JP2008054433A - Electric vehicle motor control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric vehicle motor control device capable of preventing an abnormal temperature rise in an inverter 14 or a motor 10, and preventing problems from occurring during restart of running if an acceleration is switched on with a parking brake switched on. <P>SOLUTION: This control unit has a temperature sensor 18 which detects the temperature of the inverter 14 or the motor 10, a parking brake status detecting sensor 20 which detects an on/off status of the parking brake, an acceleration status detecting sensor 22 which detects an on/off status of the acceleration, and a motor control part 16. The motor control unit 16 performs torque limit control when the on status of the parking brake and the on status of the acceleration are detected, and the temperature of the inverter 14 or the motor 10 is a predetermined temperature or more. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric vehicle motor control device including an inverter that drives a motor of an electric vehicle and a motor control unit that sends a control signal for driving the motor to the inverter.

  Conventionally, in an electric vehicle equipped with a motor such as an electric vehicle or a hybrid vehicle, an inverter and a motor control unit are provided between the motor that is a multi-phase rotating machine and a power supply device, and a drive signal is sent to the motor by the inverter. It is known to send a motor current to drive the motor. The inverter converts the DC power from the power supply device into an AC current determined according to the torque command value, and sends the motor current to the motor. The motor control unit sends a control signal for generating a motor current to the inverter.

  In such an electric vehicle, the vehicle may be stopped in a state where the parking brake is turned on in the middle of an uphill (a state in which the parking brake is pulled when the hand brake is applied and a foot brake is depressed). . In this case, there is a possibility that the driver turns on the accelerator, for example, depresses the accelerator while the parking brake is turned on accidentally while trying to resume traveling. When such a situation occurs, the driving force may not overcome the braking force of the parking brake, and the motor may be locked. When the motor locks, a large amount of current flows through some of the inverter's electrical elements and some phases of the motor's coils, i.e., significantly more current flows than other electrical elements and other phase coils. There is a possibility of flowing in the electrical elements and coils of the part.

  For example, the inverter is constituted by electric elements such as a plurality of power transistors and IGBTs, but when the motor is locked, a large current flows through some electric elements in a concentrated manner. In this case, the temperature of some electric elements of the inverter and the coils of some phases of the motor may rise abnormally. On the other hand, conventionally, in order to prevent a failure due to a temperature rise of the inverter or the motor, it is considered that the motor control unit performs the load factor limiting control for limiting the motor load factor.

  Here, for example, as shown in FIG. 5, for example, the motor load factor increases as the accelerator opening increases. A map representing the relationship as shown in FIG. 5 is mounted in the motor control unit, and the motor control unit obtains the motor load factor Rm from the accelerator opening and the map input as an accelerator signal. The torque command calculation means constituting the motor control unit calculates a torque command value Tc based on the motor load factor Rm thus determined. That is, the torque command value is obtained by proportionally dividing the torque range determined by the maximum torque Tmax and the minimum torque Tmin of the motor by the motor load factor, as shown by the following equation (1). The maximum torques Tmax and Tmin can be obtained from the motor rotation speed N with reference to the Tmax table and the Tmin table.

Tc = (Tmax−Tmin) × Rm + Tmin (1)
The motor control unit obtains a current command value corresponding to the torque command value Tc obtained by the equation (1), and controls the motor torque by sending a control signal corresponding to the current command value to the inverter.

  On the other hand, when the motor load factor is limited when the temperature of the inverter or the motor is abnormally increased, for example, a map of the motor load factor and the accelerator opening is used regardless of the size of the accelerator opening. It is conceivable to change to a load factor limiting map that limits the maximum value of the rate to a predetermined value lower than the normal value, and calculate the torque command value from the load factor based on the load factor limiting map. Due to such limitation of the motor load factor, the current flowing through the motor is reduced, and the temperature of the inverter and the motor is lowered.

  In Patent Document 1, all of the three-phase coils of the motor are provided with temperature-sensitive resistance elements that directly or indirectly detect temperature, and the voltages at both ends of a circuit in which the temperature-sensitive resistance elements are electrically connected in parallel are provided. When the controller uses a voltage / temperature conversion table that is different between when the motor is locked and during steady operation based on the voltage signal, and the temperature obtained from the table exceeds the set temperature Describes a motor control device that performs temperature rise suppression control for limiting the output of the motor.

