JP2005145278A - Power source device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power source device for a vehicle having reliability and safety at a higher level by realizing a power source back-up unit which estimates the service life as an auxiliary power source, and at the same time, detects the state of the auxiliary power source. <P>SOLUTION: This power source device for a vehicle comprises the power source back-up unit 2 using a capacitor unit 15 which is formed of a plurality of capacitors, as an auxiliary power source. The power source device for a vehicle has an auxiliary power source output section 19 in order to always output power in a feeding direction from the auxiliary power source to an electronic control section 3 when the voltage of the battery becomes lower than the voltage of the capacitor unit 15. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In particular, the present invention relates to a vehicle power supply device that electrically brakes a vehicle.

  In recent years, the development of hybrid cars and electric cars has been progressing rapidly, and with this, the development of braking from vehicles has been rapidly progressing from conventional mechanical control to electrical control. Has been made.

  In general, a battery may be used as a power source to electrically control the vehicle. In this case, the vehicle cannot be controlled if power cannot be supplied for any reason. Therefore, proposals have been made that an auxiliary battery can be installed as an auxiliary power source to cope with an emergency.

As prior art document information related to this application, for example, Patent Document 1 is known.
Japanese Patent Laid-Open No. 5-116571

  However, since the auxiliary power supply is related to vehicle braking in an emergency, it is extremely important that power supply is reliably performed in an emergency, so that the life of the auxiliary power supply can be reliably predicted and the auxiliary power supply The ability to always detect the state is an extremely important point.

  Here, when a battery is used as an auxiliary power source, it is very difficult to predict the life of the battery, and even if the battery status and voltage can be confirmed, it is possible to detect even a change in status with the voltage alone. Due to the difficulty, it was necessary to make early and early periodic replacements, and thereby to ensure higher safety.

  However, even if this battery is regularly replaced early and early, it is difficult to check the state of the battery every day or every time the vehicle is started, so it is difficult to further improve safety.

  The present invention solves the above-described conventional problems, and by using a capacitor as an auxiliary power source, it becomes easy to detect the state, and in addition, a state in which power can be constantly output from the auxiliary power source to the electronic control unit. Accordingly, an object is to realize a vehicle power supply device that can supply power without delay in operation of the auxiliary power supply and that is more reliable and safe.

  In order to achieve the above-mentioned object, the invention described in claim 1 of the present invention is a vehicle power supply device used particularly when braking a vehicle by electrical control, and includes information from a brake operating device and And / or an electronic control unit provided so that information according to the traveling state of the vehicle is input and information for controlling braking of the vehicle based on the information is output to the brake; A battery for supplying electric power to the brake via the control unit; and an auxiliary power source for supplying electric power to the brake via the electronic control unit. A power backup unit using the formed capacitor unit, and when the voltage of the battery falls below the voltage of the capacitor unit, Wherein a vehicle power supply device having an auxiliary power supply output unit for enabling the output power to supply direction to the electronic control unit.

  As a result, a power backup unit comprising a capacitor is used as an auxiliary power supply, so that charges can be stored in the power backup unit as an emergency power supply only during vehicle operation, and the stored charge is released at the end of vehicle operation. Therefore, it is possible to greatly reduce the deterioration of the capacitor unit constituting the power backup unit, thereby greatly extending the life as an auxiliary power source and extending it to almost the same as the endurance life of the vehicle. As a result, maintenance-free operation as a power backup unit can be realized.

  In addition, since it is possible to supply power from the auxiliary power supply to the electronic control unit when the voltage of the battery falls below the voltage of the capacitor unit, there is no delay in the event of power failure such as battery voltage drop or disconnection. Electric power can be supplied from the auxiliary power source to the electronic control unit.

  The invention according to claim 2 of the present invention is the vehicular power supply device according to claim 1 in which the voltage of the capacitor unit is used as the reference voltage value of the battery, and thereby the battery is reduced until the reference voltage is lowered. Since it can be used, it becomes possible to improve the reliability of the power supply device for vehicles.

