JP2012034488A - Charger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charger capable of quick charging.SOLUTION: In a charger 100, a rectification circuit 10 converts a commercial power supply to a DC power supply. A secondary cell 20, such as a lithium-ion battery, charges a DC voltage generated by the rectification circuit 10. The charger 100 can supply a composite current of a current supplied from the commercial power supply rectified by the rectification circuit 10 and a current discharged from the secondary cell 20, to an on-vehicle battery 320 installed on an electric vehicle to be charged.

Description

  The present invention relates to a charging device for charging an in-vehicle battery.

  In recent years, electric vehicles (hereinafter referred to as EV) have begun to spread, and it has become an urgent task to install a charging device for charging EV in-vehicle batteries. Charging devices installed at home are allowed to be charged over a certain amount of time, but charging devices installed on the roadside such as commercial charging devices and commercial facilities are required to be rapidly charged. In this specification, the plug-in hybrid car is also included in the EV.

JP 2008-199780 A

  This invention is made | formed in view of such a condition, The objective is to provide the charging device which can be charged rapidly.

  A charging device according to an aspect of the present invention includes a rectifier circuit that converts a commercial power source into a DC power source, and a secondary battery that charges a DC voltage generated by the rectifier circuit. A combined current of the current supplied from the commercial power source rectified by the rectifier circuit and the current discharged from the secondary battery can be supplied to the in-vehicle battery mounted on the EV to be charged by the charging device.

  According to the present invention, a charging device capable of rapid charging can be provided.

It is a figure which shows the example of installation of the charging device which concerns on embodiment of this invention. It is a circuit diagram which shows the structure of the charging device which concerns on embodiment of this invention. FIGS. 3A and 3B are diagrams for explaining rapid charge / discharge of the internal storage battery. It is a figure for demonstrating the quick charge to a vehicle-mounted battery. It is a flowchart which shows the operation example of the charging device which concerns on embodiment of this invention. It is a figure which shows the example of installation of the charging device which concerns on the modification 1. FIG. It is a figure which shows the example of installation of the charging device which concerns on the modification 2. FIG. FIG. 11 is a circuit diagram showing a configuration of a charging device according to Modification 2.

  FIG. 1 is a diagram showing an installation example of the charging device 100 according to the embodiment of the present invention. Here, it is assumed that the charging device 100 is installed in a facility such as an existing gas station, convenience store, shopping center, or a dedicated charging station.

  The charging device 100 is supplied with commercial power from a commercial power supply (AC power supply). Hereinafter, an example in which a three-phase AC voltage of 200 V is supplied will be described in this specification. The EV 300 includes an ECU (Electronic Control Unit) and an in-vehicle battery 320. The in-vehicle battery 320 is a secondary battery, and a nickel metal hydride battery, a lithium ion battery, or the like can be used. Hereinafter, an example in which a lithium ion battery is used will be described in this specification.

  When charging the on-vehicle battery 320, the connector on the EV 300 side and the connector on the charging device 100 side are connected. At that time, control signals are exchanged between the ECU 310 and the charging device 100 (specifically, a control unit 40 (see FIG. 2 described later)) using CAN (Controller Area Network) communication or the like.

  In the CAN communication, first, when the charging apparatus 100 is in a chargeable state, operation status information indicating that fact is transmitted to the ECU 310. When ECU 310 receives the operation status information, ECU 310 transmits a charging permission signal to charging device 100. In that case, ECU310 transmits the electric current command value which shows the charging current value according to the specification of each vehicle-mounted battery 320 to the charging device 100. FIG. Thereafter, the charging apparatus 100 outputs a direct current for charging the in-vehicle battery 320 to the in-vehicle battery 320.

  FIG. 2 is a circuit diagram showing a configuration of charging apparatus 100 according to the embodiment of the present invention. The charging device 100 mainly includes a rectifier circuit 10, a secondary battery 20, and various circuit elements that constitute a DC-DC converter and a control unit 40. Hereinafter, in the present specification, the secondary battery 20 is referred to as a built-in storage battery 20e, focusing on the fact that the secondary battery 20 is installed in the charging device 100. Hereinafter, an example in which a lithium ion battery is used as the internal storage battery 20e will be described.

