Charging control method and charging control device

Abstract

Provided is a charging control method for an electric vehicle comprising: a motor; a battery; and an inverter that is connected to the motor and the battery and converts power between the motor and the battery. In this charging control method, when charging the battery using an external charger, warm-up control by d-axis energization for warming up the motor and the battery by supplying only the d-axis current to the motor by output power from the external charger and warm-up control by boosting control for warming up the motor and the battery by boosting the output voltage of the external charger by boosting control using the neutral point of the motor, supplying the output power of the external charger to the battery, and charging the battery are sequentially executed.

Description

Charging control method and charging control device

[0001] The present invention relates to a charge control method and a charge control device.

[0002] As the battery voltage of electric vehicles increases, there are cases where the voltage differs between the battery and a conventional external charging device. In such cases, when charging the battery, it is necessary to boost the output voltage of the charging device.

[0003] One method of boosting the output voltage of a charging device is to use a device such as a DC / DC converter, but this method may increase costs because a separate device is used, and there is also a risk that power consumption may worsen due to the need to operate the device.

[0004] On the other hand, there is known a charging method using a boost control, which uses a boost circuit using a motor and an inverter to boost the output voltage of a charging device and charge a battery. For example, the charging system described in US11230200B2 uses a charging method in which power supplied from an external source to the neutral point of a motor is boosted to a voltage that can be charged by the motor and inverter (boosting control using the neutral point).

[0005] However, when the battery is at a low temperature, the input current limit value at which the battery can be charged is small, and there is a risk that the battery cannot be charged efficiently.

[0006] In contrast, in a mechanism that uses a charging method using boost control, when the battery temperature is low, the boost efficiency is reduced, and the heat loss is transferred to the battery through the refrigerant passage, warming up the battery (hereinafter referred to as warm-up control using boost control).

[0007] However, in warm-up control using boost control, the boost efficiency is reduced to warm up the battery, which reduces the input current value to the motor (boost circuit), making it impossible to warm up the battery efficiently and potentially reducing the battery charging efficiency.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a charge control method and a charge control device that improve charging efficiency.

[0009] According to one aspect of the present invention, there is provided a charge control method for an electric vehicle including a motor, a battery, and an inverter connected to the motor and the battery for converting power between the motor and the battery. In this charge control method, when charging the battery using an external charger, warm-up control by d-axis current supply, which warms up the motor and the battery by supplying only a d-axis current to the motor using output power from the external charger, and warm-up control by boosting the output voltage from the external charger using boost control using the neutral point of the motor, and supplying the output power of the external charger to the battery to charge the battery, are sequentially performed.

[0010] FIG. 1 is a block diagram showing a schematic configuration of a rotating electric machine system in an electric vehicle to which a charge control method according to a first embodiment of the present invention is applied. FIG. 2 is a schematic circuit diagram of the rotating electric machine system. FIG. 3 is a schematic diagram of a cooling water channel of the rotating electric machine system. FIG. 4 is a flowchart illustrating the charge control method according to the first embodiment. FIG. 5 shows simulation results of motor temperature and battery temperature when the charge control method according to the first embodiment is executed. FIG. 6 shows simulation results of battery SOC when the charge control method according to the first embodiment is executed. FIG. 7 is a schematic circuit diagram of a rotating electric machine system in an electric vehicle to which a charge control method according to a second embodiment of the present invention is applied. FIG. 8 is a schematic diagram of a cooling water channel of the rotating electric machine system. FIG. 9 is a flowchart illustrating the charge control method according to the second embodiment. FIG. 10 shows simulation results of battery temperature when the charge control method according to the second embodiment is executed.

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] 1 is a block diagram showing a schematic configuration of a rotating electrical machine system 100. The rotating electrical machine system 100 is a vehicle drive system or a power generation system mounted on an electric vehicle to which a charge control method according to a first embodiment of the present invention is applied. The electric vehicle here is, for example, a hybrid vehicle, an electric vehicle, or the like.

[0013] 1 , the rotating electric machine system 100 includes a battery 10, an inverter 11, a rotating electric machine 12, and a controller 13. Of these, the inverter 11 and the rotating electric machine 12 are, for example, formed substantially integrally to constitute a so-called electric power train 14. Furthermore, the rotating electric machine system 100 may be connected to external equipment 15.

[0014] The battery 10 is a rechargeable DC power supply. The battery 10 supplies power to drive the rotating electric machine 12. That is, when driving the rotating electric machine 12, the battery 10 supplies a DC voltage V ｄｃ On the other hand, when the rotating electrical machine 12 generates electric power, the battery 10 is charged with that electric power.

[0015] The battery 10 is provided with a temperature sensor 16 that detects the temperature of the battery 10. The temperature T ｂａｔｔ is transmitted to the controller 13.

[0016] When the external equipment 15 is a quick charger (QC) or the like, the battery 10 is charged by the power supplied by the external equipment 15 via the electric power train 14. At this time, the input voltage V ＩＮ is different from the voltage of the battery 10, the voltage is boosted by the electric power train 14 as needed. That is, as the voltage of the battery of an electric vehicle increases, there is a case where the voltage differs between the battery and the external equipment (charger) 15 that has been used conventionally. However, by boosting the voltage using the electric power train 14 as needed, the output voltage V ＯＵＴ In this embodiment, the battery 10 is charged by the voltage (DC voltage V ｄｃ ) is, for example, 800 V. The quick charger (QC) connected as the external equipment 15 is a DC power supply, and its voltage (input voltage V ＩＮ ) is, for example, 400 V or 800 V. Therefore, when a 400 V quick charger (QC) is connected, the output voltage V ＯＵＴ is boosted to 800V.

[0017] When the external equipment 15 is a device or the like that consumes power, the battery 10 can discharge and supply power to the external equipment 15 via the electric power train 14. At this time, the input voltage to the external equipment 15 is stepped down by the electric power train 14 as necessary.

[0018] The inverter 11 is connected to the rotating electric machine 12 and the battery 10, and converts power between the rotating electric machine 12 and the battery 10. The inverter 11 converts DC power output by the battery 10 into AC power and supplies it to the rotating electric machine 12. This drives the rotating electric machine 12. On the other hand, when the rotating electric machine 12 generates power, the inverter 11 converts the AC power generated by the rotating electric machine 12 into DC power and supplies it to the battery 10.

