Battery warming method and battery warming 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

[Technical Field]

[0001] This invention relates to a battery warming method and a battery warming device. [Background technology]

[0002] Conventionally, in electric vehicles (electric cars and hybrid cars, etc.) equipped with electric motors used as a driving source, a method is known for controlling the heat generated by the motor or the self-heating of the battery by adjusting the current supplied from the battery to the motor, 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 motor's vector control, such as during cold starts from a long period of stationary state (motor stationary state) in cold regions. [Overview of the Initiative]

[0004] On the other hand, the inventors focused on the fact that in a control system that warms up the battery by manipulating the d-axis current when the vehicle is stopped (motor stopped), the amount of heat generated for the same d-axis current differs 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 the d-axis current is manipulated may vary, potentially resulting in an excess or deficiency of the heat required for warming up.

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

[0006] According to one aspect of the present invention, a battery warming method is provided for 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, in which the battery is warmed up when the electric motor stops due to the electric vehicle being stopped. In this battery warming method, a rotor position adjustment process is performed to adjust the rotor position to a predetermined target stop position when the electric motor is stopped, and a d-axis current adjustment process is performed to warm up the battery by manipulating the d-axis current of the electric motor while the rotor position is adjusted to the target stop position. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a block diagram showing the main configuration of an in-vehicle cooling system common to each embodiment of the present invention. [Figure 2] Figure 2 is a flowchart illustrating the overall battery warm-up control common to each embodiment. [Figure 3] Figure 3 is a flowchart illustrating the first warm-up mode according to the first embodiment. [Figure 4] Figure 4 is a schematic diagram showing the three-phase current flowing through the motor. [Figure 5] Figure 5 shows the relationship between the rotor position (rotation angle) and the three-phase current pattern. [Figure 6] Figure 6 shows the relationship between the rotation angle, d-axis current, and heat generation during the d-axis current adjustment process. [Figure 7] Figure 7 is a flowchart illustrating the first warm-up mode according to the second embodiment. [Figure 8] Figure 8 is a flowchart illustrating the first warm-up mode according to the third embodiment. [Modes for carrying out the invention]

[0008] The embodiments of the present invention will be described below with reference to the drawings.

[0009] [Prerequisite configuration] Figure 1 is a block diagram showing the main components of the on-board cooling system 1 common to each embodiment described later. Note that the on-board cooling system 1 shown in Figure 1 is installed in an electric vehicle. Furthermore, the concept of an electric vehicle in this specification includes electric vehicles (EVs) or hybrid electric vehicles (HEVs) that use an electric motor as the driving source to propel the vehicle.

[0010] More specifically, the on-board cooling system 1 is configured such that the electric motor unit 12 and the battery 14 are arranged in a common cooling circuit C. The on-board cooling system 1 also includes a chiller 16 and a radiator 18 for heat exchange between the refrigerant (cooling water) and other refrigerants in the cooling circuit C, and cooling water pumps 20-1, 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 cooling water in the cooling circuit C. Furthermore, the on-board cooling system 1 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 controls the operation of the motor 32 by operating the inverter 34.

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

[0012] The motor 32 is located downstream of the inverter 34 in the cooling circuit C. The motor 32 in this embodiment is composed of a multiphase AC motor, more specifically a three-phase AC motor.

[0013] The inverter 34 is a power converter that includes multiple 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 state of the switching elements. In particular, the inverter 34 generates a drive signal for the switching elements based on the comparison result between the PWM signal input from the motor controller 52 and a carrier triangular wave of a predetermined frequency, and turns each switching element on / off according to the drive signal. This adjusts the power supplied from the battery 14 to the motor 32 (powering 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 the inverter 34. The battery 14 discharges during powering to supply drive power to the motor 32, while being charged by receiving regenerative power from the motor 32 during regeneration.

[0015] The chiller 16 is a device that performs heat exchange between the liquid refrigerant supplied to the air conditioner heat exchange circuit (such as an air conditioning condenser) and the cooling water in the cooling circuit C. The radiator 18 dissipates the heat contained in the cooling water in the cooling circuit C through heat exchange with the outside air. Valves 22-1 to 22-4 switch the flow path of the cooling water between the chiller 16, the radiator 18, the motor unit 12, and the battery 14. The PTC heater 24 heats the cooling water (especially the cooling water flowing into the battery 14). Cooling water pumps 20-1 and 20-2 regulate the flow rate of the cooling water in the cooling circuit C.

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

[0017] For example, by operating the opening of valve 22-1, it is possible to control the amount of coolant flowing into the chiller 16 and thereby control the temperature of the coolant. Furthermore, by operating valves 22-2 to 22-4, it is possible to control the amount of coolant flowing into the radiator 18, and to switch the flow of coolant from the radiator 18 to the electric motor unit 12 or battery 14 on and off, thereby controlling the temperature of the coolant supplied to each part.

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

[0019] The vehicle controller 50 consists of, for example, a central processing unit (CPU), read-only memory (ROM), random access memory (RAM), and an input / output interface (I / O interface), and is comprised of a computer programmed to perform the processing specified in each embodiment.

