JP6187341B2 - In-vehicle charging system - Google Patents

Description

  The present invention relates to an in-vehicle charging system, and more particularly to an in-vehicle charging system capable of charging a main battery and an auxiliary battery from a power source outside the vehicle.

  An electric vehicle and a plug-in hybrid vehicle are configured to be able to charge a main battery for traveling from a power source outside the vehicle. Japanese Patent Laid-Open No. 2012-244875 (Patent Document 1) discloses a charger that supplies power from a power source outside a vehicle to a main battery, and receives power from the main battery and outputs power to the auxiliary load and the auxiliary battery. A vehicle having a DC / DC converter is disclosed.

JP 2012-244875 A JP 2012-257394 A

  As described in Japanese Patent Application Laid-Open No. 2012-244875, many hybrid vehicles are equipped with a DC / DC converter that charges an auxiliary battery with electric power of a main battery. When the capacity of the DC / DC converter is small, if the auxiliary machine load is used and the power consumption is large, the auxiliary battery cannot be sufficiently charged, and the discharge of the auxiliary battery may proceed. . Therefore, the capacity of the DC / DC converter is designed to have a sufficient margin.

  Hybrid vehicles and electric vehicles are required to improve energy efficiency, and various studies have been made for that purpose. The inventors of the present application, when charging the main battery from a power source external to the vehicle (hereinafter referred to as external charging), have a small DC capacity designed exclusively for external charging apart from the conventional DC / DC converter. / DC converters are being installed and used. This is because most of the load on the auxiliary machine is not used at the time of external charging, and therefore, if the auxiliary battery is charged with a DC / DC converter having an excessive capacity, the energy efficiency is deteriorated. In addition, although the technique described in the said Unexamined-Japanese-Patent No. 2012-244875 mounts two DC / DC converters in order to transfer electric power with two auxiliary machinery batteries, There is room for improvement as the charging has not been studied in detail.

  As a result of diligent study, the inventors of the present application, when charging an auxiliary battery with a DC / DC converter having a small capacity dedicated to external charging, has a remaining capacity (SOC: State Of Charge) of the auxiliary battery in a specific vehicle situation. It came to discover that it may decline. If the SOC of the auxiliary battery becomes equal to or less than a predetermined value during external charging, the charging control system of the vehicle that is supplied with the power from the auxiliary battery is turned off, and charging may not be continued. As a countermeasure, it is not a good idea to uniformly improve the capacity of the DC / DC converter dedicated for external charging in view of energy efficiency during external charging. Therefore, when a vehicle situation that may cause the SOC of the auxiliary battery to decrease during external charging is detected, it is desirable to increase the current supply capacity to the auxiliary battery before the SOC actually decreases. .

  The present invention has been made to solve such a problem, and an object of the present invention is to reduce the SOC of the auxiliary battery during external charging and to reliably charge the auxiliary battery. Is to realize.

  An in-vehicle charging system according to the present invention includes a power receiving unit that receives electric power from the outside of a vehicle, a main battery that supplies electric power to a traveling motor, an auxiliary battery that supplies electric power to an auxiliary load, and electric power from the main battery. DC / DC converter that converts the voltage of the power and supplies it to the auxiliary battery, a sub DC / DC converter that converts the power supplied from the power receiving unit to supply the auxiliary battery, a main DC / DC converter, and a sub And a control unit that controls the DC / DC converter. When the main battery is charged from the outside of the vehicle via the power receiving unit and the auxiliary battery is charged by the sub DC / DC converter, the control unit has a remaining capacity of the auxiliary battery. The main DC / DC converter is activated at the time when a vehicle situation that causes a decrease in the power is detected, and the auxiliary battery is charged.

  According to the above configuration, since the main DC / DC converter is activated when a vehicle situation that causes a decrease in the SOC of the auxiliary battery is detected, the current supply capability to the auxiliary battery is enhanced. Accordingly, it is possible to prevent a decrease in the remaining capacity of the auxiliary battery.

  Preferably, the main DC / DC converter has a higher current supply capability than the sub DC / DC converter. When the main battery is charged from the outside of the vehicle and the auxiliary battery is charged by the sub DC / DC converter, the control unit detects the above-described vehicle situation and detects the main DC / DC. The converter is activated to charge the auxiliary battery, and the sub DC / DC converter is stopped.

  The DC / DC converter may perform feedback processing to make the voltage constant. When a plurality of DC / DC converters are used in parallel for the same power source, problems such as feedback processing interference occur, and it is necessary to take countermeasures. If the main DC / DC converter has a higher current supply capability than the sub DC / DC converter, the sub DC / DC converter may be stopped in many cases, so that it is not necessary to take countermeasures for the problem and the control is easy. Become.

