Motor control device and motor control program

Abstract

To prevent a large current from continuously flowing through elements constituting an inverter before the locked state of the motor is completely released.SOLUTION: When it is determined that a motor 30 is in a locked state, a control device 40 limits a current supplied to the motor 30. The limit on the current supplied to the motor 30 is ended when a period during which the release condition for determining whether the locked state of the motor 30 is released has continued for a predetermined period. Therefore, when the locked state of the motor 30 is not completely released and the release condition is temporarily satisfied but is soon no longer satisfied, the limit on the current supplied to the motor 30 is not ended. This makes it possible to prevent a large current from continuously flowing through a switching module 24 constituting the inverter before the locked state of the motor 30 is completely released.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an electric motor control device and an electric motor control program that control an electric motor to which current is passed via an inverter. [Background technology]

[0002] For example, Patent Document 1 describes that when the motor locks and the motor's rotation speed is in the low rotation speed range, a first torque and a second torque greater than the first torque are set, and lock-up control is executed in which the motor outputs a torque that is changed between the set first torque and second torque. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-296881 A Summary of the Invention [Problem to be solved by the invention]

[0004] Here, if a large current is passed through the motor in an attempt to generate a relatively large torque in the motor to release the locked state of the motor, the current continues to flow through the coils of the same phase, which leads to a rise in temperature of the elements that make up the inverter that adjusts the current passed through the motor.For this reason, if the locked state continues for a certain period of time, it is desirable to limit the current passed through the motor to a current of a magnitude that can suppress the temperature rise of the inverter elements, within a range in which the locked state can be expected to be released.

[0005] However, in the technology described in Patent Document 1, the motor torque is changed between the first torque and the second torque, and when the rotation speed of the motor exceeds a threshold value that defines a low rotation speed range, the locked state of the motor is considered to be released. Therefore, if the locked state of the motor is not completely released and the rotation speed of the motor that once exceeded the threshold value immediately drops to a rotation speed below the threshold value, the locked state control is executed again. When a torque that changes between the first torque and the second torque is generated as the locked state control, a relatively large current flows through the inverter element again. Therefore, if such a locked state control is repeated, a large current continues to flow through the inverter element, which may cause a temperature rise.

[0006] The present disclosure has been made in consideration of the above-mentioned points, and aims to provide a motor control device and a motor control program that are capable of suppressing a large current from continuously flowing through elements that constitute an inverter before the locked state of the motor is completely released. [Means for solving the problem]

[0007] In order to achieve the above object, an electric motor control device according to the present disclosure is a electric motor control device for controlling an electric motor (30) to which a current is applied via an inverter, comprising: A lock state determination unit (S100) that determines a lock state of the electric motor; a current limiting unit (S250) that limits a current supplied to the motor when the locked state determining unit determines that the motor is in a locked state; a release determination unit (S330, S336) that determines whether a release condition for determining whether the locked state of the electric motor is released is satisfied; The control system further includes a limitation ending unit (S450, S455, S470) that, when the release condition is satisfied for a predetermined period of time, determines that the locked state of the motor has been released and ends the current limiting by the current limiting unit.

[0008] Further, a motor control program according to the present disclosure is a motor control program for controlling an electric motor (30) to which a current is applied via an inverter, the program comprising: At least one processor has A locked state of the motor is determined (S100), If it is determined that the motor is locked, the current supplied to the motor is limited (S250). A determination is made as to whether or not a release condition for determining whether the locked state of the electric motor is released is satisfied (S330, S336); The method includes instructions to terminate the limit on the current flowing through the motor (S450, S455, S470) when the period during which the release condition is satisfied continues for a predetermined period of time, assuming that the locked state of the motor has been released.

[0009] According to the motor control device and the motor control program described above, the limit on the current flowing through the motor is ended when the release condition for determining whether the locked state of the motor is released has been satisfied for a predetermined period of time. Therefore, even if the locked state of the motor is not completely released and the release condition is temporarily satisfied, the limit on the current flowing through the motor is not ended if the release condition is not satisfied immediately. This prevents the repetition of the locked state control described in Patent Document 1, and makes it possible to suppress a large current from continuously flowing through the elements constituting the inverter before the locked state of the motor is completely released.

[0010] The reference numbers in parentheses above are merely an example of a correspondence with a specific configuration in an embodiment described below, in order to facilitate understanding of the present disclosure, and are not intended to limit the scope of the present disclosure in any way.

[0011] In addition, the technical features described in each claim in addition to the features of the present disclosure described above will become apparent from the description of the embodiments described below and the accompanying drawings. [Brief description of the drawings]

[0012] [Figure 1]1 is a configuration diagram showing a schematic configuration of an entire system including a control device that controls an electric motor according to a first embodiment. [Diagram 2] 4 is a flowchart showing a process executed by the control device each time the vehicle starts moving from a stopped state. [Diagram 3] 3 is a flowchart showing details of a lock determination process in the flowchart of FIG. 2. [Figure 4] 3 is a flowchart showing details of a timer start process in the flowchart of FIG. 2. [Diagram 5] 3 is a flowchart showing details of the release process in the flowchart of FIG. 2; [Figure 6] 11 is a time chart showing an example of operational waveforms in a case where the electric motor falls into a locked state when the vehicle starts moving, but the locked state is resolved while a current limit value is being applied to the electric motor. [Figure 7] 11 is a time chart showing an example of operational waveforms when, when the vehicle starts moving, a determination to release a locked state of the electric motor and a cancellation determination to cancel the release determination are repeated, and then the locked state is released. [Figure 8] 10 is a flowchart showing details of a timer start process performed in a control device according to a second embodiment. [Figure 9] 13 is a flowchart showing details of a lock determination process performed in a control device according to a third embodiment. [Figure 10] 10 is a time chart showing an example of operational waveforms when the lock determination process shown in the flowchart of FIG. 9 is performed. [Figure 11] 13 is a flowchart showing details of a timer start process performed in a control device according to a fourth embodiment. [Figure 12] 13 is a flowchart showing details of a release process performed in a control device according to a fourth embodiment. [Figure 13] 13 is a time chart showing an example of operational waveforms when the timer start process shown in the flowchart of FIG. 11 and the release process shown in the flowchart of FIG. 12 are performed. [Figure 14] 13 is a time chart for explaining a process performed by a control device according to a fifth embodiment. [Figure 15] 13 is another time chart for illustrating the processing by the control device according to the fifth embodiment. [Figure 16] 13 is a time chart for explaining a process performed by a control device according to a sixth embodiment. [Figure 17] 13 is another time chart for illustrating the processing by the control device according to the sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, several embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, the same reference numerals may be used to designate parts corresponding to matters described in the preceding embodiment, and duplicated descriptions may be omitted. In each embodiment, when only a part of the configuration is described, the other embodiment described previously may be applied to the other parts of the configuration.

[0014] In addition to combinations of parts that are specifically specified as being possible in each embodiment, it is also possible to partially combine embodiments together, embodiments and variations, and variations together, even if it is not specified that such combinations are possible, provided that there are no particular problems with the combination.

[0015] (First embodiment) First, the overall configuration of a system 100 including a control device 40 that controls an electric motor 30 to which current is applied via an inverter will be described with reference to Fig. 1. This system 100 is mounted on a vehicle such as an electric vehicle, a hybrid vehicle, or a fuel cell vehicle. The electric motor 30 generates driving force for driving the vehicle.