  Further, in Patent Document 2, when it is determined that the electric vehicle is in a locked state, the temperature monitor detects the switching element having the highest current value of the switching elements constituting the inverter, and the detected switching element There is described a motor control device that changes a current command value so as to reduce a current value flowing through the switching element while maintaining the same torque output when it is determined that the temperature is equal to or higher than a predetermined temperature.

  Further, in Patent Document 3, the electric vehicle falls into a locked state on an uphill, that is, the rotational speed of the motor is smaller than a predetermined value, and a torque command value for controlling the switching elements constituting the inverter is predetermined. There is described an overload prevention device for an electric vehicle that reduces a torque limit value of a motor with respect to a junction temperature of a switching element by a predetermined value by a torque reduction means when the value exceeds a value.

  Further, Patent Document 4 includes an accelerator sensor that detects an accelerator on state, a lock state detection sensor that detects a lock state of a side brake, and a control unit in a power supply control device for an electric vehicle. The part describes that when the lock state is detected by the lock state detection sensor and the on state is detected by the accelerator sensor, the power switch inserted between the motor and the battery is opened. .

JP 2002-315383 A JP 2005-354785 A JP 11-215687 A JP-A-8-65801

  As mentioned above, when the accelerator is turned on while the parking brake is on on the slope during climbing, etc., the motor is locked and the motor control unit performs load factor limiting control. In this case, even if the parking brake is turned off and the accelerator is turned on to restart the running of the electric vehicle, the motor control unit may continue to perform the load factor limiting control while the temperature of the inverter and the motor rises. is there. In this case, even if the accelerator is depressed, there is a possibility that the electric vehicle may slide down without obtaining the torque required for climbing.

  In addition, in order to prevent an abnormal temperature rise of the inverter or motor, the motor load factor map is not switched to the load factor limiting map, but the torque command value calculated by the torque command calculating means of the motor control unit or the torque command It is also conceivable to perform torque limit control for limiting the maximum value of the current command value calculated by the current command calculation means to a predetermined value or less corresponding to the value. However, in this case as well, there is a possibility that the necessary torque cannot be obtained when the vehicle is restarted when the accelerator is turned on while the parking brake is kept on.

  On the other hand, the motor control device described in Patent Literature 1 and Patent Literature 2, the overload prevention device for an electric vehicle described in Patent Literature 3, and the power supply control device for driving an electric vehicle described in Patent Literature 4 In either case, the inverter or motor temperature is prevented from rising abnormally, even while the vehicle is running, and the accelerator is accidentally turned on while the parking brake is on on the slope. There is a possibility that inconvenience that occurs when the vehicle stops, that is, even if the accelerator is depressed to restart the running later, the required torque cannot be obtained and the effect of preventing the electric vehicle from sliding down may not be obtained.

  An object of the present invention is to prevent an inverter or motor temperature from rising abnormally even during traveling in an electric vehicle motor control device and to turn on an accelerator while a parking brake is kept on a slope. The purpose is to prevent inconveniences that occur when resuming traveling.

  An electric vehicle motor control device according to the present invention includes an inverter that drives a motor of an electric vehicle, a motor control unit that sends a control signal for driving the motor to the inverter, and a temperature detection means that detects the temperature of the inverter or the motor. A parking brake state detection sensor for detecting an on / off state of the parking brake, and an accelerator state detection sensor for detecting an on / off state of the accelerator, and the motor control unit generates a current based on a torque command value input from the torque command calculation means. Current command calculation means for outputting a command value is provided, and the first torque limit control is performed when the parking brake ON state and the accelerator ON state are detected, and the temperature of the inverter or the motor is equal to or higher than a predetermined temperature. Is detected, the second torque limit control is performed, and the first torque limit control And the second torque limit control is an electric motor characterized in that the maximum value of the torque command value calculated by the torque command calculation means is lowered or the maximum value of the current command value corresponding to the torque command value is lowered. It is a vehicle motor control device. In addition, lowering the maximum value of the torque command value calculated by the torque command calculation means is based on the map of the motor load factor and the accelerator opening described in the above Background Art section, and the maximum value of the motor load factor. Is changed to a load factor limiting map that limits the value to a predetermined value lower than the normal value, and the torque command value is calculated from the load factor based on the load factor limiting map.

  Preferably, in at least one of the first torque limit control and the second torque limit control, a torque command value calculated by the torque command calculation means or a current command value corresponding to the torque command value exceeds a threshold value In this case, the torque command value or the current command value is changed to a threshold value.