[0019] When an external device 15 is connected to the rotating electric machine system 100, the inverter 11 can configure a step-up circuit or a step-down circuit together with the rotating electric machine 12. Specifically, all or some of the switching elements and free wheel diodes that configure the inverter 11 are used as elements of the step-up circuit or the step-down circuit. When the external device 15 is a quick charger (QC) or the like, the inverter 11 configures a step-up circuit together with the rotating electric machine 12, and the input voltage V ＩＮ The output voltage V ＯＵＴ is applied to the battery 10. When the external equipment 15 is a device that consumes power, the inverter 11 and the rotating electric machine 12 form a step-down circuit. This allows the external equipment 15 to be supplied with power from the battery 10 at the required voltage.

[0020] The rotating electric machine (motor) 12 is an electric motor or a generator. When the rotating electric machine 12 is an electric motor, the rotating electric machine system 100 is a drive system for an electric vehicle or the like that is equipped with the rotating electric machine 12. When the rotating electric machine 12 is a generator, the rotating electric machine system 100 is a power generation system for a hybrid vehicle or the like that is equipped with the rotating electric machine 12. In this embodiment, the rotating electric machine 12 is an electric motor (drive motor) for driving a vehicle.

[0021] The rotating electric machine 12 is an AC synchronous motor with embedded permanent magnets and has multiple phases. Therefore, the rotating electric machine 12 includes a rotor with embedded permanent magnets and a stator with multiple independent coils. The rotating electric machine 12 rotates due to the interaction between the magnetic flux generated by the permanent magnets (hereinafter referred to as permanent magnet magnetic flux) and the composite magnetic flux (hereinafter referred to as coil magnetic flux) generated by the multiple-phase coils. The multiple-phase coils are connected in a so-called star connection (Y connection) and have a neutral point. In this embodiment, the rotating electric machine 12 is a three-phase AC synchronous motor with embedded permanent magnets. Therefore, the rotating electric machine 12 includes a rotor with permanent magnets and a stator with three-phase (UVW) stator coils connected in a Y connection.

[0022] When the external equipment 15 is connected to the rotating electric machine system 100, the rotating electric machine 12 and the inverter form a voltage step-up circuit or a voltage step-down circuit. Specifically, the coils of each phase are used as inductors of the voltage step-up circuit or the voltage step-down circuit. In this case, one terminal of the external equipment 15 is connected to the neutral point of the rotating electric machine 12 (see FIG. 2).

[0023] The current flowing through the coils of each phase (UVW) (hereinafter referred to as the three-phase current I ＵＶＷ ), and neutral point voltage V ｎ , the rotation angle θ of the rotor (permanent magnet) ｒ can be detected at any timing. ＵＶＷ is detected by the current sensor 17. The neutral point voltage V ｎ is detected by the voltage sensor 18. The rotation angle θ ｒ is detected by the rotation sensor 19. The rotation angle θ ｒ In the UVW coordinate system, the position of the U-phase coil (U) is set as the reference angle (0°), and the detected three-phase current I ＵＶＷ , rotation angle θ ｒ and neutral point voltage V ｎ is transmitted to the controller 13.

[0024] The rotating electrical machine 12 is also provided with a temperature sensor 20 that detects the temperature of the rotating electrical machine 12. The temperature T ＭＴis transmitted to the controller 13.

[0025] The controller 13 is a control device that comprehensively controls the operation of each part of the rotating electrical machine system 100. The controller 13 is configured, for example, with one or more computers, and is programmed to cause each part to perform a predetermined operation. Each program may be provided in the form of being stored on a storage medium.

[0026] The controller 13 controls charging or discharging of the battery 10 by forming a voltage step-up or voltage step-down circuit with the inverter 11 and the rotating electric machine 12 .

[0027] Specifically, the controller 13 controls the overall operation of the rotating electric machine system 100 by inputting a PWM (pulse width modulation) signal to the inverter 11. For example, the controller 13 generates a PWM signal (referred to as a rotation control PWM signal) for controlling the rotation of the rotating electric machine 12, and controls the rotation speed and torque of the rotating electric machine 12 by inputting this to the inverter 11. The controller 13 generates the rotation control PWM signal based on, for example, the amount of accelerator operation or the like.

[0028] Furthermore, even when an external facility 15 is connected to the rotating electric machine system 100, the controller 13 inputs a PWM signal (a PWM signal for stepping up or stepping down) to the inverter 11 to use the electric power train 14 as a step-up or step-down circuit. As a result, the inverter 11 and the rotating electric machine 12 function as a step-up or step-down circuit. The controller 13 controls the three-phase current I ＵＶＷ , neutral point voltage V ｎ , and the rotation angle θ ｒ In this way, the controller 13 executes voltage step-up or voltage step-down control (voltage step-up or voltage step-down control using the neutral point).

[0029] In addition, in this embodiment, the controller 13 executes a charge control program that controls the power supply from the external equipment 15 to the battery 10 (charging the battery) by warming up the battery 10. That is, in this embodiment, the controller 13 constitutes a charge control device for controlling the power supply from the external equipment 15 to the battery 10 (charging the battery). Details of the charge control program will be described later.

[0030] The external equipment 15 is equipment, a device, or the like that is provided separately from the vehicle on which the rotating electric machine system 100 is mounted. The external equipment 15 supplies power to the rotating electric machine system 100 or is supplied with power from the rotating electric machine system 100. The external equipment 15 that supplies power to the rotating electric machine system 100 is, for example, a quick charger (QC) or other charger installed in a charging station. The external equipment 15 to which power is supplied from the rotating electric machine system 100 is, for example, outdoor equipment. In this embodiment, the external equipment 15 is an external charger, particularly a quick charger (QC). Therefore, the external equipment 15 charges the battery 10 when connected to the rotating electric machine system 100.

[0031] Fig. 2 is a schematic circuit diagram of the rotating electric machine system 100. As shown in Fig. 2, the battery 10 includes a battery main body 21 and relay switches 22a and 22b. The inverter 11 includes a smoothing capacitor 23 and a bridge circuit 24. The rotating electric machine 12 includes a U-phase coil (U), a V-phase coil (V), and a W-phase coil (W) as multi-phase coils.

