Control device, drive device and control method

Abstract

To provide a control apparatus, a driving device, and a control method, capable of making a motor delivery sufficient performance while suppressing a temperature rise of the motor.SOLUTION: A control apparatus for controlling a motor, includes: a temperature sensor that measures a temperature of the motor; and a torque limit part that limits torque of the motor on the basis of the temperature measured by the temperature sensor. The torque limit part performs a first torque limit for limiting the torque of the motor by a limit rate represented by a primary function when a first constant number is set as an inclination to the measured temperature when the measured temperature is a first threshold value or more, performs a second torque limit for limiting the torque of the motor by a limit rate represented by the primary function when a second constant number is set as the inclination to the measured temperature when the measured temperature is a second threshold value or more which is higher than the first threshold value, and performs a third torque limit for stopping a power conduction to the motor when the measured temperature is a third threshold value or more which is higher than the second threshold value. The first constant number is larger than the second constant number.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a control device, a drive device, and a control method. [Background technology]

[0002] In recent years, there has been active development of drive motors to be mounted on electric vehicles. In such motors, if the temperature of the motor becomes too high, there is a risk that the insulating coating of the coil wire of the motor will be damaged. Patent Document 1 discloses a drive device that limits the drive torque of the motor when the temperature of the motor becomes high. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-189764 A Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional driving devices, the limit of the motor's driving torque is linearly controlled by the temperature of the motor. However, since the temperature measurement result by the temperature sensor is output with a delay relative to the actual temperature change of the motor, when the temperature of the motor rises rapidly, the limit of the driving torque may be insufficient, and the rise in the temperature of the motor may not be suppressed. On the other hand, if the limit of the driving torque relative to the rise in the temperature of the motor is simply increased in consideration of the delay of the temperature sensor, the performance of the motor may be restricted more than necessary.

[0005] In view of the above circumstances, an object of the present invention is to provide a control device, a drive device, and a control method that are capable of suppressing a temperature rise in the motor while allowing the motor to fully exhibit its performance. [Means for solving the problem]

[0006] One embodiment of the driving device of the present invention is a control device for controlling a motor, the control device having a temperature sensor for measuring a temperature of the motor, and a torque limiting unit for limiting the torque of the motor based on the temperature measured by the temperature sensor. When the measured temperature is equal to or higher than a first threshold, the torque limiting unit performs a first torque limit for limiting the torque of the motor at a limiting rate expressed by a linear function with a slope of a first constant with respect to the measured temperature, when the measured temperature is equal to or higher than a second threshold higher than the first threshold, performs a second torque limit for limiting the torque of the motor at a limiting rate expressed by a linear function with a slope of a second constant with respect to the measured temperature, when the measured temperature is equal to or higher than a second threshold higher than the first threshold, and performs a third torque limit for stopping the supply of electricity to the motor when the measured temperature is equal to or higher than a third threshold higher than the second threshold. The first constant is greater than the second constant. Effect of the Invention

[0007] According to one aspect of the present invention, it is possible to provide a control device, a drive device, and a control method that are capable of suppressing a temperature rise in the motor while allowing the motor to fully exhibit its performance. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a drive device 1 according to an embodiment. [Diagram 2] FIG. 2 is a diagram for explaining the torque limiting of the motor by the torque limiting unit according to one embodiment. [Diagram 3] FIG. 3 is a flowchart showing a procedure of torque control in the temperature increase mode by the torque limiting unit according to one embodiment. [Figure 4] FIG. 4 is a flowchart showing a procedure of torque control in the high temperature mode by the torque limiting unit according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments to which the present invention is applied will be described in detail with reference to the drawings. In the drawings used in the following description, the characteristic parts may be enlarged for the purpose of emphasizing the characteristic parts, and the dimensional ratios of each component may not be the same as in reality. Also, for the same purpose, non-characteristic parts may be omitted.

[0010] FIG. 1 is a schematic diagram of a drive device 1 of the present embodiment. The drive unit 1 is mounted on a vehicle to drive the vehicle. The vehicle on which the drive unit 1 is mounted is a vehicle that uses a motor as a power source, such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHV), or an electric vehicle (EV).

[0011] The drive device 1 of this embodiment has a motor 2, a control device 10 that controls the motor 2, a battery 7 that supplies power to the motor 2 via the control device 10, and a first cooling device (cooling device) 80 and a second cooling device (cooling device) 90 that cool the motor 2.

[0012] The motor 2 of this embodiment is a three-phase AC motor. The motor 2 is an outer rotor type motor. The motor 2 functions both as an electric motor and as a generator.

