JP2011041426A - Power supply controller for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply controller for a vehicle, capable of preventing remarkable reduction of power supply voltage to a controller of a driving motor, not requiring a large mounting space and preventing an increase in gross vehicle weight. <P>SOLUTION: The power supply controller for the vehicle includes: a first battery 4 for driving the driving motor 1 for the vehicle, and a first voltage step-down circuit 5 which is connected between auxiliary machines mounted on the vehicle, steps down the voltage of the first battery 4 and outputs the voltage. The controller further includes: an electric double layer capacitor 8 for supplying power to the auxiliary machines, a second voltage step-down circuit 7 which is connected in parallel to the first voltage step-down circuit 5, has power capacity smaller than that of the first voltage step-down circuit 5, steps down the voltage of the first battery 4 and outputs the voltage, and a control section 11 for selecting any one of the first voltage step-down circuit 5 and the second voltage step-down circuit 7 and operating it when the voltage of the first battery 4 is stepped down and outputted. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vehicle power supply control device including a battery that drives a motor for driving a vehicle, and an auxiliary device mounted on the vehicle, and includes a step-down circuit that steps down and outputs a voltage on the battery side. It is.

  Hybrid vehicles and electric vehicles include a drive motor and a high-voltage battery for supplying power to the drive motor. The output voltage of the high-voltage battery is boosted by the boost converter and given to the drive motor, and is stepped down by the step-down converter and given to the auxiliary machines.

FIG. 3 is a block diagram showing a configuration example of a main part of a conventional vehicle power supply control device used for such a hybrid vehicle and an electric vehicle.
In this vehicle power supply control device, the drive motor 1 is driven by the inverter 2, and the inverter 2 converts the DC voltage boosted by the boost (DCDC) converter 3 into a three-phase AC and applies it to the drive motor 1. Boost converter 3 has a positive terminal connected to the anode terminal of high-voltage main battery 4 through system relay SRB, and a negative terminal connected to the cathode terminal of high-voltage main battery 4 through system relay SRG. In the case of a hybrid vehicle, the drive motor 1 also functions as a generator that is linked to an engine (not shown).

  The output voltage of the high voltage main battery 4 is stepped down by a large capacity step-down (DCDC) converter 5 and charged to the low voltage auxiliary battery 6 through the fuse F1. The voltage charged in the low voltage auxiliary machine battery 6 is applied to the low voltage load group (auxiliary machine) through the fuses F2, F3 or F4.

  In Patent Document 1, a load and a control device are supplied with electric power from a main battery via a DC / DC converter, and are directly connected to the main battery. A DC / DC converter control circuit and two DC / DC converters And the power supply device with which the system relay was integrated with the main battery is disclosed.

  In Patent Document 2, a small-capacity DC-DC converter and a large-capacity DC-DC converter are connected in parallel as a voltage drop DC-DC converter between a high-voltage DC power source including a high-voltage battery and a low-voltage load. A power supply circuit for a vehicle interposed in the vehicle is disclosed. When the necessary supply power of the DC load is large under the control of the switching control device, the large capacity DC-DC converter is used. When the necessary supply power of the DC load is small, the large capacity DC-DC converter is turned on. It is made to rest and it will be in the state which uses a small capacity DC-DC converter.

JP 2006-254565 A JP 2001-204137 A

  In the above-described conventional vehicle power supply control device, the low voltage auxiliary battery 6 supplies the power supply voltage to the control device of the drive motor 1 as well, but the remaining capacity of the low voltage auxiliary battery 6 has been remarkably reduced (battery rise). ) When the state occurs, there is a problem that the drive motor 1 may not be started. Further, since the low voltage auxiliary battery 6 is mounted in addition to the high voltage main battery 4, there is a problem that a large mounting space is required and the total vehicle weight increases.

In the power supply device disclosed in Patent Document 1, a large-capacity DC-DC converter is operated because of a slight dark current used for holding a low-voltage load memory during parking. Since the output power of the DC converter is significantly different from the rated power, the efficiency is remarkably inferior and the main battery may rise.
In the vehicle power supply circuit disclosed in Patent Document 2, since the low-voltage power supply is only the DC-DC converter, when a large number of low-voltage loads are operated simultaneously, when the rated capacity of the large-capacity DC-DC converter is exceeded, There is a possibility that the supply voltage decreases (the same applies to Patent Document 1).

