Vehicle control device and vehicle control method

Abstract

To provide a vehicle control device and a vehicle control method capable of suppressing unnecessary torque limitation.SOLUTION: A state estimation unit 251 of the vehicle control device estimates a current state quantity of the motor on the basis of the driving state information. The state predicting units 252a and 252b predict a future state quantity of the motor based on the operating state information and the current state quantity. The cooling-amount control instructing units 254a and 254b control a cooling circuit for cooling the motor based on the future state quantity. The torque control instructing unit 254c controls the torque of the motor based on the future state quantity. The state predicting units 252a and 252b set the period to the future (N2 time) when predicting the future state quantity to be output to the torque control instructing unit 254c to be shorter than the period to the future (N1 time) when predicting the future state quantity to be output to the cooling-amount control instructing units 254a and 254b.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] A technology for cooling a vehicle motor is described, for example, in Patent Document 1. The motor control device described in Patent Document 1 predicts (estimates) the temperatures of the magnets and motor coils and changes the flow rate of refrigerant in the cooling circuit according to the predicted temperatures. The motor control device also limits the upper torque limit of the motor according to the predicted temperatures. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-53765 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the motor control device described in Patent Document 1 controls the motor torque and the cooling circuit flow rate independently, which can result in unnecessary torque restriction in motor torque control without considering the effect of cooling circuit flow rate control.

[0005] In consideration of the above problems, an object of the present invention is to provide a vehicle control device and a vehicle control method that can suppress unnecessary torque limitation. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the object of the present invention, a vehicle control device according to one aspect of the present invention includes a state estimation unit, a state prediction unit, a cooling amount control instruction unit, and a torque control instruction unit. The state estimation unit acquires operating state information including parameters related to the temperature of the motor, and estimates a current state quantity of the motor based on the operating state information. The state prediction unit predicts a future state quantity of the motor based on the operating state information and the current state quantity. The cooling amount control instruction unit controls a cooling circuit for cooling the motor based on the future state quantity. The torque control instruction unit controls the torque of the motor based on the future state quantity. The state prediction unit sets a future period when predicting the future state quantity to be output to the torque control instruction unit to be shorter than a future period when predicting the future state quantity to be output to the cooling amount control instruction unit.

[0007] In one aspect of the present invention, a vehicle control method includes a state estimation unit that acquires driving state information including parameters related to the temperature of the motor and estimates a current state quantity of the motor based on the driving state information. Next, a state prediction unit predicts a future state quantity of the motor based on the driving state information and the current state quantity. A cooling amount control instruction unit controls a cooling circuit for cooling the motor based on the future state quantity. Furthermore, a torque control instruction unit controls the torque of the motor based on the future state quantity. The state prediction unit then sets a future period when predicting the future state quantity to be output to the torque control instruction unit to be shorter than a future period when predicting the future state quantity to be output to the cooling amount control instruction unit. [Effects of the Invention]

[0008] According to the vehicle control device and vehicle control method configured as described above, unnecessary torque limitation can be suppressed. Problems, configurations, and effects other than those described above will become clear from the following description of the embodiments. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an overall configuration diagram showing an example of a basic configuration of a vehicle according to an embodiment; [Figure 2]FIG. 2 is a schematic diagram illustrating the configuration of a motor, a cooling circuit, and the like according to an embodiment. [Figure 3] FIG. 2 is a functional block diagram of a control unit according to an embodiment. [Figure 4] 4 is a flowchart illustrating an example of a vehicle control process according to an embodiment. [Figure 5] FIG. 4 is a diagram showing the relationship between the flow rate of the first refrigerant and the heat transfer coefficient when the temperature of the first refrigerant changes according to one embodiment. [Figure 6] 10 is a temperature time history result comparing torque and temperature of an embodiment and a prior art motor. [Figure 7] 10 is a time history result comparing motor torque and temperature, cooling circuit flow rate and temperature of an embodiment and the prior art; DETAILED DESCRIPTION OF THE INVENTION

[0010] A vehicle control device and a vehicle control method according to an embodiment of the present invention will be described below. Note that common members in the various drawings are given the same reference numerals.

[0011] [Vehicle configuration] First, the overall configuration of a vehicle equipped with a motor and a cooling circuit will be described with reference to FIG. FIG. 1 is an overall configuration diagram showing an example of the basic configuration of a vehicle according to an embodiment.

[0012] 1, the vehicle 100 includes a motor 101, a transmission 102, a differential gear 103, a drive shaft 104, and wheels 105. The vehicle 100 also includes a first cooling circuit, a second cooling circuit, and a third cooling circuit.

[0013] The motor 101 is a power source for driving the vehicle 100. The power output by the motor 101 is transmitted to wheels 105 via a transmission 102, a differential gear 103, and a drive shaft 104. The number of motors 101 provided in the vehicle 100 is not limited to one, and may be, for example, two, four, or more.