[0013] The motor 2 is accommodated in the housing 1a. The motor 2 is connected to the wheels of the vehicle via a transmission mechanism (not shown). The motor 2 has a stator and a rotor that rotates relative to the stator. The stator has a coil wire. The coil wire is connected to an inverter 3 of the control device 10 and is supplied with an AC voltage.

[0014] The motor 2 is driven by AC current supplied from the inverter 3 to rotate the wheels. This causes the motor 2 to drive the vehicle. The motor 2 also regenerates the rotation of the wheels to generate AC current. The generated power is stored in the battery 7 via the inverter 3.

[0015] A temperature sensor 20 is attached to the motor 2. The temperature sensor 20 measures the temperature of the coil wire of the motor 2. That is, the temperature sensor 20 measures the temperature of the motor 2. Oil O is stored inside the housing 1a that accommodates the motor 2. That is, the oil O is accommodated in the housing 1a together with the motor 2.

[0016] The first cooling device 80 has a water jacket 82, a cooling water passage 81, and a water pump (pump) 88. The first cooling device 80 may also have a radiator (not shown) that is disposed in the cooling water passage 81 and cools the cooling water.

[0017] The water jacket 82 surrounds the outer periphery of the housing 1a. The cooling water passage 81 is a circulation flow path through which the cooling water circulates. The cooling water passage 81 is connected to the water jacket 82 and passes through the inside of the water jacket. The water pump 88 pumps the cooling water in the cooling water passage 81. That is, the water pump 88 circulates the cooling water that cools the motor 2 in the cooling water passage 81.

[0018] The first cooling device 80 cools the motor 2 in the housing 1a via the housing 1a. The first cooling device 80 of the present embodiment cools the oil O in the housing 1a. In this way, the first cooling device 80 indirectly cools the motor 2 immersed in the oil O.

[0019] The second cooling device 90 has an oil passage 91, an oil pump 98, and an oil cooler 99. Oil O circulates in the oil passage 91. The oil passage 91 passes through the inside of the housing 1a. The oil pump 98 pumps the oil O in the oil passage 91. The oil cooler 99 cools the oil O in the oil passage 91. The second cooling device 90 cools the motor 2 by passing the oil O cooled by the oil cooler 99 through the housing 1a.

[0020] The control device 10 includes an inverter 3, an ECU (Electronic Control Unit) 10a, and a temperature sensor 20.

[0021] The inverter 3 is connected to the battery 7 and the motor 2. The inverter 3 converts the DC voltage supplied from the battery 7 into a three-phase AC voltage based on a signal from the ECU 10a, and outputs the converted three-phase AC voltage to the motor 2. This drives the motor 2 to generate a target torque TT specified by the ECU 10a. Furthermore, during regenerative braking of the vehicle, the inverter 3 converts the three-phase AC voltage generated by the motor 2 into a DC voltage and outputs it to the inverter 3.

[0022] The battery 7 is a chargeable and dischargeable DC power source. The battery 7 supplies DC power to the inverter 3. The battery 7 is charged by receiving DC power output from the inverter 3 during regenerative braking of the vehicle.

[0023] The ECU 10a includes a torque limiting unit 11, a voltage calculation unit 12, and a signal conversion unit 13. That is, the control device 10 includes the torque limiting unit 11, the voltage calculation unit 12, and the signal conversion unit 13.

[0024] The ECU 10a is connected to a VCU (Vehicle Control Units) 9. The VCU 9 is an external device of the drive unit 1 and is mounted on the vehicle. The VCU 9 controls each part of the vehicle. The VCU 9 calculates a target torque TT, which is a torque to be output by the motor 2, based on the depression amount of the accelerator pedal and the brake pedal and the running state of the vehicle.

[0025] The ECU 10 a calculates a target torque TT of the motor 2 based on information received from the VCU 9 and the temperature sensor 20 , and further generates a signal for obtaining the target torque TT and outputs it to the inverter 3 .

[0026] The torque limiting unit 11 receives the measured temperature T of the motor 2 from the temperature sensor 20. The torque limiting unit 11 calculates a torque limiting rate LR based on the measured temperature T. The torque limiting unit 11 also receives a command torque RT from the VCU 9. The torque limiting unit 11 calculates a target torque TT of the motor 2 from the calculated limiting rate LR and the received command torque RT. The target torque TT is the torque that the motor 2 should output, taking into account the torque limit. The target torque TT is calculated by multiplying the command torque RT by a value (100%-LR) obtained by subtracting the limiting rate LR from 100%.