[0032] The bridge circuit 24 has legs L corresponding to the UVW phases. Ｕ , L Ｖ , L Ｗ Each leg L Ｕ , L Ｖ , L Ｗ Each of the inverters 11 consists of two arms, an upper arm and a lower arm, and the coils U, V, and W of each phase are connected between them. Each arm is formed by a switching element and a freewheeling diode. The controller 13 inputs a PWM signal to the inverter 11 to control the timing of turning on (conducting) and off (disconnecting) the switching element of each arm.

[0033] Furthermore, the rotating electrical machine system 100 includes relay switches 25, 26, and 27, a capacitor 28, and an external input / output terminal 29. These are components for connecting the external equipment 15 and the rotating electrical machine system 100.

[0034] The relay switch 25 is provided between a first terminal of the external input / output terminal 29 and one end of the battery 10, and the relay switch 26 is provided between a second terminal of the external input / output terminal 29 and the other end of the battery 10. The relay switch 27 is provided on a line connecting the first terminal of the external input / output terminal 29 and the neutral point of the rotating electric machine 12. The capacitor 28 is provided between the relay switch 27 and the neutral point of the rotating electric machine 12 so as to connect the first and second terminals of the external input / output terminal 29 in parallel.

[0035] The relay switches 25, 26, and 27 are each independently turned on / off by the controller 13. When the voltages of the external equipment (external charger) 15 and the battery 10 are the same and no boosting is required, the relay switches 25 and 26 are turned on (conductive) and the relay switch 27 is turned off (disconnected). As a result, the external equipment 15 is directly connected to the battery 10 without going through the inverter 11 and the rotating electric machine 12. On the other hand, when the voltage of the external equipment 15 is lower than the voltage of the battery 10 and a boosting is required, the relay switch 25 is turned off and the relay switches 26 and 27 are turned on, and a PWM signal for boosting the voltage is sent from the controller 13 to the inverter 11. As a result, the external equipment 15 is connected to the battery 10 via the rotating electric machine 12 and the inverter 11, the output voltage of the external equipment 15 is boosted, and the output power of the external equipment 15 is charged to the battery 10 (boost control using the neutral point).

[0036] FIG. 3 is a schematic diagram of the cooling water passage 30 of the rotating electrical machine system 100.

[0037] As shown in Fig. 3 , the cooling water passage 30 passes through an electric power train (ePT) 14 including a rotating electric machine 12 and an inverter 11, and a battery (BT) 10. When the rotating electric machine 12, the inverter 11, and the battery 10 are at high temperatures, cooling water (Long Life Coolant (LLC)) is supplied from a circulation device (not shown) such as a pump and a compressor provided in the cooling water passage 30 upstream of the electric power train (ePT) 14 to cool the electric power train 14 and the battery 10. When power is supplied to the battery 10 from an external facility 15, the circulation device such as a pump and a compressor is driven by surplus power from the external facility 15 that cannot be fully absorbed by the battery 10. The operation of the circulation device is controlled by a controller 13.

[0038] 3 indicate the flow of heat when the battery 10 is warmed up. As will be described later, when the battery 10 is at a low temperature, the power train (ePT) 14 (rotating electric machine 12) is warmed up, and heat from the power train (ePT) 14 (rotating electric machine 12) is input to the coolant (LLC) in the cooling water passage 30 and transferred to the battery 10 via the cooling water passage 30. In this way, the battery 10 is warmed up.

[0039] As described above, when the voltage of the external equipment (external charger) 15 is lower than the voltage of the battery 10, the rotating electric machine system 100 boosts the output voltage of the external equipment 15 through boost control using the neutral point of the rotating electric machine 12, and supplies the output power to the battery 10 to charge the battery 10. In this way, boosting is performed without using a separate device such as a DC / DC converter, thereby reducing costs. Furthermore, since no power is required to operate a separate device, electricity efficiency is improved.

[0040] However, when the battery 10 is at a low temperature, the input current limit value that can charge the battery 10 is small, and there is a risk that the battery 10 cannot be efficiently charged. Therefore, it is necessary to warm up the battery 10.

[0041] A known method for warming up a battery is d-axis current warm-up control, in which only a d-axis current is supplied to a rotating electrical machine (motor). In d-axis current warm-up control, only a d-axis current is supplied to the motor to warm up the motor so that no motor torque is generated. This causes heat from the motor to enter the refrigerant in the refrigerant passage (the cooling water in the cooling water passage 30 in this embodiment), and the heat is transferred to the battery via the refrigerant passage, thereby warming up the battery.

[0042] On the other hand, in a mechanism that uses a charging method based on boost control using the neutral point, as in this embodiment, when the battery temperature is low, the inverter's switching operation reduces boost efficiency, increasing loss, and the heat equivalent to the loss is transferred to the battery via the refrigerant passage (cooling water passage), thereby warming up the battery through boost warm-up control. During boost warm-up control, the battery is simultaneously charged, which also warms up the battery.

[0043] However, in warm-up control using voltage boost control, the battery is warmed up at a reduced voltage boost efficiency, so the input current to the rotating electrical machine (motor) is lower than in warm-up control using d-axis current supply, and the motor temperature is less likely to rise than in warm-up control using d-axis current supply. As a result, the amount of heat input to the refrigerant passage is reduced, which may result in worse battery warm-up efficiency than in warm-up control using d-axis current supply, and may reduce battery charging efficiency.

[0044] In response to this, the inventors of the present invention discovered that sequentially executing warm-up control using d-axis current and warm-up control using voltage boost control can warm up the battery more efficiently than executing either warm-up control using d-axis current or warm-up control using voltage boost control alone. Therefore, in this embodiment, when charging the battery 10 using external equipment (external charger) 15, a charging control program is executed that sequentially executes warm-up control using d-axis current and warm-up control using voltage boost control. This improves the warm-up efficiency of the battery 10, shortens the time until the input current limit value of the battery 10 is relaxed, and increases the charging efficiency of the battery 10.

[0045] Hereinafter, the charge control method according to the first embodiment will be described with reference to FIGS.

