Charging control device and vehicle

Abstract

Disclosed are a charging control device and a vehicle. An ECU controls external charging in which a battery of the vehicle is charged with electric power from a power station. A step-up converter steps up a voltage of electric power input to the step-up converter from the power station via a socket, and outputs the stepped-up voltage to the battery. The step-up converter is configured to charge the battery. A processing device of the ECU is configured to perform drive control of the step-up converter. The processing device is configured to set a ratio of the input voltage to the stepped-up voltage, i.e., a step-up ratio, in accordance with a temperature of the step-up converter.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a charging control device and a vehicle. BACKGROUND

[0002] Japanese Patent Application Publication No. 2009-194986 discloses a vehicle equipped with an electric power storage device, a control device, and a step-up converter. The electric power storage device is configured to be chargeable. The control device controls the step-up converter. The step-up converter steps up an input voltage thereof and outputs the stepped-up voltage. SUMMARY

[0003] A vehicle is sometimes configured to be capable of performing external charging that charges an electric power storage device of the vehicle using electric power supplied from an electric power device outside the vehicle via a power reception portion. A control device of such a vehicle is configured to control the external charging. In a case where a step-up device is provided between the power reception portion and the electric power storage device, the step-up device is configured to charge the electric power storage device by stepping up a voltage of electric power that is received by the power reception portion and outputting the stepped-up voltage (step-up voltage) to the electric power storage device. On the other hand, such a step-up device has a possibility of overheating due to heat generation at the time of operation.

[0004] The present disclosure protects a step-up device from overheating in a charging control device that controls external charging of a vehicle equipped with a step-up device that charges an electric power storage device by stepping up a voltage of electric power from an electric power device.

[0005] The present disclosure protects a step-up device from overheating in a vehicle equipped with a step-up device that charges an electric power storage device by stepping up a voltage of electric power from an electric power device.

[0006] A charging control device according to the present disclosure controls external charging that charges an electric power storage device of a vehicle using electric power from an electric power device outside the vehicle. The vehicle includes a power reception portion and a step-up device. The power reception portion is configured to receive electric power from the electric power device. The step-up device is provided between the power reception portion and the electric power storage device. The step-up device steps up a voltage of electric power that is input to the step-up device from the electric power device via the power reception portion, and outputs the stepped-up voltage to the electric power storage device. The step-up device is configured to charge the electric power storage device by supplying electric power of the stepped-up voltage, i.e., output electric power, to the electric power storage device. The charging control device includes an electronic control device that includes a storage device. The electronic control device is configured to perform drive control of the step-up device. The electronic control device is configured to set a ratio of the input voltage to the stepped-up voltage, i.e., a step-up ratio, in accordance with a temperature of the step-up device.

[0007] With the above-described configuration, the temperature of the step-up device is reflected to the step-up ratio. Therefore, the step-up ratio can be set in a manner that the temperature of the step-up device does not excessively rise. As a result, the step-up device can be protected from overheating.

[0008] The electronic control device can be configured to execute a loss reduction process of setting the step-up ratio in such a manner that the power loss in the step-up device is reduced in a case where the temperature of the step-up device is high, as compared to a case where the temperature of the step-up device is low.

[0009] According to the above structure, in a case where the temperature of the step-up device is high, the amount of heat generated due to the power loss in the step-up device is reduced as compared to a case where the temperature of the step-up device is low. Thus, it is possible to suppress the temperature of the step-up device from further rising.

[0010] In the loss reduction process, the electronic control device can be configured to set the step-up ratio in such a manner that the power loss is reduced in a case where the temperature of the step-up device is equal to or higher than a threshold temperature, as compared to a case where the temperature of the step-up device is lower than the threshold temperature.

[0011] According to the above structure, it is possible to set the step-up ratio regardless of the reduction of the power loss, until the temperature of the step-up device becomes the threshold temperature. Thus, it is possible to set the step-up ratio without limiting the step-up ratio in order to reduce the power loss.

[0012] The electronic control device can be configured to transmit an instruction value of a current supplied from the power supply device to the power receiving portion to the power supply device. Also, the electronic control device can reduce the instruction value in a case where the temperature of the step-up device is equal to or higher than a threshold temperature after the loss reduction process is executed.

[0013] According to the above structure, in a case where the temperature of the step-up device is not reduced to be lower than the threshold temperature after the loss reduction process, the current input to the step-up device from the power supply device via the power receiving portion is reduced. Thus, the power input to the step-up device is reduced. As a result, it is possible to further reduce the amount of heat generated due to the power loss in the step-up device. Therefore, it is possible to more effectively suppress the temperature rise of the step-up device.

[0014] In the loss reduction process, the electronic control device can be configured to set the step-up ratio in such a manner that the power loss is reduced as the temperature of the step-up device rises.

[0015] According to the above structure, the power loss is reduced as the temperature of the step-up device rises. Thus, the heat generation in the step-up device is suppressed as the temperature of the step-up device rises. As a result, it is possible to more effectively suppress the temperature rise of the step-up device.

[0016] The electronic control device can be configured to execute an output increase process of setting the step-up ratio in such a manner that the output power is increased in a case where the temperature of the step-up device is low, as compared to a case where the temperature of the step-up device is high.

[0017] The greater the output power of the voltage increasing device, the greater the power supplied to the power storage device. According to the above configuration, the power supplied to the power storage device is increased in the case where the temperature of the voltage increasing device is low, as compared with the case where the temperature of the voltage increasing device is high. Thus, the charging speed of the power storage device in external charging can be increased.

[0018] In the output increase processing, the electronic control device can be configured to maximize the output power within the range of the power that the voltage increasing device can output to the power storage device.

[0019] According to the above configuration, the power supplied to the power storage device is increased as much as possible. Thus, the charging speed of the power storage device in external charging can be increased as much as possible.