[0027] The voltage calculation unit 12 calculates the voltages to be applied to the coils of the U, V, and W phases of the motor 2 based on the target torque TT from the torque limiting unit 11, and outputs the calculated coil voltages of each phase to the signal conversion unit 13.

[0028] Signal conversion unit 13 generates a signal for actually turning each transistor of inverter 3 on / off based on each phase coil voltage received from voltage calculation unit 12, and outputs the generated signal to each transistor of inverter 3.

[0029] <Control method> Next, a torque control method in the torque limiting section 11 of the ECU 10a will be described. In order to protect the motor 2, the ECU 10a causes the torque limiting section 11 to reduce the target torque TT of the motor 2 when the temperature of the motor increases.

[0030] 2 is a diagram for explaining the torque limiting of the motor 2 by the torque limiting unit 11. In FIG. 2, the horizontal axis represents the temperature T of the motor 2 measured by the temperature sensor 20, and the vertical axis represents the limiting rate LR of the torque of the motor 2 by the torque limiting unit 11.

[0031] The torque limiting unit 11 has a temperature increase mode which is performed when the measured temperature T increases, and a temperature decrease mode which is performed when the measured temperature T decreases. The temperature increase mode and the temperature decrease mode transition to each other when certain conditions are satisfied. The torque limiting unit 11 selects the temperature increase mode as the initial mode.

[0032] (heating mode) FIG. 3 is a flowchart showing a procedure of torque control in the temperature increase mode. In the temperature increase mode, the torque limiting section 11 performs control in accordance with, for example, steps S101 to S111 which will be described below.

[0033] The torque limiting unit 11 in the temperature increase mode first acquires the measured temperature T of the motor 2 measured by the temperature sensor 20 (step S101).

[0034] Next, the torque limiting section 11 in the temperature increase mode checks whether the temperature increase mode should be maintained (steps S102 and S103), and if the temperature increase mode should not be maintained, transitions to the temperature decrease mode.

[0035] More specifically, first, in step S102, the torque limiting unit 11 determines whether the measured temperature T is decreasing. That is, the torque limiting unit 11 determines whether the change over time (ΔT) of the measured temperature T is a negative value (ΔT<0). If the measured temperature T is decreasing (step S102: YES), the torque limiting unit 11 further determines in step S103 whether the temperature change (|ΔT|) is equal to or greater than a temperature constant Tb. If the temperature change is equal to or greater than the temperature constant Tb (step S103: YES), the torque limiting unit 11 transitions to the temperature decreasing mode (step S104). On the other hand, if the temperature change is less than the temperature constant Tb (step S103: NO), the torque limiting unit 11 maintains the temperature increasing mode even if the measured temperature T is decreasing.

[0036] In the temperature increase mode, the torque limiting unit 11 performs any one of the following control operations according to the measured temperature T: no torque limit (step S106), a first torque limit (step S108), a second torque limit (step S110), or a third torque limit (step S111). Each control will be described in detail later.

[0037] If the measured temperature T does not decrease (step S102: NO), that is, if the measured temperature T is constant or increases, the torque limiting unit 11 further determines whether the measured temperature T is less than a first threshold T1 (step S105). If the measured temperature T is less than the first threshold T1 (step S105: YES), the torque limiting unit 11 does not limit the torque (step S106). Therefore, the control device 10 drives the motor 2 with the command torque RT received from the VCU 9.

[0038] If the measured temperature T is not less than the first threshold T1 (step S105: NO), that is, if the measured temperature T is equal to or greater than the first threshold T1, the torque limiting unit 11 further determines whether the measured temperature T is less than a second threshold T2 (step S107). If the measured temperature T is less than the second threshold T2 (step S107: YES), the torque limiting unit 11 performs a first torque limit (step S108).

[0039] If the measured temperature T is not less than the second threshold T2 (step S107: NO), i.e., if the measured temperature T is equal to or greater than the second threshold T2, the torque limiting unit 11 further determines whether the measured temperature T is less than a third threshold T3 (step S109). If the measured temperature T is less than the third threshold T3 (step S109: YES), the torque limiting unit 11 performs the second torque limiting (step S110). If the measured temperature T is not less than the third threshold T3 (step S109: NO), i.e., if the measured temperature T is equal to or greater than the third threshold T3, the torque limiting unit 11 performs the third torque limiting (step S111).

