Power supply equipment

Abstract

To provide a power supply device that prevent an auxiliary battery of an electric automobile mounting a wireless charging system from being over.SOLUTION: A power supply device comprises: a switch that is connected to a radio charging device charging a power received from an external power source to the main battery in a radio to a main battery accumulating a part or all of a driving energy source of a mobile body, and an auxiliary battery charged by the main battery in order to operate equipment mounted onto the mobile body, and stops a charging to the auxiliary battery from the main battery; a power reception part that receives a power to the radio charging device supplying a power from the auxiliary battery; a power switch part that switches a power reception to the power reception part; and a control part that controls the power switch part. The control part continues the power reception to the power reception part while keeping a close path of the power switch part during a predetermined period after the switch stops the charging to the auxiliary battery.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a power supply device that transfers electric power between a main battery mounted on an electric vehicle and an external device.

Background Art

[0002] Electric vehicles are beginning to become popular. A vehicle that is an electric vehicle uses a large-capacity lithium-ion battery as a main battery and drives a motor for running with the electric power stored in the main battery. The vehicle is equipped with an auxiliary battery such as a lead storage battery that serves as a power source for starting the main battery and as a power source for electrical components, etc., separately from the main battery. The auxiliary battery is charged, for example, by supplying the electric power stored in the main battery while the vehicle is running. The vehicle also includes electrical components that operate even when the vehicle is not running. If these electrical components frequently operate while the vehicle is not running, the amount of power stored in the auxiliary battery will naturally decrease, resulting in a battery run-down.

[0003] Patent Document 1 discloses a monitoring battery that controls the power supply to electrical components such as a drive recorder that operates by receiving power supply from an accessory power source of a vehicle. The monitoring battery in Patent Document 1 has an internal battery and charges the internal battery while there is power from the accessory power source, and operates the drive recorder with the power from the internal battery when the power supply from the accessory power source stops. In Patent Document 1, when the power supply from the accessory power source is absent for a long period and the amount of power stored in the internal battery decreases, the drive recorder cannot record.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Wireless charging systems have been put into practical use. Wireless charging systems charge the main battery of an electric vehicle without using a charging cable. In a wireless charging system, the power supply device that supplies power to the main battery cannot detect the trigger for starting charging preparation, which is the connection of a power cable or communication cable, via a wired connection. The power supply device in a wireless charging system receives power from one of the batteries in the vehicle and periodically detects whether wireless communication with the power supply source is possible. Therefore, if an auxiliary battery is used as the battery, and the detection operation of the charging control device continues while the vehicle is stopped and wireless charging is not taking place, there is a risk that the auxiliary battery will run out of power.

[0006] The present invention aims to provide a power supply device that prevents the auxiliary battery of an electric vehicle equipped with a wireless charging system from running out of power. [Means for solving the problem]

[0007] A power supply device according to one embodiment includes a main battery that stores part or all of the drive energy source of a mobile body, and an auxiliary battery that is charged by the main battery in order to operate equipment mounted on the mobile body. The device is connected to a wireless charging device that wirelessly charges the main battery with power received from an external power source, and includes a switch that stops charging from the main battery to the auxiliary battery, a power receiving unit that receives power supplied from the auxiliary battery to the wireless charging device, a power switching unit that opens and closes the power receiving unit, and a control unit that controls the power switching unit. The control unit maintains the closed state of the power switching unit for a predetermined period after the switch stops charging the auxiliary battery, and continues to receive power from the power receiving unit. [Effects of the Invention]

[0008] According to one embodiment of the power supply device, if wireless charging is not performed, the device can automatically stop transferring power from its own auxiliary battery, thereby preventing the auxiliary battery of a mobile device (e.g., an electric vehicle) equipped with a wireless charging system from running out of power. [Brief explanation of the drawing]

[0009] [Figure 1] This is a block diagram showing the connection configuration of the power supply device according to this embodiment. [Figure 2] This is a block diagram showing the configuration of a power supply device. [Figure 3] This is a block diagram showing the configuration of the control circuit of a power supply device. [Figure 4] This is a schematic circuit diagram of the input / output circuit. [Figure 5] This flowchart shows an example of a control processing procedure by a power supply device. [Figure 6] This flowchart shows an example of a control processing procedure by a power supply device. [Modes for carrying out the invention]

[0010] A specific example of the power supply device 1 of this disclosure will be described below with reference to the drawings.