[0020] In the case where the user performs an operation to set the voltage increasing ratio in the case where the voltage increasing ratio is equal to the temperature of the voltage increasing device is high and the loss reduction processing is performed, the electronic control device can be configured not to perform the output increase processing but to set the voltage increasing ratio in accordance with the result of the user's operation.

[0021] According to the above configuration, even in the case where the temperature of the voltage increasing device is low, the voltage increasing ratio is set as in the case where the loss reduction processing is performed. Thus, even in the case where the temperature of the voltage increasing device is low, the power loss can be reduced. Further, the user's intention is reflected in the amount of power loss in the voltage increasing device. As a result, the convenience of the user can be increased.

[0022] The voltage increasing device can include a first element connected to the positive electrode of the power storage device. The electronic control device can be configured to increase the voltage increasing ratio when the temperature of the first element, which is the temperature of the voltage increasing device, exceeds a first reference temperature.

[0023] The greater the voltage increasing ratio, the less the current flowing through the first element. According to the above configuration, when the temperature of the first element exceeds the first reference temperature, the current flowing through the first element is reduced. Thus, the amount of heat generated due to the power loss in the first element is reduced. As a result, the first element of the voltage increasing device can be protected from overheating.

[0024] The voltage increasing device can include a second element connected to the negative electrode of the power storage device. The electronic control device can be configured to decrease the voltage increasing ratio when the temperature of the second element, which is the temperature of the voltage increasing device, exceeds a second reference temperature.

[0025] The greater the voltage increasing ratio, the less the current flowing through the second element. According to the above configuration, when the temperature of the second element exceeds the second reference temperature, the current flowing through the second element is reduced. Thus, the amount of heat generated due to the power loss in the second element is reduced. As a result, the second element of the voltage increasing device can be protected from overheating.

[0026] Other aspects of the present disclosure provide a vehicle equipped with the above-described charge control device.

[0027] According to aspects of the present disclosure, a voltage of power from a power device can be boosted to protect a voltage-boosting device that charges an electrical storage device from overheating. BRIEF DESCRIPTION OF DRAWINGS

[0028] Features, advantages, and technical and industrial significance of exemplary embodiments of the present application will be described below with reference to the accompanying drawings, wherein the same or similar components are designated by the same or similar reference numerals, and wherein:

[0029] Figure 1 is a diagram schematically illustrating a charging system in Embodiment 1.

[0030] Figure 2 is a diagram illustrating a structure of a vehicle in detail.

[0031] Figure 3 is a diagram illustrating a structure of a voltage-boosting converter in detail.

[0032] Figure 4 is a diagram for explaining one example of a method of setting a voltage-boosting ratio by an ECU according to Embodiment 1.

[0033] Figure 5 is a diagram for explaining another example of a method of setting a voltage-boosting ratio by an ECU.

[0034] Figure 6 is a diagram illustrating one example of a map stored in a storage device of an ECU.

[0035] Figure 7 is a flowchart illustrating one example of a process executed by an ECU according to Embodiment 1.

[0036] Figure 8 is a flowchart illustrating one example of a process executed by an ECU according to Modification 1 of Embodiment 1.

[0037] Figure 9 is a flowchart illustrating one example of a process executed by an ECU according to Modification 2 of Embodiment 1.

[0038] Figure 10 is a flowchart illustrating one example of a process executed by an ECU according to Modification 3 of Embodiment 1. DETAILED DESCRIPTION

[0039] Embodiments of the present disclosure will be described below in detail with reference to the accompanying drawings. In the drawings, the same or similar components are designated by the same or similar reference numerals, and description thereof will not be repeated.

[0040] [Embodiment 1]

[0041] Figure 1 is a diagram schematically showing a charging system 5 in Embodiment 1. Referring to Figure 1 , the charging system 5 is provided with a vehicle 100 and a power station 80. The vehicle 100 is configured to be able to perform external charging of a storage battery 10 (described later) using the power station 80 provided outside the vehicle 100.

[0042] In Embodiment 1, the vehicle 100 is a battery electric vehicle (BEV). The vehicle 100 may, for example, also be a hybrid vehicle (HV) or a fuel cell vehicle (FCV) or the like, which is an electric vehicle, further mounting an internal combustion engine (not shown).

[0043] The vehicle 100 is provided with the storage battery 10 and a socket 31. The storage battery 10 is a secondary battery such as a lithium ion battery or a nickel hydrogen battery. The storage battery 10 can also be replaced by an electric storage device such as an electric double layer capacitor. The storage battery 10 is a high-voltage storage battery (for example, 800 V) for accumulating electric power for running.

[0044] The socket 31 is configured to be powered from the power station 80. The socket 31 is configured to be connected to a connector 81 of the power station 80.

[0045] The power station 80 is a power device (charging device) that is able to perform rapid charging of the vehicle 100, for example, by supplying direct-current electric power having a voltage of 400 V to the vehicle 100.

[0046] The power station 80 is provided with a power cable 82, the connector 81, a power source 85, an HMI device 89, a storage 88, and a control device 87.

[0047] The power cable 82 includes a power line and a signal line (both not shown). When the connector 81 is connected to the socket 31, the power station 80 is connected to the vehicle 100 via the power line and the signal line described above. Thereby, for example, CAN (Controller Area Network) communication, PLC (Power Line Communication) communication, or both of these communications can be established between the power station 80 and the vehicle 100.

[0048] The power source 85 is configured to supply electric power to the vehicle 100 via the power cable 82 and the connector 81. Thereby, electric power from the power station 80 is supplied to the storage battery 10 via the socket 31 (external charging of the vehicle 100 is performed).