[0040] Next, the torque limiting performed in the temperature increase mode will be specifically described with reference to FIG. The torque limiting unit 11 in the temperature increase mode starts substantial torque limitation when the measured temperature T is equal to or higher than the first threshold T1. The torque limiting unit 11 in the temperature increase mode performs the first torque limitation when the measured temperature T is equal to or higher than the first threshold T1, performs the second torque limitation when the measured temperature T is equal to or higher than the second threshold T2, and performs the third torque limitation when the measured temperature T is equal to or higher than the third threshold T3. The second threshold T2 is a temperature higher than the first threshold T1. The third threshold T3 is a temperature higher than the second threshold T2.

[0041] The first torque limit is performed when the measured temperature T is between a first threshold value T1 and a second threshold value T2. The first torque limit is a control method for limiting the torque of the motor 2 with a limit rate LR expressed as a linear function with a first constant a1 as a slope with respect to the measured temperature T. Here, the first constant a1 is expressed as ΔLR / ΔT. In the first torque limit, the torque limiting unit 11 increases the limit rate LR by a1×ΔT (=ΔLR) when the measured temperature T increases by ΔT.

[0042] The second torque limit is performed when the measured temperature T is between the second threshold value T2 and the third threshold value T3. The second torque limit is a control method for limiting the torque of the motor 2 by a limit rate LR expressed as a linear function with a slope of a second constant a2 relative to the measured temperature T. In the second torque limit, the torque limiting unit 11 increases the limit rate LR by a2×ΔT (=ΔLR) when the measured temperature T increases by ΔT.

[0043] Generally, when the motor 2 generates heat, the measured temperature T of the motor 2 output from the temperature sensor 20 is delayed from the actual temperature of the motor 2. For this reason, if torque limitation is imposed on the motor 2 with a limiting rate LR according to the measurement result, there is a risk that the limiting rate LR will be insufficient and the temperature rise will not be appropriately suppressed.

[0044] In this embodiment, the first constant a1 is greater than the second constant a2. Therefore, the torque limiting unit 11 does not tolerate a temperature rise when the measured temperature T is in the range of the first threshold value T1 or more and less than the second threshold value T2. versus This makes it possible to rapidly increase the limiting rate LR, which is the rate at which the torque limiting unit 11 increases the torque of the motor 2, within a range equal to or less than the second threshold value T2, even if there is a delay in measuring the temperature T of the motor 2 by the temperature sensor 20.

[0045] In addition, when the measured temperature T is equal to or higher than the second threshold T2, the torque limit is already imposed on the drive of the motor 2, and the rate of temperature rise is therefore relatively slow. versusEven if the limiting rate LR is gradually increased by the second constant a2, there is little effect of the delay of the temperature sensor 20. Furthermore, by the torque limiting unit 11 gradually increasing the limiting rate LR in the temperature range equal to or higher than the second threshold value T2, the range of the measured temperature T up to which the limiting rate reaches 100% can be expanded upward, and even during high-speed operation of the motor 2, control can be performed without impairing the maximum speed characteristics.

[0046] The third torque limit is a control method in which the supply of electricity to the motor 2 is stopped and the drive torque of the motor 2 is set to 0. For this reason, the torque limiting unit 11 that performs the third torque limit sets the target torque TT to 0 and sends it to the voltage calculation unit 12, regardless of the command torque RT received from the VCU 9. Note that the third torque limit can be said to set the limit rate of the drive torque of the motor 2 to 100%.

[0047] According to this embodiment, the torque limiting unit 11 stops the supply of electricity to the motor 2 when the measured temperature T rises in a temperature range equal to or greater than the third threshold value T3, thereby eliminating a cause of heat generation in the motor 2. Therefore, the torque limiting unit 11 can rapidly reduce the temperature of the motor 2 in a temperature range equal to or greater than the third threshold value T3, thereby improving the reliability of the motor 2.

[0048] (Cooling mode) FIG. 4 is a flowchart showing a procedure of torque control in the temperature decreasing mode. In the temperature decreasing mode, the torque limiting section 11 performs control in accordance with, for example, steps S201 to S211 which will be described below. The torque limiting unit 11 in the temperature decreasing mode first acquires the measured temperature T of the motor 2 measured by the temperature sensor 20 (step S201).

[0049] Next, the torque limiting section 11 in the temperature decreasing mode checks whether the temperature decreasing mode should be maintained (steps S202 and S203), and if the temperature decreasing mode should not be maintained, transitions to the temperature increasing mode.

