Electric vehicle control method and electric vehicle control system

Abstract

Provided is an electric vehicle control method in which, when a driving torque is applied to one of two motors by means of a driving voltage command value for driving a first inverter being calculated on the basis of a driving torque command value and being output to the first inverter, in the case that a first braking torque is generated in the other motor of the two motors, a battery is charged with regenerative power generated by the first braking torque, wherein: when the regenerative power is greater than an allowable charging power, which is the maximum power that can be used to charge the battery, an IH frequency for induction heating a stator core of the one motor of the two motors is set, and a heating voltage command value for supplying a differential power to the one motor of the two motors is calculated, said differential power obtained by subtracting the allowable charging power from the regenerative power; a combined voltage command value is calculated by combining the driving voltage command value and the heating voltage command value; and the voltage command value output to the first inverter is changed from the driving voltage command value to the combined voltage command value.

Description

Control method for electric vehicle and control system for electric vehicle

[0001] The present invention relates to a control method for an electric vehicle and a control system for an electric vehicle.

[0002] JP2010-200551A discloses a technology for recovering braking energy generated when braking an electric vehicle as regenerative power and charging the battery. However, if the braking energy is greater than the regenerative power that the battery can accept, it is difficult to recover the surplus braking energy as regenerative power. In JP2010-200551A, if the regenerative power is greater than the charging power that the battery can accept, the surplus regenerative power is charged into a capacitor. However, a capacitor that recovers regenerative power without waste is physically large and costly.

[0003] It has been proposed to reduce the power consumption of the battery heat source by using the waste heat from the motor (powertrain) of an electric vehicle as a heat source for heating the vehicle interior. However, the waste heat from the powertrain is due to electrical losses that occur as a result of driving the powertrain, and there is a limit to the amount of waste heat that can be generated.

[0004] Therefore, an object of the present invention is to provide a control method and a control system for an electric vehicle that reduces the power consumption of the battery as a heat source by directly using surplus regenerative power that cannot be accepted by the battery as power to generate heat in the motor.

[0005] According to one aspect of the present invention, there is provided a control method for an electric vehicle, which includes exchanging electric power between one of two motors and a battery via a first inverter, releasing exhaust heat from at least one of the two motors into a refrigerant circulating through an exhaust heat circulation path, calculating a drive voltage command value for driving the first inverter based on a drive torque command value, and outputting the calculated drive voltage command value to the first inverter, so that when a first braking torque is generated in the other of the two motors while a drive torque is being applied to one of the two motors, the regenerative power generated by the first braking torque is charged to the battery. In this control method, when the regenerative power is greater than the allowable charging power, which is the maximum power that can be charged to the battery, the IH frequency is set to inductively heat the stator core of one of the two motors, a heating voltage command value is calculated to supply the power difference obtained by subtracting the allowable charging power from the regenerative power to one of the two motors, the drive voltage command value and the heating voltage command value are summed to calculate a combined voltage command value, and the voltage command value to be output to the first inverter is switched from the drive voltage command value to the combined voltage command value.

[0006] FIG. 1 is a diagram showing the basic configuration of an electric vehicle to which a control system for an electric vehicle according to a first embodiment is applied. FIG. 2 is a circuit diagram of a heat exchange system of the electric vehicle. FIG. 3 is a configuration diagram of the control system for the electric vehicle according to the first embodiment. FIG. 4 is a control configuration diagram of a three-phase voltage command value calculation unit constituting the control system for the electric vehicle according to the first embodiment. FIG. 5 is a map showing the relationship between a first function related to the temperature of a first refrigerant and a first set power that is set based on the first function and corresponds to the amount of heat that can be accepted by an exhaust heat circulation path. FIG. 6 is a map showing the relationship between a second function related to the temperature of a powertrain and a second set power that is set based on the second function and can be accepted by the powertrain. FIG. 7 is a control flow diagram of the control system for the electric vehicle according to the first embodiment. FIG. 8A is a diagram showing an example of three-phase voltage command values ​​before correction generated by the three-phase voltage command value calculation unit according to the first embodiment. FIG. 8B is a diagram showing an example of a corrected three-phase voltage command value (U phase) (B1) and an induction heating voltage (B2) generated by the three-phase voltage command value calculation unit according to the first embodiment. 8C is a diagram showing an example of a final three-phase voltage command value (U phase) obtained by summing the induction heating voltage and the corrected three-phase voltage command value generated by the three-phase voltage command value calculation unit of the first embodiment. FIG. 8D is a diagram showing an example of a final three-phase voltage command value (U phase, V phase, W phase) obtained by summing the induction heating voltage and the corrected three-phase voltage command value generated by the three-phase voltage command value calculation unit of the first embodiment. FIG. 9 is a diagram showing eddy currents (induction heating) generated around the windings of the stator core. FIG. 10 is a diagram showing the relationship between the IH frequency and the penetration depth of the induction heating region. FIG. 11 is a diagram comparing energy loss and consumption occurring in an electric vehicle, between the energy loss and consumption when brake loss is not converted to motor loss and the energy loss and consumption when brake loss is converted to motor loss by induction heating. Fig. 12 is a diagram comparing an instantaneous value of a motor loss, an instantaneous value of a brake loss, an integrated value of the instantaneous values ​​of the motor loss, an integrated value of the instantaneous values ​​of the brake loss, and a sum of the integrated value of the instantaneous values ​​of the motor loss and the integrated value of the instantaneous values ​​of the brake loss. Fig. 13 is a configuration diagram of a control system for an electric vehicle according to a second embodiment. Fig. 14 is a control configuration diagram of a three-phase voltage command value calculation unit constituting the control system for an electric vehicle according to the second embodiment.

[0007] An embodiment of the present invention will now be described with reference to the drawings. [Basic Configuration of Electric Vehicle 100] FIG. 1 is a diagram illustrating the basic configuration of an electric vehicle 100 to which a control system for an electric vehicle 100 according to this embodiment is applied. The electric vehicle 100 is a vehicle equipped with a drive motor 4 as a drive source and driven by generating drive force resulting from torque generated by the drive motor 4 on one or more wheels. Therefore, the electric vehicle 100 includes not only so-called electric vehicles but also hybrid vehicles that use both the drive motor 4 and an engine as a drive source. For example, the electric vehicle 100 also includes a hybrid vehicle that uses the drive motor 4 as a drive source for one of the front wheels 82f and the rear wheels 82r and an engine as a drive source for the other wheel. Furthermore, a four-wheel drive vehicle refers to a vehicle that uses four wheels as drive wheels. Four-wheel drive vehicles include vehicles that always use four wheels as drive wheels, as well as vehicles that can switch between two-wheel drive (front-wheel drive) or four-wheel drive (rear-wheel drive) and four-wheel drive. In addition, a four-wheel drive vehicle may control some of the four wheels as interlocking drive wheels, or may control the four wheels as independently driven drive wheels. Therefore, in this embodiment, the electric four-wheel drive vehicle refers to an electric vehicle 100 that runs by generating drive force resulting from torque generated by a drive motor 4 in some or all of the four wheels.

[0008] 1, the electric vehicle 100 is an electric four-wheel drive vehicle, but may also be an electric two-wheel drive vehicle with only the front wheels 82f or only the rear wheels 82r. The electric vehicle 100 includes a front drive system (FDS), a rear drive system (RDS), a battery 9, and a motor controller 2.

[0009] The front drive system (FDS) receives power from the battery 9 and drives the front wheels 82f under the control of the motor controller 2. The front drive system (FDS) includes a front inverter 3f, a front drive motor 4f, a front reduction gear 5f, a front rotation sensor 6f, a front drive shaft 81f, and front wheels 82f, with the subscript "f" indicating a front-side configuration. The front wheels 82f are a pair of wheels that are relatively forward of the electric vehicle 100, out of the four wheels included in the electric vehicle 100. The forward direction of the electric vehicle 100 is a predetermined direction that is formally determined depending on the orientation of the driver's seat, etc. By the front drive system (FDS), the front wheels 82f function as drive wheels that generate driving force for the electric vehicle 100.

[0010] The rear drive system (RDS) receives power from the battery 9 and drives the rear wheels 82r under the control of the motor controller 2. Symmetrically to the front drive system (FDS), the rear drive system (RDS) includes a rear inverter 3r, a rear drive motor 4r, a rear reduction gear 5r, a rear rotation sensor 6r, a rear drive shaft 81r, and rear wheels 82r. The subscript r indicates a rear-side configuration. The rear wheels 82r are a pair of wheels that are relatively rearward of the electric vehicle 100, out of the four wheels equipped on the electric vehicle 100. The rearward direction of the electric vehicle 100 refers to the direction opposite to the forward direction of the electric vehicle 100. With the rear drive system (RDS), the rear wheels 82r function as drive wheels that generate driving force for the electric vehicle 100.

[0011] The battery 9 is connected to the drive motor 4 via the inverter 3 and supplies drive power to the drive motor 4 by discharging. The battery 9 can also be charged by receiving regenerative power from the drive motor 4. In a front drive system (FDS), the battery 9 is connected to the front drive motor 4f via a front inverter 3f. Similarly, in a rear drive system (RDS), the battery 9 is connected to the rear drive motor 4r via a rear inverter 3r.

[0012] The vehicle controller 1 is a control device for the electric vehicle 100, and is a computer comprising a central processing unit (CPU), read-only memory (ROM), random access memory (RAM), an input / output interface (I / O interface), etc. The vehicle controller 1 generates control signals for controlling the front drive motor 4f and the rear drive motor 4r based on vehicle variables of the electric vehicle 100. The vehicle variables are information indicating the operating state or control state of the electric vehicle 100 as a whole or of each part that constitutes the electric vehicle 100, and can be obtained by detection, measurement, calculation, etc. The vehicle variables include, for example, the accelerator opening APO, the rotational speed of the front drive motor 4f, the rotational speed of the rear drive motor 4r, longitudinal G and lateral G, vehicle speed V, gradient value, steering angle, wheel speed, etc.

[0013] The vehicle controller 1 outputs a torque command value (Tf ＊ ), the torque command value for the rear drive motor (Tr ＊ ) is output.

[0014] The vehicle controller 1 calculates the target drive torque T_req, which is the torque required by the driver, as a torque command value (Tf ＊ ) and the torque command value (Tr ＊ ) and there is a case where one of them generates a driving torque and the other generates a braking torque (first braking torque).

[0015] Furthermore, the vehicle controller 1 calculates the allowable charging power, which is the maximum power that can be charged to the battery 9, based on the SOC (State of Charge) of the battery 9, the temperature of the battery 9, etc., and outputs the calculated power to the motor controller 2 (three-phase voltage command value calculation units 23f, 23r) (see Figure 3).

[0016] Although not shown, the drive wheels (front wheels 82 f, rear wheels 82 r) are fitted with mechanical brakes that brake the drive wheels by frictional force. When braking amount information is input from the motor controller 2 (three-phase voltage command value calculation units 23 f, 23 r) as described below, the vehicle controller 1 sets a braking torque (second braking torque) of the mechanical brakes based on the braking amount.

[0017] The motor controller 2 determines the torque command value (Tf ＊ ), the torque command value for the rear drive motor (Tr ＊ ) and controls the front drive motor 4f and the rear drive motor 4r, respectively.

