JP2021182818A - Power control device - Google Patents

Abstract

To provide a power control device that keeps a boost function stable.SOLUTION: A power control device includes: a boost coil 4 connected between a power supply 1 and a load 3 of a vehicle; a switch 5 connected in parallel with the load 3 in an output path 10 connecting the boost coil 4 and the load 3; a control unit 7 that controls switching of the switch 5 such that a power supply voltage of the power supply 1 is boosted by the boost coil 4 and output to the load 3; an input path 9b that connects between the power supply 1 and the control unit 7 and inputs an input voltage for operating the control unit 7; and a return path 11 connecting the output path 10 and the input path 9b such that a current of the output path 10 returns to the input path 9b.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a power supply control device.

Conventionally, a power supply control device that controls an output voltage output from a vehicle power supply to a predetermined load has been put into practical use. Here, various electronic devices other than the predetermined load are connected to the power supply of the vehicle, and the voltage of the power supply drops due to the driving of the electronic devices, and the predetermined output voltage is not output to the load. There was a risk. In particular, during the cranking period for starting the engine, a large amount of electric power is consumed by the starter motor, so that the voltage of the power supply may drop significantly.

Therefore, as a technique for stably outputting a predetermined output voltage from the power supply to the load, for example, in Patent Document 1, the voltage of the battery is boosted by operating a booster circuit, and the boosted output voltage is loaded. A power supply circuit for a vehicle that outputs to is disclosed. At this time, the voltage of the battery is boosted by the control circuit controlling the switching of the boosting switching element.

Japanese Unexamined Patent Publication No. 2013-247803

However, in the power supply circuit for a vehicle of Patent Document 1, only the voltage of the battery is input to the control circuit as an input voltage. Therefore, when the voltage of the battery drops further, the operation of the control circuit is stopped and the operation of the control circuit is stopped. There was a risk that the output voltage could not be boosted.

It is an object of the present disclosure to provide a power supply control device that stably continues the boosting function.

The power supply control device according to the present disclosure includes a booster coil connected between the power supply and the load of the vehicle, a switch connected in parallel with the load in the output path connecting the booster coil and the load, and a power supply. The control unit that controls the switching of the switch so that the power supply voltage is boosted by the boost coil and output to the load is connected between the power supply and the control unit, and the input voltage for operating the control unit is input. It includes an input path and a return path connecting the output path and the input path so that the current of the output path returns to the input path.

According to the present disclosure, the boosting function can be stably continued.

It is a figure which shows the structure of the vehicle equipment provided with the power source control device which concerns on embodiment of this disclosure. It is a graph which shows how the power supply voltage drops in a cranking period. It is a figure which shows the structure of the conventional power supply control device. It is a graph which shows the change of the output voltage with respect to the drop of the power supply voltage in the conventional power supply control device. It is a graph which shows the change of the output voltage with respect to the drop of the power supply voltage in the power supply control apparatus of this disclosure.

Hereinafter, embodiments according to the present disclosure will be described with reference to the accompanying drawings.

FIG. 1 shows a configuration of a vehicle device provided with a power supply control device according to an embodiment of the present disclosure. The vehicle equipment has a power supply 1, a power supply control device 2, and a load 3. The vehicle may be, for example, a commercial vehicle such as a truck, but is not limited to this, and may be a passenger car, a two-wheeled vehicle, or the like.

The power supply 1 supplies electric power to each part of the vehicle, and is electrically connected to the load 3 via the power supply control device 2. In addition to the load 3, the power supply 1 is connected to a plurality of electronic devices such as a starter motor for starting an engine (not shown).

The load 3 is an electronic device driven by electric power supplied from the power source 1, and is connected between the power supply control device 2 and the grounding point. Examples of the load 3 include electronic devices for an engine such as a pressure sensor, a temperature sensor, and an injector.

_{The power supply control device 2 controls the output voltage V out} output to the load 3 with respect to the power supply voltage of the power supply 1. The boost coil 4, the switch 5, the capacitor 6, the control unit 7, and the commutator. It has 8a to 8c.

