JP2010058609A - Vehicular power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular power supply device which is free from resistance loss in the connection between cells of an electric double layer capacitor and energy loss for suppressing voltage dispersion in a plurality of cells, and in which functional failure due to the drop of the power supply voltage does not occur even when rush current of a motor or the like is generated. <P>SOLUTION: The vehicular power supply device comprises one electric double-layer capacitor C connected parallel to a battery B, a voltage detection means 10 for detecting the voltages applied from the battery B to loads 3, 19, a means 9 for determining whether or not the detected voltage is higher than the first voltage equal to or higher than the voltage to be output by the battery B at SOC (State Of Charge) 0%, a voltage dropping means 8 for dropping the voltage and applying it to the electric double-layer capacitor C when it is determined that the detected voltage is higher than the first voltage, a means 9 for determining whether or not the voltage detected by the voltage detection means 10 is lower than the second voltage lower than the first voltage, and a boosting means 8 which boosts the output voltage of the electric double-layer capacitor C and applies it to the loads 3, 19 when it is determined that the detected voltage is lower than the second voltage. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle power supply device that includes a battery that is charged with power generated by a generator in conjunction with an engine, and that supplies power discharged from the battery and power generated by the generator to a load.

In the vehicle power supply device, the power generated by the generator linked to the engine is supplied to each load mounted on the vehicle, and the battery is charged. When the power generated by the generator is insufficient, the engine is stopped. In this case, power is supplied from the battery to each load.
Recently, electric double layer capacitors that have a very large capacitance of several tens of farads or more and are excellent in charge / discharge cycle characteristics (lifetime) and rapid charge / discharge have become widespread. It has been proposed for use.

In Patent Document 1, the power from the ACC power source connected to the ACC (accessory) power source and the ACC power source connected to the ACC power source and supplied to the car navigation system has become a predetermined value or less. In particular, a voltage-dependent vehicle-mounted device including a capacitor bank that supplies power to a car navigation system is disclosed. In response to a momentary power failure of the ACC power supply accompanying the restart of the engine, power is instantaneously supplied from the capacitor bank to the car navigation system, so that the car navigation system is not affected by the momentary power failure.
JP 2005-199739 A

In the electric double layer capacitor, the charge / discharge voltage is not constant, and changes linearly in the range of about 0 to 2.5V. For this reason, when used for a vehicle power source, a plurality of electric double layer capacitor cells are connected in series, including the case of the above-described voltage-dependent in-vehicle device.
However, when a plurality of electric double layer capacitor cells are connected in series, there is a problem that resistance loss occurs between the cells. In addition, in order to suppress voltage variation between cells, it is necessary to connect resistors in parallel to the respective cells. Since current always flows through these resistors, there is a problem that energy loss occurs.

Further, in the vehicle power supply device, when a load such as a motor is started when a headlamp, an air conditioner, a seat heater, a defogger, etc. are used and the load is excessive, There is a problem that the power supply voltage is temporarily lowered and the load may not function properly depending on the load.
The present invention has been made in view of the above-described circumstances, and there is no loss of resistance for inter-cell connection of an electric double layer capacitor and energy loss for suppressing voltage variation in a plurality of cells. It is an object of the present invention to provide a vehicular power supply device that does not cause malfunction due to a drop in power supply voltage even when an inrush current occurs.

  A power supply device for a vehicle according to a first aspect of the present invention includes a battery that is charged by electric power generated by a generator linked to an engine, and that supplies electric power discharged from the battery and electric power generated by the generator to a load. In the power supply apparatus for a vehicle, one electric double layer capacitor connected in parallel to the battery, voltage detection means for detecting a voltage applied from the battery to the load, and a voltage detected by the voltage detection means are represented by SOC (State Means for determining whether or not the battery is higher than the first voltage that is equal to or higher than the voltage to be output when the battery is 0%, and the applied voltage when the means is determined to be higher than the first voltage. A step-down unit that steps down the voltage and applies the voltage to the electric double layer capacitor; a unit that determines whether the voltage detected by the voltage detection unit is lower than a second voltage that is lower than the first voltage; There when it is determined to be lower than the second voltage, characterized in that it comprises a step-up means to be supplied to the load by boosting the output voltage of the electric double layer capacitor.