[0014] The first cooling circuit has a first pipe 106, a heat exchanger 107, and a first refrigerant pump 108. The motor 101 is connected to the heat exchanger 107 via the first pipe 106. The first refrigerant pump 108 pumps the first refrigerant in the first pipe 106. As a result, the first refrigerant is sent to the heat exchanger 107.

[0015] The second cooling circuit has a second refrigerant pump 111, a radiator 112, a second pipe 113, and a heat exchanger 107. The second cooling circuit cools an inverter 110. The inverter 110 is connected to the heat exchanger 107 and the radiator 112 via the second pipe 113. The second refrigerant pump 111 pumps out the second refrigerant in the second pipe 113. As a result, the second refrigerant is sent to the heat exchanger 107 and the radiator 112.

[0016] When the inverter 110 receives DC power from the battery 109, it operates a switching element to convert the DC power into AC power. The inverter 110 supplies AC power to the motor 101. When the inverter 110 receives a signal from the motor 101, it operates a switching element to convert the AC regenerative power of the motor 101 into DC power. The inverter 110 charges the battery 109 with the converted DC power. The battery 109 is, for example, a secondary battery such as a lithium-ion battery.

[0017] The radiator 112 exchanges heat with the outside air to cool a second refrigerant and a third refrigerant, which will be described later. A radiator fan 114 is attached to the radiator 112. The rotation speed of the radiator fan 114 is controlled by a control unit 250 (see FIG. 2), which will be described later. The control unit 250 controls the amount of heat exchange by the radiator 112 by changing the rotation speed of the radiator fan 114.

[0018] The third cooling circuit has a radiator 112, a third refrigerant pump 115, and a third pipe 116. The third cooling circuit cools the battery 109. The battery 109 is connected to the radiator 112 via the third pipe 116. The third refrigerant pump 115 pumps the third refrigerant in the third pipe 116. As a result, the third refrigerant is sent to the radiator 112.

[0019] [Motor and cooling circuit configuration] Next, the motor 101, the inverter 110, the battery 109, the first cooling circuit, the second cooling circuit, and their control systems will be described with reference to FIG. FIG. 2 is a schematic diagram showing the configuration of the motor 101, the cooling circuit, etc.

[0020] As shown in FIG. 2, the motor 101 includes a housing 201 , a stator 202 , a rotor 203 , and a shaft 204 .

[0021] Stator 202 is fitted inside housing 201. Stator 202 has stator core 205 made of laminated magnetic material and stator coil 206 wound around stator core 205. Rotor 203 is installed on the inner periphery of stator 202. Rotor 203 has rotor core 207 made of laminated magnetic material and magnets 208 embedded inside rotor core 207 on the outer periphery side.

[0022] The shaft 204 is integrated with the rotor 203. A rotation angle resolver (not shown) is attached to one end of the shaft 204. The rotation angle resolver detects the number of rotations and the rotation angle of the shaft 204. A bearing 201a is attached to the housing 201. The bearing 201a supports the shaft 204 so that it can rotate.

[0023] The inverter 110 operates a switching element to convert DC power sent from the battery 109 into AC power. The inverter 110 supplies the converted AC power to the motor 101. When a current is applied to the stator coil 206 of the motor 101, a rotating magnetic field and the magnetic attraction force of the magnet 208 act to generate axial torque in the rotor 203. This causes the rotor 203 and the shaft 204 to rotate.

[0024] The speed of vehicle 100 required by the driver (required speed) is calculated from, for example, the amount of operation of an accelerator pedal (not shown) or a brake pedal (not shown). Control unit 250 calculates the torque required of motor 101 (required torque) based on the required speed. Control unit 250 generates a command for controlling the amount of current supplied to stator coil 206 in accordance with the calculated required torque, and outputs the command to inverter 110.

[0025] When current is applied to the stator coil 206, a portion of the power is lost and converted into heat in the stator coil 206. Furthermore, when the rotor core 207 rotates, eddy currents are generated inside the rotor core 207. The loss due to the eddy currents is converted into heat in the rotor core 207. The heat generated by the stator coil 206 and the rotor core 207 heats the stator 202, the rotor 203, the magnet 208, etc. As a result, the temperature of the motor 101 rises.

[0026] The first cooling circuit releases heat generated in the motor 101 to the outside of the motor 101. The first refrigerant pumped by the first refrigerant pump 108 passes through a heat exchanger 107 and is supplied to a housing 201 of the motor 101. The first refrigerant then absorbs heat from the stator 202 and the rotor 203 via the housing 201. This cools the stator 202 and the rotor 203.

[0027] The first refrigerant that has absorbed heat from stator 202 and rotor 203 returns to first refrigerant tank 118. In first refrigerant tank 118, the first refrigerant is cooled by heat exchange with outside air. The heat of a portion of the first refrigerant that has not been cooled in first refrigerant tank 118 is transferred to the second cooling circuit when the first refrigerant is pumped by first refrigerant pump 108 and passes through heat exchanger 107. This cools the first refrigerant.

[0028] In this embodiment, the stator 202 and the rotor 203 are cooled via the housing 201. However, the cooling of the motor according to the present invention is not limited to this, and for example, a direct-cooling type motor may be adopted to directly cool the stator and rotor.

