  Here, as shown in FIG. 2, in principle, one PWM signal is generated for one triangular wave in the triangular wave signal. With this PWM signal, the switching element is turned on and off, and the current of each phase changes. For this reason, it is convenient to sample the sensor detection signal for motor control at a timing synchronized with the change of the triangular wave signal. In this way, the sampling period is shortened when the rotation speed of the motor is increased, and conversely, the sampling period is lengthened when the rotation speed is decreased. Therefore, the sampling period can be changed so as to follow the period of change of the parameter to be detected.

  FIG. 4 shows an example in which a sensor detection signal for motor control is sampled and stored in the RAM 35 as control data at the timing when peaks and valleys of a triangular wave signal are generated, and failure analysis is performed at the same timing. The waveform diagram at the time of storing the data for each block in the storage area of the RAM 35 is shown. In FIG. 4, the control data and the alphabet written in each block indicate at which point the data is sampled. FIG. 4 shows an example in which the number of blocks for storing failure analysis data is “4”.

  In this case, as shown in FIG. 4, when the rotational speed of the motor is relatively high, the frequency of the triangular wave signal is also high. For this reason, since data can be sampled with a relatively short cycle, a sufficient data group can be stored in the failure analysis data storage area of the RAM 35. Therefore, when a failure occurs in the motor control device 21, it is possible to analyze the location of failure and the mode of failure from the failure analysis data.

  On the other hand, as shown in FIG. 5, when the rotational speed of the motor is relatively low, the frequency of the triangular wave signal also decreases. For this reason, the data sampling cycle also becomes relatively long. When a failure occurs, for example, the current value supplied to each phase of the motor may change suddenly. From this point of view, when the rotational speed of the motor is low, the failure analysis data may be insufficient.

  Therefore, in the motor control device 21 according to the present embodiment, as shown in FIG. 6, when the rotational speed of the motor is relatively low, in addition to the timing of the peak and valley of the triangular wave signal, the peak and valley The data group is stored in the failure analysis data storage area of the RAM 35 even at a timing in the middle of the section. That is, the data group is sampled at a frequency higher than the frequency at which the triangular wave signal changes, and stored in the failure analysis data storage area. As a result, when an abnormality occurs in the motor control device 21, it is possible to obtain a sufficient data group for failure analysis regardless of the rotational speed of the motor.

  Hereinafter, specific control processing for storing failure analysis data executed in the motor control device 21 will be described with reference to the flowcharts of FIGS. First, the process shown in the flowchart of FIG. 7 will be described. This process is executed every time a predetermined time elapses.

  First, in step S100, it is determined whether or not the sampling timing of the data group stored in the RAM 35 has arrived as failure analysis data. Whether or not the sampling timing has come can be determined based on, for example, the count value of the up / down counter described above. If it is determined that the sampling timing has arrived, the process proceeds to step S110. On the other hand, if it is determined that the sampling timing has not yet arrived, the system waits until the sampling timing is reached.

  In step S110, it is determined whether or not an abnormal code has already been written in the RAM 35. When an abnormal code is written, the failure analysis data storage area of the RAM 35 is protected. Therefore, the process shown in the flowchart of FIG. 7 is terminated without executing the processes after step S120. On the other hand, if no abnormal code is written, the process proceeds to step S120.

  In step S120, the multiplexer 22 and the A / D converter 23 are operated, and the detection signals of the sensors are sampled and acquired. In the subsequent step S130, the sensor detection signal acquired in step S120 is written and stored in the corresponding block of the failure analysis data storage area of the RAM 35. At this time, if old data is stored in the corresponding block, the newly acquired data is overwritten with the old data, and the data content is updated.

  Here, as shown in step S200 of the flowchart of FIG. 8, the abnormality detection process is repeatedly executed at a predetermined cycle separately from the process of the flowchart of FIG. As described above, this abnormality detection processing is performed by checking whether or not the detection value of each sensor is within the normal fluctuation range, or the overcurrent signal output from the overcurrent detection circuit 24 is a predetermined time (several tens of ms). ) It is detected that an abnormality has occurred in the motor control device 21 based on whether or not it has continued.