  Preferably, at least one of the first torque limit control and the second torque limit control is a map representing the relationship between the accelerator opening and the torque command value, and the maximum torque command value is calculated from the map at the normal time. The map is switched to a torque limit map that makes the value lower than the normal map or reduces the degree to which the torque command value increases in accordance with the accelerator opening.

  More preferably, in the first torque limit control, when the accelerator opening is not zero, the torque command value is not zero.

  The electric vehicle motor control device according to the present invention includes a temperature detection unit that detects the temperature of the inverter or the motor and a motor control unit, and the motor control unit is based on a torque command value input from the torque command calculation unit. Having a current command calculation means for outputting a current command value, and lowering the maximum value of the torque command value calculated by the torque command calculation means when it is detected that the temperature of the inverter or the motor is equal to or higher than a predetermined temperature; Alternatively, since the second torque limit control for reducing the maximum value of the current command value corresponding to the torque command value is performed, it is possible to prevent the temperature of the inverter or the motor from rising abnormally even during traveling. In addition, according to the present invention, the parking brake state detection sensor that detects the on / off state of the parking brake and the accelerator state detection sensor that detects the on / off state of the accelerator are provided, and the motor control unit includes the on state and the accelerator of the parking brake. A first torque limit that lowers the maximum value of the torque command value calculated by the torque command calculation means or lowers the maximum value of the current command value corresponding to the torque command value Even if the accelerator is turned on while the parking brake is on the slope during the climbing of the vehicle, the motor torque limit is set before the inverter or motor temperature rises abnormally. Yes. For this reason, if the parking brake is turned off and the accelerator is turned on in order to resume running later, the motor torque is not limited by the abnormal temperature rise of the inverter or motor, and normal driving can be performed immediately. The inconvenience at the time of resuming the traveling that the vehicle slides down on the slope regardless of the depression of the vehicle is not caused.

  In the first torque limit control, when the accelerator opening is not 0, the torque command value is not 0. According to the configuration, the parking brake is kept on on the slope during the climbing of the vehicle. When the accelerator is turned on, the parking brake is turned off to resume driving and the accelerator is turned on, so that the required torque can be obtained more quickly and the driver is less likely to feel discomfort. it can.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. 1 to 4 show an embodiment of the present invention. The electric vehicle motor control apparatus according to the present embodiment is used by being mounted on an electric vehicle such as a hybrid vehicle or an electric vehicle. As shown in FIG. 1, the electric vehicle motor control device includes a battery 12 that supplies DC power, an inverter 14 that converts DC power from the battery 12 into AC power, and an AC current (U-phase current) generated by the inverter 14. (ium, V-phase current ivm, W-phase current iwm), a three-phase AC motor 10 that drives the vehicle, a motor controller 16 that sends a control signal for driving the motor 10 to the inverter 14, and a temperature A temperature sensor 18, which is a detection means, a parking brake state detection sensor 20, and an accelerator state detection sensor 22 are provided.

  Inverter 14 is connected to a positive electrode and a negative electrode of battery 12, and includes a switching element that is a plurality of electric elements such as an IGBT and a power transistor, and a protective diode connected corresponding to each switching element. The plurality of switching elements are respectively connected to three-phase (U-phase, V-phase, W-phase) windings of the motor 10. For example, when the switching element is a power transistor, three inverter arms each composed of two power transistors connected in series are provided between a pair of power supply lines extending from the positive electrode and the negative electrode of the battery 12, and the midpoint of the power transistor Are connected to the three-phase coils of the motor 10, respectively. Then, the connection between the motor 10 and the battery 12 is controlled by controlling on / off of the switching element.

  The temperature sensor 18 detects the temperature of the inverter 14 or the motor 10. The parking brake state detection sensor 20 detects whether or not the parking brake is in a locked state. For example, when the parking brake is a hand brake, the parking brake state detection sensor 20 is a limit switch linked to the hand brake lever. When the foot brake is used, the limit switch is linked to the foot brake pedal. The accelerator state detection sensor 22 detects whether or not the accelerator is in an on state, and is, for example, a limit switch that is linked to the accelerator pedal. The accelerator state detection sensor 22 can be replaced by an accelerator opening sensor 24 that detects the accelerator opening. The accelerator opening sensor 24 detects the accelerator pedal depression amount to obtain the accelerator opening. In place of the limit switch, a non-contact switch such as a proximity sensor that detects the approach of an object from an electrical change or a photoelectric switch that detects the presence or absence of an object using light can be used.