[0020] In particular, the vehicle controller 50 of this embodiment provides a required driving force T for the electric vehicle. re The system controls the output of each cooling water pump 20-1, 20-2, the opening degree of each valve 22-1 to 22-4, and the output of the PTC heater 24, based on the detection of cooling system state variables (such as the flow rate and temperature of the cooling water) obtained from sensors (not shown). re This could include the amount of input to the accelerator pedal (accelerator opening) on ​​an electric vehicle, and / or the commanded driving force generated by a separately provided automatic driving controller.

[0021] Furthermore, the vehicle controller 50 controls the required driving force T re Based on the vehicle speed detection value and other factors, a torque command value T is defined as the torque that the motor 32 should output. * The calculation is performed and output to the motor controller 52.

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

[0023] The details of the battery warm-up control will be described below.

[0024] FIG. 2 is a flowchart for explaining the battery warm-up control. The processing shown in FIG. 2 is repeatedly executed at a predetermined control cycle based on the reception of the scheduled charging information I sc .

[0025] As shown in the figure, first, the vehicle controller 50 determines whether the electric vehicle is in a parking preparation state for charging based on the scheduled charging information I sc (S100).

[0026] Here, the scheduled charging information I sc means information such as the location of the external charging facility for performing the scheduled charging and the distance from the current location to the external charging facility. In particular, the scheduled charging information I sc is generated based on the premise that an external charging facility is set as the destination on a car navigation system (not shown) by the driver or other occupants of the electric vehicle. That is, in this case, the vehicle controller 50 receives the scheduled charging information I sc from the car navigation system.

[0027] Also, the parking preparation state means a state immediately before the electric vehicle comes to a complete stop (motor rotational speed = 0) (at a predetermined value or less close to 0 motor rotational speed).

[0028] Therefore, the vehicle controller 50, for example, receives the scheduled charging information I sc from a car navigation system (not shown).The system detects when the electric vehicle comes to a stop at the external charging facility by referring to the above-mentioned data, and estimates the stopping preparation state by referring to the vehicle speed detection value or motor rotation speed detection value in that scene.

[0029] Then, when the vehicle controller 50 determines that the electric vehicle is in a state of preparation for stopping, the battery temperature T B The following is obtained (S200), and the battery temperature T B Refer to this to determine whether or not the battery 14 needs to be warmed up (S300).

[0030] Specifically, the vehicle controller 50 controls the battery temperature T B The battery temperature T is compared with the predetermined warm-up execution standard temperature. B If the temperature falls below the warm-up execution standard temperature, it is determined that warm-up is necessary and the process from S400 onwards is executed; otherwise, it is determined that warm-up is unnecessary and this routine is terminated. The warm-up execution standard temperature is set to an appropriate value to determine whether the limitation of the charging current (prolonged charging time) due to the electrodeposition limit is within an acceptable range when charging the battery 14 by connecting the charging plug to the electric vehicle with external charging equipment.

[0031] When the vehicle controller 50 determines that the battery 14 needs to be warmed up, it sets a predetermined target temperature for the battery 14 during warm-up (hereinafter referred to as "target battery temperature T"). Bt The system reads (also known as) from memory (S400) and executes the first warm-up mode and the second warm-up mode (S500, S600).

[0032] In particular, in the first warm-up mode, the vehicle controller 50 generates a warm-up command to the motor controller 52 to perform the rotor position adjustment process and the d-axis current adjustment process described later, and outputs it to the motor controller 52. On the other hand, in the second warm-up mode, the coolant is heated by operating the actuators such as the PTC heater 24 in the cooling circuit C to warm up the battery 14.

[0033] Furthermore, the vehicle controller 50, after going through the first warm-up mode and the second warm-up mode, determines the battery temperature TB Target battery temperature T Bt If it is determined that the condition has been reached, this process is terminated (S700).

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

[0035] In particular, the motor controller 52 receives the torque command value T from the vehicle controller 50. * Based on the warm-up command and input signals from various sensors, a PWM signal is generated to drive the inverter 34 described above.

[0036] More specifically, the motor controller 52 controls the operation of the motor 32 using a torque command value T as the basic control. * , the detected value (rotation angle θ) from the rotor position sensor 42, and the detected value (three-phase current i) from the current sensor 44. u ,i v ,i w The input is a three-phase voltage command value v which defines the voltage to be applied to the motor 32. u ,v v ,v w Vector control is performed to determine the three-phase voltage command value v u ,v v ,v w The PWM signal for inverter 34 is generated from this.

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

[0038] The following describes the configuration of the first warm-up mode according to each embodiment.

[0039] [First Embodiment] Figure 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 θ. st The rotor position adjustment process (S510) is executed to adjust the rotor position to the target stop rotation angle θ at the time the motor 32 stops. More specifically, in the rotor position adjustment process, the motor controller 52 adjusts the rotation angle θ at the time the motor 32 stops to the target stop rotation angle θ. st Operate inverter 34 to match the value.