[0016] The system 100 includes a battery 10, a boost circuit 12, a power conversion circuit 20 including an inverter, a cooling device 26, an electric motor 30, and a control device 40. The battery 10 includes a plurality of battery stacks electrically connected in series or parallel. Each of the plurality of battery stacks includes a plurality of secondary batteries electrically connected in series. As the secondary batteries, lithium ion secondary batteries, nickel hydrogen secondary batteries, organic radical batteries, and the like can be used. The battery 10 may be a fuel cell.

[0017] The boost circuit 12 has a DC-DC converter and boosts the DC voltage of the battery 10 to a voltage level suitable for powering the motor 30. For example, the boost circuit 12 mainly boosts the DC power of the battery 10 in accordance with the amount of depression of the accelerator pedal by the vehicle driver so that the voltage level becomes higher as the amount of depression increases. The boost operation by the boost circuit 12 may be controlled by the control device 40 or may be controlled by a control device separate from the control device 40. The DC voltage boosted by the boost circuit 12 is charged to the smoothing capacitor 22 of the power conversion circuit 20.

[0018] The power conversion circuit 20 has an inverter. The inverter converts DC power supplied from the boost circuit 12 (smoothing capacitor 22) into AC power. This AC power is supplied to the electric motor 30, causing the electric motor 30 to rotate. The inverter also converts AC power generated (regenerated) by the electric motor 30 into DC power. The boost circuit 12 steps down this DC power to a voltage level suitable for charging the battery 10. This stepped-down DC power is supplied to the battery 10 and various electric loads of the vehicle.

[0019] The inverter is a three-phase inverter. An upper arm and a lower arm of each phase are provided with a switching module 24. The switching module 24 is composed of a semiconductor switch such as a MOSFET or an IGBT, and a diode connected in anti-parallel to the semiconductor switch. The midpoints of the upper arm and the lower arm of each phase are connected to the U-phase coil, the V-phase coil, and the W-phase coil of the electric motor 30, respectively.

[0020] The power conversion circuit 20 is provided with a cooling device 26 and various sensors including a temperature sensor 28 and a current sensor 29. The cooling device 26 is configured to, for example, cause a refrigerant to flow in a cooling pipe arranged to be able to exchange heat with each switching module 24 corresponding to an element constituting an inverter. The cooling device 26 may, for example, change the flow rate of the refrigerant according to the temperature of each switching module 24. Specifically, the cooling device 26 may adjust the temperature of each switching module 24 to an appropriate temperature range by increasing the flow rate of the refrigerant as the temperature of each switching module 24 increases.

[0021] The temperature sensor 28 is provided near each switching module 24 and detects the temperature of each switching module 24. A plurality of temperature sensors 28 may be provided, for example, for each switching module 24, or for each of a plurality of switching modules 24 arranged in the vicinity.

[0022] The current sensor 29 detects the current flowing through each connection line that connects the midpoint of each phase of the inverter with the U-phase coil, V-phase coil, and W-phase coil of the electric motor 30. When the rotation of the electric motor 30 is detected from the current detected by the current sensor, the rotation sensor 32 described later may be omitted.

[0023] In addition to the temperature sensor 28 and the current sensor 29, the power conversion circuit 20 may be provided with a voltage sensor, a refrigerant temperature sensor, a refrigerant flow rate sensor, etc. The voltage sensor detects the input voltage to the inverter, i.e., the voltage across the smoothing capacitor 22. The refrigerant temperature sensor detects the temperature of the refrigerant in the cooling device 26. The refrigerant flow rate sensor detects the flow rate of the refrigerant in the cooling device 26. Both the refrigerant temperature and the refrigerant flow rate correlate with the temperature of the switching module 24, which corresponds to an element that constitutes the inverter. In other words, both the refrigerant temperature and the refrigerant flow rate are parameters related to the temperature of the switching module 24 that constitutes the inverter.

[0024] The electric motor 30 has, for example, an output shaft, a rotor provided on the output shaft, and U-phase, V-phase, and W-phase stator coils arranged to face the outer periphery of the rotor. The output shaft of the electric motor 30 is connected to an axle of a driving wheel of a vehicle, for example, via a gearbox. Therefore, the rotational torque generated by the electric motor 30 is transmitted to the driving wheel of the vehicle via the gearbox and the axle. The electric motor 30 is powered by AC power supplied from the power conversion circuit 20. As a result, the driving force generated by the electric motor 30 is applied to the driving wheel.

[0025] The rotation sensor 32 may be a resolver, an MR sensor, an encoder, or the like, and outputs a detection signal according to the rotational position of the electric motor 30. The detection signal of the rotation sensor 32 is output to the control device 40.

[0026] The control device 40 has at least a storage unit and a calculation unit. The storage unit is a non-transient substantial storage medium that non-temporarily stores data and programs that can be read by a processor. The storage unit has a volatile memory and a non-volatile memory. The volatile memory of the storage unit temporarily stores, for example, various information input to the control device 40 and the processing results of the calculation unit. The non-volatile memory of the storage unit stores, for example, various programs and various reference values ​​for the calculation unit to perform calculation processing.

[0027] The calculation unit includes at least one processor. The calculation unit stores various information input to the control device 40 in the storage unit. Furthermore, the calculation unit executes various calculation processes according to each command of the stored program based on the information stored in the storage unit, and outputs, for example, a control signal for controlling each switching module 24 of the inverter.

[0028] Specifically, the control device 40 receives a torque command indicating the torque to be generated by the electric motor 30 from a higher-level control device. The torque command can also be calculated by the control device 40 based on the amount of depression of the accelerator pedal, the vehicle speed, etc. The control device 40 converts the received torque command into a current command, outputs a control signal so that a current corresponding to the converted current command is supplied to the electric motor 30, and performs PWM control on each switching module of the inverter.

[0029] In addition, when starting a stopped vehicle by the torque generated by the motor 30, the control device 40 judges whether the motor 30 has entered a locked state. The locked state refers to a state in which the rotation speed of the motor 30 remains at a low rotation speed equal to or lower than the lock judgment rotation speed even though the motor 30 generates a torque equal to or higher than a predetermined value. This may occur, for example, when the vehicle is attempting to start on an uphill road or is subjected to resistance due to unevenness in the road surface when starting, and the resistance force when the motor 30 starts to rotate is large. When the control device 40 judges that the motor 30 has entered a locked state, it limits the current flowing to the motor 30 to a current of a magnitude capable of suppressing the temperature rise of the switching module 24 constituting the inverter, within a range in which the locked state can be expected to be resolved.

[0030] However, if the rotation speed of the motor 30 exceeds the unlocking determination rotation speed and the current limit is terminated, the following problems may occur. For example, when the vehicle is about to go over a bump on the road surface that was resisting the start, but is unable to go over it completely and returns to its original position, the rotation speed of the motor 30 may immediately drop to a rotation speed below the unlocking determination rotation speed even if it once exceeds the unlocking determination rotation speed. If this occurs repeatedly, and the current limit is terminated and a large current corresponding to the torque command is passed through the inverter to the motor 30, a large current will flow through the inverter every time the unlocking determination rotation speed is exceeded. As a result, a large current may continuously flow through the switching module 24 corresponding to the element constituting the inverter, causing a temperature rise.

