JP5182576B2 - Vehicle power supply control device - Google Patents

Description

  The present invention relates to a vehicle power supply control device, and more particularly to a vehicle power supply control device that controls a vehicle power supply including a battery and a capacitor.

  An example of a conventional vehicle power supply control device is described in Patent Document 1 below. According to the technique described in Patent Document 1, when the vehicle is stopped, the electric power accumulated in the capacitor is transferred to the battery until it becomes equal to the battery voltage, and the remaining accumulated electric power is transferred to the coil of the motor generator. Flow to discharge.

JP 2007-082376 A

  By the way, in order to effectively use the electric power stored in the capacitor, it is desired to use the electric power stored in the capacitor for starting the engine. On the other hand, if power is stored in the capacitor for a long time, deterioration of the capacitor proceeds.

  Therefore, an object of the present invention is to provide a vehicular power supply control device capable of effectively using electric power stored in a capacitor while suppressing deterioration of the capacitor.

  In order to achieve the above object, according to the vehicle power supply control device of the present invention, the battery voltage detection means for detecting the voltage of the battery that supplies power to the vehicle electrical load, and the capacitor that supplies power to the battery are provided. Capacitor voltage detection means for detecting voltage, remaining time setting means for setting a remaining time based on a parameter value related to the deterioration of the capacitor, and a period from when the ignition switch is turned off until the remaining time elapses And power transfer control means for transferring the power stored in the capacitor to the battery via a voltage converter while maintaining the capacitor voltage at or above the battery voltage.

  Thereby, since the battery is charged with the electric power stored in the capacitor, the electric power stored in the capacitor can be effectively used. In addition, since the capacitor voltage decreases, the progress of the deterioration of the capacitor is suppressed. Furthermore, during the remaining time, the capacitor voltage is maintained at or above the battery voltage, so that a certain amount of power remains accumulated in the capacitor. The electric power can be expected to be used for starting the engine. Therefore, according to the present invention, it is possible to effectively use the electric power stored in the capacitor while suppressing the deterioration of the capacitor.

In the present invention, preferably, the remaining time setting means uses the outside air temperature of the vehicle as the parameter value, and sets the remaining time shorter as the outside air temperature is higher.
In a state where electric power is stored in the capacitor, generally, the higher the outside air temperature, the faster the deterioration of the capacitor tends to progress. Therefore, if the remaining time is set to be shorter as the outside air temperature is higher, the capacitor voltage can be lowered below the battery voltage after the remaining time has elapsed, so that deterioration of the capacitor is reliably suppressed.

Preferably, in the present invention, when the engine is started during the remaining period, the power transfer control means uses the electric power stored in the capacitor for driving the engine starting motor.
Thereby, when the engine is restarted after the engine is stopped for a short time such as idling stop, the electric power remaining in the capacitor can be used. Thereby, suppression of battery consumption can be achieved.

Preferably, the present invention further includes a switching connection device that connects the capacitor and a consumption load, and the power transfer control means causes the switching connection device to conduct after the remaining time has elapsed, thereby consuming the capacitor. Connect to load.
In this way, after the remaining time has elapsed, the power stored in the capacitor is consumed, and the capacitor voltage further decreases. As a result, the state in which the electric power stored in the capacitor can be effectively used is maintained until the remaining time elapses, and the deterioration of the capacitor is further suppressed after the remaining time elapses.

  Thus, according to the vehicle power supply control device of the present invention, it is possible to effectively use the electric power stored in the capacitor while suppressing the deterioration of the capacitor.

Hereinafter, an embodiment of a power supply control device for a vehicle according to the present invention will be described with reference to the accompanying drawings.
First, with reference to the block diagram of FIG. 1, the configuration of the vehicle power supply control device of the embodiment will be described. The vehicle power supply control device of the present embodiment has a configuration suitable for controlling a vehicle power supply device including a battery 5 that supplies power to a vehicle electrical load and a capacitor 1 that supplies power to the battery 5. .

  As shown in FIG. 1, the rotating shaft of a motor generator 2 that is an engine starting motor is connected to the rotating shaft of the engine 6 through power transmission means such as a belt. When the vehicle is decelerated, the motor generator 2 functions as a generator by regenerative braking. The output voltage of the motor generator 2 is converted from an AC voltage to a desired DC voltage by the inverter 8. The regenerative power is supplied to the capacitor 1 and also to the battery 5 via the DC / DC converter 10.

The capacitor 1 shown in FIG. 1 is composed of nine capacitor cells connected in series. The maximum voltage per capacitor cell is 2.8V. Therefore, the maximum voltage of the whole normal capacitor 1 is 25.2V (= 2.8V × 9).
Note that any suitable number of capacitor cells constituting the capacitor 1 can be selected. However, it is desirable that the maximum voltage of the entire capacitor 1 is equal to or higher than the voltage of the battery 5 (for example, 14V).