  The rectifier circuit 10 is composed of a diode bridge circuit, and converts the commercial power source 200 into a DC power source. More specifically, the rectifier circuit 10 includes a first series circuit including a first diode D1 and a second diode D2, a second series circuit including a third diode D3 and a fourth diode D4, and a fifth diode D5 and a second diode. A third series circuit with six diodes D6. The first series circuit, the second series circuit, and the third series circuit are respectively connected in parallel between a high-potential side output line and a low-potential side reference voltage line (hereinafter described as an example of ground). The first diode D1, the second diode D2, the third diode D3, the fourth diode D4, the fifth diode D5, and the sixth diode D6 are all connected in the forward direction from the ground toward the output line. Three nodes are respectively provided between the node between the first diode D1 and the second diode D2, the node between the third diode D3 and the fourth diode D4, and the node between the fifth diode D5 and the sixth diode D6. Each of the phase AC voltages is input.

  A capacitor C1 is connected between the output terminal of the rectifier circuit 10 and the ground, and the voltage of the output line is smoothed. Between the output terminal of the rectifier circuit 10 and the high-potential side terminal of the secondary battery 20, the first switching element S1 and the first inductor L1 are connected in series in this order. A second switching element is connected between a node between the first switching element S1 and the first inductor L1 and the ground.

  The third switching element S3 and the second inductor L2 are connected in series in this order between the output terminal of the rectifier circuit 10 and the high potential side terminal of the on-vehicle battery 320 connected externally. The low potential side terminals of the secondary battery 20 and the in-vehicle battery 320 are connected to the ground. A seventh diode D7 is connected between a node between the third switching element S3 and the second inductor L2 and the ground. More specifically, the cathode terminal of the seventh diode D7 is connected to the node, and the anode terminal is connected to the ground.

  The first switching element S1, the second switching element S2, and the third switching element S3 can be configured by a power transistor, a power MOSFET, or the like. The base or gate receives a control signal from the control unit 40.

  The control unit 40 controls the entire charging device 100 and communicates with the ECU 310. The control unit 40 can charge the built-in storage battery 20e with the DC power generated by the rectifier circuit 10 by PWM-controlling the first switching element S1. Moreover, this charge can be stopped by turning off the first switching element S1. On the other hand, the DC power can be discharged from the internal storage battery 20e by turning off the first switching element S1 and PWM controlling the second switching element S2 from this state.

  The charging device 100 configured in this way supplies a combined current of the current supplied from the commercial power source 200 rectified by the rectifier circuit 10 and the current discharged from the built-in storage battery 20e to the in-vehicle battery 320 to be charged. This is a possible configuration.

  Secondary batteries, particularly lithium ion batteries, are required to be charged / discharged within the recommended upper limit and recommended lower limit of the charge amount. If overcharge or overdischarge is performed beyond this range, the battery life is shortened. The recommended upper limit value and the recommended lower limit value of the charge amount are set in advance by each battery manufacturer according to the characteristics of each battery.

  In addition, in order to quickly charge a lithium ion battery safely, the battery voltage is rapidly charged by constant current charging (CC charging) while the battery voltage rises to a predetermined setting voltage, and when reaching the setting voltage, constant voltage charging (CV In general, a method of charging at a low speed is used. In order to execute the quick charging, the control unit 40 detects the voltage and / or current of the node A, and appropriately controls on / off of the first switching element S1 and the second switching element S2 and their duty ratios. To do. The same applies to the discharge. However, the value of the set voltage for transition to constant voltage discharge may be different.

  FIGS. 3A and 3B are diagrams for explaining rapid charge / discharge of the internal storage battery 20e. FIG. 3A shows the transition of the current of node A when charging from the commercial power source 200 to the internal storage battery 20e. In FIG. 3A, the set voltage is reached at time t1, and constant current charging is terminated. Thereafter, switching to constant voltage charging is performed, and the recommended upper limit value is reached at time t2, and charging ends.

  FIG. 3B shows a transition of the current of the node A when discharged from the internal storage battery 20e. In FIG.3 (b), it discharges with a certain electric current value in order to suppress the electric current from a commercial power source to below a regulation value until the time t3. From time t3, the in-vehicle battery 320 switches to CV charging and the charging current decreases, so the discharging current from the internal storage battery 20e also decreases.

  Returning to FIG. 2, the first inductor L <b> 1 and the second switching element S <b> 2 constitute a booster circuit, and can boost the DC voltage discharged from the secondary battery 20. More specifically, the control unit 40 can boost the DC voltage by inputting a predetermined PWM signal to the base or gate of the second switching element S2 and turning on / off the base or gate. . At this time, the higher the ON duty ratio of the PWM signal, the higher the step-up rate.

  Note that a step-down circuit may be provided instead of or in addition to the step-up circuit. That is, the DC-DC converter for converting the direct current voltage discharged from the internal storage battery 20e into a different direct current voltage is provided in the discharge path of the internal storage battery 20e.