[0041] Next, the motor controller 52 sets the rotation angle θ to the target stop rotation angle θ. st With the settings adjusted, the d-axis current adjustment process (S520) is executed. More specifically, in the d-axis current adjustment process, the q-axis current i in the vector control of the motor 32 is adjusted. q While keeping the d-axis current i at zero d The q-axis current i, which contributes to the motor torque (motor speed), is adjusted to the desired value. q Setting i to zero as the d-axis current i d This process involves operating the inverter 34 to provide only the d-axis current, thereby maintaining the motor in a stopped state while generating heat in the windings of the motor 32 and the heat-generating parts (switching elements, etc.) of the inverter 34. As shown in Figure 1, the motor unit 12 and the battery 14 are located in the same cooling circuit C. Therefore, the heat generated by the motor 32 and inverter 34 due to the d-axis current adjustment process can warm up (heat) the battery 14 using the cooling water as a heat transfer medium.

[0042] Here, the present inventors have found that in the d-axis current adjustment process, the same d-axis current i dHowever, the inventors focused on the fact that the heat loss (amount of heat generated) in the motor unit 12 (more specifically, the heat-generating parts such as the windings of the motor 32 and the switching elements of the inverter 34) differs depending on the rotor position (rotation angle θ) when the motor 32 is stopped. Based on this, the inventors determined that the amount of heat generated in the motor unit 12 by the d-axis current adjustment process varies depending on the rotation angle θ when the motor is stopped, and the three-phase current i u ,i v ,i w The sum of the absolute values ​​of (hereinafter referred to as "total three-phase current i") tot It was discovered that it is given by (also known as )

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

[0044] In the illustrated example, for example, the rotation angle θ when the motor is stopped is equal to the U-phase current i u If it is a positive value and its absolute value is the V-phase current i v and W-phase current i w If the d-axis current i is within a range greater than the absolute values ​​of each of the other values d When given, due to the properties of three-phase alternating current, the V-phase current i v and W-phase current i w Both take negative values. That is, U-phase current i u The current flows in the direction of the solid arrow, and the V-phase current i v and W-phase current i w Each current flows in the direction of the dashed arrow. Therefore, the U-phase current i, which has the largest absolute value among the phase currents, is the largest. u However, the V-phase current i passes through the neutral point N. v and W-phase current i w The current will be divided into two parts. Therefore, the total current flowing through the windings of motor 32 is i u -i v -i wIt is given as follows: That is, this is the total three-phase current i tot This is the result. Furthermore, the total three-phase current i within inverter 34 is almost identical. tot This fluid flows, causing heat to be generated in the heat-generating section.

[0045] Here, the relative magnitudes of the absolute values ​​of each phase current change depending on the rotation angle θ, but considering the symmetry of each phase in three-phase AC, the total three-phase current i can be calculated using the same calculation algorithm in all cases. tot It is possible to determine this.

[0046] Figure 5 shows the relationship between the rotation angle θ of the motor 32 and the three-phase current pattern. Note that in Figure 5, for the sake of simplicity, the three-phase current i is shown. u ,i v ,i w This is shown in an ideal sinusoidal shape. On the other hand, the actual three-phase current i u ,i v ,i w The resulting profile exhibits a slight deviation from an ideal sine wave due to factors such as the switching effects in the inverter 34. However, by appropriately considering the effects of this deviation in light of the common technical knowledge at the time of filing and making necessary corrections, the following explanation, which assumes an ideal sine wave shape, can be similarly applied.

[0047] As shown in the figure, the relative magnitudes of the absolute values ​​of the phase currents are reversed within one period of rotation angle θ (0° ≤ θ ≤ 360°). More specifically, the V-phase current i v V-phase current large interval I (0°≦θ≦60°), U-phase current i u The U-phase current is positive and its absolute value is larger than that of the other two phases in the large interval II (60° < θ ≤ 120°), and the W-phase current is i w W-phase current large interval III (120° < θ ≤ 180°), where the value is negative and its absolute value is larger than that of the other two phases, V-phase current i v The V-phase current is positive and its absolute value is larger than that of the other two phases in the large interval IV (180° < θ ≤ 240°), and the U-phase current is i uA large U-phase current region V (240° < θ ≤ 300°) where the U-phase current is negative and its absolute value is larger than those of the other two phases, and the W-phase current i w A large W-phase current region VI (300° < θ ≤ 360°) where the W-phase current is positive and its absolute value is larger than those of the other two phases occurs.

[0048] Furthermore, the total three-phase current i tot in each region can be defined as follows.

[0049] ·i u -i v +i w (Large V-phase current region I) ·i u -i v -i w (Large U-phase current region II) ·i u +i v -i w (Large W-phase current region III) ·-i u +i v -i w (Large V-phase current region IV) ·-i u +i v +i w (Large U-phase current region V) ·-i u -i v +i w (Large W-phase current region VI)

[0050] Here, for example, the total three-phase current i tot in the large U-phase current region II shows an increasing and decreasing tendency similar to that of the U-phase current i u itself with respect to the rotation angle θ. That is, the total three-phase current i tot takes the maximum value at θ = 90° where the U-phase current i u takes the positive peak, and takes the minimum value at θ = 120° where the U-phase current i u becomes the lowest (the rotation angle θ when the V-phase current i v becomes 0). Note that this tendency is the same for the total three-phase current i tot in other regions.