The boost coil 4 is for boosting the power supply voltage of the power supply 1, and is connected in series between the power supply 1 and the load 3. Specifically, one end of the boost coil 4 and the power supply 1 are connected by an input path 9a, and the other end of the boost coil 4 and the load 3 are connected by an output path 10 to a commutator 8a and a capacitor 6. It is connected via.

The switch 5 is connected in parallel to the load 3 between the output path 10 and the grounding point. The switch 5 can be configured, for example, from a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), an IGBT (Insulated Gate Bipolar Transistor), or the like.

The capacitor 6 smoothes and holds the voltage output from the commutator 8a, and is connected in parallel to the switch 5 between the output path 10 and the grounding point. At this time, the capacitor 6 is connected to the output path 10 between the switch 5 and the commutator 8a and the load 3, that is, on the output side of the switch 5 and the commutator 8a.

The control unit 7 is connected to the switch 5 via a signal line, and controls the switching of the switch 5 so that the power supply voltage of the power supply 1 is boosted by the step-up coil 4. Further, the control unit 7 is connected to the power supply 1 by input paths 9b and 9c. Specifically, one end of the input path 9b is connected to the power supply 1 via the input path 9a, and the other end of the input path 9b is connected to the commutator 8b. On the other hand, one end of the input path 9c is connected to the commutator 8b, and the other end of the input path 9c is connected to the control unit 7. In this way, the input path 9b and the input path 9c are connected to each other via the commutator 8b. The input path 9b and 9c, the input voltage V _in for the control unit 7 is operated is inputted from the power source 1 to the control unit 7.

Here, the output path 10 and the input path 9c are connected by the return path 11 so that the current of the output path 10 returns to the input path 9c. One end of the return path 11 is connected between the capacitor 6 and the load 3 in the output path 10, that is, on the output side of the capacitor 6. Further, the other end of the return path 11 is connected to the input path 9c, that is, is connected between the commutator 8b and the control unit 7. Thus, the control unit 7, when the power supply voltage of the power supply 1 drops from output voltage V _out, the output voltage V _out of _the output path 10 which has been boosted by the boost coil 4 via the return path 11 and the input path 9c Will be entered.

Further, the control unit 7 is connected to the return path 11 via the reference path 12 and measures the _{reference voltage V ref input from the return path 11.} The reference voltage V _ref indicates a value corresponding to the output voltage V _out , and the control unit 7 controls switching of the switch 5 based on the _{reference voltage V ref.}
The control unit 7 can be composed of, for example, an ECM (Engine Control Model), an ECU (Engine Control Unit), or the like.

The commutator 8a is arranged in the output path 10 so as to allow a current to flow from the boost coil 4 toward the load 3. Specifically, the commutator 8a is connected in series with the step-up coil 4 between the switch 5 and the capacitor 6 in the output path 10.
The commutator 8b is arranged in the input paths 9b and 9c so as to allow a current to flow from the power supply 1 to the control unit 7.

The commutator 8c is arranged in the return path 11 so as to allow a current to flow from the output path 10 to the input path 9c.
The commutators 8a to 8c can be composed of, for example, a diode.

Next, the operation of this embodiment will be described.

First, as shown in FIG. 1, in a vehicle device mounted on a vehicle, electric power is supplied from the power source 1 to the load 3 via the power supply control device 2. At this time, the control unit 7 of the power supply control device 2 sequentially measures the _{reference voltage V ref input from the reference path 12.} Control unit 7, when the reference voltage V _ref is equal to or higher than the predetermined value, substantially the same case as for example the reference voltage V _ref is the nominal voltage of the power supply 1 may be turned off switch 5.

When the switch 5 is turned off, the power supply voltage of the power supply 1 is not boosted, and the same output voltage V _out as the power supply voltage is output to the load 3. _{At this time, since the output voltage V out, which} is the same as the nominal voltage of the power supply 1, is output to the load 3, the pressure sensor, temperature sensor, injector, and the like constituting the load 3 can be stably driven.