[0011] Figure 1 is a block diagram showing the connection configuration of the power supply device 1 in this embodiment. The power supply device 1 is mounted on a vehicle V. The vehicle V is an electric vehicle that runs by driving a motor with electricity stored in a main battery 20 such as a lithium-ion battery. The vehicle V may also be a so-called hybrid electric vehicle equipped with both a motor for driving and an engine that generates power by burning fuel.

[0012] Vehicle V in this embodiment is an electric vehicle equipped with a function to charge the main battery contactlessly without using a charging cable, i.e., a wireless charging function. Vehicle V comprises a power supply device 1 for wireless charging, a main battery 20, a first onboard charger 21, and an auxiliary battery 22.

[0013] The power supply device 1 is connected to the first on-board charger 21 by a power line. The first on-board charger 21 is connected to the main battery 20 by a power line. The main battery 20 is connected to the auxiliary battery 22 by a power line.

[0014] The main battery 20 is a power source that supplies stored electricity to the drive motor (not shown) of the vehicle V, and uses that electricity to rotate the motor, i.e., the wheels of the vehicle V, thereby driving the vehicle V.

[0015] The first on-board charger 21 charges the main battery 20 using power output from the power supply device 1. The first on-board charger 21 is equipped with an AC / DC converter (not shown) that converts the alternating current power supplied from the power supply device 1 or an external AC power source into direct current power for the main battery 20, thereby charging the main battery 20.

[0016] The auxiliary battery 22 supplies the necessary power to each electrical component installed in the vehicle V. The auxiliary battery 22 is rechargeable by receiving power from the main battery 20. The auxiliary battery 22 supplies power to each electrical component when the switch on the power line connected to that component is ON. Therefore, the auxiliary battery 22 also supplies a predetermined voltage power (e.g., 12V) to the power supply device 1.

[0017] Furthermore, the configuration other than the power supply device 1 described above will operate similarly even if another charging unit that enables wired charging via a cable is installed in place of the power supply device 1.

[0018] FIG. 2 is a block diagram showing the configuration of the power supply device 1. The power supply device 1 includes a power receiving coil 11 and is a device that supplies power from an external power supply device (external power source) installed outside to the main battery 20 to achieve wireless charging. The power supply device 1 includes a power receiving coil 11, a rectifying and smoothing circuit 12, a capacitor 13 (EDLC: Electric Double-Layer Capacitor, or Supercapacitor), a DC / AC converter 14, and a control circuit 10.

[0019] The power receiving coil 11 is provided, for example, at the bottom of the vehicle body of the vehicle V such that the axial direction is along the vertical direction. In this case, the power receiving coil 11 can receive power in a state of being close to a power transmitting coil buried with the vertical direction as the axis on the ground or the floor surface. The power receiving coil 11 may be provided on the side portion of the vehicle body of the vehicle V such that the axial direction is along the horizontal direction. In this case, the power receiving coil 11 can receive power in a state of being close to a power transmitting coil provided with the horizontal direction as the axis in a standing power transmission device.

[0020] The rectifying and smoothing circuit 12 is a circuit that combines a rectifying circuit for rectifying an alternating current into a direct current and a smoothing circuit for smoothing the pulsating current included in the direct current. The rectifying and smoothing circuit 12 converts the power received by the power receiving coil 11 into direct current power and outputs it.

[0021] The capacitor 13 is a supercapacitor using an electric double layer. The capacitor 13 is connected to the output terminal of the rectifying and smoothing circuit 12. The capacitor 13 stores the power received by the power receiving coil 11 obtained through the rectifying and smoothing circuit 12.

[0022] The DC / AC converter 14 converts direct current power into alternating current power. The DC / AC converter 14 converts the direct current power output from the rectifying and smoothing circuit 12 or the capacitor 13 into alternating current power corresponding to the AC / DC converter of the first in-vehicle charger 21 of the vehicle V and outputs it.

