Battery warm-up method and battery warm-up device

Abstract

Provided is a battery warm-up method for warming up, in an electric vehicle in which a battery and an electric motor unit including an electric motor and an inverter for adjusting electric power of the electric motor are disposed in a common cooling circuit, the battery when the electric motor is stopped due to a stop of the electric vehicle. In particular, this battery warm-up method involves: executing the rotor position adjusting process for adjusting, to a predetermined target stop position, a rotor position at the time when the electric motor is stopped; and executing the d-axis current adjusting process for warming up the battery by operating a d-axis current in a state where the rotor position is adjusted to the target stop position.

Description

Battery warm-up method and battery warm-up device

[0001] The present invention relates to a battery warm-up method and a battery warm-up device.

[0002] BACKGROUND ART Conventionally, in electric vehicles (such as electric vehicles and hybrid vehicles) equipped with an electric motor used as a driving source, etc., a method is known in which the current supplied from the battery to the motor is adjusted to control heat generation from the motor or self-heat generation from the battery, thereby warming up the battery.

[0003] In particular, JP2012-16552A discloses a control method for warming up the battery by adjusting the d-axis current (current component that does not contribute to motor torque) in the vector control of the motor in situations such as when starting a vehicle from a cold start after a long period of stoppage (motor stopped state) in cold regions.

[0004] On the other hand, the inventors have noticed that when the d-axis current is manipulated to warm up the battery while the vehicle is stopped (when the motor is stopped), the amount of heat generated for the same d-axis current varies depending on the rotor position when the motor is stopped. Therefore, depending on the rotor position when the motor is stopped, the amount of heat generated when manipulating the d-axis current varies, and the amount of heat required for warming up may be either excessive or insufficient.

[0005] Therefore, an object of the present invention is to more appropriately adjust the amount of heat generated by manipulating the d-axis current when the motor is stopped, in a control for warming up the battery by manipulating the d-axis current.

[0006] According to one aspect of the present invention, there is provided a battery warm-up method for warming up the battery when the electric motor is stopped due to a stop of the electric vehicle, in which an electric motor unit including an electric motor and an inverter that adjusts the electric power of the electric motor and a battery are arranged in a common cooling circuit. This battery warm-up method performs a rotor position adjustment process that adjusts the rotor position when the electric motor is stopped to a predetermined target stop position, and then performs a d-axis current adjustment process that manipulates the d-axis current of the electric motor to warm up the battery with the rotor position adjusted to the target stop position.

[0007] FIG. 1 is a block diagram showing the main configuration of an on-board cooling system common to all embodiments of the present invention. FIG. 2 is a flowchart illustrating the overall battery warm-up control common to all embodiments. FIG. 3 is a flowchart illustrating a first warm-up mode according to a first embodiment. FIG. 4 is a diagram schematically showing three-phase current flowing through a motor. FIG. 5 is a diagram illustrating the relationship between rotor position (rotation angle) and a three-phase current pattern. FIG. 6 is a diagram illustrating the relationship between rotation angle, d-axis current, and heat generation amount during d-axis current adjustment processing. FIG. 7 is a flowchart illustrating a first warm-up mode according to a second embodiment. FIG. 8 is a flowchart illustrating a first warm-up mode according to a third embodiment.

[0008] Hereinafter, each embodiment of the present invention will be described with reference to the drawings.

[0009] [Prerequisite Configuration] Fig. 1 is a block diagram showing the main configuration of an on-board cooling system 1 common to each embodiment described below. The on-board cooling system 1 shown in Fig. 1 is mounted on an electric vehicle. The concept of an electric vehicle in this specification also includes an electric vehicle (EV) or a hybrid vehicle (HEV) that uses an electric motor as a driving source to drive the vehicle.

[0010] More specifically, the vehicle-mounted cooling system 1 is configured such that an electric motor unit 12 and a battery 14 are arranged in a common cooling circuit C. The vehicle-mounted cooling system 1 also includes a chiller 16 and a radiator 18 for exchanging heat between the refrigerant (coolant) in the cooling circuit C and another refrigerant, and cooling water pumps 20-1 and 20-2, valves 22-1 to 22-4, and a PTC heater 24 as actuators for adjusting cooling system state quantities such as the flow path, flow rate, and temperature of the coolant in the cooling circuit C. The vehicle-mounted cooling system 1 also includes a vehicle controller 50 that comprehensively controls each element of the entire electric vehicle, including the operation of each actuator in the cooling circuit C, and a motor controller 52 that operates an inverter 34 to control the operation of the motor 32.

[0011] The electric motor unit 12 is mainly composed of a motor 32 that functions as a drive source for the electric vehicle, and an inverter 34 that adjusts the power supplied to the motor 32 .

[0012] The motor 32 is provided downstream of the inverter 34 in the cooling circuit C. The motor 32 in this embodiment is configured as a polyphase AC motor, more specifically, a three-phase AC motor.

[0013] The inverter 34 is a power converter that includes a plurality of switching elements (for example, power semiconductor elements such as IGBTs (Insulated Gate Bipolar Transistors) and MOS-FETs (Metal-Oxide-Semiconductor Field-Effect Transistors)) and a drive circuit that controls the on / off of the switching elements. In particular, the inverter 34 generates drive signals for the switching elements based on the results of comparing a PWM signal input from the motor controller 52 with a carrier triangular wave of a predetermined frequency, and turns each switching element on / off in accordance with the drive signals. This adjusts the power supplied from the battery 14 to the motor 32 (driving power) and the power regenerated from the motor 32 to the battery 14 (regenerative power).

[0014] The battery 14 is an on-board secondary battery connected to the motor 32 via an inverter 34. The battery 14 discharges power during power running to supply drive power to the motor 32, and receives regenerative power from the motor 32 during regeneration to be charged.