[0049] The HMI device 89 accepts an input of a user operation that indicates a manner of operation of the power station 80. For example, in order to instruct the start or stop of power supply from the power station 80 to the vehicle 100, a user operation is performed. A user operation can also be performed in order to set the voltage or current output from the power station 80 to the socket 31 of the vehicle 100.

[0050] The memory 88 stores programs and data used by the control device 87. The memory 88 also stores information indicating the range of voltage and current that the power station 80 can output to the socket 31 of the vehicle 100.

[0051] The control device 87 controls the power supply from the power station 80 to the vehicle 100 by executing the programs stored in the memory 88.

[0052] Figure 2 is a diagram that shows the structure of the vehicle 100 in detail. Referring to Figure 2 , the vehicle 100 has, in addition to the battery 10 and the socket 31, a power control unit (PCU) 1, a motor generator (MG) 2, a power transmission gear 3, and a drive wheel 4. The vehicle 100 also has the step-up converter 20, the monitoring unit 11, a system main relay (SMR) 40, a charging relay 30, an HMI device 90, and an electronic control unit (ECU) 70.

[0053] The PCU 1 is a power conversion device that converts power bidirectionally between the MG 2 and the battery 10.

[0054] The MG 2 is shown as an example of a rotating electric machine that is driven by the PCU 1, and is, for example, an interior permanent magnet synchronous motor. The output torque of the MG 2 is transmitted to the drive wheel 4 via the power transmission gear 3. Thus, the vehicle 100 travels.

[0055] The step-up converter 20 is provided between the inlet 31 and the storage battery 10. In this example, the step-up converter 20 is a non-isolated DC-DC converter. The step-up converter 20 receives input of electric power from the power station 80 via the inlet 31 and the positive line PLa and the negative line PNa. The step-up converter 20 steps up the voltage of the input electric power, i.e., the input voltage. The step-up converter 20 outputs the stepped-up voltage, i.e., the output voltage, to the positive line PL and the negative line PN. The step-up converter 20 is configured to charge the storage battery 10 by supplying the output electric power, i.e., the output voltage, to the storage battery 10. Depending on the specifications of the step-up converter 20, the range of the input voltage, which is also referred to as "inputtable voltage", that can be input to the step-up converter 20 is determined in advance. The configuration of the step-up converter 20 is described in detail later.

[0056] The monitoring unit 11 includes a voltage sensor, a current sensor, and a temperature sensor (none of which is shown). The voltage sensor detects the voltage between the terminals of the storage battery 10, i.e., the voltage VB. The current sensor detects the input / output current of the storage battery 10, i.e., the current IB. The temperature sensor detects the temperature TB of the storage battery 10. The sensors of the monitoring unit 11 output their detection results to the ECU 70.

[0057] The SMR 40 is electrically connected to the positive line PL and the negative line PN. The positive line PL is configured to connect the step-up converter 20 and the PCU 1 to the positive electrode of the storage battery 10. The negative line PN is configured to connect the step-up converter 20 and the PCU 1 to the negative electrode of the storage battery 10. In the case where the SMR 40 is closed (ON), i.e., in the on state, the storage battery 10 can be charged using the output electric power of the step-up voltage. On the other hand, in the case where the SMR 40 is open (OFF), i.e., in the off state, the electrical connection between the storage battery 10 and the step-up converter 20 is cut off, so the storage battery 10 is not charged.

[0058] The charging relay 30 is provided between the inlet 31 and the step-up converter 20 and is electrically connected to the positive line PLa and the negative line PNa. The charging relay 30 is configured to switch the electrical connection between the power station 80 and the step-up converter 20. In the case where the charging relay 30 is in the open state (OFF), the electrical connection between the power station 80 and the step-up converter 20 is cut off. On the other hand, in the case where the charging relay 30 is in the closed state (ON), the step-up converter 20 is electrically connected to the power station 80. Thus, the electric power from the power station 80 can be input to the step-up converter 20.

[0059] The HMI device 90 is a touch panel that can receive input of various operations from a user. The HMI device 90 can receive input of, for example, the setting of the operation mode (described later) of the step-up converter 20 in external charging.

[0060] The ECU 70 includes a storage device 74 and a processing device 72. The storage device 74 includes a ROM (Read Only Memory) and a RAM (Random Access Memory). The ROM stores programs and data used by the processing device 72. The RAM functions as a work memory. The storage device 74 stores, for example, information indicating the range of the inputtable voltage of the step-up converter 20. Examples of the data stored in the storage device 74 are described in detail later.

[0061] The processing device 72 performs various processes by executing the programs stored in the storage device 74. The processing device 72 includes a processor such as a CPU (Central Processing Unit). The processing device 72 performs, for example, drive control of the step-up converter 20.

[0062] The ECU 70 controls each machine of the vehicle 100, such as the PCU 1, the MG 2, the step-up converter 20, the charge relay 30, the SMR 40, and the HMI device 90, in accordance with the signals accepted from the monitoring unit 11, the signals from various sensors (not shown), and the programs stored in the storage device 74.

[0063] The ECU 70 calculates the SOC of the battery 10, for example, in accordance with the detected values of the voltage VB, the current IB, and the temperature TB from the monitoring unit 11. The ECU 70 is configured to communicate with the power station 80 via the power cable 82 (for example, by CAN communication).

[0064] The ECU 70 is configured to perform external charging control for controlling external charging of the vehicle 100. When the start of the external charging of the vehicle 100 is instructed using the HMI device 89 of the power station 80, a signal indicating the instruction is transmitted from the power station 80 to the vehicle 100 via the power cable 82. The ECU 70 outputs a request for the start of the power supply to the vehicle 100 to the power station 80 in response to the reception of the signal, and controls the charge relay 30 and the SMR 40 to the closed state. Thereby, the external charging of the vehicle 100 starts. After that, when the SOC of the battery 10 rises to a predetermined threshold value SOC, the ECU 70 stops the external charging of the vehicle 100 by outputting a request for the stop of the power supply to the power station 80. The threshold value SOC is, for example, the SOC at which the battery 10 is fully charged. The ECU 70 is also configured to transmit an instruction value CV of the current supplied from the power station 80 to the socket 31 to the power station 80 via, for example, CAN communication.