  In this vehicle power supply device, the battery is charged with the power generated by the generator linked to the engine, and the power discharged from the battery and the power generated by the generator are supplied to the load. One electric double layer capacitor is connected in parallel to the battery, and the voltage detecting means detects the voltage applied from the battery to the load. The determining means determines whether or not the voltage detected by the voltage detecting means is higher than a first voltage that is equal to or higher than a voltage that the battery should output when SOC (State Of Charge) is 0%. When it is determined that the voltage is higher, the step-down means steps down the voltage applied to the load and gives it to the electric double layer capacitor. When the determining means determines whether the voltage detected by the voltage detecting means is lower than the second voltage lower than the first voltage, and determines that the voltage is lower than the second voltage, the boosting means The output voltage is boosted and applied to the load.

  According to a second aspect of the present invention, there is provided the vehicle power supply device according to the third voltage, wherein the voltage detected by the voltage detecting means is intermediate between the first voltage and the second voltage when the step-down means steps down the applied voltage. When it is determined whether the voltage is lower than the third voltage, the step-down of the applied voltage is stopped, and when the boosting unit boosts the output voltage of the electric double layer capacitor, It is determined whether or not the output voltage is higher than the fourth voltage that is intermediate between the second voltage and the third voltage, and when it is determined that the output voltage is higher than the fourth voltage, the boosting of the output voltage is stopped. And

  In this vehicle power supply device, whether or not the voltage detected by the voltage detection means is lower than a third voltage that is intermediate between the first voltage and the second voltage when the voltage reduction means steps down the voltage applied to the load. When it is determined that the voltage is lower than the third voltage, the step-down of the voltage applied to the load is stopped. When the boosting means boosts the output voltage of the electric double layer capacitor, it is determined whether it is higher than the fourth voltage that is intermediate between the second voltage and the third voltage, and when it is determined that it is higher than the fourth voltage Then, the boosting of the output voltage of the electric double layer capacitor is stopped.

  According to the power supply device for a vehicle according to the present invention, there is no resistance loss in connection between cells of the electric double layer capacitor and energy loss for suppressing voltage variation in a plurality of cells, and an inrush current of a motor or the like is generated. However, it is possible to realize a vehicular power supply device in which the power supply voltage does not drop and malfunction does not occur.

Hereinafter, the present invention will be described with reference to the drawings illustrating embodiments thereof.
FIG. 1 is a block diagram showing a schematic configuration of an embodiment of a vehicle power supply device according to the present invention.
In this vehicle power supply device, an alternator (on-vehicle generator, AC generator) 1 generates power in conjunction with an engine (not shown). The electric power generated by the alternator 1 is rectified in the alternator 1 and then charged to the battery B through the fuse F2 in the junction box 6.
The output voltage of the battery B is supplied to, for example, the headlamp (load) 4 through the fuse F3 and the relay Ry2 in the junction box 6, and is supplied to, for example, the room lamp (load) 5 through the fuse F4. The interior light 5 is turned on / off by the switch 20. The output voltage of the battery B is also given to the starter (load) 2.

  The output voltage of the alternator 1 and the output voltage of the battery B through the fuse F2 are supplied to the electric power steering device (load) 3 through the fuse F1 and to the engine ECU (Electronic Control Unit) (load) 19 through the fuse F5. The output voltage of the alternator 1 and the output voltage of the battery B through the fuse F2 are given to other loads through the respective fuses. The relay Ry1 is turned on / off by the ignition switch 18, and gives the output voltage of the alternator 1 and the output voltage of the battery B through the fuse F2 to the sub power supply control unit 9 and other loads (not shown).

The output voltage of the alternator 1 and the output voltage of the battery B through the fuse F2 are also supplied to the sub power source 7 through the input / output terminal P.
Inside the sub power supply 7, the input / output terminal P is connected to one terminal of the electric double layer capacitor C through the bidirectional DCDC converter 8, and the other terminal of the electric double layer capacitor C is grounded.

The step-down circuit side of the bidirectional DCDC converter 8 steps down the voltage at the input / output terminal P and applies it to the electric double layer capacitor C. The booster circuit side of the bidirectional DCDC converter 8 boosts the output voltage of the electric double layer capacitor C and supplies it to the input / output terminal P through the diode D1.
The voltage at the input / output terminal P is detected by the voltage detection means 10 in the sub power supply control section 9, and the sub power supply control section 9 is based on the voltage detected by the voltage detection means 10. Turn on / off the step-down circuit.