[0031] For this reason, the control device 40 according to this embodiment is configured to end the limitation of the current flowing through the motor 30 not only when the unlocking condition for determining whether the locked state of the motor 30 is released is satisfied, but also when the period during which the unlocking condition is satisfied continues for a predetermined period of time. Therefore, even if the locked state of the motor 30 is not completely released and the unlocking condition is temporarily satisfied, if the unlocking condition is soon no longer satisfied, the limitation of the current flowing through the motor 30 is not ended. For this reason, it is possible to prevent a large current from flowing through the switching module 24 constituting the inverter before the locked state of the motor 30 is completely released.

[0032] Hereinafter, the process executed by the control device 40 in accordance with the stored program will be described with reference to the flowchart of Fig. 2. The process shown in the flowchart of Fig. 2 is executed every time the vehicle starts moving from a stopped state.

[0033] In step S100, the control device 40 executes a lock-up determination process. Details of the lock-up determination process are shown in the flowchart of Fig. 3. The lock-up determination process will be described below with reference to the flowchart of Fig. 3.

[0034] In step S200, the control device 40 determines whether or not the lock flag is on, that is, whether or not the locked state of the electric motor 30 has already been determined. The lock flag is turned on in step S240 when a lock determination condition is satisfied in step S230, which will be described later. If it is determined that the lock flag is on, there is no need to perform a further lock determination, and the control device 40 ends the process shown in the flowchart of Fig. 3. On the other hand, if it is determined that the lock flag is not on, the control device 40 proceeds to the process of step S210.

[0035] In step S210, the control device 40 receives a torque command from a higher-level control device. In step S220, the control device 40 calculates and acquires the rotation speed of the electric motor 30 based on the detection signal of the rotation sensor 32 or the detection signal of the current sensor. In step S230, the control device 40 determines whether the electric motor 30 is in a locked state based on whether the lock determination condition is satisfied. The lock determination condition can be, for example, as shown in the time chart of FIG. 6, that the torque command is equal to or greater than the lock determination torque and the rotation speed of the electric motor 30 is equal to or less than the lock determination rotation speed. This is because, even if a torque command of a certain magnitude is issued, if the actual rotation speed of the electric motor 30 is a low rotation speed equal to or less than the lock determination rotation speed, the electric motor 30 can be considered to be in a locked state. However, the lock determination condition is not limited to the above-mentioned condition. For example, instead of the torque command, a current command converted from the torque command may be used. FIG. 6 is a time chart showing an example of an operational waveform in a case where the motor 30 falls into a locked state when the vehicle starts moving, but the locked state is resolved while current is being limited and a current limit value is being applied to the motor 30.

[0036] If it is determined in step S230 that the lock determination condition is satisfied, the control device 40 proceeds to the process of step S240. On the other hand, if it is determined that the lock determination condition is not satisfied, the electric motor 30 is not in a locked state, so the control device 40 ends the process shown in the flowchart of FIG.

[0037] In step S240, the control device 40 turns on a lock flag indicating that the motor 30 is in a locked state, as shown in the time chart of Fig. 6. In step S250, the control device 40 limits the current flowing to the motor 30 to a current limit value that is large enough to suppress a temperature rise in the switching module 24 that constitutes the inverter, within a range in which the locked state can be expected to be resolved, as shown in the time chart of Fig. 6. This ends the lock determination process. The lock determination process may be repeatedly executed until a predetermined time has elapsed since the vehicle starts moving.

[0038] 2 again, in step S110, the control device 40 determines whether or not it has been determined in the lock determination process that the electric motor 30 is in a locked state. If it has been determined that the electric motor 30 is in a locked state, the control device 40 proceeds to the process of step S120. On the other hand, if it has been determined that the electric motor 30 is not in a locked state, the control device 40 proceeds to step S150.

[0039] In step S120, the control device 40 executes a timer start process. Details of the timer start process are shown in the flowchart of Fig. 4. Hereinafter, the timer start process will be described with reference to the flowchart of Fig. 4.

[0040] In step S300, the control device 40 determines whether the timer is counting, that is, whether the timer has already started counting in response to the unlocking condition being satisfied. When the control device 40 determines in step S330 that the unlocking condition is satisfied, the timer starts counting in step S340. If it is determined that the timer is counting, the control device 40 does not need to determine whether to start counting the timer, and therefore ends the process shown in the flowchart of FIG. 4. On the other hand, if it is determined that the timer is not counting, the control device 40 proceeds to the process of step S310.

[0041] In step S310, the control device 40 receives a torque command from a higher-level control device. In step S320, the control device 40 acquires the rotation speed of the electric motor 30 based on the detection signal of the rotation sensor 32 or the detection signal of the current sensor. In step S330, the control device 40 determines whether the locked state of the electric motor 30 has been released based on whether an unlocking condition is satisfied. The unlocking condition can be, for example, the rotation speed of the electric motor 30 being equal to or higher than the unlocking rotation speed, as shown in the time chart of FIG. 6. This is because, when the rotation speed of the electric motor 30 becomes equal to or higher than the unlocking rotation speed, it can be determined that the electric motor 30 is unlocked at that time.

[0042] The unlocking condition is not limited to the above-mentioned condition. For example, when the carrier frequency for PWM control changes proportionally according to the rotation speed of the electric motor 30, the unlocking of the electric motor 30 may be determined when the carrier frequency becomes equal to or higher than the unlocking frequency. In other words, the carrier frequency is a parameter that correlates with and is related to the rotation speed of the electric motor 30, and the unlocking condition may be set for this carrier frequency.

[0043] Furthermore, the unlocking condition may be that the torque command is equal to or lower than the release torque, as shown in the time chart of FIG. 6. When the motor 30 falls into a locked state, the driver of the vehicle may release the accelerator pedal once and then press the accelerator pedal again, rather than continuing to depress the accelerator pedal. When the driver releases the accelerator pedal, the torque command also decreases. Therefore, when the torque command decreases to equal to or lower than the release torque, it can be considered that the motor 30 is unlocked at that point. When the unlocking condition related to the torque command is not determined, the process of step S310 may be omitted. Also, when the boost voltage by the boost circuit 12 changes proportionally in response to the torque command, the unlocking of the motor 30 may be determined when the boost voltage of the boost circuit 12, i.e., the voltage across the smoothing capacitor 22, becomes equal to or lower than the unlocking voltage. In other words, the voltage across the smoothing capacitor 22 is a parameter that correlates with and is related to the torque command, and the unlocking condition may be set for the voltage across the smoothing capacitor 22.

[0044] In addition, the unlocking condition may be set for the temperature of the elements constituting the inverter, i.e., the temperature of the switching module 24, or the refrigerant temperature or refrigerant flow rate of the cooling device 26. For example, if the temperature of the switching module 24 drops below a predetermined threshold temperature, even if a large current continues to flow through the switching module 24, the temperature rise of the switching module 24 is likely to be within an appropriate temperature range. For this reason, if the temperature of the switching module 24 is below a predetermined threshold temperature, there is no need to continue to determine the locked state of the motor 30 in order to limit the current flowing to the motor 30. The refrigerant temperature and the refrigerant flow rate of the cooling device 26 are parameters that are correlated and related to the temperature of the switching module 24. Therefore, instead of the temperature of the switching module 24, the unlocking condition may be set for the refrigerant temperature or the refrigerant flow rate of the cooling device 26.