[0015] The chiller 16 is a device that exchanges heat between the liquid refrigerant supplied to an air conditioner heat exchange circuit (such as an air conditioning condenser) (not shown) and the coolant in the cooling circuit C. The radiator 18 dissipates heat retained in the coolant in the cooling circuit C by heat exchange with outside air. Valves 22-1 to 22-4 switch the coolant flow path between the chiller 16, the radiator 18, the electric motor unit 12, and the battery 14. The PTC heater 24 heats the coolant (particularly the coolant flowing into the battery 14). The coolant pumps 20-1 and 20-2 adjust the flow rate of the coolant in the cooling circuit C.

[0016] In the vehicle cooling system 1 of this embodiment, the amount of cooling water flowing into the chiller 16, the radiator 18, the motor unit 12, and the battery 14 can be individually adjusted by individually operating each of the valves 22-1 to 22-4.

[0017] For example, by manipulating the opening of valve 22-1, it is possible to adjust the amount of cooling water flowing into the chiller 16 and control the temperature of the cooling water. In addition, by manipulating each of valves 22-2 to 22-4, it is possible to adjust the amount of cooling water flowing into the radiator 18, and to switch between allowing and blocking the flow of cooling water from the radiator 18 to the motor unit 12 or the battery 14, thereby controlling the temperature of the cooling water supplied to each part.

[0018] In particular, by operating the valves 22-2 to 22-4 so that the cooling water flows from the electric motor unit 12 to the battery 14, and by appropriately adjusting the output of the cooling water pumps 20-1, 20-2, the heat generated in the motor 32 and the inverter 34 by the first warm-up mode described below can be more effectively transferred to the battery 14.

[0019] The vehicle controller 50 is configured by a computer that includes, for example, a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface), and is programmed to execute the processing defined in each embodiment.

[0020] In particular, the vehicle controller 50 of this embodiment calculates the required driving force T ｒｅ , and cooling system state quantities (such as the flow rate and temperature of the cooling water) obtained by sensors (not shown) are used as inputs to control the outputs of the cooling water pumps 20-1 and 20-2, the openings of the valves 22-1 to 22-4, and the output of the PTC heater 24. ｒｅ Examples of the driving force include the amount of operation of an accelerator pedal (accelerator opening) mounted on an electric vehicle and / or a command driving force generated by an automatic driving controller provided separately.

[0021] The vehicle controller 50 also calculates the required driving force T ｒｅand a torque command value T that is specified as the torque to be output by the motor 32 based on the vehicle speed detection value, etc. ＊ and outputs the result to the motor controller 52.

[0022] Furthermore, the vehicle controller 50 stores the charging schedule information I ｓｃ and the detected value of the battery temperature sensor 40 (battery temperature T Ｂ ) is input, and battery warm-up control is executed to warm up (heat) the battery 14 to a desired temperature when the electric vehicle is stopped.

[0023] The battery warm-up control will be described in detail below.

[0024] 2 is a flowchart illustrating the battery warm-up control. The process shown in FIG. 2 is performed based on the charging schedule information I ｓｃ The process is repeated at a predetermined control period, starting from the reception of the command.

[0025] As shown in the figure, first, the vehicle controller 50 receives charging schedule information I ｓｃ Based on the above, it is determined whether the electric vehicle is in a state of preparation for stopping for charging (S100).

[0026] Here, the charging schedule information I ｓｃ The charging schedule information I refers to information such as the location of an external charging facility for scheduled charging and the distance from the current location to the external charging facility. ｓｃ The charging schedule information I is generated based on the fact that the external charging facility is set as a destination on a car navigation system (not shown) by a passenger of the electric vehicle or the like. ｓｃ is received from the car navigation system.

[0027] The stop preparation state refers to a state immediately before the electric vehicle comes to a complete stop (motor rotation speed = 0) (motor rotation speed is equal to or less than a predetermined value close to 0).

[0028] Therefore, the vehicle controller 50 receives charging schedule information I from, for example, a car navigation system (not shown). ｓｃThe vehicle speed detection value or the motor rotation speed detection value is referenced in the scene to detect a scene in which the electric vehicle is about to come to a stop at the external charging facility. The vehicle stop preparation state is estimated by reference to the vehicle speed detection value or the motor rotation speed detection value in the scene.

[0029] Then, when the vehicle controller 50 determines that the electric vehicle is in a state of preparing to stop, the vehicle controller 50 calculates the battery temperature T Ｂ (S200), and the battery temperature T Ｂ , and determines whether or not the battery 14 needs to be warmed up (S300).

[0030] Specifically, the vehicle controller 50 detects the battery temperature T Ｂ The battery temperature T Ｂ If the warm-up reference temperature is lower than the warm-up reference temperature, it is determined that warm-up is necessary and the process from S400 onwards is carried out, but if not, it is determined that warm-up is not necessary and this routine ends. The warm-up reference temperature is set to an appropriate value for determining whether the limit on charging current (extension of charging time) due to the electrodeposition limit is within an allowable range when the charging plug is connected to the electric vehicle at an external charging facility and the battery 14 is charged.

[0031] When the vehicle controller 50 determines that the battery 14 needs to be warmed up, it sets a predetermined target temperature of the battery 14 during warm-up (hereinafter referred to as the “target battery temperature T Ｂｔ ") is read from the memory (S400), and the first warm-up mode and the second warm-up mode are executed (S500, S600).

[0032] In particular, in the first warm-up mode, the vehicle controller 50 generates a warm-up process command to cause the motor controller 52 to execute a rotor position adjustment process and a d-axis current adjustment process, which will be described later, and outputs the command to the motor controller 52. On the other hand, in the second warm-up mode, the vehicle controller 50 operates each actuator, such as the PTC heater 24, in the cooling circuit C to heat the coolant and warm up the battery 14.