  The third switching element S3, the second inductor L2, and the seventh diode D7 constitute a step-down circuit, and can step down a DC voltage applied to the in-vehicle battery 320. More specifically, the control unit 40 can step down the DC voltage by inputting a predetermined PWM signal to the base or gate of the third switching element S3 and turning on / off the base or gate. . At this time, the step-down rate can be increased as the OFF duty ratio of the PWM signal is set higher.

  The charging device 100 according to the present embodiment, as in the case of the built-in storage battery 20e described above, charges the vehicle battery 320 at a constant current up to a predetermined set voltage, and after reaching the set voltage, charges quickly at a constant speed. Charge. In order to execute this quick charging, the control unit 40 detects the voltage and / or current of the node B, and appropriately controls on / off of the third switching element S3 and its duty ratio. Further, the first switching element S1 and / or the second switching element S2 are controlled as necessary.

  FIG. 4 is a diagram for explaining rapid charging of the in-vehicle battery 320. FIG. 4 shows the transition of the current of node B when charging the in-vehicle battery 320 from the charging device 100. The control unit 40 turns on the first switching element S1, and starts constant-current charging of the in-vehicle battery 320 with the combined current of the current from the commercial power source and the current from the built-in storage battery 20e. At time t4 when the vehicle battery 320 reaches a predetermined set voltage, switching to constant voltage charging is reached. At time t5, the recommended upper limit value of the vehicle battery 320 is reached, and charging ends.

  FIG. 5 is a flowchart showing an operation example of the charging apparatus 100 according to the embodiment of the present invention. The control unit 40 charges the built-in storage battery 20e from the commercial power supply while not accepting a charge start instruction with a charging current value (hereinafter referred to as a specified current value) in accordance with the standard of the in-vehicle battery 320 from the ECU 310 (N in S10). Is possible. During that period, the control unit 40 compares the charge amount in the internal storage battery 20e with the recommended upper limit value of the charge amount of the internal storage battery 20e (S11). When the former exceeds the latter (N of S11), the process proceeds to step S10 without charging. When the former is equal to or less than the latter (Y in S11), the built-in storage battery 20e is charged from a commercial power source (S12).

  When the charge amount in the internal storage battery 20e reaches the recommended upper limit value and the charging is to be terminated (Y in S13), the control unit 40 stops the charging (S14), and proceeds to step S10. When charging should not be terminated (N in S13), the process directly proceeds to step S10.

  When the control unit 40 receives a charge start instruction with the specified current value (Y in S10), the control unit 40 compares the charge amount in the internal storage battery 20e with the recommended lower limit value of the charge amount of the internal storage battery 20e (S15). . When the former is less than the latter (N in S15), the control unit 40 supplies only the current supplied from the commercial power supply 200 rectified by the rectifier circuit 10 to the in-vehicle battery 320 without discharging from the internal storage battery 20e (S19). ). At that time, it is preferable to supply a limit value (upper limit current value) of the current supplied from the commercial power source 200.

  When the charge amount in the internal storage battery 20e is equal to or more than the recommended lower limit value (Y in S15), the control unit 40 uses the specified current value to supply the current (upper limit current) supplied from the commercial power source 200 rectified by the rectifier circuit 10. A discharge current (a) corresponding to a value obtained by subtracting (preferably a value) is calculated (S16). And the control part 40 controls the PWM signal of 2nd switching element S2, and discharges this discharge current (a) from the internal storage battery 20e (S17).

  The control unit 40 charges the vehicle-mounted battery 320 with the combined current (corresponding to the specified current) of the discharge current (a) and the current supplied from the commercial power source 200 (S18). When the charge amount of the in-vehicle battery 320 mounted on the EV 300 reaches the recommended upper limit value due to charging in step S18 or step S19 and charging should be terminated (Y in S20), the charging is stopped (S21). When charging should not be terminated (N in S20), the process directly proceeds to step S10. When the power supply of the charging device 100 is turned off (Y in S22), the above charging process is terminated. While the power of the charging apparatus 100 is not turned off (N in S22), the process proceeds to step S10 and the above charging process is continued.

  As described above, according to the present embodiment, the vehicle-mounted battery 320 can be charged with the combined current of the current from the commercial power source 200 and the current from the built-in storage battery 20e, so that more rapid charging is possible. . Further, by acquiring a specified current value from the ECU 310 and adjusting the discharge amount from the built-in storage battery 20e, it is possible to charge with a maximum current value that complies with the specified current value.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are also within the scope of the present invention. is there.

  FIG. 6 is a diagram illustrating an installation example of the charging device 100 according to the first modification. In the modification 1, the solar cell 500 and the power conditioner 550 are additionally installed. Solar cell 500 generates power during the period of sunlight and outputs the generated power to power conditioner 550. The power conditioner 550 mainly converts DC power generated by the solar cell 500 into AC power and outputs it to a commercial power supply system. This AC power can be charged into the internal storage battery 20e. According to the first modification, the electricity bill can be reduced.