[0045] If it is determined in step S330 that the unlocking condition is satisfied, the control device 40 proceeds to the process of step S340. On the other hand, if it is determined that the unlocking condition is not satisfied, the control device 40 ends the process shown in the flowchart of FIG.

[0046] In step S340, the control device 40 starts measuring the timer as shown in the time chart of Fig. 6. As described later, in this embodiment, when the time measured by the timer reaches a predetermined period set in accordance with the unlocking condition without the unlocking cancellation condition for canceling the unlocking determination being satisfied, the control device 40 determines for the first time that the locked state of the motor 30 has been released. With this, the timer start process ends.

[0047] 2 again, following the timer start process of step S120, the control device 40 executes a release process of step S130. Details of the release process are shown in the flowchart of Fig. 5. The release process will be described below with reference to the flowchart of Fig. 5.

[0048] In step S400, the control device 40 judges whether the timer is measuring. If it is judged that the timer is measuring, the control device 40 proceeds to the process of step S410. On the other hand, if it is judged that the timer is not measuring, the control device 40 does not need to judge whether the time measured by the timer has reached a predetermined period, and therefore ends the process shown in the flowchart of FIG. 5.

[0049] In step S410, the control device 40 receives a torque command from a higher-level control device. In step S420, the control device 40 acquires the rotation speed of the electric motor 30 based on the detection signal of the rotation sensor 32 or the detection signal of the current sensor. In step S430, the control device 40 determines whether or not the release cancellation condition is satisfied. The release cancellation condition is a criterion for determining that the locked state of the electric motor 30 has been released after the unlocking condition, which is the criterion for determining that the locked state of the electric motor 30 has been released, has been satisfied, and then the locked state of the electric motor 30 has not been completely released, and thereby canceling the unlocking.

[0050] For example, when the unlocking condition is set for the rotation speed of the electric motor 30, the release cancellation condition may be that the rotation speed of the electric motor 30, which has become equal to or higher than the release rotation speed, drops to equal to or lower than the reset rotation speed set to equal to or lower than the release rotation speed, as shown in the time chart of Fig. 6. Also, for example, when the unlocking condition is set for the torque command, the release cancellation condition may be that the torque command, which has dropped to equal to or lower than the release torque, rises to equal to or higher than the reset torque (not shown) set to equal to or higher than the release torque. Furthermore, for example, when the unlocking condition is set for the temperature of the switching module 24, the release cancellation condition may be that the temperature of the switching module 24, which has dropped to equal to or lower than a predetermined threshold temperature, rises to a cancel temperature set to be higher than the predetermined threshold temperature.

[0051] If it is determined that the unlock cancellation condition is satisfied, the control device 40 proceeds to the process of step S440. In step S440, the control device 40 resets the timer that is measuring, and stops measuring the elapsed time from when the lock release condition is satisfied. After that, the control device 40 ends the process shown in the flowchart of FIG.

[0052] On the other hand, if it is determined that the release cancellation condition is not satisfied, the control device 40 proceeds to the process of step S450. In step S450, the control device 40 determines whether or not the time measured by the timer has reached a predetermined time equivalent to the predetermined period set in correspondence with the lock release condition. For example, as shown in the time chart of FIG. 6, when the time measured by the timer has reached the predetermined time, the control device 40 considers that the locked state of the electric motor 30 has been released, and proceeds to the process of step S460. Thus, in this embodiment, the control device 40 determines that the locked state of the electric motor 30 has been released for the first time when the time measured by the timer has reached the predetermined period set in correspondence with the lock release condition without the release cancellation condition being satisfied.

[0053] In step S460, the control device 40 turns off the lock flag as shown in the time chart of Fig. 6. Furthermore, in step S470, the control device 40 releases the current limitation as shown in the time chart of Fig. 6. This causes the current flowing through the electric motor 30 to increase to a current command value corresponding to the torque command. After that, in step S150 of the flowchart in Fig. 1, the control device 40 PWM controls the electric motor 50 so that a current corresponding to the torque command flows.

[0054] If it is determined that the locked state of the motor 30 is released when the unlocking condition is satisfied, then, for example, as shown by the dotted line in the time chart of Fig. 7, the lock flag is turned off at the point in time when the rotation speed of the motor 30 exceeds the release rotation speed. Then, as shown by the dotted line in the time chart of Fig. 7, the current value of the current supplied to the motor 30 increases toward the current command value corresponding to the torque command. However, thereafter, the rotation speed of the motor 30 falls below the lock determination rotation speed, and the locked state of the motor 30 is determined again. In response to this determination of the locked state, the current supplied to the motor 30 is reduced toward the current limit value, as shown by the dotted line in the time chart of Fig. 7.

[0055] In this way, if the locked state of the motor 30 is not completely released and the rotation speed of the motor 30 temporarily exceeds the unlock rotation speed but then immediately drops below the lock determination rotation speed, a large current is repeatedly passed through the motor 30, as shown by the dotted line in the time chart of Fig. 7. As a result, there is concern about an excessive rise in temperature of the switching module 24 that constitutes the inverter.

[0056] In contrast, according to this embodiment, the control device 40 starts measuring the elapsed time with a timer when the unlocking condition (unlocking rotation speed or higher) for determining whether the locked state of the electric motor 30 is released is satisfied. If the locked state of the electric motor 30 is not completely released and the release cancellation condition for canceling the unlocking condition (reset rotation speed or lower) is satisfied, the timer being measured is reset and measurement of the elapsed time with the timer is stopped, as shown in the time chart of Fig. 7. In this embodiment, the control device 40 determines that the locked state of the electric motor 30 has been released only when the elapsed time measured by the timer reaches a predetermined period, i.e., when the measurement by the timer expires.

[0057] For this reason, in this embodiment, the lock flag is not turned off when the unlocking condition is satisfied, but remains on, as shown in the time chart of Fig. 7. Therefore, even in a situation where the unlocking condition is temporarily satisfied, but the lock determination is immediately repeated, the current flowing to the motor 30 can be continuously limited to the current limit value. As a result, it is possible to suppress an excessive rise in temperature of the switching module 24 constituting the inverter until the locked state of the motor 30 is completely released.

[0058] Second embodiment Next, a control device 40 for the electric motor 30 according to a second embodiment of the present disclosure will be described. The control device 40 according to this embodiment is configured similarly to the control device 40 according to the first embodiment, and therefore a description of the configuration will be omitted.

[0059] In the above-described first embodiment, it has been described that the unlocking condition can be set for the temperature of the switching module 24 constituting the inverter, or the refrigerant temperature or refrigerant flow rate of the cooling device 26. In this case, the timer starts measuring when the unlocking condition is satisfied. Then, when the time measured by the timer reaches a predetermined period set for the temperature of the switching module 24, or the refrigerant temperature or refrigerant flow rate of the cooling device 26, the control device 40 determines that the locked state of the motor 30 has been released.

[0060] However, the temperature of the switching module 24, or the coolant temperature of the cooling device 26, or the coolant flow rate of the cooling device 26 may be used to change the predetermined period corresponding to the unlocking condition set for the rotation speed and / or torque command of the motor 30, or a parameter related to at least one of them, rather than setting each unlocking condition.