[0023] The control circuit 10 controls the operation of the power supply device 1, specifically the ON / OFF state of the DC / AC converter 14. Turning the DC / AC converter 14 ON starts charging the main battery 20 and auxiliary battery 22 from the power supply device 1, and turning it OFF ends charging the main battery 20 and auxiliary battery 22. The control circuit 10 receives signals from the in-vehicle equipment. The control circuit 10 can determine the charge state of the main battery 20 (whether it is fully charged or not) by referring to the capacitor 13 of the power supply device 1. Specifically, the control circuit 10 can determine the presence or absence of charging current in the capacitor 13 by detecting it with a current sensor. The control circuit 10 may also refer to the charge state of the main battery 20 (whether it is fully charged or not) via the first in-vehicle charger 21. Furthermore, the control circuit 10 communicates wirelessly with the power transmission side control device that controls the power transmission coil and controls the start of power reception.

[0024] Figure 3 is a block diagram showing the configuration of the control circuit 10 of the power supply device 1. The control circuit 10 includes a processor 100 (control unit), a memory 101, a communication circuit 102, a power receiving unit 103, and an input / output circuit 104. The processor 100, memory 101, communication circuit 102, and power receiving unit 103 may be integrated on a single board to form a microcontroller, or they may be implemented as individual components.

[0025] The processor 100 is started by power supplied via the power receiving unit 103, reads and executes program 1P stored in memory 101 to perform the control processing described later. The processor 100 can input and output signals via the input / output circuit 104. The processor 100 may also be configured to receive data signals indicating parameters from the first onboard charger 21 and use them for control.

[0026] Memory 101 uses non-volatile memory. Program (program product) 1P is stored in memory 101. Program 1P is incorporated into the memory during the manufacture of the power supply device 1. Program 1P may also be stored in memory 101 by the processor 100 after being read from a recording medium readable by a computer (processor).

[0027] The communication circuit 102 enables wireless communication with a power transmission device having a power transmission coil. The communication circuit 102 communicates using, for example, Bluetooth®. The wireless communication standard used by the communication circuit 102 is not limited to Bluetooth.

[0028] The power receiving unit 103 receives a predetermined voltage power supply and distributes the predetermined voltage power to each component implemented in the control circuit 10, thereby operating them.

[0029] The input / output circuit 104 is a circuit for receiving signals from in-vehicle equipment and power supply from the auxiliary battery. The input / output circuit 104 includes a switch Q1 (power switch, see Figure 4) that switches whether or not to supply power from the auxiliary battery 22 to the power receiving unit 103. This switch Q1 can be controlled by a holding signal output from the processor 100. The input / output circuit 104 is connected to the in-vehicle equipment by signal lines and receives an IG signal indicating the ON / OFF status of the ignition switch (power switch), thereby controlling switch Q1. The input / output circuit 104 branches the IG signal and inputs it to the processor.

[0030] Figure 4 is a schematic circuit diagram of the input / output circuit 104. The input / output circuit 104 includes switches Q1, Q2, and Q3. Switch Q1 switches the connection / disconnection between the auxiliary battery 22 and the power receiving section 103 in the control circuit 10. Switch Q1 uses a P-channel FET. The source of switch Q1 is connected to the auxiliary battery 22, and the drain is connected to the power receiving section 103 of the control circuit 10. A transistor may also be used for switch Q1. Switch Q2 turns switch Q1 ON / OFF. A transistor may also be used for switch Q2. The collector of switch Q2 is connected to the auxiliary battery 22 via resistors R1 and R2. The contact between resistors R1 and R2 is connected to the gate of switch Q1. The output from the ignition switch (IG signal) is input to the base of switch Q2. The emitter of switch Q2 is grounded. The output from the ignition switch (IG signal) is also input to the processor 100. A FET may also be used for switch Q2. Switch Q3 also turns switch Q1 ON / OFF. Switch Q3 uses a transistor. The collector of switch Q3 is connected to the auxiliary battery 22 via resistors R1 and R3. The other end of resistor R3 is connected to the contact between resistors R1 and R2, which is connected to the gate of switch Q1. The base of switch Q3 receives a hold signal output from processor 100. The emitter of switch Q3 is grounded. Switch Q3 may use a FET or a photocoupler.

[0031] The resistance values ​​of resistors R1, R2, and R3 are selected to ensure that when switch Q2 or switch Q3 is ON, switch Q1 turns ON, resulting in appropriate gate and source potentials.

[0032] When the ignition switch of vehicle V is turned ON, switch Q2 turns ON regardless of the state (ON (Hi) / OFF (Low)) of the hold signal output from processor 100. When switch Q2 turns ON, the gate potential of switch Q1 drops below the source potential, and switch Q1 turns ON. When vehicle V stops and is parked, and the ignition switch of vehicle V is turned OFF, switch Q2 turns OFF. In this case, unless switch Q3 turns ON due to the hold signal and the gate potential drops, switch Q1 turns OFF, and the operation of power supply device 1 stops.