  FIG. 7 is a diagram illustrating an installation example of the charging apparatus 100 according to the second modification. In Modification 2, a load 600 is connected to the commercial power supply system. In the above-described embodiment, the example in which the charging apparatus 100 is installed in a business facility has been described. Even when used for business, when installed in a store such as a convenience store or a shopping center, the commercial load 600 (for example, an air conditioner, a refrigerator, etc.) and the charging device 100 have the same commercial power supply. Power is supplied from the grid. Even when the charging apparatus 100 is installed for home use, the household load 600 (white appliances, AV equipment, etc.) and the charging apparatus 100 are supplied with power from the same commercial power supply system. Of course, a dedicated commercial power supply system may be installed for the charging device 100.

  FIG. 8 is a circuit diagram illustrating a configuration of the charging device 100 according to the second modification. The configuration of the charging device 100 illustrated in FIG. 8 is a configuration in which a fourth switching element S4 is added to the configuration of the charging device 100 illustrated in FIG. The fourth switching element S4 is connected in series to the output terminal of the rectifier circuit 10, and the control unit 40 can turn off the fourth switching element S4 to cut off the output terminal of the rectifier circuit 10 from the subsequent stage element. That is, the control unit 40 can charge the in-vehicle battery 320 only with the current discharged from the internal storage battery 20e.

  The electricity bill is generally in a contract form determined by the maximum peak power value. In the case of the contract form, if the peak power value is exceeded, the electricity charge becomes high. Therefore, the control unit 40 detects the power consumption of the load 600, and when it is predicted that the peak power value will be exceeded, by turning off the fourth switching element S4, at least the power consumption due to charging the in-vehicle battery 320 is cut. can do.

  In addition, electricity charges in the midnight hours (23:00 to 7:00 in TEPCO) are often discounted compared to other times (7:00 to 23:00). . The control unit 40 may control to charge the built-in storage battery 20e from the commercial power supply 200 with priority on the midnight time zone when the electricity rate is discounted. Further, in a time zone other than the midnight time zone, the vehicle battery 320 may be controlled to be charged with the current discharged from the internal storage battery 20e as much as possible by turning off the fourth switching element S4. In these cases, electricity charges can be reduced. In particular, when installed in a home, charging for a certain amount of time may be permitted, and the user can select whether to give priority to cost or charging time.

  Further, the secondary battery 20 is not limited to the form built in the charging device 100, and may be externally attached.

  DESCRIPTION OF SYMBOLS 100 Charger, 10 Rectifier circuit, 20 Secondary battery, 20e Built-in storage battery, 40 Control part, D1 1st diode, D2 2nd diode, D3 3rd diode, D4 4th diode, D5 5th diode, D6 6th diode D7 7th diode, C1 capacity, S1 1st switching element, S2 2nd switching element, S3 3rd switching element, S4 4th switching element, L1 1st inductor, L2 2nd inductor, 200 commercial power supply, 300 EV, 310 ECU, 320 vehicle-mounted battery, 500 solar cell, 550 power conditioner, 600 load.

Claims (5)

A rectifier circuit that converts commercial power into DC power;
A secondary battery for charging a DC voltage generated by the rectifier circuit,
A combined current of a current supplied from a commercial power source rectified by the rectifier circuit and a current discharged from the secondary battery can be supplied to an in-vehicle battery mounted on an electric vehicle to be charged by the charging device. A charging device characterized by that.   The charging device according to claim 1, further comprising a DC-DC converter that converts a DC voltage discharged from the secondary battery into a different DC voltage. A control unit that receives a charging instruction from the control device of the electric vehicle and controls charging of the in-vehicle battery from the charging device; and
The control unit is a case where a charging instruction with a charging current value in accordance with a standard of the in-vehicle battery is received from the control device, and a charge amount of the secondary battery is equal to or more than a set lower limit value. The current corresponding to a value obtained by subtracting a current supplied from a commercial power source rectified by the rectifier circuit from the charging current value is discharged from the secondary battery. Charging device.   When the charge amount of the secondary battery is less than the lower limit value, the control unit does not discharge the secondary battery, and supplies current supplied from the commercial power source rectified by the rectifier circuit to the in-vehicle battery. The charging device according to claim 3. The in-vehicle battery is a lithium ion battery,
5. The charging device according to claim 1, wherein the power supply device charges the lithium ion battery with a constant current up to a predetermined set voltage, and charges the constant voltage after reaching the set voltage. 6.

Images