[0061] For example, based on the temperature of the switching module 24 or a parameter related thereto, such as the coolant temperature or coolant flow rate of the cooling device 26, the control device 40 can set the predetermined period so as to shorten the predetermined period corresponding to the unlocking condition set for the rotation speed and / or torque command of the electric motor 30, or a parameter related to at least one of them, when the temperature of the switching module 24 is low, compared to when the temperature of the switching module 24 is high. If the temperature of the switching module 24 is relatively low, there is little concern that the temperature of the switching module 24 will rise beyond an appropriate temperature range even if a large current is continuously applied to the same switching module 24 to release the locked state of the electric motor 30. Therefore, when the temperature of the switching module 24 is relatively low, it is acceptable to change the predetermined period to a shorter period and determine that the locked state of the electric motor 30 has been released early.

[0062] The flowchart in Fig. 8 shows a timer start process executed in the control device 40 according to the second embodiment. The timer start process shown in the flowchart in Fig. 8 is obtained by adding steps S332 and S334 to the timer start process shown in the flowchart in Fig. 4 in the first embodiment.

[0063] In step S332, the control device 40 detects the temperature of the switching module 24, which corresponds to an element constituting the inverter, or a parameter related to the temperature of the switching module 24. In step S334, the control device 40 sets a predetermined period corresponding to an unlocking condition set for the rotation speed and / or torque command of the electric motor 30, or a parameter related to at least one of them, according to the detected temperature of the switching module 24 or the related parameter. At this time, as described above, the predetermined period is set to be shorter when the temperature of the switching module 24 is low compared to when it is high.

[0064] Third embodiment Next, a control device 40 for the electric motor 30 according to a third embodiment of the present disclosure will be described. The control device 40 according to this embodiment is configured similarly to the control device 40 according to the first embodiment, and therefore a description of the configuration will be omitted.

[0065] The control device 40 according to the first embodiment described above, when it determines that the electric motor 30 is in a locked state, immediately limits the current supplied to the electric motor 30 to a current limit value, as shown in the time chart of Fig. 6. However, when the electric motor 30 is in a locked state, there may be cases where the locked state of the electric motor 30 is released by temporarily supplying a large current to the electric motor 30. In this case, the vehicle can start smoothly, improving drivability when starting.

[0066] Therefore, even if the control device 40 of this embodiment determines that the motor 30 is locked, it does not immediately limit the current flowing to the motor 30, but instead flows a large current corresponding to the torque command to the motor 30 for a certain reservation period.

[0067] The flowchart in Fig. 9 shows a lock-up determination process executed in the control device 40 according to the third embodiment. The lock-up determination process shown in the flowchart in Fig. 9 has steps S242 and S244 added to the lock-up determination process shown in the flowchart in Fig. 3 in the first embodiment.

[0068] In step S242, after it is determined in step S230 that the motor 30 is in a locked state, the control device 40 supplies a current corresponding to the torque command to the motor 30. Then, in step S242, the control device 40 determines whether or not the time elapsed since it was determined in step S230 that the motor 30 is in a locked state has reached the reservation time. If the elapsed time has reached the reservation time, the control device 40 proceeds to processing in step S250, and if the elapsed time has not reached the reservation time, the control device 40 continues processing in step S242.

[0069] As a result, as shown in the time chart of FIG. 10, even after the locked state of the motor 30 is determined and the lock flag is turned on, a large current corresponding to the torque command is passed through the motor 30 until the hold period has elapsed. This makes it possible to quickly resolve the locked state of the motor 30. When the hold period has elapsed, the current value passed through the motor 30 is limited to the current limit value. This makes it possible to suppress a temperature rise in the switching module 24 even if the locked state is not resolved by passing a large current during the hold period. In this embodiment, when the lock flag is turned on and the hold period begins, a timer start process is executed.

[0070] (Fourth embodiment) Next, a control device 40 for the electric motor 30 according to a fourth embodiment of the present disclosure will be described. The control device 40 according to this embodiment is configured similarly to the control device 40 according to the first embodiment, and therefore a description of the configuration will be omitted.

[0071] The control device 40 according to the first embodiment determines whether the locked state of the electric motor 30 is released based on one unlocking condition. In contrast, the control device 40 according to the present embodiment is different in that it sets a plurality of unlocking conditions and determines whether the locked state of the electric motor 30 is released based on the plurality of unlocking conditions.

[0072] A plurality of unlocking conditions may be set for a plurality of parameters among the rotation speed of the electric motor 30, the torque command commanding the torque to be generated by the electric motor 30, the temperature of the switching module 24 constituting the inverter, and parameters correlated and related thereto. Additionally or instead, a plurality of unlocking conditions may be set for one parameter among the rotation speed of the electric motor 30, the torque command commanding the torque to be generated by the electric motor 30, the temperature of the switching module 24 constituting the inverter, and parameters correlated and related thereto.

[0073] When multiple unlocking conditions are set for multiple parameters, for example, an unlocking rotation speed (e.g., 100 rpm) and a predetermined period (e.g., 50 ms) may be set for the rotation speed of the electric motor 30, an unlocking torque (e.g., 10 Nm) and a predetermined period (e.g., 100 ms) may be set for the torque command, an unlocking temperature (e.g., 100° C.) and a predetermined period (e.g., 10 ms) may be set for the temperature of the switching module 24, and an unlocking temperature (e.g., 25° C.) and a predetermined period (e.g., 10 ms) may be set for the coolant temperature. Furthermore, unlocking conditions for other parameters may be added, and some of the above-mentioned unlocking conditions may be deleted as long as multiple unlocking conditions remain.

[0074] Furthermore, when a plurality of unlock conditions are set for one parameter, for example, for the rotation speed of the electric motor 30, a first unlock rotation speed (e.g., 100 rpm) and a first predetermined period (e.g., 50 ms) may be set, a second unlock rotation speed (e.g., 300 rpm) and a second predetermined period (e.g., 30 ms) may be set, and a third unlock rotation speed (e.g., 500 rpm) and a third predetermined period (e.g., 10 ms) may be set. The parameter for which the plurality of unlock conditions are set is not limited to the rotation speed of the electric motor 30, and may be a torque command or other parameters. Furthermore, the plurality of unlock conditions set for one parameter may be two or more. For example, when a plurality of unlock conditions are set for a torque command, at least a first unlock condition in which the torque command is equal to or less than a first torque and a second unlock condition in which the torque command is equal to or less than a second torque lower than the first torque are included, and the predetermined period individually set for the second unlock condition is set to be shorter than the predetermined period individually set for the first unlock condition.

[0075] In this way, when multiple parameters and / or multiple unlocking conditions are set for one parameter, the predetermined period is determined individually for each of the multiple unlocking conditions. When the control device 40 determines that the period during which any of the multiple unlocking conditions is satisfied reaches the predetermined period determined individually for each of the multiple unlocking conditions, it considers the locked state of the electric motor 30 to be released, and ends the current limiting of the electric motor 30.

[0076] The flowchart in Fig. 11 shows a timer start process executed in the control device 40 according to the fourth embodiment. In the timer start process shown in the flowchart in Fig. 11, the processes of steps S300, S330, and S340 are deleted from the timer start process shown in the flowchart in Fig. 4 in the first embodiment, and the processes of steps S336, S338, and S342 are added.