[0046] 4 is a flowchart illustrating a charge control method according to the charge control program. The following control is all executed by the controller (charge control device) 13. The controller 13 controls the three-phase current I ＵＶＷ , neutral point voltage V ｎ , rotation angle θ ｒ , the temperature T of the rotating electrical machine 12 ＭＴ and the temperature T of the battery 10 ｂａｔｔ Also, the voltage of the external equipment (external charger) 15 is assumed to be lower than the voltage of the battery 10, and the external equipment 15 is assumed to be connected to the battery 10 via the rotating electric machine 12 and the inverter 11 (i.e., the relay switch 25 in FIG. 2 is OFF, and the relay switches 26 and 27 are ON).

[0047] When the external input / output terminal 29 of the rotating electrical machine system 100 is connected to a quick charger (QC) which is the external equipment 15, control by the charge control program is started.

[0048] In step S101, the controller 13 detects the temperature T ｂａｔｔ is a predetermined value, ｔｈ１ It is determined whether the temperature is lower than the first temperature threshold T ｔｈ１ is set to a temperature value (hereinafter referred to as a value that allows charging in high efficiency mode) at which the input current limit value of the battery 10 is large enough to prevent power supply from the quick charger (QC) to the battery 10 from being restricted even when charging is performed in high efficiency mode by the quick charger (QC), and can be determined by experiment or the like. ｂａｔｔ is the first temperature threshold T ｔｈ１ In the above cases, the controller 13 executes the process of step S102.

[0049] In step S102, the controller 13 executes charging in the high-efficiency mode. At this time, the controller 13 boosts the output voltage of the external equipment 15 to a voltage suitable for charging the battery 10 by boost control using the neutral point of the rotating electric machine 12, and supplies the output power of the external equipment 15 to the battery 10. As a result, the battery 10 is rapidly charged. When the battery 10 is rapidly charged, the controller 13 ends control by the charging control program.

[0050] On the other hand, in step S101, the temperature T ｂａｔｔ is the first temperature threshold T ｔｈ１ If it is lower, the controller 13 executes the process of step S103.

[0051] In step S103, the controller 13 calculates the temperature T ＭＴ is a predetermined value, ｔｈ２ It is determined whether the temperature is lower than the second temperature threshold T ｔｈ２ The second temperature threshold T is a value that improves the warm-up efficiency by performing the warm-up control by voltage boost control rather than by performing the warm-up control by energizing the d-axis. ｔｈ２ For example, even if warm-up control is performed by energizing the d-axis, the temperature T ＭＴ The temperature T of the rotating electrical machine 12 is set to a temperature at which the temperature T of the rotating electrical machine 12 increases only slowly, and can be determined by experiment or the like. ＭＴ is the second temperature threshold T ｔｈ２ If it is lower, the controller 13 executes the processes of steps S104 and S105.

[0052] In step S104, the controller 13 controls the relay switches 22a and 22b of the battery 10 to be turned off. In step S105, the controller 13 supplies only the d-axis current to the rotating electrical machine 12, and executes warm-up control by the d-axis current supply. As a result, the rotating electrical machine 12 is warmed up, and the temperature T ＭＴAs the temperature rises, heat from the rotating electric machine 12 is input to the cooling water in the cooling water passage 30 and transferred to the battery 10 via the cooling water passage 30, warming up the battery 10. Here, the d-axis current can be supplied to the rotating electric machine 12 from the inverter 11 side by turning on the relay switch 25, but in this embodiment, output power from the external equipment 15 is supplied from the rotating electric machine 12 side, and only the d-axis current is supplied to the rotating electric machine 12 by switching operation of the inverter 11. Therefore, in this embodiment, warm-up control is performed by supplying current to the d-axis with the relay switch 25 turned off and the relay switches 26 and 27 turned on.

[0053] In step S105, when the warm-up control by energizing the d-axis is executed, the controller 13 executes the process of step S103 again to calculate the temperature T ＭＴ is the second temperature threshold T ｔｈ２ It is determined whether the temperature T of the rotating electrical machine 12 is lower than ＭＴ is still below the second temperature threshold T ｔｈ２ If the temperature T ＭＴ is the second temperature threshold T ｔｈ２ Until this is reached, the warm-up control by energizing the d-axis (steps S104 and S105) continues.

[0054] On the other hand, in step S103, the temperature T ＭＴ is the second temperature threshold T ｔｈ２ In the above cases, in step S106, the controller 13 does not perform warm-up control by energizing the d-axis, or if warm-up control by energizing the d-axis is being performed, ends warm-up control by energizing the d-axis, and then executes the processing of steps S107 and S108.

[0055] In step S107, the controller 13 controls the relay switches 22a and 22b of the battery 10 to be on. In step S108, the controller 13 executes warm-up control by boost control using the neutral point of the rotating electric machine 12. Specifically, the controller 13 controls the switching operation of the inverter 11 to lower the current value of only one of the three phases of the rotating electric machine 12, thereby boosting the output voltage from the external equipment 15 with reduced boost efficiency. This increases losses during boost. Therefore, as the battery 10 is charged, heat equivalent to the loss is transferred to the cooling water in the cooling water passage 30 and transferred to the battery 10 via the cooling water passage 30, warming up the battery 10. In this way, by reducing boost efficiency and increasing losses, the rate of temperature rise of the battery 10 increases compared to when boosting without reducing efficiency. That is, the warm-up efficiency of the battery 10 is improved.

[0056] When warm-up control is performed using boost control, circulation devices such as a pump and compressor provided in the cooling water passage 30 upstream of the electric powertrain (ePT) 14 are driven by surplus power from the external equipment 15 that cannot be fully absorbed by the battery 10. This allows the circulation devices to be driven without consuming power from the batteries for the headlamps, meters, and other electrical equipment.

[0057] In this way, the warm-up control by the voltage boost control is performed by controlling the temperature T ＭＴ is the second temperature threshold T ｔｈ２ As described above, in the warm-up control by the voltage boost control, the voltage boost efficiency is reduced to warm up the battery 10, so that the input current value to the rotating electric machine (motor) 12 is reduced, and the temperature T ＭＴ Therefore, if warm-up control is performed by boost control when the rotating electrical machine 12 is at a low temperature, the warm-up efficiency of the battery 10 may be poor, and the charging efficiency of the battery 10 may be reduced. ＭＴ is the second temperature threshold T ｔｈ２ If the temperature T ＭＴTherefore, the warm-up efficiency of the battery 10 is improved, and the charging efficiency of the battery 10 is improved.