[0065] Figure 3 is a view that shows the structure of the step-up converter 20 in detail. Refer to Figure 3The voltage step-up converter 20 is a voltage step-up chopper circuit including a capacitor Cl and an input voltage sensor 24. The voltage step-up converter 20 further includes an inductor LI, an inductor current sensor 210, an upper arm circuit CUl, a lower arm circuit CL2, and a temperature sensor 26. The voltage step-up converter 20 further includes a capacitor CO and a voltage step-up voltage sensor 22.

[0066] The capacitor Cl is connected between the positive line PLa and the negative line NLa. The capacitor Cl smoothes an alternating component of a voltage variation between the positive line PLa and the negative line NLa.

[0067] The input voltage sensor 24 detects a voltage across the capacitor Cl (an input voltage VL of the voltage step-up converter 20) and outputs a detection value thereof to the ECU 70.

[0068] The inductor LI is connected to the positive line PLa and is electrically connected to an intermediate point (a connection node) of the switching element Ql and the switching element Q2.

[0069] The inductor current sensor 210 detects a current flowing in the inductor LI (also denoted as "inductor current IL") and outputs a detection value thereof to the ECU 70.

[0070] The upper arm circuit CUl is connected to the positive electrode of the storage battery 10 via the positive line PL. The upper arm circuit CUl includes the switching element Ql, a diode Dl, and a temperature sensor 261.

[0071] The lower arm circuit CL2 is connected to the negative electrode of the storage battery 10 via the negative line NL. The lower arm circuit CL2 includes the switching element Q2, a diode D2, and a temperature sensor 262.

[0072] The switching elements Ql, Q2 are connected in series between the positive line PL and the negative line PN. The switching elements Ql, Q2 are configured to substantially complementarily and alternately operate (turn-on / turn-off operation) in each switching period in accordance with signals SI, S2 output from the ECU 70, respectively. The switching elements Ql, Q2 are, for example, IGBTs (Insulated Gate Bipolar Transistors), MOS (Metal Oxide Semiconductor) transistors, or bipolar transistors. The diodes Dl, D2 are connected in anti-parallel with the switching elements Ql, Q2, respectively.

[0073] The temperature sensor 261 detects a temperature TC1 of the upper arm circuit CUl (the diode Dl in this example). The temperature sensor 262 detects a temperature TC2 of the lower arm circuit CL2 (the switching element Q2 in this example). Detection values of the temperature sensors 261, 262 are output to the ECU 70.

[0074] The temperature sensor 26 detects the temperature TC of the voltage step-up converter 20 and outputs the detected value to the ECU 70. The temperature sensor 26 can be configured to detect the temperature of the reactor LI or the temperature of the switching elements Ql, Q2.

[0075] The capacitor CO is connected between the positive line PL and the negative line NL. The capacitor CO smoothes the voltage between the positive line PL and the negative line NL. The voltage across the capacitor CO corresponds to the voltage step-up voltage VH of the voltage step-up converter 20. The voltage step-up sensor 22 detects the voltage step-up voltage VH and outputs the detected value to the ECU 70.

[0076] The voltage step-up action of the voltage step-up converter 20 is performed by supplying the electromagnetic energy accumulated in the reactor LI during the on period of the switching element Q2 to the positive line PL via the switching element Ql and the diode Dl. The voltage step-up ratio (power conversion ratio) in the voltage step-up action is represented by the ratio of the input voltage VL to the voltage step-up voltage VH (VH / VL). The voltage step-up ratio is determined according to the ratio of the on period of the switching elements Ql, Q2 to the switching period (duty ratio). The duty ratio of the switching elements Ql, Q2 is set by the ECU 70 using the signals S l, S2.

[0077] In order to achieve a high output of the storage battery 10, it is sometimes desired to increase the voltage of the storage battery 10 more than ever. In this case, it is desired to further increase the voltage step-up voltage VH in external charging of the vehicle 100. The voltage step-up converter 20 has a possibility of overheating when operating (for example, the higher the voltage step-up voltage VH is).

[0078] The ECU 70 according to Embodiment 1 has a structure for coping with the above-described problem. The ECU 70 (more specifically, the processing device 72) is configured to set the voltage step-up ratio, which is the ratio of the input voltage VL to the voltage step-up voltage VH, according to the temperature of the voltage step-up converter 20.

[0079] By making the above-described structure, the temperature of the voltage step-up converter 20 is reflected to the voltage step-up ratio. Therefore, the voltage step-up ratio can be set in such a manner that the temperature of the voltage step-up device does not excessively rise. As a result, the voltage step-up device can be protected from the influence of overheating.

[0080] In this example, the ECU 70 is configured to perform a loss reduction process of setting the above-described voltage step-up ratio in such a manner that the power loss in the voltage step-up converter 20 is reduced when the temperature TC of the voltage step-up converter 20 is high, as compared with when the temperature TC is low. The ECU 70 sets the voltage step-up ratio, for example, in accordance with the voltage output from the power station 80 to the socket 31 and the voltage VB of the storage battery 10.

[0081] According to such a configuration, in the case where the temperature TC is high, the amount of heat generation due to the power loss in the step-up converter 20 is reduced compared to the case where the temperature TC is low. Thus, it is possible to suppress the temperature TC from further rising. As a result, it is possible to protect the step-up converter 20 from being affected by overheating. Hereinafter, the control by the ECU 70 will be described in detail.