[0033] Furthermore, the vehicle controller 50 goes through the first warm-up mode and the second warm-up mode to determine the battery temperature T Ｂ is the target battery temperature T Ｂｔ If it is determined that the number of the digits has reached the predetermined number, the process ends (S700).

[0034] Returning to FIG. 1, the motor controller 52 is configured by a computer that includes, for example, a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface), and is programmed to execute the processing defined in each embodiment.

[0035] In particular, the motor controller 52 receives the torque command value T ＊ Based on the warm-up process command and input signals from various sensors, the PWM signal for driving the inverter 34 is generated.

[0036] More specifically, the motor controller 52 controls the operation of the motor 32 by controlling a torque command value T ＊ , the detected value of the rotor position sensor 42 (rotation angle θ), and the detected value of the current sensor 44 (three-phase current i ｕ , i ｖ , i ｗ ) is input, and a three-phase voltage command value v ｕ , v ｖ , v ｗ Furthermore, the motor controller 52 performs vector control to determine the three-phase voltage command value v ｕ , v ｖ , v ｗ The PWM signal for the inverter 34 is generated from the

[0037] On the other hand, when the motor controller 52 of this embodiment receives a warm-up process command from the vehicle controller 50, it executes the processes defined in the first warm-up mode described above.

[0038] The first warm-up mode according to each embodiment will be described below.

[0039] [First Embodiment] FIG. 3 is a flowchart illustrating the details of the first warm-up mode (S500) in this embodiment.

[0040] As shown in the figure, the motor controller 52 first sets the rotor position (rotation angle θ) when the motor 32 stops to a predetermined target stop rotation angle θｓｔ More specifically, in the rotor position adjustment process, the motor controller 52 adjusts the rotation angle θ at the timing when the motor 32 stops to the target stop rotation angle θ. ｓｔ The inverter 34 is operated so that the output voltage Vout coincides with the reference voltage Vout.

[0041] Next, the motor controller 52 adjusts the rotation angle θ to the target stop rotation angle θ ｓｔ In the state where the d-axis current is adjusted to , the d-axis current adjustment process (S520) is executed. More specifically, in the d-axis current adjustment process, the q-axis current i ｑ is kept zero while the d-axis current i ｄ That is, the d-axis current adjustment process adjusts the q-axis current i ｑ is set to zero, and the d-axis current i ｄ This is a process in which the windings of the motor 32 and heat-generating parts (switching elements, etc.) of the inverter 34 are heated while maintaining the motor stopped by operating the inverter 34 to apply only the d-axis current. As shown in FIG. 1, the electric motor unit 12 and the battery 14 are arranged in the same cooling circuit C. Therefore, the heat generated by the motor 32 and the inverter 34 due to the d-axis current adjustment process can be used to warm up (heat) the battery 14 using the cooling water as a heat medium.

[0042] Here, the inventors have determined that in the d-axis current adjustment process, the same d-axis current i ｄ Even if the motor 32 is stopped, the inventors have focused on the fact that the heat loss (amount of heat generated) in the electric motor unit 12 (more specifically, heat generating parts such as the windings of the motor 32 and the switching elements of the inverter 34) varies depending on the rotor position (rotation angle θ) when the motor 32 is stopped. Based on this, the inventors have determined that the amount of heat generated in the electric motor unit 12 by the d-axis current adjustment process varies depending on the rotation angle θ when the motor is stopped. ｕ , i ｖ , i ｗ The sum of the absolute values ​​of the three-phase currents i ｔｏｔ It has been found that the equation is given by

[0043] FIG. 4 shows the three-phase current i flowing through the motor 32.ｕ , i ｖ , i ｗ It is a diagram showing a three-phase current i ｕ , i ｖ , i ｗ The sign of the current is defined as positive in the direction toward the neutral point N of the motor 32 (solid arrow) and negative in the direction away from the neutral point N (dashed arrow).

[0044] In the illustrated example, for example, when the motor is stopped, the rotation angle θ is ｕ is a positive value, and its absolute value is the V-phase current i ｖ and W-phase current i ｗ When the absolute value of the d-axis current i ｄ is given, due to the nature of three-phase AC, the V-phase current i ｖ and W-phase current i ｗ are both negative values. That is, the U-phase current i ｕ flows in the direction of the solid arrow, and the V-phase current i ｖ and W-phase current i ｗ The U-phase current i has the largest absolute value among the phase currents. ｕ However, V-phase current i flows through the neutral point N. ｖ and W-phase current i ｗ Therefore, the total current flowing through the windings of the motor 32 is ｕ -i ｖ -i ｗ That is, this is the total three-phase current i ｔｏｔ In addition, the inverter 34 also has a substantially identical total three-phase current i ｔｏｔ This causes heat to be generated in the heat generating portion.

[0045] Here, the relative magnitude of the absolute values ​​of the phase currents changes depending on the rotation angle θ. However, if the symmetry of each phase in a three-phase AC is taken into consideration, the total three-phase current i can be calculated using the same calculation algorithm in either case. ｔｏｔ can be determined.

[0046] 5 is a diagram showing the relationship between the rotation angle θ of the motor 32 and the three-phase current pattern. In FIG. 5, for the sake of simplicity, the three-phase current i ｕ , i ｖ , iｗ is shown as an ideal sinusoidal wave. On the other hand, the actual three-phase current i ｕ , i ｖ , i ｗ The profile of (a) is slightly deviated from an ideal sine wave due to the influence of switching in the inverter 34. However, by making necessary corrections taking into account the influence of the deviation appropriately in light of the common general technical knowledge at the time of filing, the following description, which is based on the assumption of an ideal sine wave shape, can be similarly applied.