[0051] Therefore, the total three-phase current i corresponds to the amount of heat required during warm-up. tot To achieve this, the target stopping rotation angle θ st By setting the desired rotation angle θ in each section I to VI, the amount of heat generated in the motor unit 12 during the d-axis current adjustment process can be appropriately controlled.

[0052] In particular, when aiming to maximize the amount of heat generated during warm-up, the target stopping rotation angle θ st The total three-phase current i within each section I to VI tot The rotation angle θ that is largest (hereinafter referred to as "first stopping rotation angle θ") st1 It is preferable to set it to (also called ). This allows the d-axis current i in the d-axis current adjustment process to d This maximizes the amount of heat generated per unit area, thereby improving warm-up efficiency.

[0053] More specifically, the first stopping rotation angle θ st1 θ = 30° (V-phase current i v (When negative, the absolute value is maximum), 90° (U-phase current i u (where the absolute value is maximum when it is positive), 150° (W phase current i w (where the absolute value is maximum when it is negative), 210° (V-phase current i v (where the absolute value is maximum when it is positive), 270° (U-phase current i u (where the absolute value is maximum when it is negative), and 330° (W phase current i w It is preferable to set it to either (where is positive and has the largest absolute value).

[0054] On the other hand, if you want to limit the amount of heat generated during warm-up as much as possible, the target stopping rotation angle θ st The total three-phase current i within each section I to VI tot The rotation angle θ at which this value is smallest (hereinafter referred to as "second stopping rotation angle θ") st2 It is preferable to set it to (also called ). This allows the d-axis current i in the d-axis current adjustment process to d This allows for warm-up while minimizing the amount of heat generated per unit area and taking into account the heat resistance of each component.

[0055] More specifically, the second stopping rotation angle θst2 θ = 60° (W phase current i w (0), 120° (V-phase current i) v (0), 180° (U-phase current i) u (0), 240° (W phase current i) w (0), 300° (V-phase current i) v (is 0), and 360° (U-phase current i u It is preferable to set it to one of the following (0).

[0056] Figure 6 shows the rotation angle θ and d-axis current i during d-axis current adjustment processing. d This figure shows the relationship between the temperature and the amount of heat generated. In Figure 6, the parameter that suggests the amount of heat generated (vertical axis) is the difference (ΔT) between the temperature of the cooling water outlet of the motor 32 and the temperature of the cooling water inlet of the inverter 34 in the cooling circuit C. Hereafter, 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 stops is the first stop rotation angle θ st1 By performing d-axis current adjustment processing, the same d-axis current i d The maximum heat generation ΔT per unit area is achieved. On the other hand, the rotation angle θ when the motor is stopped is the second stop rotation angle θ st2 By performing d-axis current adjustment processing, the same d-axis current i d The minimum heat generation rate ΔT per unit area is achieved.

[0058] Also, the target stopping rotation angle θ st The first stopping rotation angle θ that results in the maximum heat generation ΔT. st1 and the second stopping rotation angle θ that results in the minimum heat generation ΔT st2 By setting the rotation angle θ to a value other than the specified value, the same d-axis current i can be applied as needed. d The amount of heat generated per unit area ΔT can be made variable.

[0059] The configuration of the battery warming method of this embodiment described above, and its effects, will now be explained.

[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 warming method is provided for warming up the battery 14 when the motor 32 stops due to the electric vehicle coming to a stop.

[0061] In this battery warming method, the rotor position (rotation angle θ) when stopping the motor 32 is set to a predetermined target stopping position (target stopping rotation angle θ). st The rotor position adjustment process (S510) is executed to adjust the rotation angle θ to the target stop rotation angle θ. st While maintained in this state, the d-axis current i of motor 32 d The d-axis current adjustment process (S520) is executed by operating the d-axis to warm up the battery 14.

[0062] This allows the d-axis current i to be adjusted by controlling the rotation angle θ when the motor stops due to the vehicle coming to a stop. d When warming up the battery 14 by operating this device, the amount of heat generated by the electric motor unit 12, ΔT, can be appropriately adjusted.

[0063] More specifically, in this embodiment, the target stopping rotation angle θ st The total three-phase current i that flows to the motor 32 when the d-axis current adjustment process is executed is... tot The rotation angle θ is defined as the angle at which the desired value is obtained. Note that the total three-phase current i tot The phase current i u ,i v ,i w The sum of the absolute values ​​(|i u |+|i v |+|i w It is determined as |).

[0064] This allows us to determine the total three-phase current i, which suggests the amount of heat generated ΔT by the motor unit 12 during warm-up. tot Refer to the target stopping rotation angle θ. st This allows for the determination of the rotation angle θ at motor stop, which is necessary to achieve the desired heat generation ΔT during battery warm-up.