  In step S140 of the flowchart of FIG. 7, it is determined whether or not an abnormality has been detected based on the detection result of the abnormality detection process described above. At this time, if it is determined that an abnormality is detected, the process proceeds to step S150, and an abnormality code indicating the type of the detected abnormality is set in the RAM 35.

  Next, the process shown in the flowchart of FIG. 9 will be described. This process is executed every time the frequency of the triangular wave signal is changed.

  In step S300, it is determined whether or not the frequency of the triangular wave signal is equal to or lower than a predetermined threshold value. In this determination process, when it is determined that the value is equal to or less than the predetermined threshold, the process proceeds to step S310. On the other hand, if it is determined that the value is higher than the predetermined threshold value, the process proceeds to step S320.

  When the process proceeds to step S310, the rotational speed of the motor is relatively low and the frequency of the triangular wave signal is adjusted to be relatively low. For this reason, in step S310, in addition to the timing of the peaks and valleys of the triangular wave signal, the timing in the middle of the peaks and valleys is also set as the sampling timing. In order to determine the timing between the peak and valley as the sampling timing, for example, a counter that counts a predetermined time interval shorter than the time interval from the peak to the valley is provided. Then, a fixed timing every time the counter expires a predetermined time interval may be set as a sampling timing.

  In this way, the lower the frequency of the triangular wave signal, the greater the number of scheduled timings included between the peaks and valleys. Therefore, the frequency of sampling the failure analysis data can be increased with respect to the frequency of change of the triangular wave signal as the frequency of the triangular wave signal is lowered.

  At this time, as shown in FIG. 6, the counter may count a predetermined time interval starting from the timing at which the peaks and valleys occur. In this way, it is possible to make the sampling intervals in most sections uniform. However, in this case, it is conceivable that the scheduled timing due to the expiration of the count of the counter overlaps with the timing of the peaks and valleys, or closes. Since it is not necessary to repeat the sampling of the failure analysis data within a very short time, if the time difference between the scheduled timing and the peak and valley timings is within a predetermined range, it depends on the scheduled timing. Sampling may be canceled.

  Furthermore, in order to equalize the sampling interval, the time counted by the counter may be determined so that the time interval from the peak to the valley is equally divided into a predetermined number of intervals.

  In each example described above, the time counted by the counter may be changed according to the change in the frequency of the triangular wave. As a result, it is possible to determine an appropriate sampling interval corresponding to a change in the frequency of the triangular wave.

  Alternatively, the sampling interval of the failure analysis data may be determined only from the timing when the counter finishes counting, regardless of the peak and valley of the triangular wave signal. In this case, by setting the time interval counted by the counter to be shorter than the time interval between the peak and the valley at the frequency of the triangular wave signal corresponding to the predetermined threshold value in step S200, the frequency of the change of the triangular wave signal is set. Failure analysis data can be acquired at a high frequency. Furthermore, since the sampling timing is determined only by the time interval counted by the counter, the sampling interval can be made uniform.

  When the sampling timing is determined only by the time interval counted by the counter, the time interval may be changed according to the change in the frequency of the triangular wave signal. In this way, it is possible to determine an appropriate sampling interval corresponding to the change in the frequency of the triangular wave.

  On the other hand, in step S320, since the rotational speed of the motor is relatively high and the frequency of the triangular wave is also relatively high, the fixed timing by the counter is not used, and the peak and trough timings of the triangular wave are failed. Set to the sampling timing of analysis data.

  Next, the process shown in the flowchart of FIG. 10 will be described. The flowchart of FIG. 10 shows processing for determining an overcurrent abnormality based on the overcurrent signal output from the overcurrent detection circuit 24.

  First, in step S400, based on whether or not an overcurrent signal is output from the overcurrent detection circuit 24, it is determined whether or not an overcurrent is detected. If an overcurrent is detected, the process proceeds to step S410 to start counting by the overcurrent abnormality counter. If counting of the overcurrent abnormality counter has already been started, the counting is continued.

  In the subsequent step S420, it is determined whether or not the count time of the overcurrent abnormality counter has reached a predetermined time (for example, several tens of ms). If it is determined that the count time of the overcurrent abnormality counter has reached a predetermined time, the process proceeds to step S430, and an overcurrent abnormality flag is set. By such processing, it is possible to prevent erroneous detection of overcurrent when the current of the stator coil of each phase fluctuates for a very short time due to noise, for example.