[0058] Note that the warm-up control using voltage boost control is performed with relay switch 25 off and relay switches 26 and 27 on because output power from external equipment 15 is supplied from the rotating electric machine 12. That is, the warm-up control using d-axis current supply and the warm-up control using voltage boost control are performed using the same circuit. Therefore, when switching from warm-up control using d-axis current supply to warm-up control using voltage boost control, no switching operation is required, thereby shortening the charging time of the battery 10. That is, if the warm-up control using d-axis current supply and the warm-up control using voltage boost control are performed using different circuits, it would be necessary to temporarily stop the power supply from the external charger, switch the circuit, and then send a command to the external charger to resume charging, which could delay the charging time. In contrast, in this embodiment, circuit switching is not required, thereby shortening the charging time of the battery 10.

[0059] In step S108, when the warm-up control by the voltage boost control is executed, the controller 13 executes the process of step S101 again and calculates the temperature T ｂａｔｔ is the first temperature threshold T ｔｈ１ It is determined whether the temperature T of the battery 10 is lower than ｂａｔｔ is still below the first temperature threshold T ｔｈ１ If the temperature T ＭＴ is already above the second temperature threshold T ｔｈ２ Therefore, the controller 13 actually determines the temperature T ｂａｔｔ is the first temperature threshold T ｔｈ１ The warm-up control by the voltage increase control (steps S107 and S108) continues until the voltage reaches or exceeds this value.

[0060] The temperature T ｂａｔｔ is the first temperature threshold T ｔｈ１When this occurs, the controller 13 executes the process of step S102, that is, executes charging of the battery 10 in the high efficiency mode. As a result, when the battery 10 is rapidly charged, the controller 13 ends control by the charge control program.

[0061] As described above, when the battery 10 is charged using the external equipment 15, if the temperature of the battery 10 and the rotating electrical machine 12 is low (the temperature T ｂａｔｔ is the first temperature threshold T ｔｈ１ is smaller than the temperature T ＭＴ is the second temperature threshold T ｔｈ２ ), warm-up control by d-axis current and warm-up control by voltage boost control are executed sequentially.

[0062] FIG. 5 shows the temperature T of the rotating electrical machine 12 (referred to as the motor temperature in FIG. 5 ) when the warm-up control by d-axis current application and the warm-up control by voltage boost control are sequentially performed on the rotating electrical machine system 100 (this embodiment) and when only the warm-up control by voltage boost control is performed (comparison example). ＭＴ and the temperature T of the battery 10 ｂａｔｔ 5 and 6 show the results of a simulation of the SOC of the battery 10 in this embodiment and the comparative example. ０ is the time when the supply of power from the external equipment 15 to the rotating electrical machine system 100 is started. １ is the temperature T of the rotating electrical machine 12 in this embodiment. ＭＴ is the second temperature threshold T ｔｈ２ This is the time when the warm-up control is switched from the d-axis current supply to the boost control.

[0063] As shown in FIG. 5, when power supply from the external equipment 15 is started, in this embodiment, warm-up control is performed by energizing the d-axis. Therefore, the temperature (motor temperature) T ＭＴ On the other hand, in the comparative example in which the warm-up control is performed by the voltage boost control, the temperature (motor temperature) T ＭＴ The temperature T of the battery 10 increases only slowly. ｂａｔｔ For time t ２The comparative example has a higher temperature T ｂａｔｔ is slightly higher, but at time t ２ Hereafter, in this embodiment, the temperature T ｂａｔｔ In other words, in this embodiment, the input current limit value of the battery 10 is relaxed (when the temperature T ｂａｔｔ is the first temperature threshold T ｔｈ１ The time required for the temperature to rise above 100°C is reduced.

[0064] As shown in FIG. 6, after the power supply from the external equipment 15 starts, at time t ３ The SOC of the battery 10 in the comparative example is slightly higher than that in the present embodiment up to time t ３ After this, the SOC of the battery 10 in this embodiment becomes significantly higher. ３ After this, the charging efficiency is clearly improved in this embodiment. １ In the comparative example, the warm-up control is performed by energizing the d-axis until time t , and the battery 10 is not charged. In contrast, in the comparative example, the battery 10 is charged from the start of power supply from the external equipment 15. ３ This is why the SOC of the battery 10 is higher in the comparative example (where only warm-up control by voltage boost control is performed).

[0065] As described above, when charging the battery 10 using the external equipment 15, by sequentially executing warm-up control using the d-axis current and warm-up control using the voltage boost control, the warm-up efficiency of the battery 10 is improved and the charging efficiency of the battery 10 is increased.

[0066] In addition, in the warm-up control by voltage boost control, it is preferable to warm up the battery 10 by reducing the voltage boost efficiency and using the heat equivalent to the loss as in the present embodiment, but this is not necessarily limited to this. For example, even if the voltage boost efficiency is not reduced, the output power of the external equipment 15 can be supplied to the battery 10 and the battery 10 can be charged to warm up the battery 10. However, in this case, the warm-up efficiency will be lower than when the battery 10 is warmed up by using the heat equivalent to the loss.

[0067] According to the charge control method of the first embodiment described above, the following effects can be obtained.

[0068] According to the charge control method of this embodiment, when charging the battery 10 using the external equipment (external charger) 15, warm-up control by d-axis current supply, which warms up the rotating electric machine (motor) 12 and the battery 10 by supplying only a d-axis current to the rotating electric machine (motor) 12 using output power from the external equipment (external charger) 15, and warm-up control by voltage boost control, which boosts the output voltage of the external equipment (external charger) 15 by voltage boost control using the neutral point of the rotating electric machine (motor) 12 and supplies the output power of the external equipment (external charger) 15 to the battery 10 to charge the battery 10, thereby warming up the rotating electric machine (motor) 12 and the battery 10. This improves the warm-up efficiency of the battery 10, shortens the time until the input current limit value of the battery 10 is relaxed, and increases the charging efficiency of the battery 10.