  Preferably, in the above vehicle situation, the occurrence of abnormality of the sub DC / DC converter, the discharge amount from the auxiliary battery exceeds the threshold value, and the voltage of the auxiliary battery is lower than the threshold value. And a connection request for a relay that connects an electric load that uses the voltage of the main battery to the main battery is input.

  In such a vehicle situation, the discharge from the auxiliary battery is more than the charge to the auxiliary battery, and the remaining capacity of the auxiliary battery is likely to be reduced. Therefore, even if the decrease in the remaining capacity of the auxiliary battery is not accurately calculated, it can be used as a trigger for starting the main DC / DC converter if any situation is detected.

  The connection request to the relay is given when an instruction to shift to the My Room mode that enables the use of an electric load that uses the voltage of the main battery while the vehicle is stopped is input.

  In the My Room mode, for example, the user operates the air conditioner in the vehicle interior, operates the audio device, or uses the electric device brought in by the user connected to the outlet in the vehicle. Therefore, in the my room mode, the discharge from the auxiliary battery is often greatly increased as compared with the normal external charging. However, if the capacity of the sub DC / DC converter is designed in accordance with the My Room mode, the capacity becomes excessive and the efficiency of charging the auxiliary battery at the time of external charging deteriorates. On the other hand, the frequency of setting the my room mode is not necessarily high. Therefore, if the capacity of the sub DC / DC converter is designed on the assumption that it is not designated as the My Room mode, and the main DC / DC converter is activated when designated as the My Room mode, It is possible to achieve both improvement in efficiency and prevention of auxiliary battery running out in the My Room mode.

  ADVANTAGE OF THE INVENTION According to this invention, it can prevent that SOC of an auxiliary machine battery falls at the time of external charging, and the charge control system of a vehicle will be in an OFF state, and charge will stop.

1 is an overall block diagram of an electric vehicle 100 equipped with a charging system according to an embodiment of the present invention. It is a block diagram for demonstrating the power supply path | route and command system between a charger and PCU, and ECU. It is a state transition diagram showing the transition of the operation mode at the time of external charging. 4 is a flowchart of control for executing control based on the state transition diagram of FIG. 3. It is a whole block diagram of the electric vehicle 100A carrying the charging system with which the charger was deform | transformed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is an overall block diagram of an electric vehicle 100 equipped with a charging system according to an embodiment of the present invention. Referring to FIG. 1, electrically powered vehicle 100 includes a power receiving unit 320, a charger 200, a main battery 10, an auxiliary battery 150, a PCU (Power Control Unit) 110, and an ECU (Electronic Control Unit) 160. High voltage load 180, low voltage load 170, and motor generator MG are included. The PCU 110 includes a main DC / DC converter 140, an inverter 120, and a control unit 130 for controlling them. Charger 200 includes a rectifier circuit 210, a high voltage DC / DC converter 220, a smoothing capacitor 250, a sub DC / DC converter 230, and a control unit 240.

  When the vehicle travels, the system main relay SMR is connected, the electric power of the main battery 10 is supplied to the high voltage load 180 and the PCU 110, and the motor (motor generator) MG that drives the drive wheels can be driven.

  The power receiving unit 320 is also referred to as an inlet, and receives power from outside the vehicle. During external charging, charging connector 310 is connected to power receiving unit 320 and power is supplied from external power supply 300.

  The main battery 10 is a power source that supplies power to the traveling motor MG. The auxiliary battery 150 is a power source that supplies electric power to the auxiliary load (low voltage load 170). Main DC / DC converter 140 converts the electric power from main battery 10 into a voltage and supplies it to auxiliary battery 150. The sub DC / DC converter 230 converts the power supplied from the power receiving unit 320 into a voltage and supplies it to the auxiliary battery 150. ECU 160 transmits commands for controlling main DC / DC converter 140 and sub DC / DC converter 230 to control unit 130 and control unit 240, respectively. Control unit 130 and control unit 240 control main DC / DC converter 140 and sub DC / DC converter 230, respectively, based on the received command.

  The power received by the power receiving unit 320 is transmitted to the charger 200. During external charging, charging relay SMRC is connected. The rectifier circuit 210 converts AC power received by the power receiving unit 320 into DC power. The high voltage DC / DC converter 220 converts the voltage from the rectifier circuit 210 into a voltage suitable for charging the main battery 10 (for example, 200 V). The sub DC / DC converter 230 converts the voltage from the rectifier circuit 210 into a voltage suitable for charging the auxiliary battery 150 (for example, 14V).