[0029] Here, we will explain the necessity of cooling the motor 101. If the temperature of the magnet 208 exceeds the allowable upper limit, irreversible demagnetization occurs, in which the magnetic force does not return to its original characteristics even if the temperature of the magnet 208 subsequently drops. As a result, the magnetic field generated by energizing the stator coil 206 weakens, and the performance of the motor 101 deteriorates.

[0030] Furthermore, if the temperature of the stator coil 206 exceeds the allowable upper limit, the insulating coating covering the stator coil 206 will be damaged, causing an electrical short circuit in the motor 101. Therefore, it is important to control the flow rate and temperature of the first refrigerant in the first cooling circuit and the amount of electricity (i.e., torque) supplied to the motor 101 so that the temperature of the stator coil 206 and the temperature of the magnet 208 do not exceed the upper limit.

[0031] The second cooling circuit releases heat generated in the inverter 110 to the outside of the inverter 110. As described above, the second cooling circuit also cools the second refrigerant. The second refrigerant pumped by the second refrigerant pump 111 passes through the heat exchanger 107 and is supplied to the housing (not shown) of the inverter 110. The second refrigerant then absorbs heat from the inverter 110 via the housing. This cools the inverter 110.

[0032] The second refrigerant that has absorbed heat from inverter 110 passes through radiator 112 and returns to second refrigerant tank 119. In radiator 112 and second refrigerant tank 119, the second refrigerant is cooled by heat exchange with outside air. The temperature of the second refrigerant in second refrigerant tank 119 is lower than the temperature of the first refrigerant in first refrigerant tank 118.

[0033] The control unit 250 corresponds to the vehicle control device according to the present invention. The control unit 250 controls the driving of the motor 101, the first refrigerant pump 108, the second refrigerant pump 111, the third refrigerant pump 115, the inverter 110, and the radiator fan 114. The control unit 250 has a state estimation unit 251, a state prediction unit 252, a calculation unit 253, and a control instruction unit 254.

[0034] [Controller function configuration] Next, the functional configuration of the control unit 250 will be described with reference to FIG. FIG. 3 is a functional block diagram of the control unit 250.

[0035] 3, the actual temperature of motor 101, the torque value of motor 101, the rotation speed of motor 101, the flow rate of the first refrigerant, and the temperature of the first refrigerant are input to state estimation unit 251 of control unit 250. The motor temperature is temperature information of motor 101 output from a sensor (e.g., a thermocouple) attached to stator coil 206.

[0036] The actual temperature, torque value, and rotation speed of motor 101, and the flow rate and temperature of the first refrigerant correspond to the operating state information of the present invention. The operating state information of the present invention may also be the amount of power supplied to motor 101 or the outside air temperature. The operating state information of the present invention may include at least one parameter selected from the actual temperature, torque value, and rotation speed of motor 101, the flow rate and temperature of the first refrigerant, the amount of power supplied to motor 101, and the outside air temperature.

[0037] The state estimation unit 251 has a heat generation amount map (loss map), a heat transfer coefficient map, and a prediction model. The heat generation amount map defines the heat generation amount of each part (e.g., stator coil 206, stator core 205, rotor core 207, etc.) according to the rotation speed of the motor 101, the torque of the motor 101, the frequency of the inverter 110, etc. The heat transfer coefficient map defines the heat transfer coefficient of a part (housing 201, etc.) that exchanges heat with the first refrigerant according to the temperature and flow rate of the first refrigerant. The prediction model includes a system matrix A, an input matrix B, and an output matrix C of a state equation, which will be described later.

[0038] The state estimation unit 251 determines the motor loss u (input vector u) and the heat transfer coefficient h by referring to the heat generation amount map and the heat transfer coefficient map. The heat transfer coefficient h corresponds to the actual transfer coefficient according to the present invention. The control unit 250 estimates the state quantity x (temperature distribution of each part) using the input vector u, the heat transfer coefficient h, and the state equation. The control unit 250 can estimate the state quantity x using, for example, a Kalman filter. The state estimation unit 251 sends the state quantity x, the heat transfer coefficient h, and the motor loss u to the state prediction unit 252.

[0039] The state prediction unit 252 has a first state prediction unit 252a and a second state prediction unit 252b. The first state prediction unit 252a predicts the state quantity x (temperature of each part) at a future time N1 based on the state quantity x, the heat transfer coefficient h, and the input vector u. The first state prediction unit 252a sends the state quantity x at the time N1 to the calculation unit 253.

[0040] The second state prediction unit 252b predicts the state quantity x (temperature of each part) at a future time N2 based on the state quantity x, the heat transfer coefficient h, and the input vector u. For example, the time N1 is set to a time later than the time N2. The second state prediction unit 252b sends the state quantity x at the time N2 to the calculation unit 253.

[0041] In this way, the state estimation unit 251 uses values ​​detected by various sensors to estimate the state quantity x. This allows the current state quantity x to be estimated from values ​​detected by a limited number of sensors. Then, the state prediction unit 252 can use the state quantity x to accurately predict the future state quantity x.