[0047] As shown in the figure, the magnitude relationship of the absolute values ​​of the phase currents changes over one period of the rotation angle θ (0°≦θ≦360°). More specifically, the V-phase current i ｖ is negative and its absolute value is larger than that of the other two phases. ｕ is positive and its absolute value is larger than that of the other two phases, U-phase current large section II (60°<θ≦120°), W-phase current i ｗ is negative and its absolute value is larger than that of the other two phases, W-phase current large section III (120°<θ≦180°), V-phase current i ｖ is positive and its absolute value is larger than that of the other two phases, V-phase current large section IV (180°<θ≦240°), U-phase current i ｕ is negative and its absolute value is larger than that of the other two phases, and the W-phase current i ｗ is positive and its absolute value is greater than those of the other two phases, resulting in a W-phase large current section VI (300°<θ≦360°).

[0048] Furthermore, the total three-phase current i ｔｏｔ can be defined as follows:

[0049] ・i ｕ -i ｖ +i ｗ (V phase current large section I) ・i ｕ -i ｖ -i ｗ (U phase current large section II) ・i ｕ +i ｖ -i ｗ (W phase current large section III) -i ｕ +i ｖ -iｗ (V phase current large section IV) -i ｕ +i ｖ +i ｗ (U phase current large section V) -i ｕ -i ｖ +i ｗ (W phase current large section VI)

[0050] Here, for example, the total three-phase current i in the U-phase current large section II ｔｏｔ is the U-phase current i with respect to the rotation angle θ ｕ The total three-phase current i ｔｏｔ is the U-phase current i ｕ takes a positive peak at θ=90°, and the U-phase current i ｕ The lowest θ is 120° (V-phase current i ｖ The minimum value is reached at the rotation angle θ when the total three-phase current i ｔｏｔ The same is true for .

[0051] Therefore, the total three-phase current i according to the heat quantity required during warm-up is ｔｏｔ The target stop rotation angle θ ｓｔ By setting the rotation angle θ to a desired value in each of the sections I to VI, the amount of heat generated in the motor unit 12 during the d-axis current adjustment process can be appropriately adjusted.

[0052] In particular, when the amount of heat obtained during warm-up is to be maximized, the target stop rotation angle θ ｓｔ The total three-phase current i ｔｏｔ The rotation angle θ at which the value of ｓｔ１ ) in the d-axis current adjustment process. ｄ This maximizes the amount of heat generated per unit, improving warm-up efficiency.

[0053] More specifically, the first stop rotation angle θ ｓｔ１ θ=30° (V-phase current i ｖ is negative and has the maximum absolute value), 90° (U-phase current i ｕ is positive and has the largest absolute value), 150° (W-phase current iｗ is negative and has the maximum absolute value), 210° (V-phase current i ｖ is positive and has the largest absolute value), 270° (U-phase current i ｕ is negative and has the largest absolute value), and 330° (W-phase current i ｗ is positive and has the largest absolute value).

[0054] On the other hand, when the amount of heat obtained during warm-up is to be limited as much as possible, the target stop rotation angle θ ｓｔ The total three-phase current i ｔｏｔ The rotation angle θ at which the value of ｓｔ２ ) in the d-axis current adjustment process. ｄ This allows the warm-up to be performed while minimizing the amount of heat generated per unit area and taking into consideration the heat resistance of each component.

[0055] More specifically, the second stop rotation angle θ ｓｔ２ θ=60° (W-phase current i ｗ is 0), 120° (V-phase current i ｖ is 0), 180° (U-phase current i ｕ is 0), 240° (W-phase current i ｗ is 0), 300° (V-phase current i ｖ 0), and 360° (U-phase current i ｕ It is preferable to set it to either 0 or 1.

[0056] FIG. 6 shows the relationship between the rotation angle θ and the d-axis current i ｄ 6 is a diagram showing the relationship between the amount of heat generated and the temperature difference (ΔT) between the cooling water inlet temperature of the inverter 34 and the cooling water outlet temperature of the motor 32 in the cooling circuit C, as a parameter (vertical axis) indicating the amount of heat generated. Hereinafter, for the sake of simplicity, this will be simply referred to as "amount of heat generated ΔT."

[0057] As shown in the figure, the rotation angle θ when the motor is stopped is set as the first stop rotation angle θ ｓｔ１ By adjusting the d-axis current, the same d-axis current i ｄ On the other hand, the rotation angle θ when the motor is stopped is set to the second stop rotation angle θ ｓｔ２By adjusting the d-axis current, the same d-axis current i ｄ The minimum heat generation amount ΔT per unit time is achieved.

[0058] In addition, the target stop rotation angle θ ｓｔ The first stop rotation angle θ at which the maximum heat generation amount ΔT is reached ｓｔ１ and the second stop rotation angle θ at which the heat generation amount ΔT becomes minimum. ｓｔ２ By setting the rotation angle θ to a value other than ｄ The heat generation amount ΔT per unit time can be made variable.

[0059] The configuration of the battery warm-up method of the present embodiment described above and the resulting effects will now be described.

[0060] In this embodiment, in an electric vehicle in which an electric motor unit 12 including an electric motor (motor 32) and an inverter 34 that adjusts the power of the motor 32, and a battery 14 are arranged in a common cooling circuit C, a battery warm-up method is provided for warming up the battery 14 when the motor 32 is stopped due to the electric vehicle being stopped.

[0061] In this battery warm-up method, the rotor position (rotation angle θ) when stopping the motor 32 is set to a predetermined target stop position (target stop rotation angle θ ｓｔ ), and the rotation angle θ is adjusted to the target stop rotation angle θ ｓｔ In the state where the d-axis current i of the motor 32 is maintained at ｄ The d-axis current adjustment process (S520) is executed to warm up the battery 14 by operating the d-axis current adjustment process (S520).

[0062] As a result, by adjusting the rotation angle θ when the motor stops due to the vehicle stopping, the d-axis current i ｄ When warming up the battery 14 by operating the control unit 14, the heat generation amount ΔT of the electric motor unit 12 can be appropriately adjusted.