As shown in FIG. 1, the vehicle power supply control device according to the embodiment of the present invention includes a battery voltage detection unit 4 that detects the voltage of the battery 5, a capacitor voltage detection unit 3 that detects the voltage of the capacitor 1, ECU (electric control unit: electronic control unit) 7 is provided.
The capacitor voltage is measured as a potential difference between both terminals of the capacitor 1 as a whole. That is, one of the two terminals of the capacitor 1 is grounded and measured as the potential of the other terminal. The battery voltage is measured as a potential difference between both terminals of the battery.

The ECU 7 functions as a remaining time setting means for setting the remaining time t based on the parameter value related to the deterioration of the capacitor 5 and the capacitor voltage between the time when the remaining time t elapses after the ignition switch is turned off. It has a function as power transfer control means for transferring the electric power stored in the capacitor 5 to the battery 5 via the DC / DC converter 10 as a voltage converter while maintaining Vc at or above the battery voltage Vb.
The DC / DC converter 10 has only a step-down converter function from the capacitor 1 side to the battery 5 side, and does not have a step-up function.

  By charging the battery with the electric power stored in the capacitor, the electric power stored in the capacitor can be effectively used. In addition, since the capacitor voltage is reduced by supplying power to the battery, the progress of deterioration of the capacitor is suppressed. Furthermore, during the remaining time, the capacitor voltage is maintained at or above the battery voltage, so that a certain amount of power remains accumulated in the capacitor.

  However, if power is stored in the capacitor for a long time, that is, if the capacitor voltage is high and a long time elapses, the capacitor deteriorates. For this reason, in this embodiment, after the ignition switch is turned off, the capacitor voltage is maintained to be equal to or higher than the battery voltage until the predetermined remaining time elapses, but after the predetermined remaining time elapses, the capacitor voltage is decreased. Further decrease. The predetermined remaining time can be set to any suitable value, for example, about 1 hour. Furthermore, the predetermined remaining time is desirably set according to a parameter related to the deterioration of the capacitor.

In general, the higher the outside air temperature, the faster the capacitor deterioration proceeds. Therefore, in this embodiment, the outside air temperature of the vehicle is used as a parameter value related to the deterioration of the capacitor 5. The outside air temperature may be measured by a temperature sensor mounted on the vehicle, for example. Then, the ECU 7 sets the remaining time t to be shorter as the outside air temperature is higher. If the remaining time is set in this way, the deterioration of the capacitor is reliably suppressed.
Note that the ECU 7 also has a function as a timer that measures an elapsed time after the ignition switch is turned off.

  When the engine is started again after the ignition switch is turned off, the first relay switch 9 is closed by the ECU 7 to be in a conductive state, and electric power is supplied from the battery 5 to the motor generator 2. As a result, the motor generator 2 is driven, and the rotational force of the rotating shaft is transmitted to the rotating shaft of the engine 6.

  Further, if the remaining time is within the range, when the engine 6 is started, the electric power stored in the capacitor 1 is also used to drive the motor generator 2. Thereby, when the engine is restarted after the engine is stopped for a short time such as idling stop, the electric power remaining in the capacitor can be used. Thereby, consumption of the battery is suppressed.

  As shown in FIG. 1, a load 11 is also connected to the battery 5. The load 11 includes a dark current load in addition to an electric device mounted on a vehicle such as a headlight or a car air conditioner.

1 further includes a second relay switch 12 as an open / close connection device for connecting the capacitor 1 and the consumption load 13. After the remaining time has elapsed, the ECU 7 turns on the second relay switch 12 to connect the capacitor 1 to the consumption load. Thereby, after the remaining time elapses, the electric power stored in the capacitor is consumed, and the capacitor voltage further decreases. As a result, the electric power stored in the capacitor is effectively used until the remaining time elapses, and the deterioration of the capacitor is further suppressed after the remaining time elapses.
The consumption load may be, for example, the vehicle body. In that case, the electric power stored in the capacitor is discharged to the ground through the vehicle body.

Next, an operation example of the embodiment of the present invention will be described with reference to the flowchart of FIG. 2 and the timing chart of FIG.
The horizontal axis of the timing chart of FIG. 3 represents time, the first solid line I represents the operating state of the DC / DC converter 10, and the second solid line II represents the open / closed state of the second relay switch 12. The solid line III at the stage represents the capacitor voltage Vc, and the solid line IV at the fourth stage represents the state of the ignition switch.

  Referring to the flowchart of FIG. 2, first, the ECU 7 detects the battery voltage Vb, the capacitor voltage Vc, the ignition switch on / off, and the outside air temperature Ta (S1).

  Then, when the ignition switch is turned off at time T1 in the timing chart of FIG. 3 (in the case of “Yes” in S2), the ECU 7 sets the remaining time t based on the outside air temperature Ta (S3). Further, the ECU 7 activates the timer function and starts measuring the elapsed time from the time T1 when the ignition switch is turned off (S4).