[0042] For example, magnet 208 is located inside rotor 203, which rotates at high speed. Therefore, it is difficult to measure the temperature of magnet 208. State estimation unit 251 can estimate the current temperature of magnet 208, which is difficult to measure, from values ​​detected by various sensors. Furthermore, state prediction unit 252 can predict the future temperature of magnet 208 based on the current temperature of magnet 208.

[0043] Calculation unit 253 includes heat transfer coefficient calculation unit 253a, first refrigerant temperature calculation unit 253b, heat generation amount calculation unit 253c, and first refrigerant flow rate calculation unit 253d. Heat transfer coefficient calculation unit 253a calculates a heat transfer coefficient manipulated variable Δh based on the state quantity x at time N1. The heat transfer coefficient manipulated variable Δh corresponds to the required heat transfer coefficient according to the present invention. The heat transfer coefficient manipulated variable Δh is one of the physical quantities required to specify manipulated variables such as the flow rates of the first and second refrigerants and the rotation speed of radiator fan 114.

[0044] First refrigerant temperature calculation unit 253b calculates a first refrigerant temperature manipulated variable ΔTf based on the state quantity x and the heat transfer coefficient manipulated variable Δh at time N1. The first refrigerant temperature manipulated variable ΔTf is one of the physical quantities described above and is calculated based on the target temperature of the first refrigerant at the inlet of motor 101. Heat generation amount calculation unit 253c calculates an allowable heat generation amount Δu based on the state quantity x and the heat transfer coefficient manipulated variable Δh after time N2. The allowable heat generation amount Δu is the allowable heat generation amount of each part of motor 101. First refrigerant flow rate calculation unit 253d calculates a target flow rate of the first refrigerant based on the heat transfer coefficient manipulated variable Δh.

[0045] Control instructing unit 254 has a first cooling amount control instructing unit 254a, a second cooling amount control instructing unit 254b, and a torque control instructing unit 254c. First cooling amount control instructing unit 254a determines the rotation speed of first refrigerant pump 108 based on the target flow rate of the first refrigerant and the actual flow rate of the first refrigerant. First cooling amount control instructing unit 254a controls the drive of first refrigerant pump 108 according to the determined rotation speed of first refrigerant pump 108.

[0046] Second cooling amount control instructing unit 254b determines the rotation speed of radiator fan 114 and the rotation speed of second refrigerant pump 111 based on the first refrigerant temperature manipulated variable ΔTf, the temperature of the second refrigerant, and the temperature of the first refrigerant. Second cooling amount control instructing unit 254b controls the drive of radiator fan 114 in accordance with the determined rotation speed of radiator fan 114. Second cooling amount control instructing unit 254b controls the drive of second refrigerant pump 111 in accordance with the determined rotation speed of second refrigerant pump 111.

[0047] The torque control instruction unit 254c determines the torque limit value or the limit value of the amount of current supplied to the motor 101 based on the allowable heat generation amount Δu and the torque value of the motor 101. The torque control instruction unit 254c controls the torque (amount of current supplied) of the motor 101 in consideration of the torque limit value so that the temperature of each part of the motor 101 is equal to or lower than the upper limit value.

[0048] Generally, the motor, refrigerant pump, and radiator fan are controlled independently. Therefore, motor torque control may limit torque at unnecessary times. As a result, motor torque control may degrade vehicle performance. In this embodiment, vehicle control processing is performed that coordinates the control of the motor, refrigerant pump, and radiator fan, thereby suppressing unnecessary torque limiting.

[0049] [Vehicle control processing] Next, the vehicle control process performed by the control unit 250 will be described with reference to FIG. FIG. 4 is a flowchart illustrating an example of a vehicle control process according to an embodiment.

[0050] First, the state estimation unit 251 of the control unit 250 acquires the temperature sensor value Tmeas of the motor 101 (S401). Next, the state estimation unit 251 acquires the rotation speed of the motor 101, the torque of the motor 101, the flow rate of the first refrigerant, and the temperature of the first refrigerant (S402).

[0051] Next, the state estimation unit 251 refers to the heat value map and calculates the heat value u (input vector u) of each part of the motor 101 based on the rotation speed of the motor 101, the torque of the motor 101, and the frequency of the inverter 110 (S403).

[0052] In step S403, the state estimation unit 251 refers to the heat transfer coefficient map and calculates the heat transfer coefficient h (current heat transfer coefficient h) of each part of the motor 101 based on the rotation speed of the motor 101, the temperature of the first refrigerant, and the flow rate of the first refrigerant. Also in step S403, the state estimation unit 251 calculates the maximum heat transfer coefficient h of each part of the motor 101. max Calculate the following.

[0053] Next, the state estimation unit 251 calculates the state quantity x at time k, which is the current time. k is estimated (S404). The state equation at time k can be expressed by the following equation (1): In equation (1), A is the system matrix, B is the input coefficient matrix, u is the input vector, and Acnv is the area matrix of the prediction model in which heat transfer occurs.