[0063] More specifically, in this embodiment, the target stop rotation angle θ ｓｔ is the total three-phase current i flowing through the motor 32 when the d-axis current adjustment process is executed. ｔｏｔ The rotation angle θ is set to the desired value. ｔｏｔ is the phase current i ｕ, i ｖ , i ｗ The sum of the absolute values ​​of (|i ｕ |+|i ｖ |+|i ｗ |) is determined.

[0064] As a result, the total three-phase current i ｔｏｔ The target stop rotation angle θ ｓｔ That is, a more specific control logic is provided for determining the rotation angle θ at the time of motor stop that realizes the desired heat generation amount ΔT during battery warm-up.

[0065] In particular, the target stop rotation angle θ ｓｔ is the total three-phase current i ｔｏｔ The first stop position (first stop rotation angle θ ｓｔ１ ) is included.

[0066] As a result, the same d-axis current i ｄ This allows the heat generation amount ΔT of the electric motor unit 12 per unit time to be maximized, thereby improving the warm-up efficiency of the battery 14.

[0067] In the battery warm-up method of the present embodiment, charging schedule information I indicating a schedule for charging the battery 14 by a predetermined external charging facility is used. ｓｃ The acquired charging schedule information I ｓｃ When the electric vehicle reaches the stop preparation state, the rotor position adjustment process and the d-axis current adjustment process are executed. In particular, in the rotor position adjustment process, the rotation angle θ of the motor 32 is adjusted to the target stop rotation angle θ when the electric vehicle is stopped. ｓｔ The inverter 34 is operated so that

[0068] As a result, the d-axis current i of the motor 32 ｄ While appropriately detecting a vehicle stop scene for charging in which battery warm-up should be performed by operating the ｓｔ A specific control logic for adjusting the

[0069] Instead of the control logic for estimating the above-mentioned stop preparation state, the rotation angle θ may be set to the target stop rotation angle θ after the electric vehicle has actually stopped (the motor 32 has stopped). ｓｔ Alternatively, a control logic may be employed to adjust (move) the position.

[0070] More specifically, charging schedule information I indicates a schedule for charging the battery 14 by a predetermined external charging facility. ｓｃ The acquired charging schedule information I ｓｃ When the electric vehicle reaches a stopped state, the rotor position adjustment process and the d-axis current adjustment process are executed. In particular, in the rotor position adjustment process, the rotation angle θ is adjusted to a target stop rotation angle θ ｓｔ The inverter 34 is operated so that

[0071] In this case, the stopped state is, for example, when the current position of the electric vehicle is not included in the charging schedule information I ｓｃ The vehicle can be estimated as a state where the position of the external charging facility coincides with that of the external charging facility included in the table, and the vehicle speed or motor rotation speed is zero. The stopped state may also be estimated by detecting the timing when the charging plug of the external charging facility is connected to the electric vehicle. Furthermore, in the stopped state, the rotation angle θ is set to the target stop rotation angle θ ｓｔ As a specific example of adjusting the rotation angle θ to the target stop rotation angle θ ｓｔ If the rotation angle θ is equal to the target stop rotation angle θ, the rotation angle θ is maintained. ｓｔ Furthermore, at this time, it is determined to which of the sections I to VI shown in FIG. 5 the rotation angle θ in the stopped state belongs, and the target stop rotation angle θ ｓｔ For example, if the rotation angle θ in the stopped state belongs to the U-phase large current section II, the target stop rotation angle θ ｓｔ It is possible to adopt a configuration in which the angle θ is set within the range of 60°<θ≦120°.

[0072] Furthermore, in this embodiment, a motor controller 52 is provided that functions as a battery control device suitable for implementing the above-described battery warm-up method.

[0073] The motor controller 52 sets the rotor position (rotation angle θ) when stopping the motor 32 to a predetermined target stop position (target stop rotation angle θ ｓｔ ) and a rotor position adjustment processing unit (S510) that adjusts the rotation angle θ to a target stop rotation angle θ ｓｔ In the state where the d-axis current i of the motor 32 is maintained at ｄ and a d-axis current adjustment processing unit (S520) that warms up the battery 14 by operating the d-axis current adjustment processing unit (S520).

[0074] Second Embodiment A second embodiment will now be described. Elements similar to those in the previous embodiment are designated by the same reference numerals, and their description will be omitted. In particular, this embodiment provides a first warm-up mode equipped with control logic capable of warming up the battery 14 while taking into account the heat resistance limits of the motor 32 and the inverter 34.

[0075] FIG. 7 is a flowchart illustrating the details of the first warm-up mode (S500) in this embodiment.

[0076] In this embodiment, first, the motor controller 52 calculates the motor temperature T Ｍ and inverter temperature T ＩＮ In particular, the motor temperature T Ｍ is acquired as a detection value of a winding temperature sensor 46 realized by a thermistor or the like that detects the temperature of the winding of the motor 32. ＩＮ is acquired as a detection value of an element temperature sensor 48 realized by a thermistor or the like that detects the temperature of a heat generating portion (particularly a switching element) of the inverter 34, for example.

[0077] The motor temperature T Ｍ may be calculated from any parameter that can indicate the winding temperature of the motor 32, instead of the value detected by the winding temperature sensor 46. For example, the water temperature at the cooling water outlet of the motor 32 in the cooling circuit C may be detected, and the winding temperature calculated from the water temperature may be used as the motor temperature T Ｍ Alternatively, the inverter temperature T ＩＮRegarding the inverter temperature T, instead of the value detected by the element temperature sensor 48, any parameter that can indicate the heat generating portion of the inverter 34 may be used. For example, the water temperatures at the cooling water outlets of the motor 32 and the inverter 34 in the cooling circuit C may be detected, and the temperatures of the heat generating portions calculated from the respective water temperatures may be used as the inverter temperature T. ＩＮ It may be obtained as.