  The present invention has been made in view of the above-described circumstances, does not significantly reduce the power supply voltage to the drive motor control device, does not require a large mounting space, and increases the total vehicle weight. Another object of the present invention is to provide a vehicular power supply control device.

  A power supply control device for a vehicle according to a first aspect of the present invention is connected between a first battery that drives a motor for driving the vehicle and auxiliary devices mounted on the vehicle, and steps down the voltage on the first battery side. In the vehicle power supply control device including the first step-down circuit that outputs the electric power, the electric double layer capacitor that supplies power to the auxiliary devices and the first step-down circuit are connected in parallel, and the power capacity is higher than that of the first step-down circuit. The second step-down circuit for stepping down and outputting the voltage on the first battery side, and when the voltage on the first battery side is stepped down and output, any of the first step-down circuit and the second step-down circuit And a control unit that selects and operates the device.

  In this vehicle power supply control device, the first voltage step-down circuit is connected between the first battery that drives the vehicle drive motor and the auxiliary devices mounted on the vehicle, and steps down the voltage on the first battery side. Output. An electric double layer capacitor supplies power to the auxiliary machinery, and a second step-down circuit having a power capacity smaller than that of the first step-down circuit is connected in parallel to the first step-down circuit to step down the voltage on the first battery side. Output. When the voltage on the first battery side is stepped down and output, the control unit selects and operates either the first step-down circuit or the second step-down circuit.

  The vehicle power supply control device according to a second aspect of the present invention further includes a current detector that detects a current value flowing through the auxiliary machinery and supplies the detected current value to the control unit, and the control unit includes the supplied current. The second step-down circuit is configured to be selected when the value is equal to or less than a predetermined value.

  In this vehicle power supply control device, the current detector detects the current value flowing through the auxiliary machinery, and gives the detected current value to the control unit. The control unit selects and operates the second step-down circuit when the supplied current value is equal to or less than a predetermined value.

  According to a third aspect of the present invention, there is provided a vehicular power supply control device, wherein the control unit includes an interface of a multiplex communication system for performing multiplex communication by connecting the drive motor and the control device for auxiliary equipment, the interface being the multiplex communication. The second voltage step-down circuit is selected when a system sleep signal is given.

  In this vehicle power supply control device, the control unit includes an interface of a multiplex communication system that performs multiplex communication by connecting a drive motor and a control device of auxiliary machinery. The control unit selects and operates the second step-down circuit when the interface is given a sleep signal of the multiple communication system.

  The vehicular power supply control device according to a fourth aspect of the present invention is characterized in that the control unit is configured to select the second step-down voltage circuit when an ignition key is off.

  In this vehicle power supply control device, the control unit selects and operates the second step-down circuit when the ignition key is off.

  The vehicular power supply control device according to a fifth aspect of the present invention further includes a voltage detector that detects an output voltage value of the electric double layer capacitor and supplies the detected voltage value to the control unit. When the step-down circuit is selected, the second step-down circuit is configured to be turned on / off so that the given voltage value is maintained within a predetermined range.

  In this vehicle power supply control device, the voltage detector detects the output voltage value of the electric double layer capacitor and gives the detected voltage value to the control unit. When the second step-down circuit is selected, the control unit turns on / off the second step-down circuit so that the given voltage value is maintained within a predetermined range.

  According to the vehicle power supply control device according to the present invention, the power supply voltage to the drive motor control device is not significantly reduced, a large mounting space is not required, and the total vehicle weight is not increased. A control device can be realized.

It is a block diagram which shows the principal part structure of embodiment of the vehicle power supply control apparatus which concerns on this invention. It is a flowchart which shows operation | movement of embodiment of the vehicle power supply control apparatus which concerns on this invention. It is a block diagram which shows the principal part structural example of the conventional vehicle power supply control apparatus used for a hybrid vehicle and an electric vehicle.

Hereinafter, the present invention will be described with reference to the drawings illustrating embodiments thereof.
FIG. 1 is a block diagram showing a main configuration of an embodiment of a vehicle power supply control device according to the present invention.
In this vehicular power supply control device, a driving motor 1 is driven by an inverter 2, and the inverter 2 converts the DC voltage boosted by a booster (DCDC) converter 3 into a three-phase AC and supplies it to the driving motor 1. Boost converter 3 has a positive terminal connected to the anode terminal of high-voltage main battery 4 through system relay SRB, and a negative terminal connected to the cathode terminal of high-voltage main battery 4 through system relay SRG. In the case of a hybrid vehicle, the drive motor 1 also functions as a generator that is linked to an engine (not shown).