[0054]

number

[0055] Here, assuming that the nonlinear term in the heat transfer coefficient section is constant from the kth step to the next step, linearization yields the following equation (2).

[0056]

number

[0057] Then, by substituting equation (2) into equation (1) and applying the Kalman filter, the state quantity x is calculated as shown in the following equations (3) to (8). k can be estimated.

[0058]

number

[0059] Next, the first state prediction unit 252a of the control unit 250 predicts the temperature e1 of each part of the motor 101 at a future time N1 (S405). The first state prediction unit 252a predicts the temperature e1 of each part of the motor 101 at a future time N1 based on the input vector u calculated in step 403 and the state quantity x estimated in step 404. k The temperature e1 can be expressed by the following equations (9) and (10).

[0060]

number

[0061] In this way, the first state prediction unit 252a uses the formulas (9) and (10) to predict the temperature y t+N1 The various parts of the motor 101 are, for example, the housing 201, the stator coil 206, the rotor core 207, the magnet 208, and other components.

[0062] Next, the heat transfer coefficient calculation unit 253a of the control unit 250 calculates an optimal heat transfer coefficient manipulated variable Δh based on the difference between the temperature of each part of the motor 101 at time N1 (hereinafter referred to as the "predicted temperature") and the target temperature r (S406). The target temperature r corresponds to the motor target temperature according to the present invention.

[0063] The optimal heat transfer coefficient manipulated variable Δh can be calculated by reducing it to a quadratic programming problem, as shown in the following equations (11) to (16). At this time, the heat transfer coefficient calculation unit 253a can calculate the optimal heat transfer coefficient manipulated variable Δh under the constraint conditions by taking the constraint conditions into consideration. Examples of the constraint conditions include the rotation speed of the radiator fan 114 and the limit heat transfer coefficient determined by the limit value of the flow rate of the first refrigerant pump 108. Known methods for taking the constraint conditions into consideration include the active set method (active constraint method). Note that the above method is an example and is not limited to this.

[0064]

number

[0065]

number

[0066]

number

[0067] Next, the heat transfer coefficient calculation unit 253a calculates the heat transfer coefficient h, which is the sum of the heat transfer coefficient manipulated variable Δh and the current heat transfer coefficient h. var Then, the heat transfer coefficient calculation unit 253a calculates the heat transfer coefficient h var is the maximum heat transfer coefficient h max In step S407, it is determined whether the heat transfer coefficient h var is the maximum heat transfer coefficient h max If it is determined that the number is not equal to or greater than the limit (NO in S407), the control unit 250 proceeds to step S415.

[0068] Heat transfer coefficient h var is the maximum heat transfer coefficient h maxIf the target flow rate of the first refrigerant is not equal to or greater than the limit flow rate of the first refrigerant, this means that the target flow rate of the first refrigerant is not equal to or greater than the limit flow rate of the first refrigerant. The limit flow rate of the first refrigerant is determined according to the pumping capacity of the first refrigerant pump 108. If the target flow rate of the first refrigerant is not equal to or greater than the limit flow rate of the first refrigerant, the control unit 250 proceeds to step S415 and controls the drive of the first refrigerant pump 108 to set the flow rate of the first refrigerant to the target flow rate.

[0069] On the other hand, the heat transfer coefficient h var is the maximum heat transfer coefficient h max If the target flow rate of the first refrigerant is equal to or greater than the limit flow rate of the first refrigerant, this means that the target flow rate of the first refrigerant is equal to or greater than the limit flow rate of the first refrigerant. In other words, the first refrigerant pump 108 cannot make the flow rate of the first refrigerant reach the target flow rate. If the target flow rate of the first refrigerant is equal to or greater than the limit flow rate of the first refrigerant, the control unit 250 performs control to lower the temperature of the first refrigerant via the second refrigerant.

[0070] In step S407, the heat transfer coefficient h var is the maximum heat transfer coefficient h max When it is determined that the maximum value is equal to or greater than the first refrigerant temperature (YES in S407), the heat transfer coefficient calculation unit 253a outputs a maximum value determination flag to the first refrigerant temperature calculation unit 253b. min is calculated (S408).

[0071] Next, the first refrigerant temperature calculation unit 253b calculates the state quantity x estimated in step S404. k From the above, the optimum temperature Tf of the first refrigerant at the inlet of the motor 101 is tar In step S409, first refrigerant temperature calculation unit 253b calculates an optimal temperature manipulated variable ΔTf (first refrigerant temperature manipulated variable ΔTf) for the first refrigerant based on the difference between the predicted temperature at time N1 and target temperature r. Note that the predicted temperature at time N1 takes into account the heat transfer coefficient manipulated variable Δh calculated in step S406.

[0072] The first refrigerant temperature manipulated variable ΔTf can be calculated by solving a quadratic programming problem as shown in the following equations (17) to (22). At this time, the first refrigerant temperature calculation unit 253b calculates the first refrigerant temperature manipulated variable ΔTf by considering the constraints (the critical minimum temperature Tf min and the maximum temperature of the second refrigerant Tf max ) can be used to calculate the first refrigerant temperature manipulated variable ΔTf under the constraint conditions.