  The invention according to claim 3 of the present invention is the vehicle power supply device according to claim 1, wherein the auxiliary power supply output unit has a diode for preventing a backflow of current from the battery to the auxiliary power supply. This prevents the current from flowing backward from the battery to the auxiliary power supply, and thus the safety of the vehicle power supply device can be further improved.

  The invention described in claim 4 of the present invention is characterized in that, in particular, the auxiliary power supply output unit is provided with an overcurrent prevention means for stopping the power supply from the auxiliary power supply to the electronic control unit in the event of an overcurrent. 4. The vehicle power supply device according to claim 3, wherein the power backup unit can be prevented from malfunctioning when the power backup unit becomes overcurrent due to a ground fault of a load. It is possible to further improve the safety as a power supply device.

  The invention according to claim 5 of the present invention is the vehicle power supply device according to claim 4 in which a fuse is used as the overcurrent prevention means, and thereby the current flows backward from the battery to the auxiliary power supply. Since the power supply can be stopped when the output current from the auxiliary power supply is overcurrent, the safety of the vehicle power supply device can be further enhanced.

  The invention according to claim 6 of the present invention is the vehicular power supply device according to claim 4 in which a current limiting circuit is used as the overcurrent preventing means, so that an excessive output current from the auxiliary power supply can be obtained. Since it is possible to limit the output current at the time of current and to release the limit of the output current at the time of releasing the overcurrent, it is possible to further improve the reliability and safety as the vehicle power supply device.

  The vehicle power supply device of the present invention has an auxiliary power source for supplying electric power to the electronic control unit of the vehicle, and the auxiliary power source is composed of a capacitor unit, so that even when the power supply is abnormal such as battery voltage drop or disconnection. Since immediate power can be supplied to the electronic control unit, it is possible to obtain an effect that a highly reliable power supply backup unit can be obtained and a highly safe vehicle power supply device can be obtained.

(Embodiment 1)
Embodiment 1 of the present invention will be described below with reference to the drawings.

  FIG. 1 is a configuration diagram of a vehicle power supply device according to Embodiment 1 of the present invention. First, in FIG. 1, reference numeral 1 denotes a 12V battery for supplying electric power to the vehicle, and a power backup unit 2 is provided as an auxiliary power source for the battery 1. An electronic control unit 3 that outputs information for controlling braking of the vehicle is provided, and power is supplied from the battery 1 and the power backup unit 2 to the electronic control unit 3. Further, a brake pedal 4 for transmitting information for controlling braking of the vehicle to the electronic control unit 3 is provided. Information from the brake pedal 4 is controlled via the electronic control unit 3 to control the brake 5. The tire 6 is braked by the brake 5.

  Next, a detailed configuration of the vehicle power supply device according to the present embodiment will be described. FIG. 2 is a circuit diagram of the vehicle power supply device according to the embodiment of the present invention. In FIG. 2, a battery 1 is connected to an IG (ignition generator) terminal 9 provided in the power backup unit 2 via an ignition switch 8 for starting and ending the operation of the vehicle, and the power backup unit 2 And the + BC terminal 10 and the power supply terminal 20 for supplying power to the electronic control unit 3.

  The power backup unit 2 and the electronic control unit 3 are communication input terminals 11 for inputting signals from the electronic control unit 3 to the power backup unit 2, and communication outputs for outputting signals from the power backup unit 2 to the electronic control unit 3. The terminal 12 is connected to the output of the detected voltage and the OUT terminal 13 for outputting the charge stored in the power backup unit 2 when the battery 1 is abnormal.

  Here, the configuration of the power backup unit 2 will be described. The power supply backup unit 2 has a capacitor unit 15 as an auxiliary power source for supplying power to the brake 5 via the electronic control unit 3 when the battery 1 is abnormal. The capacitor unit 15 is rapidly charged, for example. It is formed using a plurality of capacitors which are electric double layer capacitors capable of discharging. The power supply backup unit 2 has a charging circuit 16 for charging the capacitor unit 15 and a discharging circuit 17 for discharging, and these are controlled based on an instruction from the backup unit control unit 14. Is done. Further, the power backup unit 2 is provided with an auxiliary power output unit 19. Normally, since the voltage of the battery 1 is higher than the voltage of the capacitor unit 15, electric power is supplied from the battery 1 to the electronic control unit 3, but when the voltage of the battery 1 falls below the voltage of the capacitor unit 15, the capacitor unit 15 Can be supplied to the electronic control unit 3 via the auxiliary power output unit 19 and the OUT terminal 13.