[0050] More specifically, in step S202, the torque limiting unit 11 determines whether the measured temperature T is rising. That is, in step S202, the torque limiting unit 11 determines whether the change over time (ΔT) of the measured temperature T is a positive value (ΔT>0). If the measured temperature is falling (step S202: YES), the torque limiting unit 11 further determines in step S203 whether the temperature change (|ΔT|) is equal to or greater than a temperature constant Tb. If the temperature change is equal to or greater than the temperature constant Tb (step S203: YES), the torque limiting unit 11 transitions to the temperature increase mode (step S204). On the other hand, if the temperature change is less than the temperature constant Tb (step S203: NO), the torque limiting unit 11 maintains the temperature decrease mode even if the measured temperature T is rising.

[0051] In the temperature decreasing mode, the torque limiting unit 11 performs any one of the following controls according to the measured temperature T: no torque limit (step S206), a fourth torque limit (step S208), a fifth torque limit (step S210), or a sixth torque limit (step S211). Each control will be described in detail later.

[0052] If the measured temperature T does not increase (step S202: NO), that is, if the measured temperature T is constant or increases, the torque limiting unit 11 further determines whether the measured temperature T is less than a fourth threshold value T4 (step S205). If the measured temperature T is less than the fourth threshold value T4 (step S205: YES), the torque limiting unit 11 does not limit the torque (step S206). Therefore, the control device 10 drives the motor 2 with the command torque RT received from the VCU 9.

[0053] If the measured temperature T is not less than the fourth threshold T4 (step S205: NO), that is, if the measured temperature T is equal to or greater than the fourth threshold T4, the torque limiting unit 11 further determines whether the measured temperature T is less than a fifth threshold T5 (step S207). If the measured temperature T is less than the fifth threshold T5 (step S207: YES), the torque limiting unit 11 performs a fourth torque limit (step S208).

[0054] If the measured temperature T is not less than the fifth threshold T5 (step S207: NO), i.e., if the measured temperature T is equal to or greater than the fifth threshold T5, the torque limiting unit 11 further determines whether the measured temperature T is less than a sixth threshold T6 (step S209). If the measured temperature T is less than the sixth threshold T6 (step S209: YES), the torque limiting unit 11 performs a fifth torque limitation (step S210). If the measured temperature T is not less than the sixth threshold T6 (step S209: NO), i.e., if the measured temperature T is equal to or greater than the sixth threshold T6, the torque limiting unit 11 performs a sixth torque limitation (step S211).

[0055] Next, the torque limiting performed in the temperature decreasing mode will be specifically described with reference to FIG. The torque limiting unit 11 in the temperature decreasing mode performs torque limiting in a range equal to or greater than a fourth threshold T4. The torque limiting unit 11 in the temperature decreasing mode performs a fourth torque limiting when the measured temperature T is equal to or greater than the fourth threshold T4, a fifth torque limiting when the measured temperature T is equal to or greater than a fifth threshold T5, and a sixth torque limiting when the measured temperature T is equal to or greater than a sixth threshold T6.

[0056] The fourth threshold T4 is a temperature lower than the first threshold T1. The fifth threshold T5 is a temperature higher than the first threshold T1 and the fourth threshold T4, and is lower than the second threshold T2. The sixth threshold T6 is a temperature higher than the second threshold T2 and the fifth threshold T5, and is lower than the third threshold T3.

[0057] The fourth torque limit is performed when the measured temperature T is between a fourth threshold T4 and a fifth threshold T5. The fourth torque limit is a control method for limiting the torque of the motor 2 by a limit rate LR expressed as a linear function with a first constant a1 as a slope with respect to the measured temperature T. The slope (ΔLR / ΔT) representing the change in limit rate ΔLR with respect to the temperature change ΔT is the same for the fourth torque limit and the first torque limit.

[0058] The fifth torque limit is performed when the measured temperature T is between a fifth threshold T5 and a sixth threshold T6. The fifth torque limit is a control method for limiting the torque of the motor 2 by a limit rate LR expressed as a linear function with a second constant a2 as a slope relative to the measured temperature T. The slope (ΔLR / ΔT) representing the change in limit rate ΔLR with respect to the temperature change ΔT is the same for the fifth torque limit and the second torque limit.

[0059] Like the third torque limit, the sixth torque limit is a control method in which power supply to the motor 2 is stopped and the drive torque of the motor 2 is set to 0. For this reason, the torque limiting unit 11 that performs the sixth torque limit sets the target torque TT to 0 and sends it to the voltage calculation unit 12, regardless of the command torque RT received from the VCU 9. Note that the sixth torque limit can be said to set the limit rate of the drive torque of the motor 2 to 100%.