[0018] The front inverter 3f and the rear inverter 3r convert the DC current supplied from the battery 9 into AC current by turning on / off switching elements in response to drive signals generated by the motor controller 2, and adjust the current supplied to the front drive motor 4f and the rear drive motor 4r, respectively. The front inverter 3f and the rear inverter 3r also inversely convert the AC current generated by the front drive motor 4f and the rear drive motor 4r due to regenerative braking force back into DC current, and adjust the current supplied to the battery 9.

[0019] The front drive motor 4f and the rear drive motor 4r are, for example, three-phase AC motors that generate drive force (drive torque) using AC current supplied from the inverter 3. The drive force generated by the front drive motor 4f is transmitted to the front wheels 82f via the front reduction gear 5f and the front drive shaft 81f. Similarly, the drive force generated by the rear drive motor 4r is transmitted to the rear wheels 82r via the rear reduction gear 5r and the rear drive shaft 81r. When the front drive motor 4f and the rear drive motor 4r rotate along with the front wheels 82f and the rear wheels 82r, respectively, they generate regenerative braking force and recover the loss of kinetic energy (brake energy) of the electric vehicle 100 as electrical energy. The front drive motor 4f constitutes a drive source (front drive source) that drives the front wheels 82f. Similarly, the rear drive motor 4r constitutes a drive source (rear drive source) that drives the rear wheels 82r independently of the front wheels 82f.

[0020] The front reduction gear 5f and the rear reduction gear 5r are each composed of a plurality of gears. The front reduction gear 5f and the rear reduction gear 5r reduce the rotational speed Nm of the drive motor 4 connected to each reduction gear and transmit the reduced torque to the drive shaft 81, thereby generating a driving torque or braking torque proportional to the reduction ratio. The front rotation sensor 6f and the rear rotation sensor 6r detect the rotor phase of the drive motor 4 connected to each reduction gear and output the detected rotor phase to the motor controller 2. The motor controller 2 detects the rotational speed Nmf of the front drive motor 4f based on the output of the front rotation sensor 6f, and the rotational speed Nmr of the rear drive motor 4r based on the output of the rear rotation sensor 6r. The front current sensor 7f and the rear current sensor 7r detect the current flowing through the drive motor 4 connected to each reduction gear and output the detected rotor phase to the motor controller 2. The front current sensor 7f detects the three-phase AC current of the front drive motor 4f, and the rear current sensor 7r detects the three-phase AC current of the rear drive motor 4r.

[0021] The electric vehicle 100 is equipped with various sensors in addition to the front rotation sensor 6f, front current sensor 7f, rear rotation sensor 6r, and rear current sensor 7r described above. The various sensors include, for example, an accelerator opening sensor, an acceleration sensor, a vehicle speed sensor, a gradient sensor, a steering angle sensor, a wheel speed sensor, and the like. The accelerator opening sensor detects the accelerator opening APO, which is the amount of accelerator operation. The acceleration sensor detects the acceleration in the longitudinal and lateral directions of the electric vehicle 100, i.e., the longitudinal G and lateral G. The vehicle speed sensor detects the vehicle speed of the electric vehicle 100. The gradient sensor detects the gradient value, which is the gradient of the road on which the electric vehicle 100 is traveling. The steering angle sensor detects the steering angle of the steering wheel. The wheel speed sensor detects the wheel speed of each drive wheel. The detected values ​​by the various sensors are input to the vehicle controller 1 (or the motor controller 2).

[0022] 2 is a circuit diagram of the heat exchange system of the electric vehicle 100. The electric vehicle 100 includes an exhaust heat circulation path 50 that extracts exhaust heat generated by exhaust heat sources (front inverter 3 f, front drive motor 4 f, rear inverter 3 r, rear drive motor 4 r), a heat pump 60 for air conditioning of the electric vehicle 100, a heat source circulation path 70 that supplies heat to a heater core 72 that heats the air and a battery heater 75 that heats the battery 9, an air conditioning system 90 that heats the vehicle interior, a chiller 61 that exchanges heat between the exhaust heat circulation path 50 and the heat pump 60, and a condenser 63 that exchanges heat between the heat pump 60 and the heat source circulation path 70.

[0023] The exhaust heat circulation path 50 circulates cooling water as a first refrigerant, the heat pump 60 circulates an alternative chlorofluorocarbon such as HFC134a as a second refrigerant, and the heat source circulation path 70 circulates cooling water as a third refrigerant.

[0024] The exhaust heat circulation path 50 connects the front inverter 3 f, the front drive motor 4 f, the rear inverter 3 r, the rear drive motor 4 r, the chiller 61, the first pump 51, and the first valve 52.

[0025] The exhaust heat circulation path 50 is provided with a first bypass path 54 that bypasses the first valve 52, and the first bypass path 54 is provided with a second valve 55 and a radiator 56.

[0026] 2 illustrates the front inverter 3f, front drive motor 4f, rear inverter 3r, and rear drive motor 4r as exhaust heat sources, but other components that emit exhaust heat when driving the electric vehicle 100 can also be used. Also, a powertrain (electric powertrain (ePT)) in which the drive motor 4 and the inverter 3 are combined as an integral unit can also be used as an exhaust heat source.

[0027] The chiller 61 heats the second refrigerant by exchanging heat between the first refrigerant flowing through the exhaust heat circulation path 50 and the second refrigerant flowing through the heat pump 60 .

[0028] The first pump 51 pumps the first refrigerant discharged from, for example, the chiller 61 to the exhaust heat source or the radiator 56. The first pump 51 is driven by receiving power from the battery 9, and is on / off controlled by the vehicle controller 1.

[0029] The first valve 52 is controlled to be turned on and off by the vehicle controller 1, and is normally in the on state (open state).

[0030] The temperature sensor 53 detects the temperature of the first refrigerant and outputs temperature information to the vehicle controller 1 and the motor controller 2 .

[0031] The second valve 55 is controlled to be turned on and off by the vehicle controller 1, and is normally in the off state (closed state).

[0032] When the temperature of the first refrigerant reaches a predetermined upper limit temperature, the vehicle controller 1 sets the first valve 52 to the off state (closed state) and sets the second valve 55 to the on state (open state), thereby supplying the first refrigerant to the radiator 56.

[0033] The radiator 56 cools the first refrigerant with outside air supplied while the electric vehicle 100 is running, and supplies the cooled first refrigerant to the front inverter 3f and the front drive motor 4f.

[0034] The heat pump 60 includes a chiller 61, a compressor 62, and a condenser 63.

[0035] The chiller 61 exchanges heat between a low-pressure, low-temperature liquid refrigerant (second refrigerant) and the first refrigerant in the exhaust heat circulation path 50, thereby evaporating the liquid refrigerant (second refrigerant) to generate refrigerant gas (second refrigerant), which is then supplied to the compressor 62.

[0036] The compressor 62 compresses the refrigerant gas (second refrigerant) supplied from the chiller 61 to generate high-temperature, high-pressure refrigerant gas (second refrigerant), which is then discharged toward the condenser 63. The compressor 62 is driven by power supplied from the battery 9, and is on / off controlled by the vehicle controller 1.

[0037] The condenser 63 exchanges heat between the high-temperature, high-pressure refrigerant gas (second refrigerant) and the third refrigerant in the heat source circulation path 70, and cools and condenses the refrigerant gas (second refrigerant) to change it into a high-pressure liquid refrigerant (second refrigerant).

[0038] Although not shown in the figure, the heat pump 60 is equipped with an expansion valve that rapidly expands the high-pressure liquid refrigerant (second refrigerant) generated in the condenser 63 to turn it into a low-pressure, low-temperature liquid refrigerant (second refrigerant) and supplies it to the chiller 61.

[0039] The heat source circulation path 70 is provided with a condenser 63 , a second pump 71 , and a heater core 72 .

[0040] The condenser 63 exchanges heat between the third refrigerant circulating through the heat source circulation path 70 and the second refrigerant circulating through the heat pump 60, thereby heating the third refrigerant.

[0041] The second pump 71 pumps the third refrigerant. The second pump 71 is driven by power supplied from the battery 9, and the output (flow rate of the third refrigerant) of the second pump 71 is controlled by the vehicle controller 1.

[0042] The opening degree of the third valve 73 is controlled by the vehicle controller 1, and the flow rate of the third refrigerant supplied to the heater core 72 is adjusted to thereby adjust the output of the heater core 72.

[0043] A second bypass path 74 is arranged in the heat source circulation path 70 so as to bypass the heater core 72 and the third valve 73, and a battery heater 75 and a fourth valve 76 are arranged in the second bypass path 74.

[0044] The battery heater 75 warms up the battery 9 .

[0045] The opening degree of the fourth valve 76 is controlled by the vehicle controller 1 , and the output of the battery heater 75 is adjusted by adjusting the flow rate of the third refrigerant supplied to the battery heater 75 .

[0046] The air conditioning system 90 includes a duct 91 that supplies air for conditioning indoors, and a PTC heater 92 (Positive Temperature Coefficient Heater) disposed in the duct 91. The heater core 72 is disposed within the duct 91.

[0047] The heater core 72 includes tubes through which the third refrigerant flows and heat dissipation fins attached to the tubes. Air for air conditioning is heated when the air comes into contact with the heat dissipation fins.

[0048] The PTC heater 92 generates heat to heat the air when power is supplied from the battery 9, and is controlled to be turned on and off by the vehicle controller 1 (at the driver's request). Also, although not shown, a PTC heater that generates heat when power is supplied from the battery 9 to heat the battery 9 is attached to the battery 9.

[0049] The vehicle controller 1 calculates a first required amount of heat required for heating by the air conditioning system 90 based on the information on the set temperature and the information on the outside air temperature transmitted from the air conditioning system 90 .

[0050] The vehicle controller 1 calculates the second required heat quantity required for the battery 9 based on the temperature transmitted from a temperature sensor (not shown) that detects the temperature of the battery 9, the set temperature information transmitted from the air conditioning system 90, and the outside air temperature information.

[0051] The vehicle controller 1 controls the output of the second pump 71 (flow rate of the third refrigerant) based on a value obtained by dividing the total heat quantity obtained by adding up the first required heat quantity and the second required heat quantity by the temperature of the third refrigerant circulating through the heat source circulation path 70, for example.

[0052] The vehicle controller 1 controls the opening degree of the third valve 73 (the flow rate of the third refrigerant to the heater core 72) based on the value obtained by dividing the first required heat quantity by the temperature of the third refrigerant.

[0053] The vehicle controller 1 controls the opening of the fourth valve 76 (the flow rate of the third refrigerant to the battery heater 75) based on the value obtained by dividing the second requested heat quantity by the temperature of the third refrigerant.

[0054] In addition, the vehicle controller 1 may set the output of the second pump 71 to a constant specified flow rate, set the opening (flow rate) of the third valve 73 based on the first required flow rate and the temperature of the third refrigerant as described above, and set the opening (flow rate) of the fourth valve 76 to an opening equivalent to the difference obtained by subtracting the flow rate of the third refrigerant flowing through the third valve 73 from the specified flow rate.

[0055] The vehicle controller 1 stops the second pump 71 and the chiller 61 when the first required flow rate and the second required flow rate are zero.