[0082] Figure 4 is a graph for explaining one example of the method of setting the step-up ratio by the ECU 70 according to Embodiment 1. Referring to Figure 4 , the step-up ratio BR of the step-up converter 20 is set in a range greater than 0 and up to the step-up ratio BR1 (0 < BR < BR1). The step-up ratio BR1 is the maximum step-up ratio decided in advance in accordance with the specifications of the step-up converter 20. In the case where the step-up ratio BR is the step-up ratio BR1, the duty ratio DU of the switching elements Q1, Q2 is the duty ratio DU1.

[0083] The line 400 indicates one example of the relationship between the power loss LS (the amount of heat generation per unit time) in the step-up converter 20 and the step-up ratio BR. The line 400 indicates that the power loss LS is minimized in the case where the step-up ratio BR is the step-up ratio BR2 (< BR1). The duty ratio DU in the case where the step-up ratio BR is the step-up ratio BR2 is the duty ratio DU2.

[0084] The line 450 indicates one example of the relationship between the step-up voltage VH and the step-up ratio BR of the step-up converter 20. The line 450 indicates that the step-up voltage VH rises as the step-up ratio BR rises. The higher the step-up voltage VH, the more the power supplied from the step-up converter 20 to the battery 10 (the output power OP from the step-up converter 20 to the battery 10) increases. Therefore, the charging speed of the battery 10 improves.

[0085] The ECU 70 executes the output increase processing of setting the step-up ratio BR in such a manner that the output power OP increases in the case where the temperature TC is low compared to the case where the temperature TC is high. Thus, it is possible to improve the charging speed of the battery 10 in external charging.

[0086] In this example, the ECU 70 maximizes the output power OP in the range of the power that the step-up converter 20 can output to the battery 10 (specifically, sets the step-up ratio BR to the step-up ratio BR1 as the maximum value) in the case where the temperature TC is less than the threshold temperature THT. Thus, the power supplied to the battery 10 increases as much as possible. As a result, it is possible to improve the charging speed of the battery 10 in external charging as much as possible. The threshold temperature THT is appropriately decided in advance through experiments as a temperature for protecting the step-up converter 20 from being affected by overheating, and is stored to the storage device 74 of the ECU 70.

[0087] In a case where the temperature TC is equal to or higher than the threshold temperature THT, the ECU 70 sets the boost ratio BR in a manner to reduce the power loss LS compared to a case where the temperature TC is lower than the threshold temperature THT (for example, changes the boost ratio BR from the boost ratio BR1 to the boost ratio BR2). The ECU 70 can set the boost ratio BR regardless of the reduction of the power loss LS during a period until the temperature TC becomes the threshold temperature THT when the boost ratio BR is thus set. The ECU 70 can set the boost ratio BR (for example, set to the boost ratio BR1) without limiting the boost ratio BR (for example, limit to the boost ratio BR2) for reducing the power loss LS during the period. Also, when the temperature TC reaches the threshold temperature THT, the ECU 70 sets the boost ratio BR in a manner to reduce the power loss LS (for example, sets to the boost ratio BR2).

[0088] Figure 5 is a graph for explaining another example of the method of setting the boost ratio by the ECU 70. Referring to Figure 5 , the line 500 indicates an example in which the boost ratio BR is set to the boost ratio BR1 in a case where the temperature TC is lower than the threshold temperature THT, and on the other hand, the boost ratio BR is set to the boost ratio BR2 in a case where the temperature TC is equal to or higher than the threshold temperature THT. This example is the same as the example explained using the line 400. Figure 4

[0089] The line 550 indicates an example in which the ECU 70 sets the boost ratio BR in a manner that the power loss LS is reduced more as the temperature TC rises. In this example, the more the temperature TC rises, the more the ECU 70 gradually reduces the boost ratio BR from the boost ratio BR1 to the boost ratio BR2 (direction of the white arrow of Figure 4 ). Thereby, the more the temperature TC rises, the more the heat generation due to the power loss in the boost converter 20 is suppressed. As a result, it is possible to more effectively suppress the rise of the temperature TC than the case of the line 500.

[0090] As explained below, it is also possible to determine the boost ratio BR in accordance with not only the temperature TC of the boost converter 20 but also the input voltage VL and the voltage VB of the battery 10.

[0091] Figure 6 is a graph showing one example of the map stored in the storage 74 of the ECU 70. Referring to Figure 6 , the map 600 is stored in the storage 74. The map 600 is a 4-dimensional map for determining the boost ratio BR in accordance with the temperature TC of the boost converter 20, the input voltage VL, and the voltage VB of the battery 10.

[0092] ​Specifically, with respect to the temperature TC, temperature regions divided at predetermined amplitudes (denoted by T1, T2,...) are set. With respect to the input voltage VL, voltage regions divided at predetermined amplitudes (denoted by VL1, VL2,...) are set. With respect to the voltage VB of the battery 10, voltage regions divided at predetermined amplitudes (denoted by VB1, VB2,...) are set.

[0093] For each combination of the divided temperature regions and voltage regions, a boost ratio BR is decided. In this example, as the boost ratio BR corresponding to the combination of the temperature region Tj, the voltage region VLm, and the voltage region VBn, a boost ratio BR(m, n, j) is shown. With respect to the boost ratio BR(m, n, j), it is appropriately decided in advance through experiments in a manner that becomes the largest in a range where the boosted voltage VH (= VL x BR(m, n, j)) is the voltage VB of the battery 10 or more and the temperature TC does not excessively (for example, above a threshold temperature THT) rise. Instead of the combination of the above-described temperature regions and voltage regions, the boost ratio BR can be decided for each combination of the values of the temperature TC, the input voltage VL, and the voltage VB.