[0077] In step S336, the control device 40 judges whether or not one or more of the unlocking conditions set for a plurality of parameters and / or a single parameter are satisfied. If none of the unlocking conditions are satisfied, the control device 40 ends the process shown in the flowchart of FIG. 11. On the other hand, if it is judged that one or more of the unlocking conditions are satisfied, the control device 40 proceeds to the process of step S338. In step S338, the control device 40 judges whether or not a timer corresponding to the unlocking condition judged to be satisfied is measuring. If the corresponding timer is measuring, the control device 40 ends the process shown in the flowchart of FIG. 11. On the other hand, if the corresponding timer is not measuring, the control device 40 proceeds to the process of step S342 and starts measuring the corresponding timer.

[0078] The flowchart in Fig. 12 shows a release process executed by the control device 40 according to the fourth embodiment. In the release process shown in the flowchart in Fig. 12, the processes of steps S430, S440, and S450 are deleted from the release process shown in the flowchart in Fig. 5 in the first embodiment, and processes of steps S435, S445, and S455 are added.

[0079] In step S435, the control device 40 determines whether one or more release cancellation conditions are satisfied. The release cancellation conditions are determined individually for each of the multiple unlock conditions. For example, when the first to third unlock rotation speeds are set for the rotation speed of the electric motor 30 as described above, the first to third release cancellation rotation speeds are determined individually for the first to third unlock rotation speeds so as to be equal to or lower than the corresponding first to third unlock rotation speeds.

[0080] If it is determined that one or more release cancellation conditions are satisfied, the control device 40 proceeds to the process of step S445. In step S445, the control device 40 first selects one or more unlock conditions corresponding to the one or more satisfied release cancellation conditions. Then, the control device 40 resets one or more timers (hereinafter also referred to as the corresponding timers) that started measuring when the selected unlock condition was satisfied, and stops measuring the elapsed time since the selected unlock condition was satisfied by the corresponding timers. After that, the control device 40 ends the process shown in the flowchart of FIG. 12.

[0081] Fig. 13 is a time chart illustrating the period from the start to the end of measurement of each timer corresponding to each unlocking condition when, for example, first to third unlocking rotation speeds, which are a plurality of unlocking conditions, are set as a single parameter for the rotation speed of the electric motor 30. As shown in the time chart of Fig. 13, for the first to third unlocking rotation speeds, the corresponding predetermined period is set to be shorter as the unlocking rotation speed becomes higher, that is, as the possibility that the locked state of the electric motor 30 has been released becomes higher.

[0082] When the locked state of the electric motor 30 is actually released, the rotation speed of the electric motor 30 increases beyond the first to third unlock rotation speeds. At this time, as shown in the time chart of FIG. 13, the order in which the timers corresponding to the unlock rotation speeds start measuring is the first unlock rotation speed, the second unlock rotation speed, and the third unlock rotation speed. However, the predetermined periods set corresponding to the unlock rotation speeds are set to become shorter as the unlock rotation speeds become higher. Therefore, the order in which the predetermined periods corresponding to the unlock rotation speeds are reached is reversed, that is, the third unlock rotation speed, the second unlock rotation speed, and the first unlock rotation speed.

[0083] In this way, by individually setting a plurality of unlocking conditions and a predetermined period corresponding to each unlocking condition for one parameter, it is possible to quickly end the determination of the locked state of the motor 30 when the locked state of the motor 30 is actually released. As a result, it is possible to improve the drivability of the vehicle when the locked state of the motor 30 is released.

[0084] Fifth embodiment Next, a control device 40 for the electric motor 30 according to a fifth embodiment of the present disclosure will be described. The control device 40 according to this embodiment is configured similarly to the control device 40 according to the first embodiment, and therefore a description of the configuration will be omitted.

[0085] The control device 40 according to the first embodiment described above determines whether a predetermined period set in accordance with the unlocking condition has elapsed based on the elapsed time measured by a timer. In contrast, the control device 40 according to the present embodiment determines whether the unlocking condition is satisfied at regular intervals, and determines whether the predetermined period set in accordance with the unlocking condition has elapsed based on whether the determination that the unlocking condition is satisfied occurs a predetermined number of times in succession. Even in this manner, it is possible to determine that the period during which the unlocking condition is satisfied has continued for the predetermined period.

[0086] Furthermore, when multiple unlocking conditions are set and multiple specified periods are set individually corresponding to the multiple unlocking conditions as in the fourth embodiment, the specified number of consecutive times that it is determined that the unlocking conditions are satisfied (i.e., the number of determinations) can be varied according to the specified period, thereby making it possible to determine whether each of the specified periods individually set corresponding to the multiple unlocking conditions has elapsed.

[0087] For example, Fig. 14 is a time chart showing an example of determining whether or not a predetermined period corresponding to each unlock condition has elapsed by varying the predetermined number of times for determining that each unlock rotation speed is satisfied, when a plurality of unlock conditions, for example, first to third unlock rotation speeds, are set as one parameter for the rotation speed of the electric motor 30. In the example shown in the time chart of Fig. 14, the first determination number for the first unlock rotation speed is set to 6 times, the second determination number for the second unlock rotation speed is set to 4 times, and the third determination number for the third unlock rotation speed is set to 2 times.

[0088] As a result, similarly to the fourth embodiment, the order in which the rotational speeds of the electric motor 30 satisfy each unlocking rotational speed is the first unlocking rotational speed, the second unlocking rotational speed, and the third unlocking rotational speed. However, the order in which the predetermined number of times for each unlocking rotational speed is satisfied is the reverse order, that is, the third unlocking rotational speed, the second unlocking rotational speed, and the first unlocking rotational speed.

[0089] In addition, instead of the number of judgments, the fixed interval (i.e., judgment period) for judging whether the unlocking condition is satisfied can also be varied for each unlocking condition to judge whether the specified period corresponding to each unlocking condition has elapsed.

[0090] For example, FIG. 15 is a time chart showing an example in which, when a plurality of unlocking conditions, for example, first to third unlocking rotation speeds, are set as one parameter for the rotation speed of the electric motor 30, the determination period for determining whether each unlocking rotation speed is satisfied is made different for each unlocking rotation speed to determine whether each predetermined period corresponding to each unlocking condition has elapsed. In the example shown in the time chart of FIG. 15, the number of determinations for determining whether each unlocking rotation speed is satisfied is the same, six. However, the determination period for determining whether the first unlocking rotation speed is satisfied is set to the longest first determination period. The determination period for determining whether the second unlocking rotation speed is satisfied is set to the intermediate second determination period. The determination period for determining whether the third unlocking rotation speed is satisfied is set to the shortest third determination period.

[0091] As a result, just as in the case where the determination number is different for each unlocking rotation count, the order in which the same determination number is satisfied for each unlocking rotation count is the third unlocking rotation count, the second unlocking rotation count, and the first unlocking rotation count.

[0092] When a plurality of unlock conditions are set, both the number of determinations and the determination cycle may be different for each unlock condition.

[0093] Sixth embodiment Next, a control device 40 for the electric motor 30 according to a sixth embodiment of the present disclosure will be described. The control device 40 according to this embodiment is configured similarly to the control device 40 according to the first embodiment, and therefore a description of the configuration will be omitted.