[0056] The vehicle controller 1 determines, for example, a front torque command value (Tf ＊ ) and the rear torque command value (Tr ＊ ) (the amount of heat generated by the loss) and the induction heating power (P ＩＨ ) to estimate the amount of exhaust heat taken into the exhaust heat circulation path 50 from the exhaust heat source.

[0057] If the amount of exhaust heat is smaller than the total amount of heat, the vehicle controller 1 drives the PTC heater 92 or the PTC heater for the battery 9 to make up for the lack of heat in air conditioning or the lack of heat in warming up the battery 9.

[0058] If the amount of exhaust heat is greater than the combined heat amount, the first refrigerant is heated by the difference in heat amount obtained by subtracting the combined heat amount from the amount of exhaust heat. When the temperature of the first refrigerant reaches a predetermined upper limit temperature, the vehicle controller 1 closes the first valve 52 and opens the second valve 55 to supply the first refrigerant to the radiator 56 and cool the first refrigerant.

[0059] [Control system for electric vehicle 100] Fig. 3 is a configuration diagram of the control system for electric vehicle 100 of the first embodiment. As shown in Fig. 3, the control system for electric vehicle 100 of this embodiment includes, as a front drive system (fds), a motor controller 2 (current command value calculation unit 21f, current control unit 22f, three-phase voltage command value calculation unit 23f, PWM modulation control unit 24f), a front inverter 3f, a pulse generator 11f (RDIC), an electrical angle calculation unit 12f, a speed calculation unit 13f, a dq-axis coordinate conversion unit 14f, etc.

[0060] Although not shown in the figures, the control system for the electric vehicle 100 of this embodiment includes, as a rear drive system (rds), a motor controller 2 (current command value calculation unit 21r, current control unit 22r, three-phase voltage command value calculation unit 23r, PWM modulation control unit 24r), a rear inverter 3r, a pulse generator 11r (RDIC), an electrical angle calculation unit 12r, a speed calculation unit 13r, a dq-axis coordinate conversion unit 14r, etc.

[0061] Of these, the current command value calculation units 21f, 21r, the current control units 22f, 22r, the three-phase voltage command value calculation units 23f, 23r, the PWM modulation control units 24f, 24r, the speed calculation units 13f, 13r, and the dq-axis coordinate conversion units 14f, 14r are control blocks written in software within a microcomputer unit (MCU) mounted in an electric unit (not shown) that controls the entire vehicle. Note that the following explanation will be given using a front wheel drive system (fds) as an example, but the same applies to a rear wheel drive system (rds).

[0062] The front drive motor 4f is supplied with a three-phase voltage obtained by converting the DC voltage of the battery 9 into AC voltage via a front inverter 3f. When the front drive motor 4f generates regenerative power, the front inverter 3f converts the regenerative power (three-phase power) into DC voltage and charges the battery 9.

[0063] A front current sensor 7f for detecting at least two-phase currents is attached to the output terminal of the front inverter 3f, and outputs a U-phase current (iu) and a V-phase current (iv).

[0064] A DC voltage sensor (not shown) is provided at the input terminal of the front inverter 3f to detect a DC voltage (Vdc).

[0065] The front drive motor 4f is provided with a resolver 10f as a rotor position detector, and transmits and receives excitation / modulation signals to and from a pulse generator 11f.

[0066] The pulse generator 11f outputs up / down counter pulses A and B and an origin signal pulse Z based on the excitation / modulation signal.

[0067] The electrical angle calculation unit 12f calculates and outputs an electrical angle (θ) based on the ABZ signal.

[0068] The speed calculation unit 13f calculates and outputs an electrical angular speed (ωe) and a mechanical angular speed (ωm) from the amount of change per unit time of the electrical angle (θ).

[0069] The dq-axis coordinate conversion unit 14f passes the U-phase current (iu) and the V-phase current (iv) through a low-pass filter to remove high-frequency current components, which will be described later.

[0070] The dq-axis coordinate transformation unit 14f multiplies the amplitudes of the filtered U-phase current (iu) and V-phase current (iv) in the fixed coordinates by a second amplitude ratio (A[vu1 ＊ ] / A[vu2 ＊ ]) and then converted into a d-axis current (id) and a q-axis current (iq) in a rotating coordinate system based on the electrical angle (θ).

[0071] The current command value calculation unit 21f receives a front torque command value (Tf ＊ ), and electrical angular velocity (ωe) (motor rotation speed) are input.

[0072] The current command value calculation unit 21f calculates the torque command value (Tf ＊ ), electrical angular velocity (ωe), d-axis current command value (id ＊ ), and the q-axis current command value (iq ＊ ) relationship.

[0073] The current command value calculation unit 21f calculates the input torque command value (Tf ＊ ), the d-axis current command value (id ＊ ) and the q-axis current command value (iq ＊ ) is calculated, and the d-axis current command value (id ＊ ) and the q-axis current command value (iq ＊ ) to the current control unit 22f.

[0074] The current control unit 22f receives a DC voltage (Vdc), a d-axis current command value (id ＊ ), q-axis current command value (iq ＊ ), electrical angular velocity (ωe), d-axis current (id), and q-axis current (iq) are input.

[0075] The current control unit 22f determines the d-axis current command value (id ＊ ) minus the d-axis current (id), and the q-axis current command value (iq ＊ The torque of the front drive motor 4f is set to the front torque command value (Tf ＊ d-axis voltage command value (vd ＊ ) and the q-axis voltage command value (vq ＊ ) is calculated, and the d-axis voltage command value (vd ＊ ) and the q-axis voltage command value (vq ＊ ) to the three-phase voltage command value calculation unit 23f.

[0076] The three-phase voltage command value calculation unit 23f receives the DC voltage (Vdc), the d-axis voltage command value (vd ＊ ), q-axis voltage command value (vq ＊ ), electrical angle (θ), etc. are input.

[0077] The three-phase voltage command value calculation unit 23f calculates the d-axis voltage command value (vd ＊ ) and the q-axis voltage command value (vq ＊ ) based on the three-phase voltage command value (vu ＊ , vv ＊ , vw ＊ ) and outputs it to the PWM modulation control unit 24f. The three-phase voltage command value calculation unit 23f will be described in detail later.

[0078] The PWM modulation control unit 24f controls the three-phase voltage command value (vu ＊ , vv ＊ , vw ＊ ) to generate a PWM signal (D ＊ uu~D ＊ wl) and outputs it to the front inverter 3f.

[0079] [Three-phase voltage command value calculation unit 23f] Figure 4 is a control configuration diagram of three-phase voltage command value calculation unit 23f that constitutes the control system for electric vehicle 100 of the first embodiment. Figure 5 is a map showing the relationship between a first function related to the temperature of the first refrigerant and a first set power that is set based on the first function and corresponds to the amount of heat that can be accepted by exhaust heat circulation path 50. Figure 6 is a map showing the relationship between a second function related to the temperature of the powertrain and a second set power that is set based on the second function and can be accepted by the powertrain.

[0080] 4, the three-phase voltage command value calculation unit 23f has calculation elements (C01) to (C10). Here, it is assumed that a driving torque is applied to the front drive motor 4f and a braking torque (regenerative torque) is applied to the rear drive motor 4r.

[0081] The calculation element (C01) calculates the d-axis voltage command value (vd ＊ ) and the q-axis voltage command value (vq ＊ ), the electrical angle (θ) of the front drive motor 4f, and the DC voltage (Vdc) (not shown in FIG. 4), a first three-phase voltage command value (vu1 ＊ , vv1 ＊ , vw1 ＊ ) is calculated.

[0082] The calculation element (C01) calculates, for example, the amplitude of the U-phase component (A[vu1 ＊ ]) is calculated.

[0083] The calculation element (C02) is the d-axis current command value (id ＊ ), q-axis current command value (iq ＊ ), and electrical angular velocity (ωe), the brake energy (corresponding to the amount of decrease in accelerator opening APO, for example) generated in the electric vehicle 100 and received by the rear drive motor 4r of the rear drive system (rds) is converted into regenerative power to calculate converted regenerative power (P1). ＊ ) and q-axis current command value (iq ＊), the d-axis current detection value (id) and the q-axis current detection value (iq) may be input.

[0084] The calculation element (CO2) calculates the converted regenerative power (P1) as follows: Here, "Φm" is the magnetic flux of the permanent magnet of the rotor 49 (FIG. 9) of the rear drive motor 4r, "Ld" is the d-axis inductance of the rear drive motor 4r, and "Lq" is the q-axis inductance of the rear drive motor 4r.

[0085] The calculation element (CO2) calculates the q-axis current command value (iq ＊ ) is a negative value, the converted regenerative power (P1) (positive value) is output, and the q-axis current command value (iq ＊ ) is a positive value equal to or greater than zero, the converted regenerative power (P1) is output as zero.

[0086] The calculation element (C03) receives the converted regenerative power (P1) input from the calculation element (C02) and the allowable charging power (P0) of the battery 9 input from the vehicle controller 1, and calculates the difference value (P1-P0) obtained by subtracting the allowable charging power (P0) from the converted regenerative power (P1).

[0087] The temperature (tc) of the first refrigerant is input to the calculation element (C04). The calculation element (C04) calculates a first function (F1=Δtc / (tmax1-tc)) related to the temperature (tc) of the first refrigerant, as shown in FIG. 5. Here, "Δtc" is the amount of temperature rise of the first refrigerant (time derivative of the temperature (tc) of the first refrigerant), and "tmax1" is the upper limit temperature of the first refrigerant.

[0088] The first function (F1) increases as the temperature rise of the first refrigerant increases, and as the temperature (tc) of the first refrigerant approaches the upper limit temperature (tmax1). Therefore, the higher the value of the first function (F1), the sooner the temperature (tc) of the first refrigerant will reach the upper limit temperature (tmax1).

[0089] 5 , when the first function (F1) is equal to or less than a predetermined first threshold (F11), the first set power (Px1) that can be set in induction heating (IH) described below becomes a maximum power (Px1max) that corresponds to the maximum amount of heat that can be received by the exhaust heat circulation path 50. On the other hand, when the first set power (Px1) exceeds the first threshold (F11), it is limited to be lower than the maximum power (Px1max), and as it becomes higher than the first threshold (F11), it monotonically decreases and becomes zero when it reaches a second threshold (F12) that is higher than the first threshold.

[0090] The calculation element (C04) calculates and outputs the first set power (Px1) based on the input temperature (tc) of the first refrigerant and the map shown in FIG.

[0091] The temperature (tp) of the power train of the front drive system (fds) (the temperature of the front inverter 3f or the temperature of the front drive motor 4f) is input to the calculation element (C05).

[0092] The calculation element (C05) calculates a second function (F2=Δtp / (tmax2-tp)) related to the temperature (tp) of the powertrain as shown in Fig. 6. Here, "Δtp" is the amount of temperature rise of the powertrain (time derivative of the temperature (tp) of the powertrain), and "tmax2" is the upper limit temperature of the powertrain.

[0093] The second function (F2) increases as the amount of temperature rise of the powertrain increases, and as the powertrain temperature (tp) approaches the upper limit temperature (tmax2). Therefore, the higher the value of the second function (F2), the sooner the powertrain temperature (tp) will reach the upper limit temperature (tmax2).