  During external charging, ECU 160 transmits a control signal to control unit 240 of charger 200 to control charging. ECU 160 receives outputs from current sensor 182 and voltage sensor 184 and monitors the current and voltage of auxiliary battery 150. When discharge occurs from auxiliary battery 150 or when the voltage of auxiliary battery 150 falls below a threshold value, ECU 160 uses sub DC / DC converter 230 to charge auxiliary battery 150 and reduce the voltage. The power supply to the load 170 is performed.

  ECU 160 charges main battery 10 from outside the vehicle via power receiving unit 320 and charges auxiliary battery 150 by sub DC / DC converter 230. The main DC / DC converter 140 is activated when a vehicle situation that causes a decrease in the remaining capacity of the battery 150 is detected, and the auxiliary battery 150 is charged.

  Preferably, the vehicle situation that causes a decrease in the remaining capacity of the auxiliary battery 150 includes occurrence of an abnormality in the sub DC / DC converter 230, an amount of discharge from the auxiliary battery 150 exceeding a threshold, A request for connection to the system main relay SMR for connecting the electric load (high voltage load 180) that uses the voltage of the main battery 10 to the main battery 10 is input, and the voltage of the auxiliary battery 150 has dropped below the threshold value. At least one of the above.

  According to the above configuration, since the main DC / DC converter 140 is activated at the time when a vehicle situation that reduces the remaining capacity of the auxiliary battery 150 is detected, the current supply capability to the auxiliary battery 150 is enhanced. Therefore, the remaining capacity (SOC) of auxiliary battery 150 can be prevented from decreasing.

  In the vehicle conditions listed above as examples, the discharge from the auxiliary battery 150 is more than the charge to the auxiliary battery 150, and the remaining capacity of the auxiliary battery 150 is likely to decrease. Therefore, even if the remaining capacity of auxiliary battery 150 is not actually calculated accurately, if any situation is detected, this can be used as a trigger for starting main DC / DC converter 140.

  More preferably, system main relay SMR is configured to connect main battery 10 to high-voltage load 180 in the vehicle interior in addition to traveling motor MG. The connection request to the system main relay SMR is given by the input of an instruction to shift to the My Room mode that enables the use of loads (low voltage load 170 and high voltage load 180) in the passenger compartment.

  In the My Room mode, for example, the user operates the air conditioner in the vehicle interior, operates the audio device, or uses the electric device brought in by the user connected to the outlet in the vehicle. In FIG. 1, an air conditioner, a 100V inverter for a vehicle outlet, and the like correspond to the high voltage load 180, and an audio device corresponds to the low voltage load 170. Therefore, in the my room mode, the discharge from auxiliary battery 150 is significantly increased as compared with normal external charging. However, if the capacity of the sub DC / DC converter 230 is designed in accordance with the My Room mode, the capacity becomes excessive and the efficiency of charging the auxiliary battery 150 during external charging becomes poor. On the other hand, the frequency of setting the my room mode is not necessarily high. Therefore, the capacity of the sub DC / DC converter 230 is designed in conformity with a vehicle situation with low power consumption that is not designated in the my room mode, and the main DC / DC converter 140 is activated when designated in the my room mode. As a result, it is possible to achieve both the efficiency improvement during external charging and the prevention of the auxiliary battery 150 from rising during the my room mode.

  Preferably, main DC / DC converter 140 has a higher current supply capability than sub DC / DC converter 230. ECU 160 causes the remaining capacity of auxiliary battery 150 to decrease when main battery 10 is charged from outside the vehicle and auxiliary battery 150 is charged by sub DC / DC converter 230. When the vehicle situation is detected, the main DC / DC converter 140 is activated to charge the auxiliary battery 150 and the sub DC / DC converter 230 is stopped.

  In general, DC / DC converters often perform feedback processing to keep the voltage constant. If a plurality of DC / DC converters are used in parallel to control the voltage of one power supply line, problems such as feedback processing interference occur, and countermeasures need to be taken. If the main DC / DC converter 140 has a higher current supply capability than the sub DC / DC converter 230, the sub DC / DC converter 230 may be stopped in many cases. Will also be easier.

  FIG. 2 is a block diagram for explaining a power supply path and a command system between the charger and the PCU and the ECU.