[0065] In particular, the target stopping rotation angle θ st The total three-phase current i tot The first stopping position (first stopping rotation angle θ) is determined as the rotation angle θ when it takes its maximum value. st1 ) includes.

[0066] This results in the same d-axis current i during warm-up. d This maximizes the heat generation ΔT of the electric motor unit 12, thereby improving the warm-up efficiency of the battery 14.

[0067] Furthermore, in the battery warming method of this embodiment, charging schedule information I indicates the scheduled charging of the battery 14 by a predetermined external charging device. sc Obtain the obtained charging schedule information I sc Based on this, the system estimates the state in which the electric vehicle is ready to stop at the external charging facility. When the electric vehicle reaches the ready to stop state, the system executes rotor position adjustment processing and d-axis current adjustment processing. In particular, in the rotor position adjustment processing, the rotation angle θ of the motor 32 is adjusted to the target stop rotation angle θ when the electric vehicle stops. st Operate the inverter 34 so that it becomes as follows.

[0068] As a result, the d-axis current i of the motor 32 d While appropriately detecting a stopping scene for charging in which battery warm-up should be performed by operating the motor 32, the rotation angle θ when the motor 32 actually stops in that scene is set as the target stopping rotation angle θ st A specific control logic for adjusting it will be implemented.

[0069] Instead of the control logic used to estimate the stopping preparation state described above, after the electric vehicle has actually stopped (motor 32 has stopped), the rotation angle θ is set to the target stopping rotation angle θ. st You could also employ a control logic that adjusts (moves) it.

[0070] More specifically, charging schedule information I indicates the scheduled charging of the battery 14 by a predetermined external charging facility. sc Obtain the obtained charging schedule information I scBased on this, the system estimates that the electric vehicle is stopped at an external charging station. Once the electric vehicle is stopped, the system performs rotor position adjustment and d-axis current adjustment. In particular, during the rotor position adjustment process, the rotation angle θ is set to the target stop rotation angle θ. st Operate the inverter 34 so that it becomes as follows.

[0071] In this case, the stationary state is, for example, the current location of the electric vehicle is the charging schedule information I sc The position of the external charging equipment included in the system coincides with the state in which the vehicle speed or motor rotation speed is 0, and this can be estimated. Alternatively, the stationary state may be estimated by detecting the timing when the charging plug at the external charging equipment is connected to the electric vehicle. Furthermore, the rotation angle θ in the stationary state can be set to the target stationary rotation angle θ. st As a specific method for adjusting, the rotation angle θ is the target stopping rotation angle θ st If they match, the rotation angle θ is maintained; if there is a difference, the rotation angle θ becomes the target stopping rotation angle θ. st Control can be applied to operate the inverter 34 to approach this target. Furthermore, at this time, it is determined which of the sections I to VI shown in Figure 5 the rotation angle θ in the stationary state belongs to, and the target stopping rotation angle θ is determined. st A configuration may be adopted in which the value is set to a value within the interval to which the rotation angle θ belongs. For example, if the rotation angle θ in the stationary state belongs to the U-phase current high interval II, the target stopping rotation angle θ st A configuration can be adopted in which the angle is defined 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 warming method.

[0073] This motor controller 52 controls the rotor position (rotation angle θ) when stopping the motor 32 to a predetermined target stop position (target stop rotation angle θ). st A rotor position adjustment processing unit (S510) adjusts the rotation angle θ to the target stop rotation angle θ. st While maintained in this state, the d-axis current i of motor 32 dIt includes a d-axis current adjustment processing unit (S520) that operates to warm up the battery 14, and

[0074] [Second Embodiment] The second embodiment will be described below. Elements similar to those in the previous embodiment will be denoted by the same reference numerals, and their descriptions 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 considering the heat resistance limits of the motor 32 and inverter 34.

[0075] Figure 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 uses the motor temperature T as a temperature parameter indicating the temperature of the electric motor unit 12. M and inverter temperature T IN Obtain (S511). In particular, motor temperature T M This is obtained, for example, as the detected value of a winding temperature sensor 46, which is implemented by a thermistor or the like that detects the temperature of the windings of the motor 32. Also, the inverter temperature T IN This is obtained, for example, as the detected value of an element temperature sensor 48, which is implemented by a thermistor or the like that detects the temperature of the heat-generating part (especially the switching element) of the inverter 34.

[0077] Note that the motor temperature T M The motor temperature T may be calculated from any parameter that can suggest 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 that water temperature may be used as the motor temperature T. M It may also be acquired as such. Furthermore, the inverter temperature T IN In this regard, instead of the detected value of the element temperature sensor 48, the temperature can be calculated from any parameter that can indicate the heat-generating part of the inverter 34. For example, the water temperature at the respective cooling water outlets of the motor 32 and inverter 34 in the cooling circuit C can be detected, and the temperature of the heat-generating part calculated from each water temperature can be used as the inverter temperature T. INYou can acquire it as such.

[0078] Next, the motor controller 52 controls 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 Compare them (S512, S513).