[0094] In the control device 40 according to the sixth embodiment, at least one second unlocking condition is defined for determining that the locked state of the electric motor 30 has been released with a higher probability than that of the unlocking condition for a parameter for which the unlocking condition is set. Then, the control device 40 determines at predetermined intervals whether the unlocking condition and the second unlocking condition are satisfied.

[0095] While the unlocking condition is continuously satisfied, the control device 40 calculates the total score of the score when the unlocking condition is satisfied and the score when a second unlocking condition set higher than the score when the unlocking condition is satisfied. When this total score exceeds a threshold, the control device 40 considers that a predetermined period has elapsed and determines that the locked state of the electric motor 30 has been released.

[0096] FIG. 16 is a time chart showing an example in which the rotation speed of the electric motor 30 is used as a parameter for setting the unlocking condition, a first unlocking rotation speed is set as the unlocking condition, and a second unlocking rotation speed and a third unlocking rotation speed are set as at least one second unlocking condition for determining that the locked state of the electric motor 30 has been released with a higher probability than the first unlocking rotation speed.

[0097] In the example shown in the time chart of FIG. 16, the control device 40 compares the rotation speed of the electric motor 30 with each release rotation speed for each predetermined period. When the rotation speed of the electric motor 30 is equal to or greater than the first release rotation speed, the control device 40 calculates the score (for example, 1 point) when the rotation speed is equal to or greater than the first release rotation speed as the total score. Even if the rotation speed of the electric motor 30 becomes equal to or greater than the first release rotation speed once, the total score does not exceed the threshold value. When the rotation speed of the electric motor 30 is equal to or greater than the second release rotation speed in the next determination cycle, the control device 40 adds the score (for example, 2 points) when the rotation speed is equal to or greater than the second release rotation speed to the calculated total score to calculate the total score. In this case, the total score does not yet exceed the threshold value. Furthermore, when the rotation speed of the electric motor 30 is equal to or greater than the third release rotation speed in the next determination cycle, the control device 40 adds the score (for example, 10 points) when the rotation speed is equal to or greater than the third release rotation speed to the calculated total score to calculate the total score. In the example shown in the time chart of FIG. 16, since the calculated total score exceeds the threshold value at this point, it is considered that the predetermined period has elapsed, and it is determined that the locked state of the electric motor 30 has been resolved.

[0098] Also, as shown in the time chart of Fig. 17, when the rotation speed of the electric motor 30 becomes equal to or higher than the second release rotation speed once, but then drops below the second release rotation speed, for example, the score for when the rotation speed becomes equal to or higher than the second release rotation speed may be subtracted from the total score. The subtraction value may be larger or smaller than the score for when the rotation speed becomes equal to or higher than the second release rotation speed. Furthermore, the previous value and the current value of the rotation speed of the electric motor 30 may be compared, and only when the current value is larger than the previous value, the score may be added to the total score.

[0099] In this embodiment, when the rotation speed of the electric motor 30 falls to or below a reset rotation speed that is set to or below the first release rotation speed, the total value calculated up to that point is reset, and measurement of the predetermined period is stopped. In addition, the predetermined period corresponding to the unlocking condition set for the rotation speed and / or torque command of the electric motor 30, or a parameter related to at least one of them, may be changed by changing the threshold value based on the temperature of the switching module 24 or a parameter related thereto, that is, the coolant temperature or coolant flow rate of the cooling device 26.

[0100] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments and can be modified in various ways without departing from the spirit and scope of the present disclosure.

[0101] For example, in each of the above-described embodiments, the electric motor 30 is used to generate driving force for a vehicle, but the electric motor 30 may be used for other purposes.

[0102] Finally, this specification discloses the following technical ideas and combinations thereof:

[0103] (Technical thought 1) 1. A motor control device for controlling an electric motor (30) to which a current is applied via an inverter, comprising: A lock state determination unit (S100) that determines a lock state of the electric motor; a current limiting unit (S250) that limits a current supplied to the motor when the locked state determination unit determines that the motor is in a locked state; a release determination unit (S330, S336) that determines whether a release condition for determining whether the locked state of the electric motor is released is satisfied; and a limitation end unit (S450, S455, S470) that, when the period during which the release condition is satisfied continues for a predetermined period, determines that the locked state of the motor has been released and ends the current limiting by the current limiting unit.

[0104] (Technical thought 2) The motor control device according to Technical Idea 1 further includes a measurement canceling unit (S430, S435, S440, S445) that cancels measurement of the predetermined period when a cancellation condition for canceling the establishment of the release condition is satisfied before the predetermined period has elapsed.

[0105] (Technical Thought 3) The motor control device according to Technical Idea 1 or 2, wherein the release condition is set for at least one of the rotation speed of the motor, a torque command that commands the torque to be generated by the motor, and an element temperature of the inverter, or at least one of parameters related thereto.

[0106] (Technical Thought 4) the release condition is set for a parameter related to at least one of a rotation speed of the electric motor and a torque command that commands a torque to be generated by the electric motor, The motor control device according to Technical Idea 1 or 2, further comprising a setting unit (S332, S334) that detects a parameter related to an element temperature of the inverter, and sets the predetermined period based on the detected parameter related to the element temperature of the inverter so as to shorten the predetermined period set in response to the release condition when the element temperature of the inverter is low compared to when the element temperature of the inverter is high.

[0107] (Technical Thought 5) The release determination unit (S336) determines whether each of the plurality of release conditions is satisfied, The predetermined period is determined individually for each of the plurality of cancellation conditions, The motor control device according to any one of Technical Ideas 1 to 4, wherein the limitation end unit (S455, S470) determines that the locked state of the motor has been released and ends the current limitation by the current limiting unit when any of the predetermined periods individually determined for each of the plurality of release conditions has elapsed.

[0108] (Technical Thought 6) The plurality of cancellation conditions are set for the same parameter, The motor control device according to Technical Idea 5, wherein the predetermined periods individually determined for the multiple release conditions set for the same parameter are different from each other.

[0109] (Technical Thought 7) the same parameter is a rotation speed of the electric motor or a parameter correlated with the rotation speed of the electric motor, The plurality of release conditions include at least a first release condition that the electric motor rotates at or above a first rotation speed, and a second release condition that the electric motor rotates at or above a second rotation speed that is higher than the first rotation speed, The motor control device according to Technical Concept 6, wherein the predetermined period determined individually for the second release condition is shorter than the predetermined period determined individually for the first release condition.

[0110] (Technical Thought 8) the same parameter is a torque command that commands a torque to be generated by the electric motor or a parameter that is correlated with the torque command, The plurality of release conditions include at least a first release condition that the torque command is equal to or less than a first torque, and a second release condition that the torque command is equal to or less than a second torque that is lower than the first torque, The motor control device according to Technical Concept 6, wherein the predetermined period determined individually for the second release condition is shorter than the predetermined period determined individually for the first release condition.

[0111] (Technical Thought 9) The motor control device according to any one of Technical Ideas 1 to 8, wherein the restriction end unit measures the specified period using a timer that starts counting time when the release condition is satisfied, or measures the specified period by determining whether the release condition is satisfied at regular intervals and determining that the release condition is satisfied a specified number of times in succession.

[0112] (Technical Thought 10) The release determination unit (S336) determines whether each of the plurality of release conditions is satisfied, The predetermined period is determined individually for each of the plurality of cancellation conditions, The motor control device according to Technical Idea 9, wherein the predetermined number of times varies depending on the predetermined period that is individually determined for each of the plurality of cancellation conditions.