[0094] As shown in FIG. 6 , when the second function (F2) is equal to or less than a predetermined first threshold (F21), the second set power (Px2) that can be set in induction heating (described below) is the maximum power (Px2max) corresponding to the maximum amount of heat that the powertrain can accept. On the other hand, when the second set power (Px2) exceeds the first threshold (F21), it is limited to be lower than the maximum power (Px2max) by a predetermined amount. The second function (F2) decreases by a predetermined amount when it exceeds a second threshold (F22) that is greater than the first threshold (F21), a third threshold (F23) that is greater than the second threshold (F22), or a fourth threshold (F24) that is greater than the third threshold (F23), and becomes zero when it exceeds the fourth threshold (F24).

[0095] The calculation element (C05) calculates and outputs the second set electric power (Px2) based on the input power train temperature (tp) and the map shown in FIG.

[0096] The first set power (Px1) and the second set power (Px2) are input to the calculation element (C06).

[0097] The calculation element (C06) selects and outputs the smaller value of the first set power (Px1) and the second set power (Px2) as the set power (Px).

[0098] The output (P1-P0) of the calculation element (C03) and the set power (Px) are input to the calculation element (C07). The calculation element (C07) calculates the induction heating power (P ＩＨ ) and the equivalent braking power (P ＢＴ ) and the calculation element (C07) calculates the induction heating power (P ＩＨ ) is output to the calculation element (C08), and the converted power (P ＢＴ ) is output to the vehicle controller 1.

[0099] The calculation element (C07) calculates the induction heating power (P) when the output (P1-P0) is a positive value and the value is higher than the set power (Px). ＩＨ ) to "P ＩＨ = P0 - P1 - Px. Similarly, the converted braking power (PＢＴ ) to "P ＢＴ = Px".

[0100] The calculation element (C07) calculates the induction heating power (P) when the output (P1-P0) is a positive value and the value is equal to or less than the set power (Px). ＩＨ ) to "P ＩＨ = P1 - P0" and calculated as the converted braking power (P ＢＴ ) to "P ＢＴ = 0".

[0101] The calculation element (C07) calculates the induction heating power (P ＩＨ ) to "P ＩＨ = 0" and calculated as the converted braking power (P ＢＴ ) to "P ＢＴ = P1 - P0.

[0102] The calculation element (C07) calculates the induction heating power (P ＩＨ ) and equivalent braking power (P ＢＴ ) is calculated as zero.

[0103] The vehicle controller 1 (FIG. 1) calculates the converted braking power (P ＢＴ ) and the rotation speed (mechanical angular velocity) of the drive motors 4 (front drive motor 4f, rear drive motor 4r) that drive the drive wheels to be braked (second braking torque), and controls the braking amount of the mechanical brake so that the drive wheels are braked by the braking torque. ＊ ) (braking torque) is reduced in absolute value by the braking torque (second torque) for the mechanical brake, thereby reducing the braking torque (regenerative torque) generated by the rear drive motor 4r.

[0104] The calculation element (C08) includes the induction heating power (P ＩＨ ) is entered.

[0105] The calculation element (C08) is the winding resistance (R) of the rear drive motor 4r and the induction heating frequency (f ＩＨ) corresponding to the IH angular velocity (ω ＩＨ ) based on the induction heating voltage (v ＩＨ ＊ ) is calculated. ＩＨ ＊ ) is calculated as follows:

[0106] The calculation element (C08) calculates the induction heating voltage (v ＩＨ ＊ ) amplitude (A[v ＩＨ ＊ ]) is calculated.

[0107] The calculation element (C09) receives the first three-phase voltage command value (vu1 ＊ , vv1 ＊ , vw1 ＊ ) and the first amplitude (A[vu1 ＊ ]) is input, and the amplitude (A[v ＩＨ ＊ ]) is entered.

[0108] The calculation element (C09) calculates the first three-phase voltage command value (vu1 ＊ , vv1 ＊ , vw1 ＊ ) first amplitude (A[vu1 ＊ ]) to the first amplitude ratio (A[vu1 ＊ ] / (A[vu1 ＊ ]+A[v ＩＨ ＊ ])) to obtain the second three-phase voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊ ) is calculated.

[0109] The calculation element (C09) calculates the amplitude (A[vu1 ＊ ]) and amplitude (A[v ＩＨ ]) is equal to or less than a predetermined threshold, it is determined that there is no adverse effect on the front inverter 3f (rear inverter 3r), and the first three-phase voltage command value (vu1 ＊ , vv1 ＊ , vw1 ＊ ) by the first amplitude ratio, ＊ , vv1 ＊ , vw1＊ ) is used as the second three-phase voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊ )

[0110] The calculation element (C09) calculates the second three-phase voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊ ) second amplitude (e.g., A[vu2 ＊ ]) to the first amplitude (A[vu1 ＊ ]) ＊ ] / A[vu2 ＊ ]) and outputs it to the dq-axis coordinate transformation unit 14f.

[0111] The calculation element (C10) receives the second three-phase voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊ ) is input, and the induction heating voltage (v ＩＨ ＊ ) is entered.

[0112] The calculation element (C10) calculates the second three-phase voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊ ) to the induction heating voltage (v ＩＨ ＊ ) to calculate the final three-phase voltage command value, which is output to the PWM modulation control unit 24f (FIG. 3).

[0113] With the above configuration, the braking energy generated in the electric vehicle 100 is calculated as the converted regenerative power (P1), but the induction heating power (P ＩＨ ) is converted into regenerative power in the rear drive motor 4r, and the regenerative power is supplied to the rear inverter 3r. However, the regenerative power is not charged into the battery 9, but is supplied to the front inverter 3f as induction heating power (P ＩＨ) (high frequency current) is supplied to the front drive motor 4f. The area around the winding 43 of the stator core 41 of the front drive motor 4f is then induction heated (FIG. 9), and the heat generated by this induction heating is taken into the first coolant. ＢＴ ) component is converted into the braking torque of the mechanical brake. Therefore, the converted regenerative power (P1) is converted into the induction heating power (P ＩＨ ) and equivalent braking power (P ＢＴ ) is subtracted to obtain the allowable charging power (P0), which is the regenerative power generated in the rear drive motor 4r and charged to the battery 9 via the rear inverter 3r.

[0114] Although the above description is directed to the three-phase voltage command value calculation unit 23f of the front drive system (fds), the three-phase voltage command value calculation unit 23r of the rear drive system (rds) has a similar configuration and performs similar calculations and outputs. In this case, it is assumed that a braking torque (regenerative torque) is applied to the front drive motor 4f and a drive torque is applied to the rear drive motor 4r.

[0115] The calculation element (C01) of the three-phase voltage command value calculation unit 23r receives the d-axis voltage command value (vd ＊ ) and the q-axis voltage command value (vq ＊ ) is entered.

[0116] The calculation element (C02) of the three-phase voltage command value calculation unit 23r includes a d-axis current command value (id ＊ ), q-axis current command value (iq ＊ ), and the electrical angular velocity (ωe). A calculation element (C02) of the three-phase voltage command value calculation unit 23r calculates converted regenerative power (P1) obtained by converting the braking energy generated in the electric vehicle 100 and received by the front drive motor 4f of the front drive system (fds) into regenerative power.

[0117] The temperature (tp) of the power train of the rear drive system (rds) (the temperature of the rear inverter 3r or the temperature of the rear drive motor 4r) is input to the calculation element (C05) of the three-phase voltage command value calculation unit 23r.

[0118] The calculation element (C05) of the three-phase voltage command value calculation unit 23r calculates the second set power (Px2) based on the temperature (tp) of the powertrain of the rear drive system (rds) using a map similar to that shown in FIG.

[0119] The calculation element (C08) of the three-phase voltage command value calculation unit 23r calculates the input induction heating power (P ＩＨ ), and the winding resistance (R) and IH angular velocity (ω) of the front drive motor 4f of the front drive system (fds). ＩＨ ) based on the induction heating voltage (v ＩＨ ＊ ) is calculated.

[0120] The calculation element (C09) of the three-phase voltage command value calculation unit 23r is the second amplitude ratio (A[vu1 ＊ ] / A[vu2 ＊ ]) is output to the dq axis coordinate conversion unit 14r of the rear drive system (rds).

[0121] With the above configuration, the braking energy generated in the electric vehicle 100 is calculated as the converted regenerative power (P1), but the induction heating power (P ＩＨ ) is converted into regenerative power in the front drive motor 4f, and the regenerative power is supplied to the front inverter 3f. However, the regenerative power is not charged to the battery 9, but is supplied to the rear inverter 3r as induction heating power (P ＩＨ ) (high frequency current) is supplied to the rear drive motor 4r. The area around the winding 43 of the stator core 41 of the rear drive motor 4r is then induction heated (FIG. 9), and the heat generated by this induction heating is taken into the first refrigerant. ＢＴ ) component is converted into the braking torque of the mechanical brake. Therefore, the converted regenerative power (P1) is converted into the induction heating power (P ＩＨ ) and equivalent braking power (P ＢＴ) is subtracted to obtain the allowable charging power (P0), which is the regenerative power generated in the front drive motor 4f and charged to the battery 9 via the front inverter 3f.

[0122] The vehicle controller 1 (FIG. 1) adjusts the d-axis current command value (id ＊ ) and q-axis current command value (iq ＊ ) is calculated.

[0123] Then, when the vehicle controller 1 is configured to apply a driving torque to the front driving motor 4f and a braking torque (regenerative torque) to the rear driving motor 4r, for example, and the temperature of the first refrigerant reaches near the upper limit temperature (tmax1), the induction heating power (P ＩＨ In this case, the vehicle controller 1 determines that it is difficult to perform induction heating using the induction heating power (P ＩＨ ) to be output to the rear inverter 3r. ＊ ) is kept constant, the d-axis current command value (id ＊ ) is the absolute value of the induction heating power (P ＩＨ Although the d-axis discharge control increases the heat generation amount of the rear drive motor 4r, the increase is less than the heat generation amount due to induction heating, so the total heat generation amount of the front drive motor 4f and the rear drive motor 4r is reduced accordingly, thereby suppressing the temperature rise of the first refrigerant.

[0124] Similarly, when the vehicle controller 1 applies a braking torque (regenerative torque) to the front drive motor 4f and a drive torque to the rear drive motor 4r, the temperature of the first refrigerant reaches near the upper limit temperature (tmax1) and the induction heating power (P ＩＨ In this case, the vehicle controller 1 determines that it is difficult to perform induction heating using the induction heating power (P ＩＨ) to be output to the front inverter 3f. ＊ ) is kept constant, the d-axis current command value (id ＊ ) is the absolute value of the induction heating power (P ＩＨ Although the d-axis discharge control increases the heat generation amount of the front drive motor 4f, it is smaller than the heat generation amount due to induction heating, so the total heat generation amount of the front drive motor 4f and the rear drive motor 4r is reduced accordingly, thereby suppressing the temperature rise of the first coolant.

[0125] 7 is a control flow diagram of the control system for the electric vehicle 100 of the first embodiment. This control flow is executed by the three-phase voltage command value calculation unit 23f (three-phase voltage command value calculation unit 23r).