[0079] Note that the first motor temperature threshold T M1 The motor temperature T M It is set to an appropriate value to determine whether the temperature is sufficiently lower than the heat resistance limit of the winding. Also, the first inverter temperature threshold T IN1 The inverter temperature T IN However, it is set to an appropriate value to determine 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 The first motor temperature threshold T M1 The following and the inverter temperature T IN The first inverter temperature threshold T IN1 If the following conditions are met (both S512 and S513 are Yes), the motor controller 52 sets the rotation angle θ at the time of motor stopping to the first stop rotation angle θ st1 Adjust to (S516).

[0081] Then, the motor controller 52 sets the rotation angle θ to the first stop rotation angle θ st1 While maintaining this state, the d-axis current i d Set the d-axis current i to a predetermined basic target value (S521). d The basic target value can be set to a more favorable value as appropriate.

[0082] On the other hand, motor temperature T M The first motor temperature threshold T M1 If it exceeds or the inverter temperature T IN The first inverter temperature threshold T IN1If it exceeds (if S512 or S513 is No), the motor controller 52 further sets 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 Compare the magnitudes of each (S514, S515).

[0083] Note that the second motor temperature threshold T M2 The motor temperature T M The second motor temperature threshold T is set to an appropriate value to determine if the temperature is relatively close to the winding's heat resistance limit. M2 The first motor temperature threshold T M1 It is set to a value greater than [this value]. Also, the second inverter temperature threshold T IN2 The inverter temperature T IN The second inverter temperature threshold T is set to an appropriate value to determine whether the temperature is relatively close to the heat resistance limit of the heat-generating part (switching element, etc.). IN2 The first inverter temperature threshold T IN1 It will be set to a value greater than [this value].

[0084] Motor temperature T M The second motor temperature threshold T M2 The following and the inverter temperature T IN The second inverter temperature threshold T IN2 If the following conditions are met (both S514 and S515 are Yes), the motor controller 52 sets the rotation angle θ at the time of motor stopping to the second stopping rotation angle θ described above. st2 Adjust to (S517).

[0085] Then, the motor controller 52 sets the rotation angle θ to the second stop rotation angle θ st2 While maintaining this state, the d-axis current i d Set the above basic target value (S521).

[0086] On the other hand, motor temperature T M The second motor temperature threshold T M2 If it exceeds or the inverter temperature T INThe second inverter temperature threshold T IN2 If it exceeds (if S514 or S515 is No), the motor controller 52 will control the d-axis current i d Set it to zero (S522).

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

[0088] Furthermore, even after the d-axis current adjustment process is completed using the logic shown in Figure 2 above, the battery temperature T B Target battery temperature T Bt Until it reaches that point, the second warm-up mode, in which each actuator in the cooling circuit C is operated under the control of the vehicle controller 50, continues. In other words, 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 described above, the battery 14 can be warmed up within a range where the temperature of the components of the electric motor unit 12 (more specifically, the windings of the motor 32 and the heat-generating part of the inverter 34) does not reach the heat resistance limit. In particular, in this embodiment, the motor temperature T M and inverter temperature T IN A threshold is set individually for each target stopping rotation angle θ. st Since the adjustment and d-axis current adjustment process are completed, the battery 14 can be warmed up while more reliably protecting the motor 32 and inverter 34 from heat.

[0090] The configuration of the battery warming method of this embodiment described above, and its effects, will now be explained.

[0091] In the rotor position adjustment process (S511~S517) in this embodiment, a temperature parameter (T) that indicates the temperature of the electric motor unit 12 is used. M ,T IN ) obtain the temperature parameter (T M ,T IN ) and a predetermined first temperature threshold (T M1 ,TIN1 ) compare. Then, the temperature parameter (T M ,T IN ) is the first temperature threshold (T M1 ,T IN1 If it is less than or equal to the first stopping rotation angle θ when the motor stops, then the rotation angle θ when the motor stops will be the first stopping rotation angle θ st1 Adjust to that.

[0092] This allows the system to detect a situation where the temperature of the components of the motor unit 12 is within margin of the heat resistance limit, and to determine the rotation angle θ at the time the motor stops, based on the total three-phase current i tot It can be adjusted to the position where it is maximized. In other words, in scenes where there is a margin of safety against the heat resistance limit, the rotation angle θ at the time the motor stops can be adjusted to maximize the amount of heat ΔT obtained by the d-axis current adjustment process (S521) and improve the warm-up efficiency.

[0093] Also, the target stopping rotation angle θ st The total three-phase current i tot The second stopping position (second stopping rotation angle θ) is determined as the rotation angle θ when the value is minimized. st2 ) is included. And in the rotor position adjustment process, the temperature parameter (T M ,T IN ) is the first temperature threshold (T M1 ,T IN1 If it is greater than ), the rotation angle θ when the motor stops will be the second stopping rotation angle θ st2 Adjust to that.

[0094] This allows the system to detect situations where the temperature of the components of the motor unit 12 falls short of its heat resistance limit, and to adjust the rotation angle θ at the time of motor stop based on the total three-phase current i tot It can be adjusted to the position where it is minimized. In other words, in situations where there is little margin for the heat resistance limit, the rotation angle θ at the time of motor stop can be adjusted so as to minimize the amount of heat ΔT obtained by the d-axis current adjustment process (S521) and suppress the temperature rise of the motor unit 12 while allowing it to warm up.