The output voltage of the high-voltage main battery 4 is stepped down by a large capacity step-down (DCDC) converter (first step-down circuit) 5 and charged to the electric double layer capacitor 8. The voltage charged in the electric double layer capacitor 8 passes through the fuse F1 and then is given to the low voltage load group (auxiliary machinery) through the fuse F2, F3 or F4.
The large-capacity step-down converter 5 is connected in parallel with a small-capacity step-down (DCDC) converter (second step-down circuit) 7 having a smaller capacity than the large-capacity step-down converter 5.

The voltage detector 9 detects the output voltage value (charge voltage value) of the electric double layer capacitor 8 and supplies it to the control device 11.
The current detector 10 detects the total current value flowing through the low voltage load (current value flowing through the auxiliary machinery) and supplies the detected current value to the control device 11.
The control device 11 is given switching position information of the ignition key 12.
Connected to the control device 11 is a multiplex communication interface 13 for performing multiplex communication with each control device (not shown) of the drive motor 1 and the low voltage load group through a multiplex communication line 14.

  Based on the output voltage value of the electric double layer capacitor 8, the total current value flowing through the low voltage load, the switching position information of the ignition key 12, and the status information of the multiplex communication system, the control device 11 On / off control of the capacity step-down converter 7 is performed.

Hereinafter, an operation example of the vehicular power supply control device having such a configuration will be described with reference to the flowchart of FIG.
When the current value I detected by the current detector 10 is not less than or equal to the predetermined current value I1, the control device 11 is when the ignition key 12 is not off, and when the multiplex communication system is not in a sleep state (wake-up state), that is, During normal operation, the large capacity step-down converter 5 is turned on. Thus, the large capacity step-down converter 5 steps down the voltage on the high voltage main battery 4 side and supplies it to the low voltage load side.

When the current value I detected by the current detector 10 is less than or equal to the predetermined current value I1, the control device 11 is in the off state or when the multiplex communication system is in the sleep state, that is, the low voltage When the current flowing through the load is small, the small capacity step-down converter 7 is turned on. Thereby, the small capacity step-down converter 7 steps down the voltage on the high voltage main battery 4 side and supplies it to the low voltage load side.
At this time, the control device 11 performs on / off control of the small-capacity step-down converter 7 so that a predetermined range of the output voltage value Vc of the electric double layer capacitor 8 is maintained, V1 ≦ Vc ≦ V2.

The control device 11 first sets the flag F to 0 (S1), then reads the current value I detected by the current detector 10 (S3), and whether the read current value I is equal to or less than the predetermined current value I1. It is determined whether or not (S5).
If the read current value I is not less than or equal to the predetermined current value I1 (S5), the control device 11 reads the switching position information of the ignition key 12 (S7), and the ignition key 12 is turned off (ACC (ACCessary), IG Whether (Ignition) and READY are off) is determined (S9).

If the ignition key 12 is not OFF (S9), the control device 11 reads a multiplex communication status signal from the multiplex communication interface 13 (S11), and determines whether the multiplex communication system is in a sleep state (S13). .
If the multiple communication system is not in the sleep state (S13), the control device 11 turns on the large capacity step-down converter 5 and turns off the small capacity step-down converter 7 (S15), and then sets the flag F to 0 (flag F). If it is already 0, the current value I detected by the current detector 10 is read (S3).
If the large capacity step-down converter 5 is already on and the small capacity step-down converter 7 is off, the control device 11 continues to turn on the large capacity step-down converter 5 and turn off the small capacity step-down converter 7 (S15). .

When the read current value I is less than or equal to the predetermined current value I1 (S5), the control device 11 is when the ignition key 12 is off (S9), or when the multiplex communication system is in the sleep state (S13). Then, it is determined whether or not the flag F is 0 (S17).
If the flag F is 0 (S17), the control device 11 turns on the small-capacity step-down converter 7 and turns off the large-capacity step-down converter 5 (S19), and then determines the voltage value Vc detected by the voltage detector 9. Read (S21).
If the small-capacity step-down converter 7 is already on and the large-capacity step-down converter 5 is off, the control device 11 continues to turn on the small-capacity step-down converter 7 and turn off the large-capacity step-down converter 5 (S19). .