[0126] In step S701, the three-phase voltage command value calculation unit 23f (calculation element (C03)) calculates the q-axis current command value (iq ＊ If the answer is YES, the process proceeds to step S702, and if the answer is NO, the process proceeds to step S708.

[0127] In step S702, the three-phase voltage command value calculation unit 23f (calculation element (C07)) determines whether the difference value (P1-P0) obtained by subtracting the allowable charging power (P0) of the battery 9 from the converted regenerative power (P1) obtained by converting the braking energy generated in the rear drive system (rds) into regenerative power is higher than zero; if the answer is YES, the process proceeds to step S703; if the answer is NO, the process proceeds to step S708.

[0128] In step S703, the three-phase voltage command value calculation unit 23f (calculation element (C07)) determines whether the difference value (P1-P0) is smaller than the set power (Px), and if NO, proceeds to step S704, and if YES, proceeds to step S705.

[0129] In step S704, the three-phase voltage command value calculation unit 23f (calculation element (C07)) calculates the induction heating power (P ＩＨ ) to "P ＩＨ= P1 - P0" and convert the power (P ＢＴ ) is set to zero, and the process proceeds to step S709.

[0130] In step S705, the three-phase voltage command value calculation unit 23f (calculation element (C07)) determines whether the set power (Px) is zero. If NO, the process proceeds to step S706, and if YES, the process proceeds to step S707.

[0131] In step S706, the three-phase voltage command value calculation unit 23f (calculation element (C07)) calculates the induction heating power (P ＩＨ ) to "P ＩＨ = Px" and convert the power (P ＢＴ ) to "P ＢＴ = P1 - P0 - Px" and the process proceeds to step S709.

[0132] In step S707, the three-phase voltage command value calculation unit 23f (calculation element (C07)) calculates the induction heating power (P ＩＨ ) is set to zero, and the converted power (P ＢＴ ) to "P ＢＴ = P1 - P0" and proceed to step S710.

[0133] In step S707, the three-phase voltage command value calculation unit 23f (calculation element (C07)) calculates the induction heating power (P ＩＨ ) and equivalent power (P ＢＴ ) is set to zero, and the process proceeds to step S710.

[0134] In step S709, the three-phase voltage command value calculation unit 23f (calculation element (C10)) calculates the second three-phase voltage command value (vu ＊ , vv ＊ , vw ＊ ) to the induction heating voltage (v ＩＨ ＊ ) to obtain the final three-phase voltage command value (vu ＊ , vv ＊ , vw ＊ ) and outputs it to the PWM modulation control section 24f.

[0135] In step S710, the three-phase voltage command value calculation unit 23f (calculation element (C10)) calculates the second three-phase voltage command value (vu＊ , vv ＊ , vw ＊ ) is used as the final three-phase voltage command value (vu ＊ , vv ＊ , vw ＊ ) and outputs it to the PWM modulation control section 24f.

[0136] [Three-phase voltage command values ​​according to the first embodiment] Fig. 8A is a diagram illustrating an example of the three-phase voltage command values ​​before correction generated by the three-phase voltage command value calculation unit 23f according to the first embodiment. Fig. 8B is a diagram illustrating an example of the corrected three-phase voltage command value (U phase) (B1) and the induction heating voltage (B2) generated by the three-phase voltage command value calculation unit 23f according to the first embodiment. Fig. 8C is a diagram illustrating an example of the final three-phase voltage command value (U phase) obtained by adding up the corrected three-phase voltage command values ​​and the induction heating voltage generated by the three-phase voltage command value calculation unit 23f according to the first embodiment. Fig. 8D is a diagram illustrating an example of the final three-phase voltage command values ​​(U phase, V phase, W phase) obtained by adding up the corrected three-phase voltage command values ​​and the induction heating voltage generated by the three-phase voltage command value calculation unit 23f according to the first embodiment.

[0137] The three-phase voltage command value (vu1 ＊ , vv1 ＊ , vw1 ＊ ) (A) is calculated by the calculation element (C01) (FIG. 4), and the corrected three-phase voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊ ) (B1) is calculated by the calculation element (C09) (FIG. 4), and the induction heating voltage (v ＩＨ ＊ ) (B2) is calculated by the calculation element (C08) (FIG. 4), and the final three-phase voltage command value (U phase) (C) in FIG. 8C and the final three-phase voltage command value (vu ＊ , vv ＊ , vw ＊ ) (D) is calculated by the calculation element (C10) (FIG. 4).

[0138] The IH frequency of the induction heating voltage (B2) is set higher than the frequencies of the three-phase voltage command value (A) and the three-phase voltage command value (B1), but is set lower than the carrier frequency (e.g., 80 kHz) of the front inverter 3f (rear inverter 3r).

[0139] As shown in FIG. 8B , the sum of the amplitude of the corrected three-phase voltage command value (B1) and the amplitude of the induction heating voltage (B2) corresponds to the amplitude of the three-phase voltage command value (A) before correction, and the absolute values ​​of the peak values ​​of the final three-phase voltage command values ​​(C) and (D) match the peak value (amplitude) of the three-phase voltage command value (A) before correction.

[0140] In the final three-phase voltage command values ​​(C) and (D), the components of the corrected three-phase voltage command values ​​shown in FIG. 2(B) are components that generate drive torque for the front drive motor 4 f (rear drive motor 4 r), and the component of the induction heating voltage (B2) shown in FIG. 8(B) is a component that generates eddy currents (induction heating) in the area around the windings 43 of the stator core 41 of the front drive motor 4 f (rear drive motor 4 r).

[0141] [Induction Heating] Fig. 9 is a diagram showing eddy currents (induction heating) generated around the windings 43 of the stator core 41. Fig. 10 is a diagram showing the relationship between the IH frequency and the penetration depth of the induction heating region 48.

[0142] As shown in Figure 9, the drive motor 4 has a stator core 41 and a rotor 49, with windings 43 inserted into slots 42 of the stator core 41, insulating material 44 arranged between the windings 43 and the slots 42, and the openings of the slots 42 sealed with insulating material 45.

[0143] When a high frequency current for induction heating is applied to the winding 43 , an eddy current is generated in the portion of the stator core 41 surrounding the winding 43 , and the region where the eddy current is generated becomes an induction heating region 48 .

[0144] Since the winding 43 extends in the axial direction of the stator core 41, the induction heating region 48 (eddy current) enters the winding 43 so as to spread in a plane perpendicular to the axial direction, with the winding 43 as the center.

[0145] The penetration depth (δ [cm]) of the induction heating region 48 in the surface direction at this time is expressed as follows using the IH frequency (f [Hz]), the resistivity of the heated material (ρ [μΩ cm]), and the relative permeability (μ) of the heated material: FIG. 10 shows the relationship between the penetration depth (δ) of the induction heating region 48 in stainless steel (SUS), which is the material of the stator core 41, and the IH frequency (f). For reference, the relationship between the penetration depth (δ) of the eddy current in aluminum (Al) and copper (Cu) and the IH frequency (f) is also shown.

[0146] The penetration depth (δ) of the induction heating region 48 is preferably set by the circumferential width of the teeth 47 between the slots 42 of the stator core 41, thereby achieving efficient induction heating. The width of the teeth 47 is often set in the range of 2 mm to 5.5 mm. When the width of the teeth 47 is 2 mm, as shown in FIG. 9, it is preferable to set the induction frequency to 40 kHz, and when the width of the teeth 47 is 5.5 mm, it is preferable to set the induction frequency to 5 kHz. Therefore, efficient induction heating can be achieved by setting the induction frequency to any frequency in the range of 5 kHz to 40 kHz.

[0147] [Energy Loss] FIG. 11 is a diagram comparing energy loss that occurs in the electric vehicle 100 when brake loss is not converted into motor loss (comparative example) with energy loss when brake loss is converted into motor loss by induction heating (this embodiment).

[0148] 11 shows the breakdown of heat sources when, for example, a predetermined amount of heat for heating (A) is supplied to the air conditioning system 90. Heating by the air conditioning system 90 is performed by the PTC heater 92 and the heater core 72, but the loss (heat generation amount) (B) of the PTC heater 92 corresponds to the power consumption of the battery 9, and the loss of the heater core 72 corresponds to the sum of the loss (C) of the air conditioning system (heat source circulation path 70 and heat pump 60) and the loss (D) of the exhaust heat circulation path 50 (losses in the front inverter 3f, front drive motor 4f, rear inverter 3r, and rear drive motor 4r).

[0149] In the comparative example, about half of the heating heat (A) is provided by the loss (B) of the PTC heater 92, and the remaining half is provided by the loss (C) of the air conditioning system and the loss (D) of the exhaust heat circulation path 50.

[0150] In the comparative example, the braking loss (E) is entirely released to the outside as heat and cannot be used as a heat source for the air conditioning system 90 .

[0151] On the other hand, in this embodiment (step S704 in FIG. 7 ), the braking loss (E) (brake energy) can be converted entirely into motor loss (and inverter loss) due to induction heating, and the braking loss (E) is added directly to the loss (D) in the exhaust heat circulation path 50.

[0152] This also increases the loss (C) of the air conditioning system that exchanges heat with the exhaust heat circulation path 50 .

[0153] Therefore, in this embodiment, most of the heat required for heating (A) can be covered by the loss in the air conditioning system (C) and a portion of the loss in the exhaust heat circulation path 50 (D)', and the loss in the PTC heater 92 (B) can be reduced, thereby reducing the energy loss of the entire electric vehicle.

[0154] FIG. 12 is a diagram comparing the instantaneous value of the motor loss (F), the instantaneous value of the brake loss (G), the integrated value of the instantaneous value of the motor loss (H), the integrated value of the instantaneous value of the brake loss (I), and the sum (J) of the integrated value of the instantaneous value of the motor loss (H) and the integrated value of the instantaneous value of the brake loss (I).

[0155] FIG. 12 shows the changes over time in motor loss and brake loss when the electric vehicle 100, which is braked by a mechanical brake, is accelerated and decelerated irregularly over time.

[0156] The instantaneous value (F) of the motor loss mainly corresponds to the heat generated when a drive torque is applied to the drive motor 4 .

[0157] The instantaneous value of the brake loss (G) corresponds to the heat generated in the mechanical brake and the drivetrain when the mechanical brake is applied, and takes on a momentary high value.

[0158] In the comparative example described above, the integrated value (H) of the instantaneous value of the motor loss can be used as a heat source for the air conditioning system 90, but the integrated value (I) of the instantaneous value of the brake loss cannot be used as a heat source for the air conditioning system 90.

[0159] On the other hand, in this embodiment, a part of the braking energy is taken in as regenerative power for induction heating of the stator core 41 (FIG. 9) by regenerative braking, and the heat generated by the induction heating is supplied to the exhaust heat circulation path 50.

[0160] As a result, in this embodiment, not only the integrated value (H) of the instantaneous value of the motor loss but also the integrated value (I) of the instantaneous value of the brake loss can be used as a heat source for the air conditioning system 90, and more heat sources can be taken in as a heat source for the air conditioning system 90 compared to the comparative example by the difference between the integrated value (J) and the integrated value (H).