[0033] The input / output circuit 104 makes it possible to maintain the operation of the control circuit 10, i.e., the power supply device 1, from the auxiliary battery 22, only while the ignition switch is ON or while the processor 100 is holding the ON signal.

[0034] The power supply device 1 configured in this way controls the power supply from the auxiliary battery 22 as described below. In the initial state (ignition OFF, no power supply from the auxiliary battery 22), the processor 100 is also in the OFF state, and the hold signal for keeping the power supply from the auxiliary battery 22 ON is also OFF, and the processor 100 is stopped from operating.

[0035] When the ignition switch of vehicle V is turned ON and operation begins, the power supply device 1 receives power from the auxiliary battery 22 and becomes operational.

[0036] The processor 100 of the power supply device 1, once it is operational, performs the following processes. Figures 5 and 6 are flowcharts showing an example of the control processing procedure by the power supply device 1.

[0037] When the ignition switch is turned ON and power is supplied from the auxiliary battery 22, the processor 100 resets the standby count (a predetermined period of standby) (step S101) and turns on the hold signal (step S102). The processor 100 also turns off (zero) the non-charging count (measurement of standby time) (step S103).

[0038] While the ignition switch is ON, power from the auxiliary battery 22 is supplied to the power supply device 1. During this time, the auxiliary battery 22 is charged as needed using the main battery 20 as a power source.

[0039] The processor 100 determines whether the ignition switch is turned OFF or not (step S104). If it is determined that the ignition switch is not turned OFF (S104: NO), the processor 100 returns the process to step S104.

[0040] If it is determined that the ignition switch is OFF (S104: YES), the processor 100 starts measuring the standby count since the switch was turned OFF (step S105). During this time, the hold signal remains ON, and the operating state of the power supply device 1 is maintained.

[0041] The processor 100 determines whether communication with the power transmission device is possible via the communication circuit 102 (step S106). If it is determined that communication is not possible (S106: NO), the processor 100 determines whether the waiting count measured from the ignition switch OFF has exceeded a predetermined timeout value (step S107).

[0042] If the processor determines that the waiting count is less than a predetermined timeout value (step S107: NO), the processor 100 returns to step S106.

[0043] If the standby count is determined to be greater than or equal to a predetermined timeout value (step S107: YES), the processor 100 turns off the hold signal (step S108). As a result, power from the auxiliary battery 22 is no longer supplied to the power supply device 1, and the power supply device 1 returns to its initial state of operation being stopped. The predetermined timeout value is set as the time required for the power supply device 1 and the external power source that supplies power to the power supply device 1 to establish a communication connection when the vehicle V is parked in a parking lot where an external power source that supplies power to the power supply device 1 is provided. As a result, if the vehicle V is parked in a parking lot where charging is not possible, the power supply device 1 will stop operating after a predetermined time and appropriately stop the power supply from the auxiliary battery 22, thereby preventing the auxiliary battery 22 from running out.

[0044] If it is determined in step S106 that communication is possible (S106: YES), the processor 100 resets the standby count (step S109). The processor 100 determines whether the main battery 20 needs charging (step S110). In step S110, the processor 100 determines that charging is necessary if the battery voltage of the main battery 20 is lower than a predetermined voltage value, and determines that the main battery 20 is fully charged and does not need charging if it is determined to be at or above the predetermined voltage value. As described above, the processor 100 determines whether the main battery 20 needs charging by monitoring the capacitor 13. If the voltage of the capacitor 13 is fully charged, it can be determined that charging of the main battery 20 is not necessary. In other words, the processor 100 can control the DC / AC converter 14 without needing to acquire information indicating the state of the main battery 20.

[0045] If it is determined that charging is necessary (S110:YES), the processor 100 determines whether or not charging is in progress by detecting the current from the capacitor 13 (step S111). If it is determined that charging is not in progress (S111:NO), the processor 100 starts measuring the period during which the capacitor is not fully charged but is not in a non-charging state (non-charging count) (step S112), and determines whether or not the non-charging count has reached a predetermined timeout value (step S113).