[0094] Figure 7 is a flowchart showing one example of the process performed by the ECU 70 (more specifically, the processing device 72) related to Embodiment 1. The process of this flowchart is started at a time when the start of power supply from the power station 80 to the vehicle 100 is instructed using the HMI device 89 of the power station 80 in a state where the connector 81 of the power station 80 is connected to the socket 31.

[0095] Referring to Figure 7 , the ECU 70 acquires a range of the voltage that can be output from the power station 80 to the socket 31 (step S105). The ECU 70 acquires the above-described range, for example, by outputting a request to the power station 80 through CAN communication or PLC communication so that information indicating the above-described range is transmitted from the power station 80 to the vehicle 100.

[0096] Next, the ECU 70 determines whether the above-described voltage range of the power station 80 is suitable for the range of the input voltage of the boost converter 20 (step S115). Specifically, the ECU 70 determines whether at least a part of the voltage range of the power station 80 is included in the range of the input voltage of the boost converter 20.

[0097] In a case where the voltage range of the power station 80 is not suitable for the range of the input voltage of the boost converter 20 (NO in step S115), the ECU 70 cannot boost the input voltage VL in a manner that the boosted voltage VH becomes the voltage VB of the battery 10 or more (cannot perform the external charging control). In this case, the ECU 70 suspends the external charging control (step S120), and the process proceeds to the return.

[0098] On the other hand, in a case where the voltage range of the power station 80 is suitable for the input voltage range of the step-up converter 20 (YES in step S115), the ECU 70 is able to step up the input voltage VL in such a manner that the step-up voltage VH becomes equal to or higher than the voltage VB of the storage battery 10, while outputting a request to the power station 80 in order to make the voltage output from the power station 80 to the outlet 31 be within the input voltage range of the step-up converter 20. In this case, the ECU 70 executes the external charging control by controlling the charging relay 30 and the SMR 40 to be in the closed state (step S121), and the process proceeds to step S125.

[0099] Next, the ECU 70 determines whether the temperature TC is equal to or higher than the threshold temperature THT (step S125). In a case where the temperature TC is equal to or higher than the threshold temperature THT (YES in step S125), the ECU 70 executes the loss reduction process described above (step S130). The ECU 70, for example, sets the step-up ratio BR to a step-up ratio BR2 (BR2 Figure 4 ) that is lower than the step-up ratio BR1.

[0100] On the other hand, in a case where the temperature TC is lower than the threshold temperature THT (NO in step S125), the ECU 70 executes the output increase process described above (step S140). The ECU 70, for example, sets the step-up ratio BR to the step-up ratio BR1 in such a manner that the output power OP becomes maximum. The ECU 70 can also set the step-up ratio BR using the map 600 Figure 6 ) in step S130 or S140.

[0101] After the process in step S130 or S140, the process proceeds to return. Thereafter, the series of processes in Figure 7 are repeatedly performed at predetermined time intervals until the SOC of the storage battery 10 rises to the threshold value SOC.

[0102] [Modification 1 of Embodiment 1]

[0103] The ECU 70 can also set the step-up ratio BR to a candidate in which the power loss LS becomes minimum, in a case where there are a plurality of candidates of the step-up ratio BR in which the output power OP becomes maximum.

[0104] Figure 8 is a flowchart showing one example of the process executed by the ECU 70 according to this modification 1. The process of this flowchart is started at the time of instruction of the start of power supply from the power station 80 to the vehicle 100 in a state where the connector 81 of the power station 80 is connected to the outlet 31.

[0105] Referring to Figure 8This flowchart is the same as the flowchart of Implementation Method 1 ( Figure 7 The difference lies in the addition of steps S222 and S224. The processes of steps S205 to S221 and S225 to S240 are the same as those of steps S105 to S121 and S125 to S140 in the flowchart of Embodiment 1.

[0106] After the processing in step S221, ECU70 determines whether there are any candidates for the output power OP to become the largest boost ratio BR (step S222). If there are such candidates for boost ratio BR (yes in step S222), ECU70 sets the candidate with the smallest power loss LS among the candidates as the boost ratio BR (step S224). On the other hand, if there are no such candidates for boost ratio BR (no in step S222), ECU70 proceeds to step S225.

[0107] According to this variation 1, in the presence of multiple candidates as described above, the output power OP can be increased as much as possible, while the power loss LS can be reduced as much as possible.

[0108] [Modification 2 of Implementation Method 1]

[0109] ECU70 can also reduce the command value CV of the current supplied from power station 80 to socket 31 if the temperature TC is still above the threshold temperature THT after the above-mentioned loss reduction processing is performed (e.g., the temperature TC is above the upper limit temperature that is higher than the threshold temperature THT). Figure 1 ).

[0110] Based on this structure, if the temperature TC does not drop below the threshold temperature THT after the loss reduction process, the current (more specifically, the current input from the power station 80 to the boost converter 20 via the socket 31) will be... Figure 3 The reactor current (IL) is reduced. Consequently, the power input to the boost converter 20 is reduced. As a result, the heat generated by power loss LS in the boost converter 20 (e.g., the heat generated in the reactor L1) can be further reduced. Therefore, the rise in temperature TC can be suppressed more effectively.

[0111] Figure 9 This is a flowchart illustrating an example of the processing performed by the ECU 70 according to this variation 2. The processing in this flowchart begins when the connector 81 of the power station 80 is connected to the socket 31, indicating the start of power supply from the power station 80 to the vehicle 100.

[0112] Reference Figure 9 This flowchart is the same as the flowchart of Implementation Method 1 ( Figure 7The difference from the flowchart of FIG. 10 is that the processes of steps S335 to S337 are added. The processes of steps S305 to S321, S325, S330, and S340 are respectively the same as the processes of steps S105 to S121, S125, S130, and S140 of the flowchart of Embodiment 1.