[0095] In particular, in scenes where the temperature of the motor unit 12 is relatively low, such as in the initial stages of warming up, maximizing the heat generation ΔT obtained by the d-axis current adjustment process can promote faster warming. On the other hand, in scenes where warming up has progressed to a certain extent and the temperature of the motor unit 12 rises above a certain level, minimizing the heat generation ΔT obtained by the d-axis current adjustment process can suppress the rise in temperature while allowing warming up to proceed at a constant speed.

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

[0097] This allows the system to detect when the temperature of the components of the motor unit 12 approaches its heat resistance limit and terminate the d-axis current adjustment process. In other words, it can appropriately detect when the d-axis current adjustment process should be terminated from the standpoint of heat protection for the motor 32 and inverter 34, and terminate it appropriately.

[0098] [Third Embodiment] The third embodiment will be described below. Elements similar to those in the previous embodiment will be denoted by the same reference numerals, and their descriptions will be omitted. In particular, this embodiment provides a control logic different from the second embodiment for warming up the battery 14, while considering the heat resistance limits of the motor 32 and inverter 34.

[0099] Figure 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 at the time the motor stops to the first stop rotation angle θ st1 Adjust to (S5101).

[0101] Next, the motor controller 52 controls the motor temperature T M and inverter temperature T IN The motor controller 52 obtains 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 Compare them (S5202, S5203).

[0102] Motor temperature T M The first motor temperature threshold T M1 The following and the inverter temperature T IN The first inverter temperature threshold T IN1 If the following conditions are met (both S5202 and S5203 are Yes), the motor controller 52 will set the d-axis current i d Set this as the basic d-axis target value (S5206).

[0103] On the other hand, motor temperature T M The first motor temperature threshold T M1 If it exceeds or the inverter temperature T IN The first inverter temperature threshold T IN1 If it exceeds (if S5202 or S5203 is No), the motor controller 52 further sets 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 Compare the magnitudes of each (S5204, S5205).

[0104] Motor temperature T M The second motor temperature threshold TM2 The following and the inverter temperature T IN The second inverter temperature threshold T IN2 If the following conditions are met (both S5204 and S5205 are Yes), the motor controller 52 will set the d-axis current i d Set the corrected d-axis target value to a value smaller than the basic d-axis target value (S5207).

[0105] On the other hand, motor temperature T M The second motor temperature threshold T M2 If it exceeds or the inverter temperature T IN The second inverter temperature threshold T IN2 If it exceeds (if S5204 or S5205 is No), the motor controller 52 will set the d-axis current i d Set it to zero (S5208).

[0106] In the first warm-up mode of the above embodiment, in particular, when 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 changed 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 remains maintained d A process that reduces the value will be executed.

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

[0108] The configuration of the battery warming method of this embodiment described above, and its effects, will now be explained.

[0109] In the rotor position adjustment process (S5101) in this embodiment, the target stop rotation angle θ st The first stopping rotation angle θ st1 Adjust to this. Then, in the d-axis current adjustment process (S5201~S5108), a temperature parameter (T) that indicates the temperature of the motor unit 12 is used. M ,T IN ) obtain the temperature parameter (TM ,T IN ) and a predetermined first temperature threshold (T M1 ,T IN1 ) compare. Then, the temperature parameter (T M ,T IN ) is the first temperature threshold (T M1 ,T IN1 If the d-axis current i is less than or equal to ) d The current is adjusted to a predetermined basic target d-axis current. Meanwhile, the temperature parameter (T M ,T IN ) is the first temperature threshold (T M1 ,T IN1 If it is greater than ), the d-axis current i d Adjust the current to a corrected target d-axis current that is smaller than the basic target d-axis current.

[0110] As a result, in situations where the temperature of the components of the motor unit 12 has a margin of safety relative to the heat resistance limit, the rotation angle θ when the motor stops is controlled by the total three-phase current i tot The d-axis current i is adjusted to a position where it is maximized and the warm-up efficiency is increased, while in situations where there is little margin, the rotation angle θ is maintained while the d-axis current i is adjusted. d This can reduce the temperature rise of the motor unit 12 and suppress it.

[0111] Although embodiments of the present invention have been described above, the configurations described in the above embodiments and each of the modifications represent only a part 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, a configuration may be adopted in which the amount of heat generated in the motor unit 12 ΔT is controlled by adjusting the switching frequency in the inverter 34 in addition to adjusting the rotation angle θ when the motor is stopped. In particular, the higher the switching frequency, the higher the loss in the switching element and the greater the amount of heat generated ΔT. For this reason, by using the adjustment of the switching frequency in conjunction with the adjustment of the rotation angle θ when the motor is stopped as described above, the amount of heat obtained during warm-up can be controlled more precisely.