[0113] (Technical Thought 11) The release determination unit (S336) determines whether each of the plurality of release conditions is satisfied, The predetermined period is determined individually for each of the plurality of cancellation conditions, The motor control device according to Technical Idea 9 or 10, wherein the fixed interval varies depending on the predetermined period individually determined for each of the plurality of cancel conditions.

[0114] (Technical Thought 12) At least one second release condition is defined for determining that the locked state has been released with a higher probability than that of the parameter for which the release condition is set, the release determination unit determines at a predetermined interval whether the release condition and the second release condition are satisfied; The motor control device described in any one of Technical Ideas 1 to 4, wherein the restriction end unit calculates a total score of the score when the release condition is satisfied and a score when the second release condition, which is set higher than the score when the release condition is satisfied, while the release condition is continuously satisfied, and when the total score exceeds a threshold value, the motor control device considers that the specified period has elapsed.

[0115] (Technical Thought 13) The motor control device according to any one of Technical Ideas 1 to 12, further comprising a current limit reservation unit (S242, S244) that reserves the limit of the current supplied to the motor for a predetermined reservation time from the start of operation of the motor even if the lock state determination unit determines that the motor is in a locked state.

[0116] (Technical Thought 14) The motor control device according to any one of Technical Ideas 1 to 13, wherein the motor is used to drive a vehicle.

[0117] (Technical Thought 15) 1. A motor control method for controlling an electric motor (30) energized via an inverter, comprising: At least one processor has Determining whether the motor is locked (S100); If it is determined that the motor is locked, the current supplied to the motor is limited (S250); Determining whether or not a release condition for determining whether the locked state of the electric motor is released is satisfied (S330, S336); and and terminating the limit on the current supplied to the motor when the period during which the release condition is satisfied continues for a predetermined period of time (S450, S455, S470). [Explanation of symbols]

[0118] 10: battery, 12: boost circuit, 20: power conversion circuit, 22: smoothing capacitor, 24: switching module, 26: cooling device, 28: temperature sensor, 30: electric motor, 32: rotation sensor, 40: control device

Claims

1. A motor control device for controlling an electric motor (30) to which a current is passed through an inverter, comprising: A lock state determination unit (S100) that determines a lock state of the electric motor; a current limiting unit (S250) that limits a current supplied to the motor when the locked state determination unit determines that the motor is in a locked state; a release determination unit (S330, S336) that determines whether a release condition for determining whether the locked state of the electric motor is released is satisfied; a limitation ending unit (S450, S455, S470) that, when the period during which the release condition is satisfied continues for a predetermined period, determines that the locked state of the motor has been released and ends the current limiting by the current limiting unit, the release determination unit determines whether or not each of the plurality of release conditions is satisfied, The predetermined period is determined individually for each of the plurality of cancellation conditions, The limitation end unit determines that the locked state of the motor has been released when any of the predetermined periods individually defined for each of the plurality of release conditions has elapsed, and ends the current limitation by the current limiting unit.

2. 2. The motor control device according to claim 1, further comprising a measurement canceling unit (S430, S435, S440, S445) that cancels measurement of the predetermined period when a cancellation condition for canceling establishment of the release condition is satisfied before the predetermined period has elapsed.

3. 3. The motor control device according to claim 1, wherein the release condition is set for at least one of a rotation speed of the motor, a torque command that commands a torque to be generated by the motor, and an element temperature of the inverter, or at least one of parameters related thereto.

4. the release condition is set for a parameter related to at least one of a rotation speed of the electric motor and a torque command that commands a torque to be generated by the electric motor, 3. The motor control device according to claim 1, further comprising a setting unit (S332, S334) that detects a parameter related to an element temperature of the inverter, and sets the predetermined period so as to shorten the predetermined period set in accordance with the release condition when the element temperature of the inverter is low compared to when the element temperature of the inverter is high, based on the detected parameter related to the element temperature of the inverter.

5. The plurality of cancellation conditions are set for the same parameter, The motor control device according to claim 1 , wherein the predetermined periods individually determined for the plurality of release conditions set for the same parameter are different from each other.

6. the same parameter is a rotation speed of the electric motor or a parameter correlated with the rotation speed of the electric motor, The plurality of release conditions include at least a first release condition that the electric motor rotates at or above a first rotation speed, and a second release condition that the electric motor rotates at or above a second rotation speed that is higher than the first rotation speed, The motor control device according to claim 5 , wherein the predetermined period determined individually for the second release condition is shorter than the predetermined period determined individually for the first release condition.

7. the same parameter is a torque command that commands a torque to be generated by the electric motor or a parameter that is correlated with the torque command, The plurality of release conditions include at least a first release condition that the torque command is equal to or less than a first torque, and a second release condition that the torque command is equal to or less than a second torque that is lower than the first torque, The motor control device according to claim 5 , wherein the predetermined period determined individually for the second release condition is shorter than the predetermined period determined individually for the first release condition.

8. 3. The motor control device according to claim 1, wherein the restriction end unit measures the predetermined period by using a timer that starts counting time when the release condition is satisfied, or by determining at regular intervals whether the release condition is satisfied and determining that the release condition is satisfied a predetermined number of times in succession, thereby measuring the predetermined period.

9. The motor control device according to claim 8 , wherein the predetermined number of times varies depending on the predetermined period that is individually determined for each of the plurality of cancel conditions.

10. The motor control device according to claim 8 , wherein the constant interval differs depending on the predetermined period that is individually determined for each of the plurality of cancel conditions.

11. At least one second release condition is defined for determining that the locked state has been released with a higher probability than that of the parameter for which the release condition is set, the release determination unit determines at a predetermined interval whether the release condition and the second release condition are satisfied; The motor control device according to claim 1 or 2, wherein the restriction end unit calculates a total score of the score when the release condition is satisfied and a score when the second release condition, which is set higher than the score when the release condition is satisfied, while the release condition is continuously satisfied, and when the total score exceeds a threshold value, the motor control device considers that the specified period has elapsed.

12. 3. The motor control device according to claim 1, further comprising a current limit reservation unit (S242, S244) that reserves limiting the current supplied to the motor for a predetermined reservation time from the start of operation of the motor even if the locked state determination unit determines that the motor is in a locked state.

13. The electric motor control device according to claim 1 or 2, wherein the electric motor is used to drive a vehicle.

14. A motor control program for controlling an electric motor (30) to which a current is applied via an inverter, comprising: At least one processor, A locked state of the electric motor is determined (S100); If it is determined that the motor is locked, the current supplied to the motor is limited (S250). A determination is made as to whether or not a release condition for determining whether the locked state of the electric motor is released is satisfied (S330, S336); The method includes a command to terminate the limit of the current supplied to the motor by determining that the locked state of the motor has been released when the period during which the release condition is satisfied continues for a predetermined period (S450, S455, S470), the instruction to determine whether or not the termination condition is satisfied determines whether or not each of the termination conditions is satisfied for a plurality of the termination conditions; The predetermined period is determined individually for each of the plurality of cancellation conditions, A motor control program in which a command to end the limit of the current flowing through the motor is issued when any of the predetermined periods individually determined for each of the plurality of release conditions has elapsed, and the program determines that the locked state of the motor has been released, and ends the limit of the current flowing through the motor.

Images