[0073]

number

[0074]

number

[0075]

number

[0076] Next, the first refrigerant temperature calculation unit 253b calculates the optimum temperature Tf of the first refrigerant. tar is the critical minimum temperature Tf of the first refrigerant min In step S410, it is determined whether the optimum temperature Tf of the first refrigerant is equal to or lower than the optimum temperature Tf tar is the critical minimum temperature Tf of the first refrigerant min If it is determined that the value is not less than or equal to the threshold (NO in S410), control unit 250 proceeds to step S414.

[0077] In step S410, the optimum temperature Tf of the first refrigerant is determined. tar is the critical minimum temperature Tf of the first refrigerant min If it is determined that the first refrigerant temperature is equal to or less than the reference temperature (YES in S410), the first refrigerant temperature calculation unit 253b outputs a most positive value determination flag to the calorific value calculation unit 253c. Next, the calorific value calculation unit 253c calculates the input vector u calculated in step 403 and the state quantity x estimated in step 404. k is used to predict the temperature e2 of each part of the motor 101 at a future time N2 (S411).

[0078] For example, the time it takes for changes in the temperature of the first refrigerant, the flow rate of the first refrigerant, and the temperature of the second refrigerant to affect the temperature changes of each part of the motor 101 is longer than the time it takes for the amount of current supplied to the motor 101 to affect the temperature changes of each part. Therefore, it is necessary to determine the predicted time taking into account the difference between the two times.

[0079] The operation amount of the first refrigerant pump 108 and the like for controlling the cooling circuit is determined based on the state quantity x at time N1. Meanwhile, the torque limit value of the motor 101 is determined based on the state quantity x at time N2. Therefore, it is desirable that the time until time N1 is reached is longer than the time until time N2 is reached. This can enhance the effect of suppressing unnecessary torque limiting.

[0080] Next, the heat generation amount calculation unit 253c calculates an optimal heat generation amount Δu based on the difference between the predicted temperature of each part of the motor 101 at time N2 and the target temperature r (S412). Note that the predicted temperature at time N2 takes into account the heat transfer coefficient manipulated variable Δh calculated in step S406.

[0081] The heat transfer coefficient manipulated variable Δh can be calculated by solving a quadratic programming problem, as shown in the following equations (23) to (28). At this time, first refrigerant temperature calculation unit 253b can calculate the optimal heat generation amount Δu under the constraint condition by taking into account the constraint condition (Δu≦0).

[0082]

number

[0083]

number

[0084]

number

[0085] Next, the torque control instruction unit 254c refers to the heat value map and calculates the limit torque taking into account the upper limit temperature of the motor 101 based on the rotation speed of the motor 101, the torque of the motor 101, and the frequency of the inverter 110 (S413).

[0086] After the process of step S413, or if the determination in step S410 is NO, second cooling amount control instructing unit 254b calculates the rotation speed of radiator fan 114 and the rotation speed of second refrigerant pump 111 based on the first refrigerant temperature manipulated variable ΔTf, the temperature of the second refrigerant, and the temperature of the first refrigerant (S414). Then, second cooling amount control instructing unit 254b controls the driving of radiator fan 114 and second refrigerant pump 111 according to the determination result.

[0087] After the process of step S414, or if the determination in step S407 is NO, first refrigerant flow rate calculation unit 253d calculates a target flow rate of the first refrigerant based on the heat transfer coefficient manipulated variable Δh (S415).

[0088] Fig. 5 is a diagram showing the relationship between the heat transfer coefficient and the flow rate and heat transfer coefficient of the first refrigerant when the temperature of the first refrigerant changes. First refrigerant flow rate calculation unit 253d has a memory unit that stores data (maps or tables) that defines the relationship between the flow rate and heat transfer coefficient of the first refrigerant as shown in Fig. 5. First refrigerant flow rate calculation unit 253d refers to the data that defines the relationship shown in Fig. 5 and calculates the target flow rate of the first refrigerant based on the sum of the heat transfer coefficient manipulated variable Δh and the current heat transfer coefficient h.

[0089] Next, based on the difference between the actual flow rate of the first refrigerant and the target flow rate, first cooling amount control instructing unit 254a determines the rotation speed of first refrigerant pump 108. Then, first cooling amount control instructing unit 254a controls the driving of first refrigerant pump 108 according to the determined rotation speed of first refrigerant pump 108.

[0090] In this embodiment, control instructions based on the future temperature are sequentially output, such as the flow rate of the first cooling circuit, the flow rate of the second cooling circuit and the rotation speed of the radiator fan 114, and the torque instruction amount to the inverter 110. This allows the control of the cooling circuits and the torque control of the motor 101 to function in coordination. As a result, unnecessary torque restrictions in the torque control of the motor 101 can be suppressed.