  Further, the power backup unit 2 is provided with an abnormality detection means for detecting an abnormality of the capacitor unit 15 based on charging / discharging behavior. The abnormality detection means includes a backup unit control unit 14, a charging circuit 16, and the like. And a discharge circuit 17.

  Next, the configuration of the auxiliary power output unit 19 will be described. FIG. 3 is a diagram showing a configuration of the auxiliary power output unit 19 in the embodiment of the present invention.

  The auxiliary power output unit 19 of the present invention has an output diode 21 as shown in FIG. The output diode 21 can always output power from the power backup unit 2 and can prevent the power from the battery 1 from flowing into the power backup unit 2 from the OUT terminal 13 side.

  Further, as shown in FIG. 3B, by adding the fuse 22, the output overcurrent of the power backup unit 2 can be prevented, and therefore the safety of the vehicle power supply device can be further improved. .

Further, FIG. 3C shows a configuration in which a current limiting circuit 23 is added to the output diode 21 as output current limiting means, and when the output of the power supply backup unit 2 is overcurrent in the current limiting circuit 23. Since the voltage applied to the output detection resistor Rs increases, the sum of the voltage V _BE applied to the transistor Tr1 and the voltage I × Rs applied to the output detection resistor Rs increases, and this is the sum of the voltages of the diodes in parallel with the transistor Tr1. It will exceed D1 + D2. At this time, the transistor Tr1 prevents the output from becoming an overcurrent by limiting the output current. When the overcurrent is released, the transistor Tr1 releases the restriction on the output current. With this configuration, the safety and reliability of the vehicle power supply device can be further improved.

  Next, the operation of the vehicle power supply device will be described. First, for example, when the ignition is turned on in order to start the operation of the vehicle, the ignition switch 8 connected from the battery 1 to the IG terminal 9 is turned on, and the charge for the auxiliary power is supplied from the battery 1 to the power backup unit 2. Supplied.

  Then, a charging permission signal for permitting charging from the battery 1 to the capacitor unit 15 is input from the electronic control unit 3 to the power supply backup unit 2 via the communication input terminal 11, and the backup unit control unit 14 receives the charging permission signal. Is transmitted to the charging circuit 16. When charging is permitted, the charge for supplying the battery 1 from the battery 1 to the capacitor unit 15 via the + BC terminal 10 and the charging circuit 16 and to the electronic control unit 3 when the battery 1 is low or abnormal is the reference voltage of the battery 1. Charged for the value 9.5V.

  Normally, when the battery 1 is normal, the voltage output from the battery 1 is equal to or higher than a reference value (9.5 V), so that electric power is supplied from the battery 1 to the electronic control unit 3, whereby the vehicle operates normally. When the brake pedal 4 is operated, the electronic control unit 3 receives information from the brake pedal 4 and outputs information for controlling braking of the vehicle to the brake 5 based on the information. To do. Then, the brake 5 is actuated by the output information, and the tire 6 can be reliably braked, and as a result, the vehicle can be reliably controlled.

  Thereafter, when the ignition is turned off to end the operation of the vehicle, the ignition switch 8 connected from the battery 1 to the IG terminal 9 is turned off, and the power supply from the battery 1 is stopped. At this time, the backup unit controller 14 transmits a signal instructing the discharge of the electric charge stored in the capacitor unit 15 to the discharge circuit 17. Based on this signal, the discharge circuit 17 discharges the electric charge stored in the capacitor unit 15. Due to this discharge, deterioration of the capacitor unit 15 can be greatly reduced, so that the power backup unit 2 can have a longer life as an auxiliary power source, and thereby can be extended to almost the same as the durability of the vehicle. Thus, maintenance-free operation of the power backup unit 2 can be realized.