  The motor control unit 16 includes a torque command calculation unit 26, a current command calculation unit 28, a current command / control signal conversion unit 30, a feedback conversion unit 32, and a torque limit control availability determination unit 34. The feedback conversion unit 32 converts the currents ium, ivm, and iwm detected by the U-phase current sensor, the V-phase current sensor, and the W-phase current sensor into d-axis current and q-axis current by three-phase / two-phase conversion. Input to the command / control signal conversion means 30. The current command calculation means 28 is based on the output torque command value input from the torque command calculation means 26, the U-phase current equivalent value, the V-phase current equivalent value, the W-phase current equivalent value, etc. input from the feedback converter 32. A d-axis current command value id * and a q-axis current command value iq *, which are current command values, are calculated and input to the current command / control signal conversion means 30. The torque command calculation means 26 calculates an output torque command value based on the accelerator opening input from the accelerator opening sensor 24 and the determination result of torque limit control availability input from the torque limit control availability determination means 34. , And input to the current command calculation means 28.

  Further, the current command / control signal conversion means 30 calculates the d-axis current command value id *, the q-axis current command value iq *, the d-axis current id input from the feedback conversion unit 32, and the q-axis current iq from d After generating the voltage command values for the axis and the q-axis, the voltage command value is converted into a three-phase AC voltage command value, and further, PWM control signals vu, vud, vvu, vvd, vwu, vwd are generated and input to the inverter 14.

On the other hand, the torque limit control enable / disable determining means 34 receives the detection signals from the parking brake state detection sensor 20 and the accelerator state detection sensor 22, and when the parking brake is on and the accelerator is on. It is determined that it is necessary to perform the torque limit control 1, and a signal representing the determination result is input to the torque command calculation means 26. On the other hand, when at least one of the parking brake and the accelerator is in the off state, the torque limit control availability determination unit 34 determines that the first torque limit control is not necessary and determines the determination result. A representative signal is input to the torque command calculation means 26. Further, when the temperature of the inverter 14 or the motor 10 detected by the temperature sensor 18 is input and the temperature is equal to or higher than a predetermined temperature t ₁ determined in advance, the torque limit control availability determination unit 34 14 or is in the motor 10 is overheated, it is determined that it is necessary to perform the second torque restriction control, when the temperature of the inverter 14 or the motor 10 is lower than the predetermined temperature t _1, the inverter 14 or the motor 10 is It is determined that the second torque limit control is not necessary because the engine is not overheated, and a signal representing the determination result is input to the torque command calculation means 26.

  In the first torque limit control and the second torque limit control, the maximum value of the output torque command value calculated by the torque command calculation means 26 is limited to a value equal to or less than a predetermined torque command value lower than normal. For example, in the case of the present embodiment, at least one of the first torque limit control and the second torque limit control is calculated by the torque command calculation means 26 (FIG. 1) as shown by the solid line in FIG. When the output torque command value exceeds a predetermined torque command value that is a threshold value, the output torque command value is changed to a predetermined torque command value. In this case, the output torque command value does not exceed the predetermined torque command value. Further, in the first torque limit control performed when the parking brake and the accelerator are both in the on state, the output torque command value is set not to be zero when the accelerator opening is not zero. In FIG. 2, the broken line indicates the output torque command value corresponding to the accelerator opening at the normal time, i.e., the required torque command value, in which torque limit control is not performed. Further, when the motor 10 is locked, the maximum value of the d-axis current command value id * is finally lower than normal by performing the first torque limit control or the second torque limit control. It shall be below the specified current command value.

  FIG. 3 is a flowchart for explaining the operation of the electric vehicle motor control device. First, as step S1, in the torque limit control availability determination means 34 (FIG. 1), it is determined whether or not the accelerator is in an on state by a signal from the accelerator state detection sensor 22 (FIG. 1), and is in an on state. If it is determined that, then in step S2, a required torque command value corresponding to the accelerator opening is calculated by the torque command calculating means 26 (FIG. 1) based on a signal from the accelerator opening sensor 24 (FIG. 1). . Next, in step S3, the torque limit control enable / disable determining means 34 determines whether or not the parking brake is on based on a signal from the parking brake state detection sensor 20 (FIG. 1). If it is determined, it is determined in step S4 that the first torque limit control needs to be performed. Then, the torque command calculation means 26 limits the required torque command value to a predetermined torque command value or less, and calculates it as a limited output torque command value (step S5). The limited output torque command value is input to the current command calculation means 28 (FIG. 1).