[0091] [Comparison between this embodiment and the prior art] Next, the present embodiment will be compared with the prior art using FIGS. Figure 6 shows time history temperature results comparing the torque and temperature of the motor of this embodiment with that of the prior art. Figure 7 shows time history results comparing the torque and temperature, cooling circuit flow rate and temperature of the motor of this embodiment with that of the prior art.

[0092] The vertical axis of Figure 6 represents motor torque and temperature. The horizontal axis of Figure 6 represents time. As shown in Figure 6, the conventional technology controls the motor torque to gradually decrease when the motor temperature reaches the protection start temperature T1. This results in torque limitation from a period when torque limitation is not yet necessary, resulting in unnecessary torque limitation.

[0093] On the other hand, in this embodiment, the future temperature of the motor is predicted, and control is performed to reduce the torque before the motor temperature exceeds the protection start temperature T1 and reaches the limit temperature T2. Therefore, even if the motor temperature exceeds the protection start temperature T1, the torque does not need to be limited immediately. Therefore, unnecessary torque limitation can be suppressed. The limit temperature T2 corresponds to the upper limit target temperature according to the present invention. The limit temperature T2 is set to be equal to or lower than the rated temperature of each part of the motor 101.

[0094] The vertical axis of Figure 7 represents the motor torque and temperature and the cooling circuit flow rate and temperature. The horizontal axis of Figure 7 represents time. In the prior art, when the motor temperature reaches the protection start temperature T1, torque limitation and cooling circuit control are initiated simultaneously. Therefore, the cooling circuit control and motor torque control do not function in coordination, resulting in unnecessary torque limitation.

[0095] In contrast, in this embodiment, the future temperature of the motor is predicted. If a rise in the motor temperature is predicted, first, control is performed to increase the flow rate of the refrigerant in the cooling circuit (driving control of the refrigerant pump). Next, control is performed to lower the temperature of the refrigerant in the cooling circuit (driving control of the radiator fan). Finally, control is performed to limit the torque of the motor (driving control of the inverter).

[0096] In this embodiment, the cooling circuit control and the motor torque control function in a coordinated manner. As a result, the torque limiting period in this embodiment is shorter than that in the prior art. As a result, the control unit 250 can suppress unnecessary torque limiting.

[0097] 7, the cooling amount control instruction units 254a and 254b control the cooling circuit so that the temperature of each part of the motor 101 is equal to or lower than the cooling circuit target temperature. In other words, the cooling circuit target temperature is a reference temperature for determining whether or not to maximize the cooling capacity of the cooling circuit. The cooling circuit target temperature corresponds to the reference temperature according to the present invention.

[0098] The torque control instruction unit 254c controls the torque of the motor 101 so that the temperature of each part of the motor 101 is equal to or lower than the limit temperature T2 (upper limit target temperature). The limit temperature T2 is set to a value higher than the cooling circuit target temperature described above. Therefore, the control unit 250 starts torque control of the motor 101 after maximizing the cooling capacity of the cooling circuit. This allows the control unit 250 to suppress unnecessary torque restrictions.

[0099] Furthermore, when the target flow rate of the first refrigerant is equal to or greater than the limit flow rate, the torque control instructing unit 254c may execute control to lower the limit temperature T2 (upper limit target temperature), thereby shortening the period during which the torque of the motor 101 is limited.

[0100] The limit temperature T2 and the cooling circuit target temperature are set for each part of the motor 101. This makes it possible to predict the future temperature of each part of the motor 101 and control the cooling circuit and limit the torque. As a result, it is possible to more accurately control the cooling circuit and limit the torque so that the motor 101 remains at or below the rated temperature.

[0101] Each part of the motor 101 includes at least a stator part and a rotor part. The temperature limit T2 of the stator part is set to be equal to or lower than the dielectric breakdown temperature of the stator coil. If the motor 101 is a permanent magnet synchronous motor, the temperature of the rotor part is the temperature of the magnet. If the motor 101 is a wound field motor, the temperature of the rotor part is the temperature of the rotor field winding.

[0102] Furthermore, according to this embodiment, it is possible to prevent the temperature of the stator coil 206 from exceeding the allowable value, which would destroy the insulating coating and cause an electrical short circuit. Furthermore, this embodiment does not limit the required torque more than necessary to protect the stator coil 206. This prevents the motor 101 from losing the opportunity to output the characteristics that it is originally capable of demonstrating. As a result, the motor 101 functions effectively, and the vehicle 100 can perform its original functions.

[0103] Furthermore, according to this embodiment, it is possible to predict the temperature of each part of the motor 101 individually, and to issue control instructions for the flow rate of the first cooling circuit, the flow rate of the second cooling circuit and the fan rotation speed, and the torque instruction amount to the inverter 110, depending on the state of each part. This makes it possible to prevent the predicted temperature value of the magnet 208 from exceeding the allowable value and causing irreversible demagnetization.

[0104] The above describes the embodiments of the vehicle control device of the present invention, including their effects. However, the vehicle control device of the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention as defined in the claims.

[0105] Furthermore, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the configurations described. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with another configuration.