[0113] After the loss reduction process (after step S330), the ECU 70 determines whether the temperature TC is equal to or higher than an allowable upper limit temperature ULT which is higher than the threshold temperature THT (step S335). The allowable upper limit temperature ULT is appropriately determined in advance through experiments as an upper limit temperature for protecting the step-up converter 20 from overheating, and is stored in the storage device 74 of the ECU 70.

[0114] In the case where the temperature TC is lower than the allowable upper limit temperature ULT (NO in step S335), the temperature TC is within a range between the threshold temperature THT and the allowable upper limit temperature ULT. In this case, the ECU 70 sets the command value CV of the current supplied from the power station 80 to the socket 31 to a first command value CV1 (step S336). In this example, the first command value CV1 is a value determined in advance as a default value. After the process of step S336, the process proceeds to the return.

[0115] On the other hand, in the case where the temperature TC is equal to or higher than the allowable upper limit temperature ULT (YES in step S335), the ECU 70 sets the command value CV to a second command value CV2 which is lower than the first command value CV1 (step S337). In other words, the ECU 70 reduces the command value CV from the first command value CV1 which is the default value to the second command value CV2. After the process of step S337, the process proceeds to the return.

[0116] In the above example, the ECU 70 determines whether to reduce the command value CV depending on whether the temperature TC is equal to or higher than the allowable upper limit temperature ULT after the loss reduction process. In contrast, the ECU 70 can determine whether to reduce the command value CV depending on whether the temperature TC is equal to or higher than the threshold temperature THT for a threshold time or more after the loss reduction process. The threshold time is appropriately determined in advance through experiments as a time for protecting the step-up converter 20 from overheating.

[0117] [Variation 3 of Embodiment 1]

[0118] In Embodiment 1, the ECU 70 executes the loss reduction process in the case where the temperature TC is equal to or higher than the threshold temperature THT, and executes the output increase process in the case where the temperature TC is lower than the threshold temperature THT. In contrast, the ECU 70 can set the step-up ratio BR with priority to the reduction of the power loss LS over the increase of the output power OP even in the case where the temperature TC is lower than the threshold temperature THT.

[0119] In this variation 3, the HMI device 90 of the vehicle 100 is used to perform user operation on the boost ratio BR when the temperature TC is low and when the temperature TC is high, and when loss reduction processing is performed. For example, the boost converter 20 is configured to switch between multiple operating modes, and the user sets the operating mode of the boost converter 20 to the loss reduction mode among the multiple operating modes.

[0120] The loss reduction mode sets the boost ratio BR to the boost ratio BR used when performing loss reduction processing (e.g., boost ratio BR2) even when the temperature TC is below the threshold temperature THT, instead of the boost ratio BR used when performing output increase processing (e.g., boost ratio BR2). Figure 4 The boost ratio (BR1) mode.

[0121] When the loss reduction mode is set in this way, power loss LS can be reduced even when the temperature TC is below the threshold temperature THT. Therefore, the user's intention is reflected in the amount of power loss LS in the boost converter 20. As a result, user convenience is improved.

[0122] Figure 10 This is a flowchart illustrating an example of the processing performed by the ECU 70 involved in this variation 3. The processing in this flowchart begins when the connector 81 of the power station 80 is connected to the socket 31, indicating the start of power supply from the power station 80 to the vehicle 100.

[0123] Reference Figure 10 This flowchart is the same as the flowchart of Implementation Method 1 ( Figure 7 The difference lies in the addition of step S427. The processing of steps S405 to S421, S425, S430, and S440 is the same as the processing of steps S105 to S121, S125, S130, and S140 in the flowchart of embodiment 1.

[0124] In this example, before the series of processes starting steps S405 to S440, the user presets the operating mode of the boost converter 20 to either a loss reduction mode or a normal mode. The normal mode is the mode in which the ECU 70 performs the above-mentioned output increase process when the temperature TC is above the threshold temperature THT.

[0125] If the temperature TC is less than the threshold temperature THT (No in step S425), the ECU 70 switches the operation mode of the boost converter 20 (step S427). If the operation mode is set to the loss reduction mode, the ECU 70 proceeds to step S430 and sets the boost ratio BR to, for example, the boost ratio BR2 (Figure 4 On the other hand, in a case where the above-described operation mode is set to the normal mode, the ECU 70 executes the output increase processing by setting the boost ratio BR to, for example, the boost ratio BR1 (step S440). Figure 4

[0126] [Modification 4 of Embodiment 1]

[0127] In the above-described explanation, the ECU 70 sets the boost ratio in accordance with the voltage output from the power station 80 to the socket 31 and the voltage VB of the storage battery 10. In contrast, the ECU 70 may, for example, set the boost ratio in accordance with only the voltage VB. In this case, the ECU 70 sets the boost ratio in accordance with the voltage VB using, for example, a map indicating the relationship between the voltage VB and the boost ratio.

[0128] [Embodiment 2]

[0129] In this Embodiment 2, the temperature TC1 of the diode D1 of the upper branch circuit CU1 or the temperature TC2 of the switching element Q2 of the lower branch circuit CL2 is used as the temperature of the boost converter 20. Also, the ECU 70 sets the boost ratio BR in accordance with the temperature TC1 or the temperature TC2. The diode D1 corresponds to one example of the "first element" of the present disclosure. The switching element Q2 corresponds to one example of the "second element" of the present disclosure. The structure of the vehicle 100 in Embodiment 2 is substantially the same as that of the vehicle 100 in Embodiment 1 (see FIG. 1) except for the point that the ECU 70 sets the boost ratio BR in accordance with the temperature TC1 or the temperature TC2. Hereinafter, the method of setting the boost ratio BR in Embodiment 2 will be described in detail. Figures 1-3

[0130] Referring again to FIG. 1, Figure 3 The ECU 70 sets the boost ratio BR in accordance with the temperature TC1 of the diode D1 of the upper branch circuit CU1 as the temperature of the boost converter 20. Specifically, the ECU 70 (the processing device 72) increases the boost ratio BR (the duty ratio DU) when the temperature TC1 exceeds a first reference temperature. The first reference temperature is appropriately determined in advance through experiments as a temperature at which the diode D1 is protected from the effects of overheating if the temperature TC1 is less than the first reference temperature.