The step-down circuit side of the bidirectional DCDC converter 8 reduces the voltage at the input / output terminal P to 2.5V when the voltage at the input / output terminal P is higher than 12.0V, as shown in FIG. The capacitor C is given. Thereafter, when the voltage at the input / output terminal P becomes lower than 11.9V, the voltage step-down at the input / output terminal P is stopped.
When the voltage at the input / output terminal P is lower than 11.5V, the booster circuit side of the bidirectional DCDC converter 8 sets the output voltage (2.5 V or less) of the electric double layer capacitor C to 11. The voltage is boosted to 5 V and applied to the input / output terminal P through the diode D1. Thereafter, when the voltage at the input / output terminal P becomes higher than 11.6 V, the boosting of the output voltage of the electric double layer capacitor C is stopped.

2A and 2B are explanatory views showing an embodiment in which the electric double layer capacitor C is housed in the junction box 6. FIG. 2A is a cross section viewed from the left side, FIG. 2B is a cross section viewed from the front, and FIG. The cross section seen from the lower surface is shown.
In this junction box 6, the casing 17 has a rectangular parallelepiped shape, and is screwed to the vehicle side by two holes 16 provided in two flanges 15 extending on the bottom surface of the casing 17. An insulating plate and wiring (power system) 14 are accommodated inside the housing 17 so as to cover the bottom surface, and the printed circuit board 13 covers the insulating plate and wiring 14 at a position slightly deeper than the middle in the housing 17. It is inserted and supported and fixed.

  Electronic circuits 12 such as relays Ry1 to Ry2, fuses F1 to F5, and bidirectional DCDC converter 8 are disposed on the surface of the printed circuit board 13. An electric double layer capacitor C is disposed on the lower left side of the surface of the printed circuit board 13 when viewed from the front. Is arranged. A connector 11 penetrating the right side surface is connected to the lower right side of the printed circuit board 13 in front view.

The operation of the sub power supply control unit 9 of such a vehicle power supply device will be described below with reference to the flowchart of FIG.
When the ignition switch 18 is turned on and the power is turned on, the sub power control unit 9 of the vehicle power supply device first resets the flags F1 and F2 (= 0) and initializes them (S1). Next, after the voltage V of the input / output terminal P detected by the voltage detection means 10 is read (S3), it is determined whether or not the flag F1 is set (= 1) (S5).

If the flag F1 is not set (= 1) (S5), the sub power control unit 9 determines whether the flag F2 is set (= 1) (S7).
If the flag F2 is not set (= 1) (S7), the sub power controller 9 determines whether the read voltage V (S3) of the input / output terminal P is lower than 11.5 V (second voltage). Is determined (S9). Here, 11.5V is defined as a voltage lower than the voltage (for example, 12.0V) that the battery B should output when the SOC (State Of Charge) is 0%.

If the voltage V of the input / output terminal P is not lower than 11.5V (S9), the sub power supply control unit 9 determines whether the voltage V of the input / output terminal P is higher than 12.0V (S11). . Here, 12.0V is defined as a voltage equal to or higher than a voltage (for example, 12.0V) that the battery B should output when the SOC is 0%.
If the voltage V of the input / output terminal P is higher than 12.0V (S11), the sub power supply control unit 9 starts to step down the voltage V of the input / output terminal P to 2.5V in the bidirectional DCDC converter 8. (S13). As shown in FIG. 4, the bidirectional DCDC converter 8 starts to step down the voltage V (12 V or more) of the input / output terminal P to 2.5 V and supplies it to the electric double layer capacitor C.

Next, after setting the flag F2 (= 1) (S15), the sub power supply control unit 9 reads the voltage V of the input / output terminal P detected by the voltage detecting means 10 (S3).
If the voltage V of the input / output terminal P is not higher than 12.0V (S11), the sub power supply control unit 9 reads the voltage V of the input / output terminal P detected by the voltage detection means 10 (S3).

If the flag F2 is set (= 1) (S7), the sub power controller 9 determines whether the read voltage V (S3) of the input / output terminal P is lower than 11.9 V (third voltage). Is determined (S27).
If the voltage V at the input / output terminal P is lower than 11.9V (S27), the sub power supply control unit 9 stops the step-down of the voltage V at the input / output terminal P to 2.5V. (S29). The bidirectional DCDC converter 8 stops stepping down the voltage V at the input / output terminal P.

Next, after resetting the flag F2 (= 0) (S31), the sub power supply control unit 9 reads the voltage V of the input / output terminal P detected by the voltage detection means 10 (S3).
If the voltage V of the input / output terminal P is not lower than 11.9V (S27), the sub power supply control unit 9 reads the voltage V of the input / output terminal P detected by the voltage detection means 10 (S3). This prevents the bidirectional DCDC converter 8 from repeating the step-down start / step-down stop (chattering) around 12.0 V of the voltage V of the input / output terminal P.