[0078] Next, the motor controller 52 calculates the motor temperature T Ｍ and the first motor temperature threshold T Ｍ１ , and inverter temperature T ＩＮ and the first inverter temperature threshold T ＩＮ１ are compared with each other (S512, S513).

[0079] The first motor temperature threshold T Ｍ１ is the motor temperature T Ｍ is set to an appropriate value for determining whether the temperature is sufficiently lower than the thermal limit of the winding. ＩＮ１ is the inverter temperature T ＩＮ is set to an appropriate value for determining whether the temperature is sufficiently lower than the heat resistance limit of the heat-generating parts (switching elements, etc.) of the inverter 34.

[0080] Motor temperature T Ｍ is the first motor temperature threshold T Ｍ１ or less and the inverter temperature T ＩＮ is the first inverter temperature threshold T ＩＮ１ If the rotation angle θ is equal to or smaller than the first stop rotation angle θ (if both S512 and S513 are Yes), the motor controller 52 sets the rotation angle θ at the time of motor stop to the first stop rotation angle θ ｓｔ１ (S516).

[0081] Then, the motor controller 52 sets the rotation angle θ to a first stop rotation angle θ ｓｔ１ With the d-axis current i ｄ is set to a predetermined basic target value (S521). ｄ The basic target value can be set to a desired value as appropriate.

[0082] On the other hand, the motor temperature T Ｍ is the first motor temperature threshold T Ｍ１or the inverter temperature T ＩＮ is the first inverter temperature threshold T ＩＮ１ If the motor temperature T Ｍ and the second motor temperature threshold T Ｍ２ , and inverter temperature T ＩＮ and the second inverter temperature threshold T ＩＮ２ are compared in size (S514, S515).

[0083] The second motor temperature threshold T Ｍ２ is the motor temperature T Ｍ is set to an appropriate value for determining whether the temperature is relatively close to the thermal limit of the winding. Ｍ２ is the first motor temperature threshold T Ｍ１ The second inverter temperature threshold T ＩＮ２ is the inverter temperature T ＩＮ is set to an appropriate value for determining whether the temperature is relatively close to the heat resistance limit of the heat generating portion (switching element, etc.). ＩＮ２ is the first inverter temperature threshold T ＩＮ１ is set to a value greater than

[0084] Motor temperature T Ｍ is the second motor temperature threshold T Ｍ２ or less and the inverter temperature T ＩＮ is the second inverter temperature threshold T ＩＮ２ If the rotation angle θ is equal to or smaller than the second stop rotation angle θ (if both S514 and S515 are Yes), the motor controller 52 sets the rotation angle θ at the time of motor stop to the second stop rotation angle θ described above. ｓｔ２ (S517).

[0085] Then, the motor controller 52 sets the rotation angle θ to a second stop rotation angle θ ｓｔ２ With the d-axis current i ｄ is set as the basic target value (S521).

[0086] On the other hand, the motor temperature T Ｍ is the second motor temperature threshold T Ｍ２ or the inverter temperature TＩＮ is the second inverter temperature threshold T ＩＮ２ (if S514 or S515 is No), the motor controller 52 adjusts the d-axis current i ｄ is set to zero (S522).

[0087] That is, in this case, it is estimated that the windings of the motor 32 or the heat-generating parts of the inverter 34 are approaching their heat resistance limit, and the d-axis current adjustment process itself, which promotes heat generation, is terminated.

[0088] In addition, according to the logic shown in FIG. 2, even after the d-axis current adjustment process is completed, the battery temperature T Ｂ is the target battery temperature T Ｂｔ Until the battery 14 reaches the predetermined value, the second warm-up mode in which the actuators in the cooling circuit C are operated continues under the control of the vehicle controller 50. That is, only the second warm-up mode is executed, and the warm-up of the battery 14 continues.

[0089] According to the first warm-up mode, the battery 14 can be warmed up within a range in which the temperatures of the components of the electric motor unit 12 (more specifically, the windings of the motor 32 and the heat-generating parts of the inverter 34) do not reach the heat-resistance limit. Ｍ and inverter temperature T ＩＮ A threshold is set individually for each target stop rotation angle θ ｓｔ Since the adjustment of the d-axis current and the end of the d-axis current adjustment process are determined, the battery 14 can be warmed up while more reliably protecting the motor 32 and the inverter 34 from heat.

[0090] The configuration of the battery warm-up method of the present embodiment described above and the resulting effects will now be described.

[0091] In the rotor position adjustment process (S511 to S517) in this embodiment, a temperature parameter (T Ｍ , T ＩＮ ) and obtain the temperature parameter (T Ｍ , T ＩＮ ) and a predetermined first temperature threshold (T Ｍ１ , T ＩＮ１ ) and compare the temperature parameter (T Ｍ, T ＩＮ ) is the first temperature threshold (T Ｍ１ , T ＩＮ１ ) or less, the rotation angle θ when the motor is stopped is set to the first stop rotation angle θ ｓｔ１ Adjust to.

[0092] This allows detecting a situation where the temperature of the components of the motor unit 12 is within the heat resistance limit, and the rotation angle θ when the motor is stopped is calculated based on the total three-phase current i ｔｏｔ That is, in a situation where there is a margin for the heat resistance limit, the rotation angle θ when the motor is stopped can be adjusted to maximize the heat generation amount ΔT obtained by the d-axis current adjustment process (S521) and increase the warm-up efficiency.

[0093] In addition, the target stop rotation angle θ ｓｔ is the total three-phase current i ｔｏｔ The second stop position (second stop rotation angle θ ｓｔ２ ) and the rotor position adjustment process includes a temperature parameter (T Ｍ , T ＩＮ ) is the first temperature threshold (T Ｍ１ , T ＩＮ１ ), the rotation angle θ when the motor is stopped is set to the second stop rotation angle θ ｓｔ２ Adjust to.