[0131] The more the boost ratio BR is increased, the more the current flowing in the lower branch circuit CL2 (the current circulating in the circuit formed by the capacitor C1, the reactor L1, and the lower branch circuit CL2) is increased. As a result, the current flowing in the upper branch circuit CU1 (particularly, the diode D1) is reduced. When the boost ratio BR is increased as described above, the current flowing in the diode D1 of the upper branch circuit CU1 is reduced. Thus, the amount of heat generated due to the power loss in the diode D1 is reduced. As a result, the diode D1 can be protected from the effects of overheating.

[0132] ​​Likewise, the ECU 70 can also set the boost ratio BR in accordance with the temperature TC2 of the switching element Q2 of the lower branch circuit CL2 as the temperature of the boost converter 20. Specifically, the ECU 70 (the processing device 72) can also reduce the boost ratio BR (the duty ratio DU) when the temperature TC2 exceeds the second reference temperature. The second reference temperature is appropriately determined in advance through experiments as a temperature at which the switching element Q2 is protected from overheating if the temperature TC2 is less than the second reference temperature.

[0133] The more the boost ratio BR is reduced, the more the current flowing in the upper branch circuit CU1 (the current supplied to the storage battery 10 via the upper branch circuit CU1 and the positive line PL) increases. As a result, the current flowing in the lower branch circuit CL2 (particularly the switching element Q2) decreases. When the boost ratio BR is reduced as described above, the current flowing in the switching element Q2 of the lower branch circuit CL2 decreases. Thus, the amount of heat generated due to power loss in the switching element Q2 decreases. As a result, the switching element Q2 can be protected from overheating.

[0134] [Other Modification Examples]

[0135] Referring again to Figure 2 An AC-DC converter can also be provided between the socket 31 of the vehicle 100 and the boost converter 20. Thus, even in the case where the power station 80 is configured to supply alternating-current electric power to the vehicle 100, the alternating-current electric power from the power station 80 is input to the boost converter 20 after being converted to direct-current electric power by the above-described AC-DC converter. Then, the ECU 70 sets the boost ratio BR (for example, performs the loss reduction processing or the output increase processing) in accordance with the temperature TC of the boost converter 20 as in the case of Embodiment 1 and Modification Examples 1 to 4 thereof and Embodiment 2.

[0136] In the above-described embodiment, a boost chopper circuit (a step-up chopper circuit) is used as one example of the boost converter 20, but other types of boost devices such as a charge pump type boost device can also be used. Figure 3 ), but other types of boost devices such as a charge pump type boost device can also be used.

Claims

1. A charging control device for controlling external charging of a vehicle's energy storage device using power from an external electrical device. The vehicles include: The power receiving unit is configured to receive power from the power equipment; as well as A booster device is disposed between the power receiving unit and the energy storage device. The booster device is configured as follows: The voltage of the power input from the power equipment via the power receiving unit to the boost device is boosted, and the boosted voltage is output to the energy storage device. The energy storage device is charged by supplying the power from the boosted voltage, i.e., the output power, to the energy storage device. The charging control device is characterized in that... An electronic control device including a storage device, wherein, The electronic control device is configured to perform drive control of the boost device. The electronic control device is configured to set the ratio of the input voltage to the boost voltage, i.e., the boost ratio, based on the temperature of the boost device. The boost device includes a first element, which is a diode, connected to the positive terminal of the energy storage device. The electronic control device is configured to increase the boost ratio when the temperature of the first element, which is the temperature of the boost device, exceeds a first reference temperature. The electronic control device is configured to perform a loss reduction process that sets the boost ratio to reduce power loss in the boost unit when the boost unit is at a high temperature compared to when the boost unit is at a low temperature. In the loss reduction process, the electronic control device is configured to set the boost ratio in a manner that reduces power loss when the temperature of the boost device is above a threshold temperature compared to when the temperature of the boost device is below the threshold temperature. The electronic control device is configured to send an instruction value for the current supplied from the power equipment to the power receiving unit to the power equipment. After performing the loss reduction process, when the temperature of the boost device is above the threshold temperature but below the allowable upper limit temperature higher than the threshold temperature, the command value is set to the first command value; when the temperature of the boost device is above the allowable upper limit temperature, the command value is set to the second command value lower than the first command value.

2. The charging control device according to claim 1, characterized in that, In the loss reduction process, the electronic control device is configured to set the boost ratio in such a way that the power loss decreases as the temperature of the boost device increases.

3. The charging control device according to claim 1 or 2, characterized in that, The electronic control device is configured to perform an output increase process that sets the boost ratio to increase the output power when the temperature of the boost device is low compared to when the temperature of the boost device is high.

4. The charging control device according to claim 3, characterized in that, In the output amplification process, the electronic control device is configured to maximize the output power within the range of the power that the boost device can output to the energy storage device.

5. The charging control device according to claim 3, characterized in that, In the event of a user operation where the boost ratio is equal to the boost ratio when the temperature of the boost device is low and the loss reduction process is performed, the electronic control device is configured to set the boost ratio according to the result of the user operation without performing the output increase process.

6. The charging control device according to claim 1, characterized in that, The boost device includes a second element connected to the negative terminal of the energy storage device. The electronic control device is configured to reduce the boost ratio when the temperature of the second element, which is the temperature of the boost device, exceeds a second reference temperature.

7. A vehicle, characterized in that, It has a charging control device according to any one of claims 1 to 6.

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