On the other hand, when the torque limit control availability determination means 34 determines in step S3 that the parking brake is in an OFF state based on a signal from the parking brake state detection sensor 20, as step S6a, the inverter 14 or the motor 10 The temperature is detected by the temperature sensor 18 (FIG. 1). Then, in step S6b, the torque limitation control determination unit 34, when the temperature sensor 18 the temperature of the inverter 14 or the motor 10 is detected to be at a predetermined temperature t ₁ or more, as step S6c, the second It is determined that it is necessary to perform torque limit control, the torque command calculation means 26 limits the required torque command value to a predetermined torque command value or less, and calculates it as a limited output torque command value (step S6d). The limited output torque command value is also input to the current command calculation means 28.

In contrast, in step S6b, the torque limitation control determination unit 34, when the temperature sensor 18 the temperature of the inverter 14 or the motor 10 that has been detected is less than the predetermined temperature t _1, the first torque It is determined that neither the limit control nor the second torque limit control needs to be performed, and in step S7, the torque command calculation means 26 outputs the requested torque command value as an output torque command value not subjected to torque limit control. Input to the command calculation means 28.

In the case of such an electric vehicle motor control device of the present embodiment, a temperature sensor 18 that detects the temperature of the inverter 14 or the motor 10 and a motor control unit 16 are provided. A current command calculation means for outputting a current command value based on the output torque command value inputted, and when the temperature sensor detects that the temperature of the inverter or the motor is equal to or higher than a predetermined temperature t ₁ Since the second torque limit control is performed to limit the maximum value of the output torque command value calculated by the torque command calculation means 26 to be lower than the predetermined torque command value, the temperature of the inverter 14 or the motor 10 is included even during traveling. An abnormal rise can be prevented, and a failure due to a temperature rise of the inverter 14 or the motor 10 can be prevented.

  In addition, a parking brake state detection sensor 20 that detects an on / off state of the parking brake and an accelerator state detection sensor 22 that detects an on / off state of the accelerator are provided. The motor control unit 16 includes an on state of the parking brake and an on state of the accelerator. Is detected, the first torque limit control is performed to limit the maximum value of the output torque command value calculated by the torque command calculation means 26 to be equal to or lower than the predetermined torque command value. Even when the accelerator is turned on while the parking brake is kept on the slope, the torque of the motor 10 can be limited before the temperature of the inverter 14 or the motor 10 rises abnormally. For this reason, if the parking brake is turned off and the accelerator is turned on in order to resume running later, the torque of the motor 10 is not limited by the abnormal temperature rise of the inverter 14 or the motor 10, and normal driving is immediately started. This can be done without causing the inconvenience at the time of resuming traveling that the vehicle slides down on a slope regardless of the depression of the accelerator.

  Further, in the first torque limit control, when the accelerator opening is not 0, the output torque command value is not 0, so that the parking brake is kept on on the slope during the climbing of the vehicle, etc. When the accelerator is turned on, the required torque can be obtained more quickly by turning off the parking brake and turning on the accelerator in order to resume running, thereby making it less likely that the driver feels uncomfortable.

FIG. 4 shows an example of the relationship between the temperature of the inverter 14 (FIG. 1) and the passage of time for explaining further effects obtained by the present embodiment. Although the case where the temperature of the inverter 14 is detected will be described here, the same effect can be obtained when the temperature of the motor 10 is detected. In the case of the present embodiment shown by a solid line in FIG. 4, when the accelerator is turned on while the parking brake is turned on at the time indicated by point A, the motor 10 is locked, but the motor control unit 16 (FIG. 1) is the first. Therefore, the maximum value of the output torque command value calculated by the torque command calculation means 26 is limited to be lower than the predetermined torque command value, and the temperature of the inverter 14 does not increase or the amount of increase is sufficient. It can be kept low. At the time indicated by point B, even if the accelerator is turned on with the parking turned off in an attempt to resume running, the second torque limit control in the case of the abnormal temperature rise of the inverter 14 is not performed, and the torque The command calculation means 26 outputs a required torque command value corresponding to the accelerator opening as an output torque command value. For this reason, the normal driving | running | working in which the torque limitation of the motor 10 is not performed can be performed. In this case, the temperature of the inverter 14 rises in accordance with the accelerator opening increases, the time from the time point indicated in point B until the temperature of the inverter 14 reaches a predetermined temperature t ₁ the second torque restriction control is executed T ₁ can be made sufficiently long or the inverter 14 can be prevented from reaching the predetermined temperature t ₁ .