[0161] [Second embodiment] Fig. 13 is a configuration diagram of a control system for an electric vehicle 100 according to a second embodiment. Fig. 14 is a control configuration diagram of a three-phase voltage command value calculation unit 23 that constitutes the control system for an electric vehicle 100 according to the second embodiment.

[0162] The electric vehicle 100 to which the second embodiment is applied has the inverter 3 and the drive motor 4 as a single vehicle, and has drive wheels (not shown) (e.g., front wheels 82f) driven by the drive motor 4, and driven wheels (not shown) (e.g., rear wheels 82r) to which the driving force of the drive motor 4 is not transmitted.

[0163] As shown in FIG. 13, the electric vehicle 100 to which the second embodiment is applied uses a torque command value (T ＊ 13, the motor controller 2 (current command value calculation unit 21, current control unit 22, three-phase voltage command value calculation unit 23, PWM modulation control unit 24) controls the inverter 3 (driving motor 4). Note that the components other than the motor controller 2 shown in FIG. 13 are the same as the components shown in FIG. 3.

[0164] The current command value calculation unit 21 calculates the input torque command value (T ＊ ), the d-axis current command value (id ＊ ) and the q-axis current command value (iq ＊ ) is calculated, and the d-axis current command value (id ＊ ) and the q-axis current command value (iq ＊ ) to the current control unit 22.

[0165] The current control unit 22 calculates the d-axis current command value (id ＊ ) minus the d-axis current (id), and the q-axis current command value (iq ＊ The torque of the drive motor 4 is set to the torque command value (T ＊ d-axis voltage command value (vd ＊ ) and the q-axis voltage command value (vq ＊ ) is calculated, and the d-axis voltage command value (vd ＊ ) and the q-axis voltage command value (vq ＊ ) to the three-phase voltage command value calculation unit 23.

[0166] As shown in FIG. 14, the three-phase voltage command value calculation unit 23 has calculation elements (C01) to (C10) similar to the first embodiment, but a description of the parts common to the first embodiment will be omitted.

[0167] The calculation element (C01) calculates the d-axis voltage command value (vd ＊ ) and the q-axis voltage command value (vq ＊ ), the electrical angle (θ) of the drive motor 4, and the DC voltage (Vdc) (not shown in FIG. 14), a first three-phase voltage command value (vu1 ＊ , vv1 ＊ , vw1 ＊ ) is calculated.

[0168] The calculation element (C02) is the d-axis current command value (id ＊ ), q-axis current command value (iq ＊ ), and the electrical angular velocity (ωe), the brake energy generated in the drive motor 4 is converted into regenerative power to calculate the converted regenerative power (P1). ＊ ) and q-axis current command value (iq ＊ ), the d-axis current detection value (id) and the q-axis current detection value (iq) may be input.

[0169] The temperature (tp) of the power train (the temperature of the inverter 3 or the temperature of the drive motor 4) is input to the calculation element (C05).

[0170] The calculation element (C05) calculates and outputs the second set electric power (Px2) based on the input power train temperature (tp) and the map shown in FIG.

[0171] The vehicle controller 1 (FIG. 1) calculates the converted braking power (P ＢＴ ) and the rotation speed (mechanical angular velocity) of the drive motor 4, and the braking amount of the mechanical brake that brakes the drive wheels driven by the drive motor 4 is controlled based on the braking torque.

[0172] The calculation element (C09) receives the first three-phase voltage command value (vu1 ＊ , vv1 ＊ , vw1 ＊ ) and the first amplitude (A[vu1 ＊ ]) is input, and the amplitude (A[v ＩＨ ＊ ]) is entered.

[0173] The calculation element (C09) calculates the first three-phase voltage command value (vu1 ＊ , vv1 ＊ , vw1 ＊ ) first amplitude (A[vu1 ＊ ]) to the first amplitude ratio (A[vu1 ＊ ] / (A[vu1 ＊ ]+A[vIH ＊ ])) to obtain the second three-phase voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊ ) is calculated.

[0174] In order to protect the inverter 3, the lower limit of the first amplitude ratio is set to 0.5, and if the calculated first amplitude ratio is lower than this lower limit, all first amplitude ratios are set to this lower limit, thereby limiting the current required for induction heating to 50% of the output performance limit of the inverter 3.

[0175] With the above configuration, the braking energy generated in the electric vehicle 100 (corresponding to the amount of decrease in the accelerator opening APO) is calculated as the converted regenerative power (P1). ＩＨ) is converted into regenerative power in the drive motor 4, and the regenerative power is supplied to the inverter 3. However, the regenerative power is converted into induction heating power (P ＩＨ ) (high frequency current) is reflected and supplied to the drive motor 4. The area around the winding 43 of the stator core 41 of the drive motor 4 is then inductively heated (FIG. 9), and the heat generated by the inductive heating is taken into the first refrigerant. ＢＴ ) component is converted into the braking torque of the mechanical brake. Therefore, the converted regenerative power (P1) is converted into the induction heating power (P ＩＨ ) and equivalent braking power (P ＢＴ ) is subtracted from the allowable charging power (P0) to obtain the allowable charging power (P0), which is the regenerative power generated in the drive motor 4 and charged to the battery 9 via the inverter 3. Note that the final three-phase voltage command values ​​(U phase, V phase, W phase) obtained by adding together the corrected three-phase voltage command values ​​and the induction heating voltage generated by the three-phase voltage command value calculation unit 23 in the second embodiment are the same as those in the first embodiment ( FIG. 8D ).

[0176] [Effects of this embodiment] The control method for the electric vehicle 100 of this embodiment exchanges electric power between one of the two motors (for example, the front drive motor 4 f) and the battery 9 via a first inverter (for example, the front inverter 3 f), and also releases exhaust heat from at least one of the two motors (the front drive motor 4 f) into a refrigerant (first refrigerant) circulating through the exhaust heat circulation path 50, and controls the torque command value for driving (for example, a front torque command value (Tf ＊ )) to drive the first inverter (front inverter 3f), ＊ , vv2 ＊ , vw2 ＊The control method for an electric vehicle 100 calculates a first braking torque (equivalent regenerative power (P1)) and outputs it to a first inverter (front inverter 3f) to apply a driving torque to one of the two motors (front drive motor 4f), and when a first braking torque is generated in the other of the two motors (rear drive motor 4r), the method charges the battery 9 with regenerative power (equivalent regenerative power (P1)) generated by the first braking torque, and when the regenerative power (equivalent regenerative power (P1)) is greater than an allowable charging power (P0) that is the maximum power that can be charged to the battery 9, the method ＩＨ ), and the difference power (P1-P0) obtained by subtracting the allowable charging power (P0) from the regenerative power (equivalent regenerative power (P1)) is supplied to one of the two motors (front drive motor 4f) as a heating voltage command value (induction heating voltage (v ＩＨ ＊ )) and calculates the driving voltage command value (three-phase voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊ )) and the heating voltage command value (induction heating voltage (v ＩＨ ＊ )) to obtain a combined voltage command value (vu2 ＊ +v ＩＨ ＊ , vv2 ＊ +v ＩＨ ＊ , vw2 ＊ +v ＩＨ ＊ , FIG. 7), and calculates the voltage command value (final three-phase voltage command value (vu ＊ , vv ＊ , vw ＊ )) to the drive voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊ ) to the combined voltage command value (vu2 ＊ +v ＩＨ ＊ , vv2 ＊ +v ＩＨ ＊ , vw2 ＊ +v ＩＨ＊ , Figure 7).

[0177] By the above method, the difference power (P1-P0) (induction heating power (P)) obtained by subtracting the allowable charging power (P0) from the regenerative power (converted regenerative power (P1)) corresponding to the braking energy generated in the electric vehicle 100 is calculated. ＩＨ ) is supplied to one of the two motors (front drive motor 4 f), causing induction heating in that motor (front drive motor 4 f), and the battery 9 can be charged with power equivalent to the allowable charging power (P0). Therefore, of the regenerative power (equivalent regenerative power (P1)) equivalent to the braking energy generated in the electric vehicle 100, the portion that cannot be charged to the battery 9 is used as power for induction heating, and the heat generated by the induction heating can be efficiently supplied to the exhaust heat circulation path 50. Therefore, for example, the power consumption of the heat pump 60 (particularly the compressor 62) that supplies heat to the air conditioning system 90, out of the power consumption of the battery 9, can be reduced.

[0178] The portion of the braking energy that cannot be recovered as regenerative power is lost due to mechanical braking, but when the outside air temperature is low (for example, 0°C or below), the allowable charging power (P0) of the battery 9 is significantly limited compared to room temperature (for example, 20°C), increasing the loss due to mechanical braking. However, in this embodiment, the portion of the regenerative power (equivalent regenerative power (P1)) equivalent to the braking energy that cannot be charged to the battery 9 is used as power for induction heating, thereby reducing the loss due to mechanical braking, and efficiently raising the temperature of the first refrigerant circulating through the exhaust heat circulation path 50 increases the heat exchange amount in the heat pump 60 (chiller 61), which allows the output of the compressor 62 to be reduced accordingly, thereby reducing the power consumption of the heat pump 60 (particularly the compressor 62).

[0179] Furthermore, since the driving motor and the induction heating motor are the same, the exhaust heat source (heat source) is concentrated in one place, which makes it possible to increase the temperature of the exhaust heat from the motor (drive motor 4) and improve the efficiency of the intake of the exhaust heat in the exhaust heat circulation path 50. Furthermore, while induction heating is generated in the stator core 41, control that increases loss (amount of heat generated) in the first inverter (front inverter 3 f) is not required, so that the burden on the first inverter (front inverter 3 f) is reduced and the portion of the regenerative power (equivalent regenerative power (P1)) equivalent to the braking energy generated in the electric vehicle 100 that cannot be charged to the battery 9 can be used as power for induction heating.

[0180] The control method for the electric vehicle 100 of this embodiment exchanges electric power between the battery 9 and the motor (drive motor 4) via the inverter 3, and also releases the exhaust heat of the motor (drive motor 4) into the coolant circulating through the exhaust heat circulation path 50, and controls the torque command value (T ＊ ) for driving the inverter 3 based on the braking voltage command value (three-phase voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊ 14 ) and outputs a braking voltage command value to the inverter 3 to generate a first braking torque in the motor (drive motor 4), and the regenerative power (equivalent regenerative power (P1)) generated by the first braking torque is charged to the battery 9 via the inverter 3. When the regenerative power (equivalent regenerative power (P1)) becomes larger than the allowable charging power (P0) that is the maximum power that can be charged to the battery 9, an IH frequency (f ＩＨ ), and the heating voltage command value (induction heating voltage (v ＩＨ ＊ )) is calculated, and the braking voltage command value and the heating voltage command value are summed to obtain a summed voltage command value (vu2 ＊ +v ＩＨ ＊ , vv2 ＊ +vＩＨ ＊ , vw2 ＊ +v ＩＨ ＊ , FIG. 7), and calculates the voltage command value (final three-phase voltage command value (vu ＊ , vv ＊ , vw ＊ )) is used as the braking voltage command value (three-phase voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊ )) to the combined voltage command value (vu2 ＊ +v ＩＨ ＊ , vv2 ＊ +v ＩＨ ＊ , vw2 ＊ +v ＩＨ ＊ , Figure 7).