[0069] According to the charge control method of this embodiment, the warm-up control by voltage boost control increases losses by the switching operation of the inverter 11 during voltage boost to warm up the rotating electrical machine (motor) 12 and the battery 10. This improves the warm-up efficiency of the battery 10.

[0070] According to the charging control method of this embodiment, the warm-up control by d-axis current supply and the warm-up control by voltage boost control are performed using the same circuit, so that when switching from the warm-up control by d-axis current supply to the warm-up control by voltage boost control, no switching operation is required, and the charging time of the battery 10 can be shortened.

[0071] According to the charge control method of this embodiment, when the temperature of the rotating electrical machine (motor) 12 is T ＭＴ is the second temperature threshold T ｔｈ２ If the temperature T (predetermined value) of the rotating electric machine (motor) 12 is exceeded, the warm-up control by the d-axis current supply is terminated or not executed, and the warm-up control by the voltage boost control is executed. ＭＴ is the second temperature threshold T ｔｈ２ Since the charging is performed only when the predetermined value is reached, the charging efficiency of the battery 10 is improved.

[0072] In this embodiment, whether or not to perform warm-up control by voltage boost control is determined based on the temperature T ｂａｔｔ Whether or not to perform warm-up control by energizing the d-axis is determined based on the temperature T ＭＴ However, the present invention is not limited to this. The conditions for executing the warm-up control by the d-axis current supply and the warm-up control by the voltage boost control may be determined arbitrarily. For example, the temperature T ｂａｔｔ If the value of the d-axis current is lower than a predetermined value, the warm-up control by the d-axis current supply and the warm-up control by the voltage boost control may be executed in sequence.

[0073] In this embodiment, the timing for switching from the warm-up control by the d-axis current supply to the warm-up control by the voltage boost control is determined based on the temperature T ＭＴ However, the present invention is not limited to this. The condition for switching from the warm-up control by the d-axis current supply to the warm-up control by the voltage boost control may be determined arbitrarily. For example, the temperature T ｂａｔｔ When the value of the d-axis current becomes equal to or greater than a predetermined value, the warm-up control may be switched from the warm-up control by the d-axis current to the warm-up control by the voltage boost control. Also, for example, after the warm-up control by the d-axis current is started, the warm-up control may be switched from the warm-up control by the d-axis current to the warm-up control by the voltage boost control after a predetermined time has elapsed.

[0074] In addition, as in the present embodiment, it is preferable to use the same circuit for the warm-up control by d-axis current application and the warm-up control by voltage boost control, but this is not necessarily limited to this. For example, the warm-up control by d-axis current application may be performed by turning on the relay switch 25 in Fig. 2 and supplying a d-axis current from the inverter 11 to the rotating electrical machine 12.

[0075] 7 to 10, a charge control method according to a second embodiment will be described. Elements similar to those in the first embodiment are designated by the same reference numerals, and a description thereof will be omitted. This embodiment differs from the first embodiment in that only a d-axis current is supplied to the rotating electric machine 32, which serves as a sub-motor, and warm-up control is performed on the sub-motor.

[0076] FIG. 7 is a schematic circuit diagram of a rotating electrical machine system 200 in an electric vehicle to which a charge control method according to the second embodiment is applied.

[0077] As shown in Fig. 7 , in the rotating electric machine system 200, a sub-motor circuit 201 including an inverter 31 and a rotating electric machine 32 serving as a sub-motor is connected to a main motor circuit 101, which is the same circuit as the rotating electric machine system 100 in the first embodiment. Note that in this embodiment, the rotating electric machine 12 of the main motor circuit 101 is a rear motor, and the rotating electric machine 32 of the sub-motor circuit 201 is a front motor, but this is not limited thereto. For example, the rotating electric machine 12 may be a front motor, and the rotating electric machine 32 may be a rear motor. The inverter 11 and the rotating electric machine 12 are formed substantially integrally to constitute a rear electric powertrain (RrePT) 14, and the inverter 31 and the rotating electric machine 32 are formed substantially integrally to constitute a front electric powertrain (FrePT) 34 (see Fig. 8 ).

[0078] The sub motor circuit 201 has a circuit configuration basically similar to that of the main motor circuit 101, and includes relay switches 22c and 22d that turn on (connect) or off (disconnect) the battery 21, inverter 11, and rotating electric machine 32, as well as a smoothing capacitor 43 and a bridge circuit 44 that constitute the inverter 31. The sub motor circuit 201 also includes a relay switch 45 that is provided between a first terminal of the external input / output terminal 29 and one end of the battery 10, and a relay switch 46 that is provided between a second terminal of the external input / output terminal 29 and the other end of the battery 10. However, the sub motor circuit 201 does not have a line connecting a terminal of the external equipment 15 to the neutral point of the rotating electric machine 32. In other words, the sub motor circuit 201 does not perform voltage boost control using the neutral point. The operation of the inverter 31 and the on / off of each relay switch in the sub motor circuit 201 are controlled by the controller 13.

[0079] FIG. 8 is a schematic diagram of the cooling water passage 50 of the rotating electrical machine system 200.

[0080] As shown in FIG. 8 , the cooling water passage 50 passes through a rear electric power train (Rr ePT) 14 consisting of a rotating electric machine 12 and an inverter 11, a front electric power train (Fr ePT) 34 consisting of an inverter 31 and a rotating electric machine 32, and a battery (BT) 10.

[0081] When the external equipment (external charger) 15 is connected to the rotating electric machine system 200, the relay switch 45 is controlled to be on, and only a d-axis current is supplied to the rotating electric machine (sub-motor) 32 by the output power from the external equipment 15, the front electric powertrain (Fr ePT) 34 (rotating electric machine 32) is warmed up, and heat from the front electric powertrain (Fr ePT) 34 (rotating electric machine 32) is input to the coolant (LLC) in the cooling water passage 30. As a result, heat from the front electric powertrain (Fr ePT) 34 (rotating electric machine 32) is transferred to the battery 10 via the cooling water passage 50, and the battery 10 is warmed up (hereinafter referred to as warm-up control of the sub-motor).