[0094] This allows detecting a situation where the temperature of the components of the motor unit 12 is not within the heat resistance limit, and the rotation angle θ when the motor is stopped is calculated based on the total three-phase current i ｔｏｔ That is, in a situation where there is no margin for error relative to the heat resistance limit, the rotation angle θ when the motor is stopped can be adjusted to minimize the heat generation amount ΔT obtained by the d-axis current adjustment process (S521) and to suppress a temperature rise in the electric motor unit 12 while promoting warm-up.

[0095] In particular, in a situation where the temperature of the electric motor unit 12 is relatively low, such as in the initial stage of warm-up, maximizing the heat generation amount ΔT obtained by the d-axis current adjustment process can promote rapid warm-up. On the other hand, in a situation where the warm-up has progressed to a certain extent and the temperature of the electric motor unit 12 has risen above a certain level, minimizing the heat generation amount ΔT obtained by the d-axis current adjustment process can suppress the temperature rise and allow the warm-up to proceed at a constant speed.

[0096] Furthermore, in the rotor position adjustment process of this embodiment, a temperature parameter (T Ｍ , T ＩＮ ) is the first temperature threshold (T Ｍ１ , T ＩＮ１ ), the temperature parameter (T Ｍ , T ＩＮ ) as the first temperature threshold (T Ｍ１ , T ＩＮ１ ) greater than a second temperature threshold (T Ｍ２ , T ＩＮ２ ) and compare the temperature parameter (T Ｍ , T ＩＮ ) is the second temperature threshold (T Ｍ２ , T ＩＮ２ ), the d-axis current adjustment process is terminated.

[0097] This makes it possible to detect when the temperature of the components of the electric motor unit 12 approaches the heat resistance limit and terminate the d-axis current adjustment process. That is, it is possible to appropriately detect when the d-axis current adjustment process should be terminated from the viewpoint of protecting the motor 32 and the inverter 34 from heat and terminate the process appropriately.

[0098] Third Embodiment A third embodiment will now be described. Elements similar to those in the previous embodiment are designated by the same reference numerals, and their description will be omitted. In particular, this embodiment provides a control logic for warming up the battery 14 that is different from that in the second embodiment, while taking into consideration the heat resistance limits of the motor 32 and the inverter 34.

[0099] FIG. 8 is a flowchart illustrating the details of the first warm-up mode (S500) in this embodiment.

[0100] In this embodiment, first, the motor controller 52 sets the rotation angle θ when the motor is stopped as a first stop rotation angle θ ｓｔ１ (S5101).

[0101] Next, the motor controller 52 calculates the motor temperature T Ｍ and inverter temperature T ＩＮ (S5201). Furthermore, the motor controller 52 acquires the motor temperature T Ｍ and the first motor temperature threshold T Ｍ１ , and inverter temperature T ＩＮ and the first inverter temperature threshold T ＩＮ１ are compared with each other (S5202, S5203).

[0102] Motor temperature T Ｍ is the first motor temperature threshold T Ｍ１ or less and the inverter temperature T ＩＮ is the first inverter temperature threshold T ＩＮ１ If it is equal to or less than this (if both S5202 and S5203 are Yes), the motor controller 52 adjusts the d-axis current i ｄ is set as the basic d-axis target value (S5206).

[0103] On the other hand, the motor temperature T Ｍ is the first motor temperature threshold T Ｍ１ or the inverter temperature T ＩＮ is the first inverter temperature threshold T ＩＮ１ If the motor temperature T Ｍ and the second motor temperature threshold T Ｍ２ , and inverter temperature T ＩＮ and the second inverter temperature threshold T ＩＮ２ are compared in size (S5204, S5205).

[0104] Motor temperature T Ｍ is the second motor temperature threshold T Ｍ２ or less and the inverter temperature T ＩＮ is the second inverter temperature threshold T ＩＮ２ If it is equal to or less than this (if both S5204 and S5205 are Yes), the motor controller 52 ｄis set to a corrected d-axis target value that is smaller than the basic d-axis target value (S5207).

[0105] On the other hand, the motor temperature T Ｍ is the second motor temperature threshold T Ｍ２ or the inverter temperature T ＩＮ is the second inverter temperature threshold T ＩＮ２ (if S5204 or S5205 is No), the motor controller 52 ｄ is set to zero (S5208).

[0106] According to the first warm-up mode in the above embodiment, particularly in a situation where the temperature of the components of the electric motor unit 12 approaches the heat resistance limit, the rotation angle θ described in the second embodiment is set to the second stop rotation angle θ ｓｔ２ Instead of adjusting the rotation angle θ to the first stop rotation angle θ ｓｔ１ The d-axis current i ｄ Therefore, a process of reducing the

[0107] Therefore, similarly to the second embodiment, the battery 14 can be warmed up within a range in which the temperature of the components of the electric motor unit 12 does not reach the heat resistance limit.

[0108] The configuration of the battery warm-up method of the present embodiment described above and the resulting effects will now be described.

[0109] In the rotor position adjustment process (S5101) in this embodiment, the target stop rotation angle θ ｓｔ The first stop rotation angle θ ｓｔ１ In the d-axis current adjustment process (S5201 to S5108), a temperature parameter (T Ｍ , T ＩＮ ) and obtain the temperature parameter (T Ｍ , T ＩＮ ) and a predetermined first temperature threshold (T Ｍ１ , T ＩＮ１ ) and compare the temperature parameter (T Ｍ , T ＩＮ ) is the first temperature threshold (T Ｍ１ , T ＩＮ１ ) or less, the d-axis current i ｄis adjusted to a predetermined basic target d-axis current. Ｍ , T ＩＮ ) is the first temperature threshold (T Ｍ１ , T ＩＮ１ ), the d-axis current i ｄ is adjusted to a corrected target d-axis current that is smaller than the basic target d-axis current.