[0046] If the non-charging count is determined to have reached the timeout value (S113: YES), the processor 100 determines that the capacitor 13 is in a state where it needs to be charged but has not been charged for a predetermined period of time, and turns off the hold signal (step S114). As a result, power from the auxiliary battery 22 is no longer supplied to the power supply device 1, and the power supply device 1 returns to its initial state of operation being stopped.

[0047] If, in step S110, it is determined that charging is not necessary, for example, that the device is fully charged (S110: NO), the processor 100 turns off the non-charging count (resets it to zero) (step S115) and returns the process to step S106.

[0048] At this time, even if the main battery 20 (capacitor 13) reaches a fully charged state, the processor 100 does not immediately proceed to step S108, which turns off the hold signal, but maintains the hold signal as long as communication is possible. Upon detecting that the battery is fully charged, the processor 100 may stop the hold signal in order to stop supplying power from the auxiliary battery 22. However, if it is determined that charging is no longer needed and the system is stopped, then when the main battery 20 (capacitor 13) discharges over time and requires charging, it will be necessary to wait for the ignition switch to be turned ON in order to recharge. As described above, by maintaining the output of the hold signal as long as it is confirmed that wireless communication is possible, recharging can be started as needed.

[0049] If it is determined in step S111 that charging is in progress (S111: YES), the processor 100 returns to step S106.

[0050] If, in step S113, it is determined that the non-charging count has not reached the timeout value (S113: NO), the processor 100 returns to step S106.

[0051] As a result, after the vehicle V stops and the ignition switch is turned OFF, a hold signal is output, maintaining the power supply from the auxiliary battery 22 to the control circuit 10. If wireless charging is not performed thereafter, the hold signal turns OFF due to a timeout, and the power supply to the control circuit 10 is automatically switched OFF. This prevents the power supply device 1 from unnecessarily remaining ON and consuming the power of the auxiliary battery 22 when the vehicle V is parked or stopped in a location where there is no external power source to supply power to the power supply device 1. If wireless charging is performed promptly after the ignition switch is turned OFF, the hold signal remains ON, so the control circuit 10 maintains power supply from the auxiliary battery 22 and charging can continue. Furthermore, even if wireless charging is started, if the parking position is inappropriate and the power reception efficiency is very low, or if charging is not performed for a predetermined waiting time or longer due to control on the vehicle V side, the power supply device 1 will continue to consume the power of the auxiliary battery 22 if it remains ON. If charging is interrupted or stopped for a predetermined waiting period or longer, even though the battery is in a state where charging is needed (not fully charged), the power supply device 1 will turn OFF, thereby avoiding power consumption of the auxiliary battery 22 and preventing the battery from running out.

[0052] The embodiments disclosed above are illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, and all modifications within the meaning and scope equivalent to the claims are included. [Explanation of Symbols]

[0053] 1 Power supply device 10 Control circuits 100 processors 104 Input / Output Circuit Q1, Q2, Q3 Switches

Claims

1. A power supply device that supplies power received wirelessly from an external power source to a main battery that stores part or all of the drive energy source of a mobile body, and an auxiliary battery that is charged by the main battery in order to operate equipment mounted on the mobile body, Includes a control circuit for controlling the operation of the power supply device, The aforementioned control circuit is A power receiving unit that receives power supplied from the auxiliary battery to each component of the control circuit, A power switch unit is controlled by a signal indicating the ON / OFF state of an ignition switch corresponding to the ON / OFF state of the moving body, and switches the power supply to the power receiving unit on and off. The system includes a control unit that controls the power switching unit, The control unit maintains the closed circuit of the power switching unit for a predetermined period after the ignition switch is turned OFF, and continues to receive power from the power receiving unit. Power supply device.

2. While the control unit is charging the main battery with power received from the external power source, it maintains the closed circuit of the power switching unit and continues to receive power from the power receiving unit. The power supply device according to claim 1.

3. If the ignition switch is turned OFF and the main battery is not charged by the power received from the external power source for a predetermined period of time, the control unit opens the power switch and stops receiving power to the power receiving unit. The power supply device according to claim 2.

4. The control unit maintains the closed circuit of the power switch when the main battery is fully charged, provided that power is being received from the external power source. The power supply device according to claim 2.

5. The control unit includes a communication circuit for communicating with the external power source, and the predetermined period is equal to or greater than the time required to establish a communication connection. A power supply device according to any one of claims 1 to 4.

Images