  Here, an example of the relationship between the outside air temperature and the remaining time is shown in the graph of FIG. The horizontal axis of the graph in FIG. 4 represents the outside air temperature, and the vertical axis represents the set remaining time. A straight line V in the graph indicates that the remaining time is shorter as the outside air temperature is higher. Note that the relationship between the outside air temperature and the remaining time is not necessarily linear.

  When the timer operating time is less than the set remaining time t (in the case of “Yes” in S5) and the capacitor voltage Vc is equal to or higher than the battery voltage Vb (“No” in S6). 3), the ECU 7 operates the DC / DC converter 10 as indicated by the solid line I in the timing chart of FIG. 3 (S7). Thereby, the electric power stored in the capacitor 1 is supplied to the battery 5 and the dark current load (S8).

As described above, when the capacitor voltage Vc is higher than the battery voltage Vb so as to correspond to the section (A) from the time T1 to the time T2 in the timing chart, the surplus power that causes the deterioration of the capacitor is DC / The battery is gradually transferred to the battery 5 through the DC converter 10. As a result, the capacitor voltage is lowered, and the electric power stored in the capacitor is effectively used.
At this time, power is also supplied to the dark current load.

  Further, when the timer operating time is less than the set remaining time t (in the case of “No” in S5) and the capacitor voltage Vc is not equal to or higher than the battery voltage Vb (in the case of “No” in S6). 3) As shown by the solid line I in the timing chart of FIG. 3, the ECU 7 stops the operation of the DC / DC converter 10 (S9). In this case, the electric power stored in the capacitor 1 is not supplied to the battery 5, but is supplied only to the dark current load (S10).

  Thus, after the surplus power of the capacitor 1 has been transferred to the battery 5 at time T2, the operation of the DC / DC converter 10 is performed, corresponding to the section (B) from time T2 to time T3 in the timing chart. Stops, and the capacitor voltage Vc is maintained at the battery voltage Vb or higher.

  If the capacitor voltage Vc is already lower than the battery voltage Vb when the ignition switch is turned off (OFF), the DC / DC converter 10 does not operate from the beginning, and when the ignition switch is turned off. The electric power stored in the capacitor is maintained until time T3.

Next, when the timer operation time reaches the remaining time t at time T3, the ECU 7 resets the timer (S11), stops the operation of the DC / DC converter 10 (S12), and the second relay switch. 13 is turned on (S13).
As a result, in the section (C) from time T3 to time T4 in the timing chart, the power of the capacitor 1 is consumed and the capacitor voltage decreases. In this way, the remaining power of the capacitor 1 is discharged, thereby further preventing deterioration of the capacitor.

  When the capacitor voltage Vc decreases to a predetermined voltage (for example, 0 V) at time T4 (in the case of “Yes” in S14), the second relay switch 13 is turned off (OFF). As described above, in this embodiment, it is possible to effectively use the electric power stored in the capacitor while suppressing the deterioration of the capacitor.

  In each embodiment mentioned above, although the example which constituted the present invention on specific conditions was explained, the present invention can perform various change and combination, and is not limited to this.

It is a block diagram explaining the structure of the power supply control device for vehicles of embodiment of this invention. It is a flowchart explaining the operation example of the power supply control device for vehicles of embodiment of this invention. It is a timing chart explaining the example of operation of the power supply controller for vehicles of the embodiment of the present invention. It is a graph which shows the relationship between external temperature and residual time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capacitor 2 Motor generator 3 Capacitor voltage electric current detection means 4 Battery voltage detection means 5 Battery 6 Engine 7 ECU
8 Inverter 9 First relay switch 10 DC / DC converter 11 Load 12 Second relay switch 13 Consumption load

Claims (4)

Battery voltage detection means for detecting a voltage of a battery for supplying electric power to the vehicle electrical load;
Capacitor voltage detection means for detecting a voltage of a capacitor for supplying power to the battery;
A remaining time setting means for setting a remaining time based on a parameter value related to the deterioration of the capacitor;
Power for transferring the electric power stored in the capacitor to the battery via the voltage converter while maintaining the capacitor voltage at the battery voltage or higher until the remaining time elapses after the ignition switch is turned off. Transfer control means;
A vehicle power supply control device comprising:   2. The vehicle power supply control device according to claim 1, wherein the remaining time setting means uses an outside air temperature of the vehicle as the parameter value, and sets the remaining time shorter as the outside air temperature is higher.   3. The power transfer control means according to claim 1, wherein, when the engine is started during the remaining period, the power stored in the capacitor is used to drive an engine start motor. Vehicle power supply control device. A switching connection device for connecting the capacitor and the consumption load;
The vehicle according to any one of claims 1 to 3, wherein the power transfer control means causes the switch-connecting device to conduct after the remaining time has elapsed to connect the capacitor to a consumption load. Power supply control device.

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