[0181] By the above method, the inverter 3 generates the induction heating power (P) by subtracting the allowable charging power (P0) from the regenerative power (equivalent regenerative power (P1)) corresponding to the braking energy generated in the electric vehicle 100 (e.g., corresponding to the amount of decrease in the accelerator opening APO). ＩＨ ) and is supplied to the motor (drive motor 4), generating induction heating in the motor (drive motor 4). Furthermore, the battery 9 can be charged with power equivalent to the allowable charging power (P0) of the regenerative power (equivalent regenerative power (P1)) equivalent to the braking energy generated in the electric vehicle 100. Therefore, the portion of the regenerative power (equivalent regenerative power (P1)) equivalent to the braking energy generated in the electric vehicle 100 that cannot be charged to the battery 9 can be used as power for induction heating, and the heat generated by the induction heating can be efficiently supplied to the exhaust heat circulation path 50. This reduces, for example, the power consumption of the heat pump 60 (particularly the compressor 62) that supplies heat to the air conditioning system 90, among the power consumption of the battery 9. Furthermore, while induction heating occurs in the stator core 41, control that increases loss (heat generation) in the inverter 3 is not required. Therefore, a portion of the regenerative power generated in the motor (drive motor 4) can be used as power for induction heating while reducing the burden on the inverter 3.

[0182] In this embodiment, the IH frequency (f ＩＨ ) to any frequency in the range of 5 Khz to 40 kHz.

[0183] By the above method, the induction heating region 48 can be formed in the stator core 41 without excess or deficiency.

[0184] In this embodiment, power is exchanged between the other of the two motors (rear drive motor 4r) and the battery 9 via a second inverter (rear inverter 3r), and a braking torque command value (rear torque command value (Tr ＊ )) based on the d-axis current command value (id ＊ ) and the q-axis current command value (iq ＊ ) for driving the second inverter (rear inverter 3r) based on the current command value. ＊ , vv1 ＊ , vw1 ＊ ), FIG. 4) is calculated and output to the second inverter (rear inverter 3r), thereby applying a first braking torque to the other of the two motors (rear drive motor 4r). In this case, when it is predicted that the temperature of one of the two motors (front drive motor 4f) will reach a predetermined upper limit temperature (tmax2), the heating voltage command value (induction heating voltage (v ＩＨ ＊ )) and the q-axis current command value (id ＊ ) is kept constant, the heating voltage command value (induction heating voltage (v ＩＨ ＊ )) based on the decrease in the d-axis current command value (id ＊ ) to increase the absolute value of

[0185] The above method increases the amount of heat generated by the rear drive motor 4r. Furthermore, while maintaining a constant amount of braking energy generated by the electric vehicle 100 that is taken in as regenerative power (equivalent regenerative power (P1)), this regenerative power can be used as power for induction heating in one of the two motors (the front drive motor 4f) and as power for d-axis discharge control in the other of the two motors (the rear drive motor 4r). In this case, the amount of heat generated in one of the two motors (the front drive motor 4f) can be reduced compared to when all of the regenerative power is used for induction heating, thereby reducing the temperature rise in one of the two motors (the front drive motor 4f).

[0186] In this embodiment, a second braking torque due to friction can be applied to the drive wheels (front wheels 82f, rear wheels 82r) driven by either of the two motors, and when power is exchanged between the other of the two motors (rear drive motor 4r) and the battery 9 via the second inverter (rear inverter 3r), if it is predicted that the operating temperature of either of the two motors (front drive motor 4f, rear drive motor 4r), the first inverter (front inverter 3f), or the second inverter (rear inverter 3r) will reach a predetermined upper limit temperature (tmax2), a heating voltage command value (induction heating voltage (v ＩＨ ＊ )) by a predetermined amount and a second braking torque is set based on the predetermined amount.

[0187] By the above method, the torque command value for braking (rear torque command value (Tr ＊ )) can reduce the absolute value of the regenerative power, which in turn reduces the heat generated by induction heating, thereby suppressing the rise in operating temperature.

[0188] In this embodiment, a second braking torque due to friction can be applied to the drive wheels (front wheels 82f, rear wheels 82r) driven by either of the two motors, and power is exchanged between the other of the two motors (rear drive motor 4r) and the battery 9 via the second inverter (rear inverter 3r), and exhaust heat from the other of the two motors (rear drive motor 4r) is released into the refrigerant (first refrigerant) circulating through the exhaust heat circulation path 50. In this case, when it is predicted that the temperature of the refrigerant (first refrigerant) will reach a predetermined upper limit temperature (tmax1), a heating voltage command value (induction heating voltage (v ＩＨ ＊ )) and applies a second braking torque to the drive wheels (front wheels 82f, rear wheels 82r), and the higher the temperature of the refrigerant (first refrigerant), the higher the heating voltage command value (induction heating voltage (v ＩＨ ＊ ) is set to be small and the second braking torque is set to be large.

[0189] By the above method, the torque command value for braking (rear torque command value (Tr ＊ )) is reduced, the regenerative power is reduced, and the heat generated by induction heating can be reduced accordingly, so that the rise in the temperature of the refrigerant (first refrigerant) can be suppressed.

[0190] In this embodiment, the electric vehicle 100 includes drive wheels (not shown) driven by a motor (drive motor 4) and driven wheels (not shown) to which the drive force of the motor (drive motor 4) is not transmitted, and a second braking torque due to friction can be applied to the drive wheels and / or the driven wheels. When it is predicted that the operating temperature of either the motor (drive motor 4) or the inverter 3 will reach a predetermined upper limit temperature (tmax2), a heating voltage command value (induction heating voltage (v ＩＨ ＊ ) by a predetermined amount (FIG. 6), and a second braking torque is set based on the predetermined amount.

[0191] By the above method, the braking torque command value (T ＊ ) reduces the absolute value of the regenerative power, which in turn reduces the heat generated by induction heating, thereby suppressing the rise in operating temperature.

[0192] In this embodiment, the electric vehicle 100 includes drive wheels (not shown) driven by a motor (drive motor 4) and driven wheels (not shown) to which the driving force of the motor (drive motor 4) is not transmitted, and a second braking torque due to friction can be applied to the drive wheels and / or the driven wheels. When it is predicted that the temperature of the refrigerant (first refrigerant) will reach a predetermined upper limit temperature (tmax1), a heating voltage command value (induction heating voltage (v ＩＨ ＊ )) is decreased and a second braking torque is set, and the higher the temperature of the refrigerant (first refrigerant), the higher the braking voltage command value (induction heating voltage (v ＩＨ ＊ ) is set small and the second braking torque is set large.

[0193] By the above method, the braking torque command value (T ＊ ) is reduced, the regenerative power is reduced, and the heat generated by induction heating can be reduced accordingly, so that the rise in the temperature of the refrigerant (first refrigerant) can be suppressed.

[0194] In this embodiment, the system includes a heat pump 60 capable of exchanging heat with the exhaust heat circulation path 50, an air conditioning means (air conditioning system 90) that uses the heat pump 60 as a heat source to heat the interior of the vehicle, and a heating means (battery heater 75) that uses the heat pump 60 as a heat source to heat the battery 9, and when the first required heat quantity required by the air conditioning means (air conditioning system 90) is lower than the exhaust heat quantity taken into the exhaust heat circulation path 50, the difference in heat quantity obtained by subtracting the first required heat quantity from the exhaust heat quantity is supplied to the heating means (battery heater 75).

[0195] By using the above method, when the temperature of the battery 9 is low and the allowable charging power (P0) is limited, the battery 9 can be warmed up using heat derived from induction heating, so that the battery 9 can be warmed up efficiently without using the power of the battery 9.

[0196] In this embodiment, the system includes a heat pump 60 capable of exchanging heat with the exhaust heat circulation path 50, an air conditioning means (air conditioning system 90) that uses the heat pump 60 as a heat source to heat the interior of the vehicle, and a heating means (battery heater 75) that uses the heat pump 60 as a heat source to heat the battery 9, and when the sum of the first required heat quantity required by the air conditioning means (air conditioning system 90) and the second required heat quantity required by the heating means (battery heater 75) is lower than the exhaust heat quantity taken into the exhaust heat circulation path 50, the refrigerant (first refrigerant) is heated within a range where the temperature of the refrigerant does not exceed a predetermined upper limit temperature (tmax1).

[0197] By using the above method, heat derived from induction heating can be efficiently stored, and heat can be efficiently supplied when the air conditioning means (air conditioning system 90) and heating means (battery heater 75) require a large amount of heat in the future.

[0198] The control system for the electric vehicle 100 of this embodiment includes two motors (front drive motor 4f, rear drive motor 4r), a battery 9 that serves as a power source for the two motors, an inverter (front inverter 3f) that supplies power from the battery 9 to one of the two motors (for example, the front drive motor 4f), an exhaust heat circulation path 50 that circulates a coolant (first coolant) that takes in exhaust heat from at least one of the two motors (front drive motor 4f), and a torque command value (Tf ＊ ) based on the voltage command value (three-phase voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊ and a voltage command value calculation unit (three-phase voltage command value calculation unit 23f) that calculates a torque command value (Tf ＊ ) for driving the inverter 3 based on the three-phase voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊In a control system for an electric vehicle 100, when a braking torque is generated in the other of the two motors (rear drive motor 4r) while a driving torque is being applied to one of the two motors (front drive motor 4f) by calculating a driving voltage command value ( , FIG. 4 )) and outputting the driving voltage command value to an inverter (front inverter 3f), a voltage command value calculation unit (three-phase voltage command value calculation unit 23f) calculates an IH frequency (f ＩＨ ), and the heating voltage command value (induction heating voltage (v ＩＨ ＊ )) and calculates the driving voltage command value (three-phase voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊ )) and the heating voltage command value (induction heating voltage (v ＩＨ ＊ )) to obtain a combined voltage command value (vu2 ＊ +v ＩＨ ＊ , vv2 ＊ +v ＩＨ ＊ , vw2 ＊ +v ＩＨ ＊ , FIG. 7), and calculates the voltage command value (final voltage command value (vu ＊ , vv ＊ , vw ＊ )) to the drive voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊ ) to the combined voltage command value (vu2 ＊ +v ＩＨ ＊ , vv2 ＊ +v ＩＨ ＊ , vw2 ＊ +v ＩＨ＊ , Figure 7).

[0199] With the above configuration, the difference in power (P1-P0) (induction heating power (P)) obtained by subtracting the allowable charging power (P0) from the regenerative power (converted regenerative power (P1)) corresponding to the braking energy generated in the electric vehicle 100 (e.g., corresponding to the amount of decrease in the accelerator opening APO) is calculated. ＩＨ ) is supplied to one of the two motors (front drive motor 4 f), causing induction heating in that motor (front drive motor 4 f), and the battery 9 can be charged with power equivalent to the allowable charging power (P0). Therefore, of the regenerative power (equivalent regenerative power (P1)) equivalent to the braking energy generated in the electric vehicle 100, the portion that cannot be charged to the battery 9 is used as power for induction heating, and the heat generated by the induction heating can be efficiently supplied to the exhaust heat circulation path 50. Therefore, for example, the power consumption of the heat pump 60 (particularly the compressor 62) that supplies heat to the air conditioning system 90, out of the power consumption of the battery 9, can be reduced.