[0110] In this way, in a situation where the temperature of the components of the motor unit 12 is within the heat resistance limit, the rotation angle θ when the motor is stopped is set to the total three-phase current i ｔｏｔ is adjusted to a position where the warm-up efficiency is increased by maximizing the rotation angle θ, while in a situation where there is no room for error, the d-axis current i ｄ This reduces the temperature rise of the motor unit 12 .

[0111] The above describes embodiments of the present invention, but the configurations described in the above embodiments and each modified example only show some of the application examples of the present invention and are not intended to limit the technical scope of the present invention.

[0112] For example, in the first warm-up mode described in each of the above embodiments, in addition to adjusting the rotation angle θ when the motor is stopped, a configuration may be adopted in which the heat generation amount ΔT in the electric motor unit 12 is controlled by adjusting the switching frequency of the inverter 34. In particular, the higher the switching frequency, the higher the loss in the switching elements, and the greater the heat generation amount ΔT. Therefore, by combining the adjustment of the rotation angle θ when the motor is stopped as described above with the adjustment of the switching frequency, the amount of heat generated during warm-up can be more precisely controlled.

[0113] Furthermore, in the above-described embodiments, the battery warm-up control that is executed when the electric vehicle is stopped at an external charging facility for charging has been described. However, the control logic described in the above-described embodiments can also be applied to situations where warm-up of the battery 14 is required when the electric vehicle is stopped for purposes other than charging (such as when starting the vehicle from a cold start after stopping).

Claims

1. In an electric vehicle in which an electric motor unit including an electric motor and an inverter for adjusting the power of the electric motor and a battery are arranged in a common cooling circuit, a battery warming method for warming the battery when the electric motor stops as the electric vehicle stops, comprising: Performing a rotor position adjustment process for adjusting the rotor position at the time of stopping of the electric motor to a predetermined target stop position; Performing a d-axis current adjustment process for warming the battery by operating the d-axis current of the electric motor in a state where the rotor position is adjusted to the target stop position; Defining the target stop position as the rotor position at which the total three-phase current flowing through the electric motor takes a desired value when the d-axis current adjustment process is executed; The total three-phase current is determined as the sum of the absolute values of the phase currents; Battery warming method.

2. The battery warming method according to claim 1, wherein: The target stop position: Includes a first stop position determined as the rotor position when the total three-phase current takes a maximum value; Battery warming method.

3. The battery warming method according to claim 2, wherein: In the rotor position adjustment process: Obtaining a temperature parameter indicating the temperature of the electric motor unit; Comparing the temperature parameter with a predetermined first temperature threshold; When the temperature parameter is less than or equal to the first temperature threshold, adjusting the rotor position to the first stop position; Battery warming method.

4. The battery warming method according to claim 3, wherein: The target stop position includes a second stop position determined as the rotor position when the total three-phase current takes a minimum value; In the rotor position adjustment process: When the temperature parameter is greater than the first temperature threshold, adjusting the rotor position to the second stop position; Battery warming method.

5. The battery warming method according to claim 3, wherein: The target stop position includes a second stop position determined as the rotor position when any one of the phase currents becomes 0; In the rotor position adjustment process: When the temperature parameter is greater than the first temperature threshold, comparing the temperature parameter with a second temperature threshold greater than the first temperature threshold; When the temperature parameter is less than or equal to the second temperature threshold, adjusting the rotor position to the second stop position; When the temperature parameter is greater than the second temperature threshold, ending the d-axis current adjustment process; Battery warming method.

6. The battery warming method according to claim 2, wherein: In the rotor position adjustment process, the rotor position is adjusted to the first stop position, In the d-axis current adjustment process, a temperature parameter indicating the temperature of the motor unit is acquired, the temperature parameter is compared with a predetermined first temperature threshold, when the temperature parameter is less than or equal to the first temperature threshold, the d-axis current is adjusted to a predetermined basic target d-axis current, when the temperature parameter is greater than the first temperature threshold, the d-axis current is adjusted to a corrected target d-axis current smaller than the basic target d-axis current, Battery warming method.

7. The battery warming method according to claim 1, acquiring charging schedule information indicating a schedule of charging the battery by a predetermined external charging facility, estimating a parking preparation state in which the electric vehicle stops at the external charging facility based on the charging schedule information, when the electric vehicle reaches the parking preparation state, executing the rotor position adjustment process and the d-axis current adjustment process, In the rotor position adjustment process, operating the inverter so that the rotor position becomes the target stop position when the electric vehicle stops, Battery warming method.

8. The battery warming method according to claim 1, acquiring charging schedule information indicating a schedule of charging the battery by a predetermined external charging facility, estimating a parking state in which the electric vehicle has stopped at the external charging facility based on the charging schedule information, when the electric vehicle reaches the parking state, executing the rotor position adjustment process and the d-axis current adjustment process, In the rotor position adjustment process, operating the inverter so that the rotor position becomes the target stop position, Battery warming method.

9. The battery warming method according to claim 1, the target stop position includes a second stop position determined as the rotor position when the total three-phase current takes a minimum value, Battery warming method.

10. The battery warming method according to claim 1, the target stop position includes a second stop position determined as the rotor position when any one of the phase currents becomes zero, Battery warming method.

11. In an electric vehicle in which a motor unit including a motor and an inverter for adjusting the power of the motor and a battery are arranged in a common cooling circuit, a battery warming device for warming the battery when the motor stops accompanying the stop of the electric vehicle, a rotor position adjustment processing unit that adjusts the rotor position at the time of stopping of the motor to a predetermined target stop position, A d-axis current adjustment processing unit that warms up the battery by operating the d-axis current of the motor in a state where the rotor position is adjusted to the target stop position; The target stop position is determined as the rotor position at which the total three-phase current flowing through the motor takes a desired value when the d-axis current adjustment process is executed; The total three-phase current is determined as the sum of the absolute values of the phase currents; Battery warming device.