[0106] In this specification, the words "parallel" and "orthogonal" are used, but these do not mean only "parallel" and "orthogonal" in the strict sense, but also include "parallel" and "orthogonal" and may also mean a "substantially parallel" or "substantially orthogonal" state within a range in which the functions can be exerted. [Explanation of symbols]

[0107] 100...vehicle, 101...motor, 102...transmission, 103...differential gear, 104...drive shaft, 105...wheel, 106...first piping, 107...heat exchanger, 108...first refrigerant pump, 109...battery, 110...inverter, 111...second refrigerant pump, 112...radiator, 113...second piping, 114...radiator fan, 115...third refrigerant pump, 116...third piping, 118...first refrigerant tank, 119...second refrigerant tank, 201...housing, 202...stator, 203...rotor, 204...shaft, 205...stator core, 206...stator coil, 207...rotor core, 208...magnet, 250...control unit, 251...state estimation unit, 252...State prediction unit, 252a...First state prediction unit, 252b...Second state prediction unit, 253...Calculation unit, 253a...Heat transfer coefficient calculation unit, 253b...First refrigerant temperature calculation unit, 253c...Heat generation amount calculation unit, 253d...First refrigerant flow rate calculation unit, 254...Control instruction unit, 254a...First cooling amount control instruction unit, 254b...Second cooling amount control instruction unit, 254c...Torque control instruction unit

Claims

1. a state estimation unit that acquires operating state information including parameters related to the temperature of the motor and estimates a current state quantity of the motor based on the operating state information; a state prediction unit that predicts a future state quantity of the motor based on the operating state information and the current state quantity; a cooling amount control instruction unit that controls a cooling circuit for cooling the motor based on the future state quantity; a torque control instruction unit that controls the torque of the motor based on the future state quantity, The state prediction unit sets a future period when predicting the future state quantity to be output to the torque control instruction unit to be shorter than a future period when predicting the future state quantity to be output to the cooling amount control instruction unit. Vehicle control device.

2. the cooling circuit includes a pipe for circulating a cooling medium for cooling the motor, a refrigerant pump for pumping the cooling medium, and a cooling unit for cooling the cooling medium; a calculation unit that calculates a target flow rate of the cooling medium based on the future state quantity and a target temperature of the cooling medium based on the future state quantity; The vehicle control device according to claim 1 .

3. The cooling amount control instruction unit controls the operation of the refrigerant pump in accordance with the target flow rate when the target flow rate is smaller than the limit flow rate of the cooling medium, and controls the operation of the cooling unit in accordance with the target temperature when the target flow rate is equal to or greater than the limit flow rate of the cooling medium. The vehicle control device according to claim 2.

4. The torque control instruction unit starts control to limit the torque of the motor when the target temperature is equal to or lower than the minimum limit temperature of the cooling medium. The vehicle control device according to claim 3.

5. the cooling unit is capable of varying an amount of outside air for cooling the refrigerant, When the target flow rate is equal to or greater than the limit flow rate of the cooling medium, the cooling amount control instruction unit executes control to increase the outside air ventilation amount of the cooling unit. The vehicle control device according to claim 3.

6. the torque control instruction unit has an upper limit target temperature for controlling the temperature of the motor so that it is equal to or lower than a predetermined rated temperature, the cooling amount control instruction unit has a reference temperature that is used as a criterion for determining whether or not to maximize the cooling capacity of the cooling circuit, The upper limit target temperature is set higher than the reference temperature. The vehicle control device according to claim 2.

7. When the target flow rate is equal to or greater than the limit flow rate of the cooling medium, the torque control command unit executes control to lower the upper limit target temperature. The vehicle control device according to claim 6.

8. The upper limit target temperature and the reference temperature are set for at least the stator portion and the rotor portion of the motor, respectively. The vehicle control device according to claim 6.

9. The calculation unit calculates a motor target temperature that is a target for adjusting the temperature of the motor, a required heat transfer coefficient between the motor and the cooling medium that is required when adjusting the temperature of the motor, and an actual heat transfer coefficient based on a flow rate of the cooling medium and an actual temperature of the cooling medium, and calculates the target flow rate based on the required heat transfer coefficient and the actual heat transfer coefficient. The vehicle control device according to claim 2.

10. The operating state information includes at least one parameter selected from the actual temperature of the motor, the rotational speed of the motor, the shaft torque output by the motor, the amount of electricity supplied to the motor, the actual temperature of the cooling medium, the actual flow rate of the cooling medium, and the outside air temperature. The vehicle control device according to claim 2.

11. a state estimation unit that acquires operating state information including a parameter related to a temperature of the motor, and estimates a current state quantity of the motor based on the operating state information; a state prediction unit predicts a future state quantity of the motor based on the operating state information and the current state quantity; a cooling amount control instruction unit controls a cooling circuit for cooling the motor based on the future state quantity; a torque control instruction unit that controls the torque of the motor based on the future state quantity; The state prediction unit sets a future period when predicting the future state quantity to be output to the torque control instruction unit to be shorter than a future period when predicting the future state quantity to be output to the cooling amount control instruction unit. Vehicle control method.

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