On the other hand, the broken line in FIG. 4 shows a comparative example. In the case of this comparative example, the motor control unit 16 does not perform the first torque limit control even when the parking brake is on and the accelerator is on. In the case of such a comparative example, when the accelerator is turned on while the parking brake is turned on at the time indicated by point A, the motor 10 is locked, so the temperature of some switching elements of the inverter 14 rises, The temperature of the inverter 14 continues to rise. When the temperature of the inverter 14 reaches the predetermined temperature t ₁ at the time indicated by the point C, the second torque limit control is performed, so that the temperature of the inverter 14 gradually decreases and falls below the predetermined temperature t ₁ . However, in the short time the temperature of the inverter 14, since not drop enough compared to the predetermined temperature t _1, trying to resume running at the time shown in the point D, when turning on the accelerator in the OFF state of the parking brake, short will the temperature of the inverter 14 reaches a predetermined temperature t ₁ at time T _2, the second torque restriction control is executed again. For this reason, even if it starts driving | running | working, the torque of a motor will be restrict | limited immediately and there exists a possibility that the output which a driver | operator desires cannot be obtained. According to this embodiment, since the first torque limit control is performed as described above, such inconvenience does not occur.

  In the above-described embodiment, the signal from the torque limit control enable / disable determining means 34 is input to the torque command calculating means 26. However, as shown by the broken arrow a in FIG. After the signal from the means 34 is input to the current command calculation means 28 and the unrestricted output torque command value corresponding to the accelerator opening is converted into a current command value by the current command calculation means 28, the first torque When at least one of the limit control and the second torque limit control is performed, the maximum value of the current command value corresponding to the output torque command value calculated by the torque command calculation means 26 is set to be equal to or less than a predetermined current command value that is a threshold value. It is also possible to limit the lower than normal. Also in this case, even if the accelerator is turned on while the parking brake is kept on the slope during the climbing of the vehicle, the torque of the motor 10 before the temperature of the inverter 14 or the motor 10 rises abnormally. If the parking brake is turned off and the accelerator is turned on in order to resume driving, the torque of the motor 10 is not limited by the abnormal temperature rise of the inverter 14 or the motor 10, and normal driving can be immediately performed. The vehicle does not cause the inconvenience of sliding down a slope.

  In the above embodiment, the temperature sensor 18 detects the temperature of the inverter 14 or the motor 10 and inputs it to the torque limit control availability determination means 34. However, a plurality of temperature sensors 18 are provided, and the inverter 14 And the temperature of the motor 10 are detected by different sensors, and the detected temperature values are input to the torque limit control enable / disable determining unit 34, and at least one of the detected temperature values is equal to or higher than a predetermined temperature defined by each. In this case, it can be determined that the temperature is abnormal.

  Further, in the motor control unit 16, a map representing the relationship between the output torque command value and the accelerator opening as shown in FIG. 2 is used as a map, and a map for normal time corresponding to the broken line in FIG. A plurality of types of maps with a torque limit map corresponding to the solid line are prepared in advance, and when performing at least one of the first torque limit control and the second torque limit control, It is also possible to switch to the torque limit map and obtain the output torque command value based on the torque limit map by the torque command calculation means 26. That is, when the accelerator opening is input from the accelerator opening sensor 24 to the torque command calculation means 26, the output torque command value in which the upper limit is limited to a predetermined torque command value or less based on the torque limit map and the accelerator opening. Ask for. Further, as shown by a one-dot chain line in FIG. 2, in the map showing the relationship between the accelerator opening and the output torque command value, the degree to which the output torque command value increases according to the accelerator opening is reduced, that is, the slope is moderated. When the torque limiting map is prepared and at least one of the first torque limiting control and the second torque limiting control is performed, the torque limiting map corresponding to the one-dot chain line in FIG. By switching to the map, the output torque command value can be obtained from the accelerator opening.

  Note that FIG. 2 is merely an example showing the relationship between the accelerator opening and the torque command value, and the torque command value rises linearly according to the accelerator opening both at the normal time and when the torque is limited. It is not limited to those that change.