  If it is determined in step S400 that no overcurrent has been detected, the process of step S440 is executed. In step S440, the overcurrent abnormality counter is cleared. In the subsequent step S450, the overcurrent abnormality flag is cleared.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. .

  For example, in the above-described embodiment, when an abnormality is detected, the data for failure diagnosis is stored by freezing the data group in the failure analysis data storage area of the RAM 35. However, a non-volatile memory may be prepared separately, and the data group in the failure analysis data storage area may be copied and stored in the non-volatile memory using the free time of processing of the CPU 37.

  In the above-described embodiment, the sensor detection signal is sampled at the peak and valley timings of the triangular wave signal as the timing synchronized with the change of the triangular wave signal. However, the timing synchronized with the triangular wave signal is not necessarily limited to the timing of the peaks and valleys, for example, the timing when a predetermined time has elapsed from the peaks and valleys, and the midpoint between the peaks and valleys The following timing may be used.

DESCRIPTION OF SYMBOLS 10 Power supply voltage sensor, 11 Inverter input voltage sensor, 12 Temperature sensor, 13 V phase current sensor, 14 W phase current sensor, 15 IG signal sensor, 16 Resolver sensor, 17 Fault diagnosis device, 18 Abnormal warning means, 19 Inverter circuit, 20 switching elements, 21 motor control device, 22 multiplexer, 23 A / D converter, 24 overcurrent detection circuit, 25 input port, 26 bus, 27 input circuit, 28 input circuit, 29 communication circuit, 30 input / output port, 31 drive Circuit, 32 output ports, 33 drive circuit, 34 output ports, 35 RAM, 36 ROM, 37 CPU, 38 oscillation circuit

Claims (7)

Motor control for controlling the rotational state of the motor by driving each switching element (20) of the inverter circuit (19) using a PWM signal generated in accordance with a comparison result between the command signal and the triangular wave carrier signal. A device (21) comprising:
The acquisition means for acquiring at least one control parameter used for controlling the motor at a timing synchronized with the change of the triangular wave carrier signal, wherein the frequency of the triangular wave carrier signal changes in accordance with the rotational speed of the motor. (S100, S120, S300 to S320),
Storage means (35) for storing the control parameter acquired by the acquisition means;
An abnormality detection means (S200) for detecting an abnormality when an abnormality occurs in the motor control device;
A storage unit (S150) that stores the control parameter stored in the storage unit when an abnormality is detected by the abnormality detection unit;
The acquisition means acquires the control parameter at a frequency higher than the frequency of the change of the triangular wave carrier signal when the frequency of the triangular wave carrier signal is lower than a predetermined frequency, and stores the control parameter in the storage means. A motor control device.   The motor control apparatus according to claim 1, wherein the acquisition unit increases the acquisition frequency of the parameter with respect to the frequency of change of the triangular wave carrier signal as the frequency of the triangular wave carrier signal decreases.   The acquisition means includes count means (S310) for counting a time interval shorter than the period of the triangular wave carrier signal, and acquires the control parameter every time the count means expires the time interval count. The motor control device according to claim 1 or 2.   The acquisition unit acquires the control parameter at a timing at which peaks and valleys occur in the triangular wave carrier signal, and the counting unit counts the time interval starting from the timing at which the peaks and valleys occur. The motor control device according to claim 3, wherein the control parameter is acquired each time the time interval elapses from the peak and valley.   The acquisition means performs control by counting the time interval when the acquisition timing of the control parameter by counting the time interval by the counting means falls within a predetermined time range from the timing at which the peak and valley portions of the triangular wave carrier signal occur. The motor control apparatus according to claim 4, wherein acquisition of parameters is canceled. The storage means is capable of storing a predetermined plurality of control parameters, and after the number of control parameters repeatedly acquired by the acquisition means reaches the predetermined plurality, the oldest control parameters 6. The control parameter is stored by rewriting the newly acquired control parameter, and the storage unit stores the control parameter by prohibiting rewriting in the storage unit. Motor control device. The abnormality detection means detects a plurality of types of abnormality,
The motor control device according to claim 6, wherein the storage unit stores information indicating the type of abnormality detected by the abnormality detection unit in the storage unit.

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