  First, the power supply path will be described. The auxiliary battery 150 can be charged from both the main DC / DC converter 140 inside the PCU 110 and the sub DC / DC converter 230 inside the charger 200. A fuse F1 and a fuse F2 are provided in these charging paths. When the fuse F2 is blown by overcurrent or the like, the sub DC / DC converter 230 cannot charge the auxiliary battery 150. ECU 160 also receives operation power supply voltage from auxiliary battery 150. Therefore, when charging to auxiliary battery 150 becomes impossible and the voltage drop of auxiliary battery 150 proceeds, ECU 160 stops operating and the vehicle cannot be charged. In this embodiment, in such a case, the main DC / DC converter 140 switches to charge the auxiliary battery.

  Next, the command system will be described. ECU 160 includes an auxiliary machine control unit 162 and a system control unit 164. The auxiliary machine control unit 162 receives the detection value of the current sensor 182 and calculates the discharge current from the auxiliary battery 150, and transmits the result of the discharge determination of the auxiliary battery 150 to the system control unit 164. The discharge determination of auxiliary battery 150 is determined to have occurred when the current flowing out of auxiliary battery 150 exceeds a predetermined threshold value. The system control unit 164 receives the detected value of the voltage of the auxiliary battery 150 from the voltage sensor 184, receives the result of the discharge determination of the auxiliary battery 150 from the auxiliary device control unit 162, and operates correctly with respect to the drive command from the charger 200. Receive status information to monitor what is happening. Based on these, the system control unit 164 performs auxiliary machine low voltage determination, DC / DC mode determination, and high voltage system connection determination.

  The DC / DC mode is set to either the main DC / DC mode or the sub DC / DC mode. The main DC / DC mode is a mode for charging the auxiliary battery 150 using the main DC / DC converter 140, and the sub DC / DC mode is the auxiliary battery 150 using the sub DC / DC converter 230. This mode is for charging.

  When the DC / DC mode is the main DC / DC mode, the system control unit 164 stops the sub DC / DC converter 230 and activates the main DC / DC converter 140. Send a drive command to. When the DC / DC mode is the main DC / DC mode, the auxiliary machine control unit 162 transmits a voltage command for the main DC / DC converter 140 to the control unit 130.

  On the other hand, when the DC / DC mode is the sub DC / DC mode, the system control unit 164 stops the main DC / DC converter 140 and operates the sub DC / DC converter 230. , 240, a drive command is transmitted. When the DC / DC mode is the sub DC / DC mode, the auxiliary machine control unit 162 transmits a voltage command for the sub DC / DC converter 230 to the control unit 240 of the charger 200.

  When the auxiliary machine battery 162 has a large discharge current of the auxiliary battery, a command to increase the voltage of the DC / DC converter is issued, and feedback control is performed.

  FIG. 3 is a state transition diagram showing the transition of the operation mode during external charging. FIG. 4 is a flowchart of control for executing control based on the state transition diagram of FIG.

  With reference to FIG. 3 and FIG. 4, the processing is started from the initial state ST0. First, in step S1, it is determined whether or not the vehicle operation mode is the charging mode. For example, when charging connector 310 is connected to power receiving unit 320 of the vehicle, ECU 160 determines that the charging mode is set. In the charging mode, charging relay SMRC is connected, and system main relay SMR is normally disconnected. When charging connector 310 is not connected to power receiving unit 320, ECU 160 determines that the non-charging mode is in effect. In the non-charge mode, for example, when the driver operates a vehicle start switch (not shown), the travel mode is set so that the vehicle can travel. In the traveling mode, charging relay SMRC is disconnected and system main relay SMR is connected.

  When it is determined that the operation mode of the vehicle is the charging mode, the process proceeds from step S1 to step S2, and ECU 160 sets the DC / DC mode to the sub DC / DC mode. As a result, in the state transition diagram of FIG. 3, a state transition occurs from the initial state ST0 to the state ST1. In the state ST1, the sub DC / DC converter 230 is driven and the main DC / DC converter 140 is stopped.

  In subsequent step S3, ECU 160 determines whether or not there is an abnormality in sub DC / DC converter 230. The sub DC / DC converter 230 has a self-diagnosis function, and when a failure occurs due to an overcurrent, an overvoltage or the like, a diagnosis result is transmitted to the ECU 160 via the control unit 240. ECU 160 determines whether or not there is an abnormality in sub DC / DC converter 230 based on the diagnosis result.

  In step S4, ECU 160 determines whether there is an auxiliary battery take-out determination based on the detection value of current sensor 182. For example, when the discharge from auxiliary battery 150 continues for a predetermined time, it is determined that the auxiliary battery has been taken out.