[0113] Furthermore, in each of the above embodiments, battery warm-up control performed when an electric vehicle stops at an external charging facility for charging has been described. On the other hand, the control logic described in each of the above embodiments can also be similarly applied in situations where warm-up of the battery 14 is required when an electric vehicle is stopped for purposes other than charging (such as when starting from a cold state).

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 up the battery when the electric motor stops due to the electric vehicle being stopped, A rotor position adjustment process is performed to adjust the rotor position to a predetermined target stop position when the electric motor is stopped. With the rotor position adjusted to the target stop position, a d-axis current adjustment process is performed to warm up the battery by manipulating the d-axis current of the electric motor. The target stopping position is defined as the rotor position where 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 each phase current. The target stopping position includes a first stopping position which is determined as the rotor position when the total three-phase current takes its maximum value. In the rotor position adjustment process, Obtain temperature parameters that indicate the temperature of the electric motor unit, The temperature parameter is compared with a predetermined first temperature threshold, If the temperature parameter is below the first temperature threshold, the rotor position is adjusted to the first stop position. Battery warm-up method.

2. 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 up the battery when the electric motor stops due to the electric vehicle being stopped, A rotor position adjustment process is performed to adjust the rotor position to a predetermined target stop position when the electric motor is stopped. With the rotor position adjusted to the target stop position, a d-axis current adjustment process is performed to warm up the battery by manipulating the d-axis current of the electric motor. The target stopping position is defined as the rotor position where 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 each phase current. The target stopping position includes a first stopping position which is determined as the rotor position when the total three-phase current takes its maximum value. In the rotor position adjustment process, The rotor position is adjusted to the first stop position, In the d-axis current adjustment process, Obtain temperature parameters that indicate the temperature of the electric motor unit, The temperature parameter is compared with a predetermined first temperature threshold, If the temperature parameter is below the first temperature threshold, the d-axis current is adjusted to a predetermined basic target d-axis current. If the temperature parameter is greater than the first temperature threshold, the d-axis current is adjusted to a corrected target d-axis current that is smaller than the basic target d-axis current. Battery warm-up method.

3. A battery warming method according to claim 1, The aforementioned target stopping position includes a second stopping position which is determined as the rotor position when the total three-phase current takes its minimum value. In the rotor position adjustment process, If the temperature parameter is greater than the first temperature threshold, the rotor position is adjusted to the second stop position. Battery warm-up method.

4. A battery warming method according to claim 1, The aforementioned target stopping position includes a second stopping position which is determined as the rotor position when any of the phase currents becomes zero. In the rotor position adjustment process, If the temperature parameter is greater than the first temperature threshold, the temperature parameter is compared with a second temperature threshold that is greater than the first temperature threshold. If the temperature parameter is below the second temperature threshold, the rotor position is adjusted to the second stop position. If the temperature parameter is greater than the second temperature threshold, the d-axis current adjustment process is terminated. Battery warm-up method.

5. A battery warming method according to claim 1, Charging schedule information is obtained that indicates the scheduled charging of the battery by a predetermined external charging device. Based on the charging schedule information, the state in which the electric vehicle is ready to stop at the external charging facility is estimated. When the electric vehicle reaches the state of preparation for stopping, the rotor position adjustment process and the d-axis current adjustment process are executed. In the rotor position adjustment process, The inverter is operated so that when the electric vehicle stops, the rotor position becomes the target stopping position. Battery warm-up method.

6. A battery warming method according to claim 1, Charging schedule information is obtained that indicates the scheduled charging of the battery by a predetermined external charging device. Based on the charging schedule information, the state in which the electric vehicle is stopped at the external charging facility is estimated. When the electric vehicle reaches the stationary state, The rotor position adjustment process and the d-axis current adjustment process are executed, In the rotor position adjustment process, The inverter is operated so that the rotor position becomes the target stop position. Battery warm-up method.

7. A battery warming method according to claim 1, The aforementioned target stopping position includes a second stopping position which is determined as the rotor position when the total three-phase current takes its minimum value. Battery warm-up method.

8. A battery warming method according to claim 1, The aforementioned target stopping position includes a second stopping position which is determined as the rotor position when any of the phase currents becomes zero. Battery warm-up method.

9. 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 device that warms up the battery when the electric motor stops due to the electric vehicle being stopped, A rotor position adjustment processing unit that adjusts the rotor position to a predetermined target stop position when the electric motor is stopped, The system includes a d-axis current adjustment processing unit that, when the rotor position is adjusted to the target stop position, performs a d-axis current adjustment process to warm up the battery by manipulating the d-axis current of the electric motor, The target stopping position is determined as the rotor position where the total three-phase current flowing through the motor takes a desired value when the d-axis current adjustment process is executed. The aforementioned total three-phase current is defined as the sum of the absolute values ​​of each phase current. The target stopping position includes a first stopping position which is determined as the rotor position when the total three-phase current takes its maximum value. The rotor position adjustment processing unit is: Obtain temperature parameters that indicate the temperature of the electric motor unit, The temperature parameter is compared with a predetermined first temperature threshold, If the temperature parameter is below the first temperature threshold, the rotor position is adjusted to the first stop position. Battery warm-up device.

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