  Further, when at least one of the first torque limit control and the second torque limit control is performed, the output torque command value is always set to 0 even when the accelerator opening is not 0, that is, when the accelerator is turned on. Torque limitation can also be performed. In this case, unlike the case of the above-described embodiment, if the accelerator is turned on while the parking brake is kept on the slope during the climbing of the vehicle, the parking brake tries to resume running. If is turned off, there is a possibility that the required torque can be obtained more quickly and the driver's uncomfortable feeling can be made less likely to be obtained. However, even in this case, when the parking brake is turned off and the running is resumed, the torque of the motor 10 is not limited by the abnormal temperature rise of the inverter 14 or the motor 10, so that the normal running can be performed immediately. The effect of the present invention can be obtained that there is no inconvenience of sliding down on a slope.

  In the above embodiment, the map representing the relationship between the accelerator opening and the motor load factor, as described in the background section above, is used for motor control. The torque limit control of the motor can be performed by switching the map to limit the load factor when performing at least one of the first torque limit control and the second torque limit control. In this case, the map for limiting the load factor is a map in which the maximum value of the motor load factor is limited to a predetermined value lower than the normal value. Then, the map is switched according to the determination result from the torque limit control availability determination means 34 (FIG. 1). The torque command calculation means 26 (FIG. 1) calculates a torque command value corresponding to the load factor obtained from the map, and inputs it to the current command calculation means 28 (FIG. 1). When the load factor limiting map is used in this way, the maximum value of the torque command value calculated by the torque command calculation means 26 becomes lower than that at the normal time.

  In the present invention, the first torque limit control and the second torque limit control need not be the same, and different controls can be performed within the scope of the present invention.

It is a block diagram which shows the electric vehicle motor control apparatus of embodiment of this invention. It is a figure which similarly shows the relationship between the accelerator opening degree in the case of performing torque restriction control by a torque command calculation means, and an output torque command value. It is a figure which similarly shows the flowchart for demonstrating operation | movement of an electric vehicle motor control apparatus. It is a figure which shows one example of the relationship between time passage and the detected temperature of an inverter for demonstrating another effect of embodiment of this invention. It is a figure which shows one example of the relationship between an accelerator opening and a motor load factor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Motor, 12 Battery, 14 Inverter, 16 Motor control part, 18 Temperature sensor, 20 Parking brake state detection sensor, 22 Accelerator state detection sensor, 24 Accelerator opening degree sensor, 26 Torque command calculation means, 28 Current command calculation means, 30 Current command / control signal conversion means, 32 feedback conversion section, 34 torque limit control availability determination means.

Claims (4)

An inverter that drives the motor of the electric vehicle;
A motor control unit for sending a control signal for driving the motor to the inverter;
Temperature detecting means for detecting the temperature of the inverter or motor;
A parking brake state detection sensor for detecting an on / off state of the parking brake;
An accelerator state detection sensor for detecting the on / off state of the accelerator,
The motor control unit has a current command calculation means for outputting a current command value based on the torque command value input from the torque command calculation means. When the parking brake on state and the accelerator on state are detected, the motor control unit The torque limit control of 1 is performed, and when it is detected that the temperature of the inverter or the motor is equal to or higher than the predetermined temperature, the second torque limit control is performed,
In the first torque limit control and the second torque limit control, the maximum value of the torque command value calculated by the torque command calculation means is decreased, or the maximum value of the current command value corresponding to the torque command value is decreased. The electric vehicle motor control apparatus characterized by the above-mentioned. In the electric vehicle motor control device according to claim 1,
At least one of the first torque limit control and the second torque limit control is performed when the torque command value calculated by the torque command calculation means or the current command value corresponding to the torque command value exceeds a threshold value. An electric vehicle motor control device characterized by changing a value or a current command value to a threshold value. In the electric vehicle motor control device according to claim 1,
At least one of the first torque limit control and the second torque limit control is a map representing the relationship between the accelerator opening and the torque command value, and the maximum value of the torque command value is determined from the normal map. An electric vehicle motor control device that switches to a torque limiting map that is lower than the map or that reduces the degree to which the torque command value increases in accordance with the accelerator opening. In the electric vehicle motor control device according to any one of claims 1 to 3,
The first torque limiting control is an electric vehicle motor control device characterized in that the torque command value is not zero when the accelerator opening is not zero.

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