[0200] The control system for the electric vehicle 100 of this embodiment includes a motor (driving motor 4), a battery 9 that serves as a power source for the motor (driving motor 4), an inverter 3 that supplies power between the battery 9 and the motor (driving motor 4), an exhaust heat circulation path 50 that circulates a refrigerant (first refrigerant) that takes in exhaust heat from the motor (driving motor 4), and a torque command value (T ＊ ) based on the voltage command value (three-phase voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊ and a voltage command value calculation unit (three-phase voltage command value calculation unit 23) that calculates a torque command value (T ＊ ) for driving the inverter 3 based on the braking voltage command value (three-phase voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊In a control system for an electric vehicle 100, a braking torque is applied to a motor (drive motor 4) by calculating a braking voltage command value and outputting the braking voltage command value to an inverter 3, and regenerative power (equivalent regenerative power (P1)) generated by the braking torque via the inverter 3 is charged to a battery 9. In this control system, a voltage command value calculation unit (three-phase voltage command value calculation unit 23) calculates an IH frequency (f ＩＨ ), and the heating voltage command value (induction heating voltage (v ＩＨ ＊ )) and calculates the braking voltage command value (three-phase voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊ )) and the heating voltage command value (induction heating voltage (v ＩＨ ＊ )) to obtain a combined voltage command value (vu2 ＊ +v ＩＨ ＊ , vv2 ＊ +v ＩＨ ＊ , vw2 ＊ +v ＩＨ ＊ , FIG. 7), and calculates the voltage command value (final voltage command value (vu ＊ , vv ＊ , vw ＊ )) is used as the braking voltage command value (three-phase voltage command value (vu2 ＊ , vv2 ＊ , vw2 ＊ )) to the combined voltage command value (vu2 ＊ +v ＩＨ ＊ , vv2 ＊ +v ＩＨ ＊ , vw2 ＊ +v ＩＨ ＊ , Figure 7).

[0201] With the above configuration, the inverter 3 converts the difference power (P1-P0) obtained by subtracting the allowable charging power (P0) from the regenerative power (converted regenerative power (P1)) corresponding to the braking energy generated in the electric vehicle 100 (e.g., corresponding to the amount of decrease in the accelerator opening APO) into induction heating power (P ＩＨ ) and is supplied to the motor (drive motor 4), generating induction heating in the motor (drive motor 4). Furthermore, the battery 9 can be charged with power equivalent to the allowable charging power (P0) of the regenerative power (equivalent regenerative power (P1)) equivalent to the braking energy generated in the electric vehicle 100. Therefore, the portion of the regenerative power (equivalent regenerative power (P1)) equivalent to the braking energy generated in the motor (drive motor 4) that cannot be charged to the battery 9 can be used as power for induction heating, and the heat generated by the induction heating can be efficiently supplied to the exhaust heat circulation path 50. This reduces, for example, the power consumption of the heat pump 60 (particularly the compressor 62) that supplies heat to the air conditioning system 90, among the power consumption of the battery 9. Furthermore, while induction heating occurs in the stator core 41, control that increases loss (heat generation) in the inverter 3 is not required. Therefore, a portion of the regenerative power generated in the motor (drive motor 4) can be used as power for induction heating while reducing the burden on the inverter 3.

[0202] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

Claims

1. A control method for an electric vehicle, which performs power exchange between one of two motors and a battery via a first inverter, and releases waste heat from at least one of the two motors into a refrigerant circulating in a waste heat circulation path, calculates a drive voltage command value for driving the first inverter based on a drive torque command value, and outputs the calculated drive voltage command value to the first inverter to apply a drive torque to one of the two motors, and when a first braking torque is generated in the other of the two motors, charges the battery with regenerative power generated by the first braking torque, wherein, when the regenerative power is greater than an allowable charging power that is the maximum power that can be charged to the battery, an IH frequency is set for induction heating a stator core of one of the two motors, and calculates a heating voltage command value for supplying the difference power obtained by subtracting the allowable charging power from the regenerative power to one of the two motors, and calculates a combined voltage command value by summing the drive voltage command value and the heating voltage command value, A control method for an electric vehicle, comprising switching a voltage command value to be output to the first inverter from the drive voltage command value to the combined voltage command value.

2. A control method for an electric vehicle which exchanges power between a battery and a motor via an inverter and releases exhaust heat from the motor into a refrigerant circulating in an exhaust heat circulation path, calculates a braking voltage command value for driving the inverter based on a braking torque command value, and outputs the braking voltage command value to the inverter to generate a first braking torque in the motor, and charges the battery with regenerative power generated by the first braking torque via the inverter, wherein, when the regenerative power becomes greater than an allowable charging power which is the maximum power that can be charged to the battery, an IH frequency is set for induction heating a stator core of the motor, and a heating voltage command value is calculated for supplying to the motor the difference power obtained by subtracting the allowable charging power from the regenerative power, and a combined voltage command value is calculated by adding together the braking voltage command value and the heating voltage command value, and the voltage command value to be output to the inverter is switched from the braking voltage command value to the combined voltage command value.

3. The method for controlling an electric vehicle according to claim 1 or 2, wherein the IH frequency is set to any frequency in the range of 5 kHz to 40 kHz.

4. A control method for an electric vehicle as claimed in claim 1, wherein, in a state where power is exchanged between the other of the two motors and the battery via a second inverter, a current command value composed of a d-axis current command value and a q-axis current command value is calculated based on a braking torque command value, a braking voltage command value for driving the second inverter is calculated based on the current command value and output to the second inverter, thereby applying the first braking torque to the other of the two motors, when it is predicted that the temperature of one of the two motors will reach a predetermined upper limit temperature, the heating voltage command value is reduced, and the absolute value of the d-axis current command value is increased based on the amount of reduction in the heating voltage command value while keeping the q-axis current command value constant.

5. A control method for an electric vehicle as described in claim 1, wherein a second braking torque due to friction can be applied to a drive wheel driven by one of the two motors, and power is exchanged between the other of the two motors and the battery via a second inverter, and when it is predicted that the operating temperature of any of the two motors, the first inverter, or the second inverter will reach a predetermined upper limit temperature, the heating voltage command value is reduced by a predetermined amount and the second braking torque is set based on the predetermined amount.

6. A control method for an electric vehicle as described in claim 1, wherein a second braking torque due to friction can be applied to a drive wheel driven by one of the two motors, power is exchanged between the other of the two motors and the battery via a second inverter, and exhaust heat from the other of the two motors is released into the refrigerant circulating through the exhaust heat circulation path, when it is predicted that the temperature of the refrigerant will reach a predetermined upper limit temperature, the heating voltage command value is reduced and the second braking torque is applied to the drive wheel so that the temperature of the refrigerant does not exceed the upper limit temperature, and the heating voltage command value is set to be smaller and the second braking torque to be larger as the temperature of the refrigerant becomes higher.

7. A control method for an electric vehicle as described in claim 2, wherein the electric vehicle includes drive wheels driven by the motor and driven wheels to which the driving force of the motor is not transmitted, and a second braking torque due to friction can be applied to the drive wheels and / or the driven wheels, and when it is predicted that the operating temperature of either the motor or the inverter will reach a predetermined upper limit temperature, the heating voltage command value is reduced by a predetermined amount so that the operating temperature does not exceed the upper limit temperature, and the second braking torque is set based on the predetermined amount.

8. A control method for an electric vehicle as described in claim 2, wherein the electric vehicle includes drive wheels driven by the motor and driven wheels to which the driving force of the motor is not transmitted, and a second braking torque due to friction can be applied to the drive wheels and / or the driven wheels, and when it is predicted that the temperature of the refrigerant will reach a predetermined upper limit temperature, the heating voltage command value is reduced and the second braking torque is set so that the temperature of the refrigerant does not exceed the upper limit temperature, and the higher the temperature of the refrigerant, the smaller the braking voltage command value is set and the larger the second braking torque is set.

9. A control method for an electric vehicle as described in claim 1 or claim 2, comprising: a heat pump capable of exchanging heat with the exhaust heat circulation path; air conditioning means that uses the heat pump as a heat source to heat the interior of the vehicle; and heating means that uses the heat pump as a heat source to heat the battery, wherein, when a first required amount of heat required by the air conditioning means is lower than the amount of exhaust heat taken into the exhaust heat circulation path, a difference in heat obtained by subtracting the first required amount of heat from the amount of exhaust heat is supplied to the heating means.

10. A control method for an electric vehicle as claimed in claim 1 or 2, comprising: a heat pump capable of exchanging heat with the exhaust heat circulation path; air conditioning means for heating the interior of the vehicle using the heat pump as a heat source; and heating means for heating the battery using the heat pump as a heat source, wherein when the sum of a first heat requirement required by the air conditioning means and a second heat requirement required by the heating means is lower than the amount of exhaust heat taken into the exhaust heat circulation path, the refrigerant is heated within a range such that the temperature of the refrigerant does not exceed a predetermined upper limit temperature.

11. A control system for an electric vehicle including: two motors; a battery that serves as a power source for the two motors; an inverter that supplies power from the battery to one of the two motors; an exhaust heat circulation path that circulates a coolant that takes in exhaust heat from at least one of the two motors; and a voltage command value calculation unit that calculates a voltage command value based on a torque command value and outputs the voltage command value to the inverter, wherein, when a braking torque is generated in the other of the two motors while a driving torque is being applied to one of the two motors by the voltage command value calculation unit calculating a driving voltage command value for driving the inverter based on a driving torque command value and outputting the driving voltage command value to the inverter, the system charges the battery with regenerative power generated by the braking torque, wherein the voltage command value calculation unit: a control system for an electric vehicle, which, when the regenerative power is greater than an allowable charging power which is the maximum power that can be charged to the battery, sets an IH frequency for induction heating one of the stator cores of the two motors, calculates a heating voltage command value for supplying to the motor a power difference obtained by subtracting the allowable charging power from the regenerative power, calculates a combined voltage command value by adding together the drive voltage command value and the heating voltage command value, and switches the voltage command value to be output to the inverter from the drive voltage command value to the combined voltage command value.

12. A control system for an electric vehicle including: a motor; a battery serving as a power source for the motor; an inverter supplying power to the motor between the battery; an exhaust heat circulation path for circulating a coolant that takes in exhaust heat from the motor; and a voltage command value calculation unit that calculates a voltage command value based on a torque command value and outputs the voltage command value to the inverter, wherein the voltage command value calculation unit calculates a braking voltage command value for driving the inverter based on a braking torque command value and outputs the braking voltage command value to the inverter, thereby applying braking torque to the motor, and charging the battery with regenerative power generated by the braking torque via the inverter, wherein the voltage command value calculation unit is set to an IH frequency for inductively heating a stator core of the motor when the regenerative power becomes greater than an allowable charging power that is the maximum power that can be charged to the battery, and calculates a heating voltage command value for supplying the motor with the difference power obtained by subtracting the allowable charging power from the regenerative power, a control system for an electric vehicle that calculates a combined voltage command value by adding together the braking voltage command value and the heating voltage command value, and switches the voltage command value to be output to the inverter from the braking voltage command value to the combined voltage command value.

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