[0060] According to this embodiment, the torque limiting unit 11 stops the supply of electricity to the motor 2 when the measured temperature T falls within a temperature range equal to or greater than the sixth threshold value T6, thereby eliminating the cause of heat generation in the motor 2. As a result, the temperature of the motor 2 can be rapidly reduced, and the reliability of the motor 2 can be improved.

[0061] In this embodiment, the fourth threshold T4 is a temperature lower than the first threshold T1 by the temperature constant Tb. The fifth threshold T5 is a temperature lower than the second threshold T2 by the temperature constant Tb. The sixth threshold T6 is a temperature lower than the third threshold T3 by the temperature constant Tb. As described above, the slope (ΔLR / ΔT) representing the change in limit rate ΔLR with respect to the temperature change ΔT matches between the first torque limit and the fourth torque limit, and matches between the second torque limit and the fifth torque limit.

[0062] According to this embodiment, as shown in Fig. 2, the torque limiting unit 11 in the temperature decreasing mode changes the limiting rate LR with a function offset by the temperature constant Tb in the negative direction with respect to the temperature increasing mode. In the temperature decreasing mode, the torque limiting unit 11 of this embodiment performs hysteresis characteristic control to limit torque at the same limiting rate at a lower temperature than in the temperature increasing mode. This allows the torque limiting unit 11 to apply sufficient torque limit when the temperature decreases, thereby improving the reliability of the motor 2.

[0063] Furthermore, according to this embodiment, if the temperature change is less than the temperature constant Tb, the mode is not switched from the temperature increase mode to the temperature decrease mode, or vice versa, so that stable torque limitation can be performed against changes in the measured value caused by errors in the temperature change.

[0064] In this embodiment, the torque limiting unit 11 is connected to the water pump 88 of the first cooling device 80 , the oil pump 98 of the second cooling device 90 , and the oil cooler 99 .

[0065] When performing any one of the first to sixth torque limits, the torque limiting unit 11 outputs a drive command to drive the first cooling device 80 and the second cooling device 90 that cool the motor 2. As a result, the torque limiting unit 11 cools the motor 2 by the first cooling device 80, and promotes a decrease in the temperature of the motor 2.

[0066] More specifically, the torque limiting unit 11 drives a water pump that circulates the cooling water in the cooling water passage 81 of the first cooling device 80 by a drive command. That is, the first cooling device 80 has a water pump 88 that circulates the cooling water that cools the motor 2, and circulates the cooling water by a drive command issued from the torque limiting unit 11. In this way, the torque limiting unit 11 causes the first cooling device 80 to cool the motor 2.

[0067] Furthermore, the torque limiting unit 11, in response to a drive command, drives the oil cooler 99 of the second cooling device 90 to cool the oil using the oil cooler 99, and drives the oil pump 98 to pump the oil. That is, the second cooling device 90 has an oil cooler 99 and an oil pump 98 that cool the oil O housed in the housing 1a together with the motor 2, and cools and circulates the oil O in response to a drive command issued from the torque limiting unit 11. In this way, the torque limiting unit 11 causes the second cooling device 90 to cool the motor 2.

[0068] (Map-based control) The torque limiting unit 11 can limit the torque of the motor 2 based on a map that indicates the relationship between the measured temperature T of the motor 2 and the limiting rate of the torque of the motor 2.

[0069] The torque limiting unit 11 uses the first map shown in Table 1 when the measured temperature T rises (temperature rise mode), and uses the second map shown in Table 2 when the measured temperature T falls (temperature fall mode).

[0070] In Tables 1 and 2, the measured temperature T at which the limit rate is 100% in the temperature rise mode is expressed as a reference temperature Ts. The reference temperature Ts corresponds to the third threshold value T3 described above. The reference temperature Ts is, for example, a temperature of 200°C to 250°C, which is equal to or lower than the heat resistance temperature of the coil wire of the motor 2.

[0071] [Table 1]

[0072] [Table 2]

[0073] In the temperature increase mode and the temperature decrease mode, the limit rate LR is linearly controlled in the region between the measured temperatures in the table. In the temperature increase mode and the temperature decrease mode, the limit rate LR is set to 0% in the region below Ts-25 in the table, and the limit rate LR is set to 100% in the region above Ts.