If the flag F is not 0 (S17), the control device 11 next reads the voltage value Vc detected by the voltage detector 9 (S21).
The control device 11 reads the voltage value Vc detected by the voltage detector 9 (S21), and then the voltage value Vc is within the range of the output voltage value of the electric double layer capacitor 8 to be maintained, V1 ≦ Vc ≦ V2. It is determined whether or not the lower limit voltage value V1 or less (S23).
If the voltage value Vc is not equal to or lower than the lower limit voltage value V1 (S23), the control device 11 determines whether or not the voltage value Vc is equal to or less than the upper limit voltage value V2 of the output voltage value range, V1 ≦ Vc ≦ V2. (S25).

If the voltage value Vc is not less than or equal to the upper limit voltage value V2 (S25), the control device 11 determines whether the flag F is 0 (S27). If the flag F is 0, the flag F is set to 1. (S29). Next, after the small capacity step-down converter 7 is turned off (S31), the current value I detected by the current detector 10 is read (S3).
If the flag F is not 0 (S27), the control device 11 reads the current value I detected by the current detector 10 as it is because the small-capacity step-down converter 7 is already off (S3).

If the voltage value Vc is equal to or lower than the upper limit voltage value V2 (S25), the control device 11 does not change the current detector because the voltage value Vc is within the range of the output voltage value of the electric double layer capacitor 8 to be maintained. 10 reads the current value I detected (S3).
If the voltage value Vc is equal to or lower than the lower limit voltage value V1 (S23), the control device 11 sets the flag F to 0 (S33). Next, after the small capacity step-down converter 7 is turned on (S35), the current value I detected by the current detector 10 is read (S3).
If the flag F is already 0 and the small capacity step-down converter 7 is on, the control device 11 continues to set the flag F to 0 (S33) and turns on the small capacity step-down converter 7 (S35).

In the present embodiment, the control device 11 reduces the small-capacity step-down voltage when the current value I is less than or equal to the predetermined current value I1, when the ignition key 12 is off, or when the multiplex communication system is in the sleep state. Although the converter 7 is turned on, the step-down converters 5 and 7 may be turned on / off based on a combination of these three conditions.
For example, when the current value I is equal to or less than the predetermined current value I1 and the ignition key 12 is off, the small capacity step-down converter 7 is turned on and the large capacity step-down converter 5 is turned off.
Further, when the ignition key 12 is off and the multiplex communication system is in the sleep state, the current detector 10 can be omitted if the small capacity step-down converter 7 is turned on and the large capacity step-down converter 5 is turned off. .

DESCRIPTION OF SYMBOLS 1 Drive motor 2 Inverter 3 Boost (DCDC) converter 4 High voltage main battery (1st battery)
5 Large capacity step-down (DCDC) converter (first step-down circuit)
7 Small capacity step-down (DCDC) converter (second step-down circuit)
8 Electric Double Layer Capacitor 9 Voltage Detector 10 Current Detector 11 Controller 12 Ignition Key 13 Multiplexing Interface F1, F2, F3, F4 Fuse SRB, SRG System Relay

Claims (5)

A vehicle power supply comprising a first battery that drives a vehicle drive motor and a first step-down circuit that is connected between an auxiliary device mounted on the vehicle and that steps down and outputs a voltage on the first battery side. In the control device,
An electric double layer capacitor that supplies power to the auxiliary machinery and the first step-down circuit are connected in parallel. The power capacity is smaller than that of the first step-down circuit, and the voltage on the first battery side is stepped down and output. And a second voltage step-down circuit, and a control unit that selects and operates either the first voltage step-down circuit or the second voltage step-down circuit when the voltage on the first battery side is stepped down and output. A vehicle power supply control device.   A current detector for detecting a current value flowing through the auxiliary machinery and supplying the detected current value to the control unit; and when the supplied current value is a predetermined value or less, the control unit The vehicular power supply control device according to claim 1, configured to select a two step-down circuit.   The control unit includes an interface of a multiplex communication system that performs multiplex communication by connecting the drive motor and the control device of the auxiliary machinery, and when the interface is given a sleep signal of the multiplex communication system, The vehicle power supply control device according to claim 1 or 2, wherein the second voltage step-down circuit is selected.   4. The vehicle power supply control device according to claim 1, wherein the control unit is configured to select the second step-down voltage circuit when an ignition key is off. 5.   A voltage detector that detects an output voltage value of the electric double layer capacitor and supplies the detected voltage value to the control unit; the control unit is provided when the second step-down voltage circuit is selected; 5. The vehicle power supply control device according to claim 1, wherein the second step-down circuit is configured to be turned on / off so that the voltage value is maintained in a predetermined range.

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