[0082] The warm-up control of the sub motor can be executed in parallel with the warm-up control by d-axis current supply or voltage boost control in the main motor circuit 101 (hereinafter also referred to as warm-up control of the main motor). The arrows in FIG. 8 indicate the heat flow when the warm-up control of the sub motor and the warm-up control of the main motor are executed simultaneously. As shown in FIG. 8, when the warm-up control of the sub motor and the warm-up control of the main motor are executed in parallel, heat from the warmed-up rear electric powertrain (Rr ePT) 14 and the warmed-up front electric powertrain (Fr ePT) 34 is transferred to the battery 10 via the cooling water passages 50, respectively. This allows the battery 10 to be warmed up more quickly.

[0083] As described above, in the sub motor circuit 201, warm-up control by voltage boost control is not performed, and only warm-up control by d-axis current application is performed.

[0084] In addition, in the cooling water passage 50 near and upstream of the battery 10, a temperature T ＬＣＣ A temperature sensor (not shown) is provided to detect the coolant temperature TＬＣＣ is transmitted to the controller 13.

[0085] 9 is a flowchart illustrating a charge control method according to the second embodiment using a charge control program. The following control is all executed by the controller (charge control device) 13. The controller 13 controls the three-phase current I of the rotating electric machine 12 and the rotating electric machine 32. ＵＶＷ , rotation angle θ ｒ , the neutral point voltage V of the rotating electric machine 12 ｎ , the temperature T of the rotating electrical machine 12 ＭＴ , the temperature T of the cooling water flowing through the cooling water passage 50 ＬＬＣ and the temperature T of the battery 10 ｂａｔｔ Also, the voltage of the external equipment (external charger) 15 is assumed to be lower than the voltage of the battery 10, and the external equipment 15 is assumed to be connected to the battery 10 via the rotating electric machine 12 and the inverter 11 (i.e., in FIG. 7 , the relay switch 25 is OFF, and the relay switches 26 and 27 are ON).

[0086] When the external input / output terminal 29 of the rotating electrical machine system 200 is connected to a quick charger (QC) which is the external equipment 15, control by the charge control program is started.

[0087] In step S201, the controller 13 detects the temperature T ｂａｔｔ is a predetermined value, ｔｈ１ It is determined whether the temperature is lower than the first temperature threshold T ｔｈ１ is set to a value that allows charging in the high efficiency mode, for example, as in the first embodiment. ｂａｔｔ is the first temperature threshold T ｔｈ１ In the above cases, the controller 13 executes the process of step S202.

[0088] The process of step S202 is similar to the process of step S102 in the first embodiment, and therefore a description thereof will be omitted.

[0089] On the other hand, in step S201, the temperature T ｂａｔｔ is the first temperature threshold T ｔｈ１ If it is lower, the controller 13 executes the process of step S203.

[0090] In step S203, the controller 13 calculates the temperature T ＬＣＣ is the third temperature threshold T ｔｈ３ It is determined whether the cooling water temperature T ＬＣＣ is the third temperature threshold T ｔｈ３ In the above cases, the controller 13 executes the process of step S206. ＬＣＣ is the third temperature threshold T ｔｈ３ If it is lower, the controller 13 executes the processes of steps S204 and S205.

[0091] Cooling water temperature T ＬＣＣ is the third temperature threshold T ｔｈ３ If the temperature T is lower than the reference temperature T , in step S204, the controller 13 turns off the relay switches 22c and 22d that connect the battery main body 21 to the sub motor circuit 201, and turns on the relay switches 45 and 46 of the sub motor circuit 201. In step S205, the controller 13 controls the switching operation of the inverter 31 to supply only the d-axis current to the rotating electric machine (sub motor) 32, thereby executing warm-up control of the sub motor. As a result, the rotating electric machine 32 is warmed up, and the temperature T ＭＴ As the temperature rises, heat from the rotating electrical machine 32 is input to the cooling water in the cooling water passage 50 and transferred to the battery 10 via the cooling water passage 50, thereby warming up the battery 10.

[0092] In step S203, the temperature T ＬＣＣ is the third temperature threshold T ｔｈ３ In the above cases, or when the warm-up control of the sub motor is executed in steps S204 and S205, the controller 13 executes the process of step S206.

[0093] In step S206, the controller 13 calculates the temperature T ＭＴ is a predetermined value, ｔｈ２ It is determined whether the temperature is lower than the second temperature threshold T ｔｈ２As in the first embodiment, even if warm-up control is performed by energizing the d-axis, the temperature T ＭＴ The temperature is set so that the temperature rises only slowly.

[0094] Temperature T of the rotating electrical machine 12 ＭＴ is the second temperature threshold T ｔｈ２ If the temperature T of the rotating electrical machine 12 is lower than the predetermined temperature T , the controller 13 executes the processes of steps S207 and S208. The processes of steps S207 and S208 (warm-up control by energizing the d-axis) are similar to the processes of steps S104 and S105 in the first embodiment, and therefore a description thereof will be omitted. After executing the processes of steps S207 and S208 (warm-up control by energizing the d-axis), the controller 13 returns to the process of step S206 again, and determines the temperature T of the rotating electrical machine 12. ＭＴ is a predetermined value, ｔｈ２ Determine whether it is lower than

[0095] In step S206, the temperature T ＭＴ is the second temperature threshold T ｔｈ２ In the above cases, the controller 13 executes the processes of steps S209 to S211. The processes of steps S209 to S211 (terminating warm-up control by energizing the d-axis and executing warm-up control by voltage boost control) are the same as the processes of steps S106 to S108 in the first embodiment, respectively, and therefore will not be described further.

[0096] If the warm-up control of the sub motor is executed in steps S204 and S205, the warm-up control of the sub motor continues until the control by the charge control program ends. As described above, the warm-up control by d-axis current supply or the warm-up control by voltage boost control executed in the main motor circuit 101 and the warm-up control of the sub motor can be executed simultaneously in parallel.

[0097] As described above, in this embodiment, the temperature T of the cooling water flowing through the cooling water passage 50 ＬＣＣ is the third temperature threshold T ｔｈ３If the cooling water temperature T ＬＣＣ Therefore, the warm-up control of the sub-motor is executed only when it is necessary, thereby suppressing deterioration of the electric power consumption.