  Further, as shown in FIG. 3A, the auxiliary power supply output unit 19 has an output diode 21 to prevent the power from the battery 1 from flowing back from the OUT terminal 13 side to the power supply backup unit 2, and safety. Is increasing.

  Furthermore, if the auxiliary power output unit 19 has the structure as shown in FIGS. 3B and 3C, the output is caused by a short circuit inside the power backup unit 2, such as a short circuit between the + BC terminal 10 and the ground terminal 21. Since the overcurrent is prevented from flowing out from the power supply backup unit 2 to the electronic control unit 3 when the current becomes an overcurrent, the safety as the vehicle power supply device can be further improved.

  Next, the operation of the vehicle power supply device when the voltage of the battery 1 is reduced or abnormal will be described.

  When the voltage of the battery 1 falls below the reference value (9.5 V), that is, the voltage of the capacitor unit 15, the voltage of the capacitor unit 15 becomes higher than the voltage of the battery 1, so that the capacitor unit 15 having the higher voltage is charged. The charged electric charges are output to the OUT terminal 13 through the auxiliary power supply output unit 19 and supplied to the electronic control unit 3. As a result, even if there is an abnormality such as a voltage drop or disconnection of the battery 1, power can be stably supplied from the immediate auxiliary power source to the electronic control unit 3 without a time delay, so the vehicle can be safely stopped. can do.

  As described above, according to this embodiment, the auxiliary power source for supplying power to the electronic control unit 3 of the vehicle is provided, and the auxiliary power source includes the capacitor unit 15 and includes the auxiliary power output unit 19. Thus, when the battery 1 is abnormal, power is supplied from the immediate capacitor unit 15 to the electronic control unit 3 via the auxiliary power output unit 19, so that the reliability as the power backup unit 2 can be further improved. A highly safe vehicle power supply device can be obtained.

  The vehicle power supply device according to the present invention has an auxiliary power supply for supplying power to the electronic control unit of the vehicle when the battery is abnormal, and is useful as a highly safe vehicle power supply device.

1 is a configuration diagram of a vehicle power supply device according to Embodiment 1 of the present invention. 1 is a circuit diagram of a vehicle power supply device according to Embodiment 1 of the present invention. (A)-(c) is a circuit diagram of the auxiliary power supply output part of this invention, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery 2 Power supply backup unit 3 Electronic control part 4 Brake pedal 5 Brake 6 Tire 8 Ignition switch 9 IG terminal 10 + BC terminal 11 Communication input terminal 12 Communication output terminal 13 OUT terminal 14 Backup unit control part 15 Capacitor unit 16 Charging circuit 17 Discharge Circuit 19 Auxiliary power output 20 Power supply terminal

Claims (6)

A power supply device for a vehicle used for braking a vehicle by electrical control, wherein information from a brake operating device and / or information corresponding to the traveling state of the vehicle is input and based on the information An electronic control unit provided so that information for controlling braking of the vehicle is output to the brake, a battery for supplying power to the brake via the electronic control unit, and the electronic control unit An auxiliary power source for supplying power to the brake via the auxiliary power source, the auxiliary power source comprising a power source backup unit using a capacitor unit formed of a plurality of capacitors, and the voltage of the battery is the capacitor unit Auxiliary power supply for enabling output of electric power from the auxiliary power supply in the direction of supply to the electronic control unit when the voltage falls below Vehicle power supply system having a power unit. The vehicle power supply device according to claim 1, wherein the voltage of the capacitor unit is a reference voltage value of the battery. The vehicular power supply device according to claim 1, wherein the auxiliary power output unit includes a diode for preventing a reverse flow of current from the battery to the auxiliary power supply. 4. The vehicle power supply device according to claim 3, wherein the auxiliary power supply output unit is provided with overcurrent prevention means for stopping power supply from the auxiliary power supply to the electronic control unit in the event of an overcurrent. The vehicle power supply device according to claim 4, wherein a fuse is used as the overcurrent prevention means. The vehicle power supply device according to claim 4, wherein a current limiting circuit is used as the overcurrent preventing means.

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