If the voltage V of the input / output terminal P is lower than 11.5V (S9), the sub power supply control unit 9 starts to boost the output voltage of the electric double layer capacitor C to 11.5V in the bidirectional DCDC converter 8. Is instructed to do so (S23). As shown in FIG. 4, the bidirectional DCDC converter 8 starts boosting the output voltage (2.5 V or less) of the electric double layer capacitor C to 11.5 V, and the electric power steering device 3, the ignition device 19 and the like. Give to the load.
Next, after setting the flag F1 (= 1) (S25), the sub power control unit 9 reads the voltage V of the input / output terminal P detected by the voltage detection means 10 (S3).

If the flag F1 is set (= 1) (S5), the sub power supply control unit 9 determines whether or not the read voltage V (S3) of the input / output terminal P is higher than 11.6 V (fourth voltage). Is determined (S17).
If the voltage V of the input / output terminal P is higher than 11.6 V (S17), the sub power supply control unit 9 instructs the bidirectional DCDC converter 8 to stop boosting the output voltage of the electric double layer capacitor C. (S19). The bidirectional DCDC converter 8 stops boosting the output voltage of the electric double layer capacitor C.

Next, after resetting the flag F1 (= 0) (S21), the sub power control unit 9 reads the voltage V of the input / output terminal P detected by the voltage detection means 10 (S3).
If the voltage V of the input / output terminal P is not higher than 11.6V (S17), the sub power supply control unit 9 reads the voltage V of the input / output terminal P detected by the voltage detection means 10 (S3). Thereby, it is possible to prevent the bidirectional DCDC converter 8 from repeating the boost start / stop boost (chattering) in the vicinity of 11.5 V of the voltage V of the input / output terminal P.

It is a block diagram which shows schematic structure of embodiment of the vehicle power supply device which concerns on this invention. It is explanatory drawing which shows the aspect which accommodated the electric double layer capacitor C in the junction box of the vehicle power supply device which concerns on this invention. It is a flowchart which shows the example of operation | movement of the sub power supply control part of the power supply device for vehicles which concerns on this invention. It is explanatory drawing which shows the example of operation | movement of the sub power supply control part of the power supply device for vehicles which concerns on this invention.

Explanation of symbols

1 Alternator (on-vehicle generator, AC generator)
2 Starter (load)
3 Electric power steering device (load)
4 Headlamp (load)
5 Interior lights (load)
6 Junction Box 7 Sub Power Supply 8 Bidirectional DCDC Converter 9 Sub Power Supply Control Unit (Means for Determining)
DESCRIPTION OF SYMBOLS 10 Voltage detection means 12 Electronic circuit 13 Printed circuit board 17 Case 18 Ignition switch 19 Engine ECU (load)
20 switch B battery C electric double layer capacitor D1 diode F1, F2, F3, F4, F5 fuse P input / output terminal Ry1, Ry2 relay

Claims (2)

In a vehicle power supply device that includes a battery that is charged with power generated by a power generator that is linked to an engine, and that supplies power discharged from the battery and power generated by the power generator to a load.
One electric double layer capacitor connected in parallel to the battery, voltage detection means for detecting the voltage applied from the battery to the load, and the voltage detected by the voltage detection means has an SOC (State Of Charge) of 0 Means for determining whether or not the battery is higher than the first voltage that is equal to or higher than the voltage to be output, and when the means determines that the voltage is higher than the first voltage, Step-down means for applying to the electric double layer capacitor, means for determining whether the voltage detected by the voltage detection means is lower than a second voltage lower than the first voltage, and determining that the means is lower than the second voltage And a booster that boosts the output voltage of the electric double layer capacitor and applies the boosted voltage to the load.   Determining whether the voltage detected by the voltage detection means is lower than a third voltage that is intermediate between the first voltage and the second voltage when the step-down means is reducing the applied voltage; When it is determined that the voltage is lower than the voltage, the step-down of the applied voltage is stopped, and when the boosting unit boosts the output voltage of the electric double layer capacitor, the second voltage and the third voltage are intermediate. The vehicular power supply apparatus according to claim 1, wherein it is configured to determine whether the output voltage is higher than the fourth voltage, and to stop boosting the output voltage when it is determined that the output voltage is higher than the fourth voltage.

Images