[0098] FIG. 10 shows the temperature T of the battery 10 in the following cases: when the warm-up control by d-axis current supply and the warm-up control by voltage boost control are sequentially performed in the main motor circuit 101 while the warm-up control by the sub-motor is being performed in the rotating electrical machine system 200 (second embodiment); when only the warm-up control by d-axis current supply and the warm-up control by voltage boost control are sequentially performed (first embodiment); and when only the warm-up control by voltage boost control is performed (comparison example). ｂａｔｔ The simulation results are shown in Fig. 10. ０ is the time when the supply of power from the external equipment 15 to the rotating electrical machine system 100 is started. １ is the temperature T of the rotating electrical machine 12 in the first and second embodiments. ＭＴ is the second temperature threshold T ｔｈ２ This is the time when the warm-up control is switched from the d-axis current supply to the boost control.

[0099] As shown in FIG. ２-１ The comparative example has a lower temperature T ｂａｔｔ is slightly higher, but at time t ２－１ Hereafter, in this embodiment, the temperature T ｂａｔｔ That is, in this embodiment (second embodiment), the input current limit value of the battery 10 is relaxed compared to the comparative example (the temperature T ｂａｔｔ is the first temperature threshold T ｔｈ１ The time required for the temperature to rise above 100°C is reduced.

[0100] In addition, after the time t1 when the warm-up control by the d-axis current supply is switched to the warm-up control by the voltage boost control, in this embodiment (second embodiment), the temperature T ｂａｔｔ In other words, in this embodiment (second embodiment), the input current limit value of the battery 10 is relaxed (the temperature T ｂａｔｔ is the first temperature threshold T ｔｈ１ The time required for the temperature to reach or exceed the predetermined temperature is further reduced compared to the first embodiment.

[0101] In this embodiment, the temperature T of the cooling water flowing through the cooling water passage 50 ＬＣＣ is the third temperature threshold T ｔｈ３ It is preferable to execute the warm-up control of the sub motor when the temperature T of the battery 10 is lower than the predetermined temperature, but this is not necessarily limited to this. The warm-up control of the sub motor is compatible with (can be executed simultaneously with) the warm-up control by the d-axis current supply in the main motor circuit 101 and the warm-up control by the voltage boost control, so that the warm-up control of the sub motor can be executed as needed. For example, when the temperature T of the battery 10 is lower than the predetermined temperature, the sub motor can be warmed up. ＭＴ In addition, for example, when warm-up control by energizing the d-axis of the main motor circuit 101 or warm-up control by boost control is performed, warm-up control of the sub-motor may also be performed at the same time.

[0102] According to the charge control method of the second embodiment described above, the following effects can be obtained.

[0103] According to the charge control method of this embodiment, warm-up control is performed on the sub-motor by supplying only a d-axis current to the rotating electric machine (sub-motor) 32 from the external equipment (external charger) 15. This further improves the warm-up efficiency of the battery 10.

[0104] According to the charging control method of this embodiment, the temperature T of the cooling water flowing through the cooling water passage 50 ＬＣＣ is the third temperature threshold T ｔｈ３ When the cooling water temperature T ＬＣＣSince the warm-up control of the sub-motor is executed based on the above, the warm-up control of the sub-motor can be executed only when it is necessary, thereby suppressing deterioration of the power consumption.

[0105] In the first embodiment, the rotating electrical machine system 100 includes the cooling water passage 30 through which the cooling water (LCC) flows, and in the second embodiment, the rotating electrical machine system 200 includes the cooling water passage 50 through which the cooling water (LCC) flows, but this is not necessarily limited to this. For example, the cooling water passages 30 and 50 may each be a refrigerant passage through which a refrigerant such as a refrigerant gas flows.

[0106] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0107] Furthermore, although the above-described embodiments have been described as separate embodiments, they may be combined as appropriate.

Claims

1. A charging control method for an electric vehicle equipped with a motor, a battery, and an inverter connected to the motor and the battery for converting power between the motor and the battery, the charging control method sequentially executing, when charging the battery using an external charger, warm-up control by d-axis current supplying only a d-axis current to the motor using output power from the external charger to warm up the motor and the battery, and warm-up control by boost control by boosting the output voltage of the external charger using boost control using the neutral point of the motor, and supplying the output power of the external charger to the battery to charge the battery, thereby warming up the motor and the battery.

2. A charge control method according to claim 1, wherein the warm-up control by the boost control warms up the motor and the battery by increasing losses through switching operation of the inverter during boosting.

3. A charging control method according to claim 1 or 2, wherein the warm-up control by the d-axis current supply and the warm-up control by the voltage boost control are performed using a same circuit.

4. A charging control method as claimed in claim 3, wherein, when the temperature of the motor is equal to or higher than a predetermined value, the warm-up control by the d-axis current supply is terminated or not performed, and the warm-up control by the voltage boost control is performed.

5. A charging control method as described in claim 4, wherein the electric vehicle further comprises a refrigerant passage through which a refrigerant flows to cool the motor, the inverter, and the battery, the battery is warmed up by heat input from the motor to the refrigerant being transferred to the battery, and a circulation device used to supply the refrigerant is driven by surplus power supplied from the external charger that cannot be absorbed by the battery.

6. A charging control method according to claim 3, wherein the electric vehicle further comprises a sub-motor, and further comprises executing a warm-up control of the sub-motor, supplying only a d-axis current from the external charger to the sub-motor.

7. A charging control method as claimed in claim 6, wherein the electric vehicle further comprises a refrigerant passage through which a refrigerant flows for cooling the motor, the inverter, the battery and the sub-motor, and when the temperature of the refrigerant is lower than a predetermined value, warm-up control is executed for the sub-motor.

8. A charge control method according to claim 6, further comprising the step of: executing warm-up control for the sub-motor when the temperature of the battery is equal to or lower than a predetermined value.

9. A charging control device that controls charging of an electric vehicle having a motor, a battery, and an inverter connected to the motor and the battery and converting power between the motor and the battery, wherein, when charging the battery using an external charger, the charging control device sequentially executes warm-up control by d-axis current supply to the motor by supplying only a d-axis current to the motor using output power from the external charger, and warm-up control by boost control that warms up the motor and the battery by boosting the output voltage of the external charger by boost control using the neutral point of the motor and supplying the output power of the external charger to the battery to charge the battery.

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