[0074] In the temperature increasing mode, the first threshold T1 corresponds to "Ts-20", the second threshold T2 corresponds to "Ts-10", and the third threshold T3 corresponds to approximately "Ts". In the temperature decreasing mode, the fourth threshold T4 corresponds to "Ts-25", the fifth threshold T5 corresponds to "Ts-20", and the sixth threshold T6 corresponds to approximately "Ts-5".

[0075] In the temperature rise mode, when the measured temperature T is less than "Ts-20", the limit rate LR is set to 0. In the temperature rise mode, when the measured temperature T is equal to or greater than "Ts-20" and less than "Ts-10", the first constant a1 is set to 7.5 (% / °C) and the limit rate LR is changed with respect to the measured temperature T. In addition, in the temperature rise mode, when the measured temperature T is equal to or greater than "Ts-10" and less than "Ts", the second constant a2 is set to 2.5 (% / °C) and the limit rate LR is changed with respect to the measured temperature T.

[0076] In the temperature decreasing mode, when the measured temperature T is less than "Ts-25", the limit rate LR is set to 0. In the temperature decreasing mode, when the measured temperature T is equal to or greater than "Ts-25" and less than "Ts-15", the first constant a1 is set to 7.5 (% / °C) and the limit rate LR is changed with respect to the measured temperature T. In addition, in the temperature decreasing mode, when the measured temperature T is equal to or greater than "Ts-15" and less than "Ts-5", the second constant a2 is set to 2.5 (% / °C) and the limit rate LR is changed with respect to the measured temperature T.

[0077] The torque limiting unit 11 switches between the maps used in the temperature increasing mode and the temperature decreasing mode. The torque limiting unit 11 calculates the torque limiting rate based on the above-mentioned first map and second map, so that the control by the torque limiting unit 11 can be simplified.

[0078] (Formula-based control) The torque limiting unit 11 may limit the torque of the motor 2 based on a formula expressing the relationship between the measured temperature T of the motor 2 and the limiting rate of the torque of the motor 2. In this case, the torque limiting unit 11 may use the following formulas for the first torque limit, the second torque limit, the third torque limit, the fourth torque limit, the fifth torque limit, and the sixth torque limit, for example.

[0079] First torque limit: Limit rate LR = (First threshold T1 - Measured temperature T) x First constant a1 Second torque limit: Limit rate LR = (Second threshold T2 - measured temperature T) x Second constant a2 + constant b Third torque limit: Limit rate LR=100 Fourth torque limit: Limit rate LR = (fourth threshold T4 - measured temperature T) x first constant a1 Fifth torque limit: Limit rate LR = (Fifth threshold T5 - measured temperature T) x second constant a2 + constant b 6th torque limit: Limit rate LR=100

[0080] In the above formula, the constant b is shown on the vertical axis in Fig. 2. The constant b represents the torque limit rate LR at the boundary temperature between the first and second torque limits (i.e., the second threshold T2) and at the boundary temperature between the fourth and fifth torque limits (i.e., the fifth threshold T5).

[0081] The torque limiting unit 11 switches the mathematical formula to be used to one of the above formulas every time the first to sixth torque limits are switched in response to a change in the measured temperature T. The control by the torque limiting unit 11 can be simplified by the torque limiting unit 11 calculating the torque limit rate based on the mathematical formulas described above.

[0082] Although various embodiments of the present invention have been described above, the configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to the embodiments. [Explanation of symbols]

[0083] 1... drive device, 1a... housing, 2... motor, 10... control device, 11... torque limiting section, 20... temperature sensor, 80... first cooling device (cooling device), 88... water pump (pump), 90... second cooling device (cooling device), 99... oil cooler, a1... first constant, a2... second constant, b... constant, LR... limiting rate, O... oil, T... measured temperature, T1... first threshold, T2... second threshold, T3... third threshold, T4... fourth threshold, T5... fifth threshold, T6... sixth threshold, Tb... temperature constant