  In step S <b> 5, ECU 160 determines whether there is a low voltage determination for auxiliary battery 150 based on the detection value of voltage sensor 184. For example, when the voltage of auxiliary battery 150 is lower than a threshold value for a predetermined time, it is determined that there is a low voltage determination.

  In step S6, ECU 160 determines whether or not there is a connection request for a high-voltage load. For example, when the user selects the My Room mode during external charging, system main relay SMR is connected so that high-voltage load 180 such as an air conditioner or a 100V inverter for vehicle outlet can be used during charging. In such a case, it is determined that there is a request for connection of a high voltage system.

  If YES is determined in any one of steps S3 to S6, the process proceeds to step S8, and ECU 160 sets the DC / DC mode to the main DC / DC mode. As a result, a state transition occurs from the state ST1 to the state ST2 in the state transition diagram. In the state ST2, the system main relay SMR is connected, the sub DC / DC converter 230 is stopped, and the main DC / DC converter 140 is driven.

  On the other hand, if NO is determined in all of steps S3 to S6, the process proceeds to step S7, and ECU 160 sets the DC / DC mode to the sub DC / DC mode. As a result, no state transition occurs in the state transition diagram in the state ST1. In the state ST1, the system main relay SMR is disconnected, the main DC / DC converter 140 is stopped, and the sub DC / DC converter 230 is driven.

  The configuration may be modified as shown in FIG. FIG. 5 is an overall block diagram of an electric vehicle 100A equipped with a charging system with a modified charger.

  Referring to FIG. 5, vehicle 100A is different from charger 200 in FIG. 1 in the interior of charger 200A. In charger 200A, sub DC / DC converter 230 receives a DC voltage from a path connecting DC / DC converter for high voltage and charging relay SMRC, converts it, and supplies it to auxiliary battery 150. Other parts in FIG. 5 are the same as those in FIG. 1, and therefore description thereof will not be repeated.

  Sub DC / DC converter 230 </ b> A shown in FIG. 5 converts at least one of the power supplied from power receiving unit 320 and the power supplied from main battery 10 to supply to auxiliary battery 150. That is, sub DC / DC converter 230A charges auxiliary battery 150 using power supplied from outside the vehicle via power receiving unit 320 or power supplied from main battery 10 via charging relay SMRC. Can be performed.

  In this way, for example, when a power failure occurs during external charging or when control is performed such that external charging is temporarily stopped and resumed, auxiliary battery 150 is continuously charged. Is possible.

  1 and 5 show that it is preferable to stop the sub DC / DC converter 230 in the main DC / DC mode. However, the sub DC / DC converter 230 is operated in the main DC / DC mode. You can leave it.

  In the present embodiment, the example in which the charging connector 310 is connected to the power receiving unit 320 is illustrated in FIG. 1, but the power receiving unit 320 may be configured to be able to receive power from the outside without contact. .

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  10 main battery, 100, 100A electric vehicle, 110 PCU, 140, 220, 230, 230A DC / DC converter, 120 inverter, 130, 240 control unit, 150 auxiliary battery, 162 auxiliary device control unit, 164 system control unit, 170 Low voltage load, 180 High voltage load, 182 Current sensor, 184 Voltage sensor, 200, 200A charger, 210 Rectifier circuit, 250 Smoothing capacitor, 300 External power supply, 310 Charging connector, 320 Power receiving unit, F1, F2 fuse, SMR system main Relay, SMRC charging relay.

Claims (2)

A power receiving unit that receives power from outside the vehicle;
A main battery that supplies power to the motor for running;
An auxiliary battery that supplies power to the auxiliary load; and
A main DC / DC converter that converts power from the main battery into voltage and supplies it to the auxiliary battery;
A sub DC / DC converter that converts the power supplied from the power receiving unit into a voltage and supplies it to the auxiliary battery;
A control unit for controlling the main DC / DC converter and the sub DC / DC converter;
The control unit charging the main battery through the power receiving portion from the outside of the vehicle is performed, and when the charging to the auxiliary battery by the sub DC / DC converter is being performed, stop The main DC / DC converter is activated at the time when it is detected that an instruction to shift to the My Room mode enabling use of the electric load in the vehicle interior is input , and power is supplied to the auxiliary battery. An in-vehicle charging system that makes it possible . The main DC / DC converter has a higher current supply capability than the sub DC / DC converter,
When the main battery is charged from the outside of the vehicle and the auxiliary battery is charged by the sub DC / DC converter, the control unit issues an instruction to shift to the my room mode. when it is detected that a command has been input, the with Ru activates the main DC / DC converter stops the sub DC / DC converter, vehicle charging system according to claim 1.

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