Claims

1. A control device for controlling a motor, A temperature sensor for measuring a temperature of the motor; a torque limiting unit that limits the torque of the motor based on the temperature measured by the temperature sensor, The torque limiting unit is When the measured temperature is equal to or higher than a first threshold value, a first torque limit is performed to limit the torque of the motor at a limit rate expressed by a linear function having a slope of a first constant with respect to the measured temperature; When the measured temperature is equal to or higher than a second threshold value that is higher than the first threshold value, a second torque limit is performed to limit the torque of the motor at a limit rate that is expressed as a linear function with a slope of a second constant with respect to the measured temperature; When the measured temperature is equal to or higher than a third threshold value that is higher than the second threshold value, a third torque limitation is performed to stop power supply to the motor. the first constant is greater than the second constant, the torque limiting unit has a temperature increase mode which is performed when the measured temperature increases, and a temperature decrease mode which is performed when the measured temperature decreases, the torque limiting unit in the temperature increase mode performs the first torque limiting, the second torque limiting, and the third torque limiting, The torque limiting unit in the temperature decreasing mode is When the measured temperature is equal to or higher than a fourth threshold value, a fourth torque limit is performed to limit the torque of the motor at a limit rate expressed by a linear function having a slope of the first constant with respect to the measured temperature; When the measured temperature is equal to or higher than a fifth threshold value that is higher than the fourth threshold value, a fifth torque limit is performed to limit the torque of the motor at a limit rate expressed by a linear function having a slope of the second constant with respect to the measured temperature; When the measured temperature is equal to or higher than a sixth threshold value that is higher than the fifth threshold value, a sixth torque limitation is performed to stop power supply to the motor. the fourth threshold is a temperature that is lower than the first threshold by a temperature constant; the fifth threshold is a temperature lower than the second threshold by the temperature constant, the sixth threshold is a temperature lower than the third threshold by the temperature constant, The sixth threshold is greater than the second threshold. Control device.

2. the torque limiting unit limits the torque of the motor based on a map that indicates a relationship between the measured temperature and a limit rate of the torque of the motor. The control device according to claim 1 .

3. The torque limiting unit uses a first map as the map when the measured temperature increases, and uses a second map as the map when the measured temperature decreases. The control device according to claim 2.

4. the torque limiting unit limits the torque of the motor based on a formula expressing a relationship between the measured temperature and a limit rate of the torque of the motor. The control device according to claim 1 .

5. When limiting the torque, a drive command is output to drive a cooling device that cools the motor. A control device according to any one of claims 1 to 4.

6. the cooling device has a water pump that circulates cooling water for cooling the motor, and circulates the cooling water in response to the drive command. The control device according to claim 5.

7. the cooling device has an oil cooler that cools oil housed in a housing together with the motor, and cools the oil in response to the drive command; The control device according to claim 5.

8. A control device according to any one of claims 1 to 7; The motor. Drive unit.

9. A method for controlling a motor, comprising the steps of: When a measured temperature of the motor measured by a temperature sensor is equal to or higher than a first threshold value, a first torque limit is performed to limit the torque of the motor at a limit rate expressed by a linear function having a slope of a first constant with respect to the measured temperature; When the measured temperature is equal to or higher than a second threshold value that is higher than the first threshold value, a second torque limit is performed to limit the torque of the motor at a limit rate that is expressed as a linear function with a slope of a second constant with respect to the measured temperature; When the measured temperature is equal to or higher than a third threshold value that is higher than the second threshold value, a third torque limitation is performed to stop power supply to the motor. the first constant is greater than the second constant, A temperature increasing mode is performed when the measured temperature increases, and a temperature decreasing mode is performed when the measured temperature decreases, In the temperature increase mode, the first torque limiting, the second torque limiting, and the third torque limiting are performed; In the temperature decreasing mode When the measured temperature is equal to or higher than a fourth threshold value, a fourth torque limit is performed to limit the torque of the motor at a limit rate expressed by a linear function having a slope of the first constant with respect to the measured temperature; When the measured temperature is equal to or higher than a fifth threshold value that is higher than the fourth threshold value, a fifth torque limit is performed to limit the torque of the motor at a limit rate expressed by a linear function having a slope of the second constant with respect to the measured temperature; When the measured temperature is equal to or higher than a sixth threshold value that is higher than the fifth threshold value, a sixth torque limitation is performed to stop power supply to the motor. the fourth threshold is a temperature that is lower than the first threshold by a temperature constant; the fifth threshold is a temperature lower than the second threshold by the temperature constant, the sixth threshold is a temperature lower than the third threshold by the temperature constant, The sixth threshold is greater than the second threshold. Control methods.

10. limiting the torque of the motor based on a map that indicates a relationship between the measured temperature and a limit rate of the torque of the motor. The control method according to claim 9.

11. As the map, a first map is used when the measured temperature increases, and a second map is used when the measured temperature decreases. The control method according to claim 10.

12. limiting the torque of the motor based on a formula expressing a relationship between the measured temperature and a limit rate of the torque of the motor; The control method according to claim 9.

13. When limiting the torque, a drive command is output to drive a cooling device that cools the motor. A control method according to any one of claims 10 to 12.

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