On the other hand, the power supply voltage of the power supply 1 may temporarily drop from a predetermined value due to the driving of an electronic device (not shown) connected to the power supply 1. For example, a starter motor for starting an engine, which consumes a large amount of electric power, is connected to the power source 1. Therefore, when the engine is started, as shown in FIG. 2, the power supply voltage of the power supply 1 drops significantly during the cranking period in which the starter motor is driven.

In this way, the control unit 7 controls the switch 5 so as to repeatedly switch between the on state and the off state of the switch 5 when _{the reference voltage V ref drops from a predetermined value.} As a result, the power supply voltage of the power supply 1 can be boosted by the boost coil 4, and the boosted output voltage V _out can be output to the load 3 to stably drive the load 3.

At this time, for example, the power supply voltage of the power supply 1 may drop further due to the charging state of the power supply 1, the deterioration of the power supply 1, the power consumption state of the starter motor, the temperature of the external environment, and the like.

Conventional power supply control device 21, for example, as shown in FIG. 3, the control unit 22 is connected only to the power source 1 through the input path 23, the same input voltage V _in the power supply voltage of the power supply 1 is the control unit 22 Was entered in.
In the power supply control device 21, similarly to the power supply control device 2, the boost coil 24 and the commutator 25 are connected in series between the power supply 1 and the load 3, and the switch 27 is connected between the output path 26 and the grounding point. And the capacitor 28 are connected in parallel to the load 3, respectively. Further, the control unit 22 measures the _{reference voltage V ref via the reference path 29.}

Thus, the control unit 22, since only the same input voltage V _in the power supply voltage of the power source 1 is input, when the power supply voltage of the power supply 1 is largely lowered than the predetermined value, the operation of the control unit 22 May become unstable. For example, if the power supply voltage of the power supply 1 drops below the specification value of the voltage of the control unit 22, the operation of the control unit 22 may become extremely unstable and the output voltage V _out may become indefinite or 0V. be. Here, the specification value is a voltage value required for the control unit 22 to operate normally.

FIGS. 4A and 4B show changes in _{the output voltage V out} when the power supply voltage of the power supply 1 is actually lowered from the specification value of the control unit 22 in the power supply control device 21. Here, the specification value of the control unit 22 is 4V.

As shown in FIG. 4A, it was found that when the power supply voltage was lowered to 3.87V, which was smaller than the specification value of the control unit 22, the output voltage V _out fluctuated violently and became indefinite. From this, it was suggested that the control unit 22 did not operate stably due to the decrease _in the input voltage Vin, and the boosting function became unstable.

Further, as shown in FIG. 4B, it was found that when the power supply voltage was lowered to 3.66V, the output voltage V _out dropped sharply to 0V. From this, it was suggested that the control unit 22 did not operate due to the decrease _in the input voltage Vin, and the boosting function stopped.

As described above, when the power supply voltage of the power supply 1 drops below the specification value of the control unit 22, the operation of the control unit 22 becomes unstable, and it becomes difficult to stably continue the boosting function.

Therefore, in the power supply control device 2 of the present disclosure, as shown in FIG. 1, the output path 10 and the input path are such that the current of the output path 10 returns to the input path 9c and the output voltage V _out is input to the control unit 7. 9c is connected by a reflux path 11. _{As a result, the output voltage V out} boosted by the boost coil 4 is input to the input path 9c instead of the power supply voltage of the power supply 1.

Therefore, when the power supply voltage of the power supply 1 _{drops from the output voltage V out} , the power supply voltage of the power supply 1 is not input to the control unit 7, and the output path 10 boosted by the boost coil 4 is sent to the control unit 7. The output voltage V _{out of} is input as _{the input voltage V in} via the return path 11. That is, no current flows in the input path 9b, and the current in the output path 10 flows in the input path 9c via the return path 11. As a result, even if the power supply voltage of the power supply unit 1 drops below the specification value of the control unit 7, the control unit 7 is unstable in operation because the voltage boosted by the boost coil 4 is input. It is possible to suppress the change and stably continue the boosting function.

At this time, by arranging the commutator 8c in the return path 11, the current can be reliably returned from the output path 10 to the input path 9c.
Further, the return path 11 is connected to the input path 9c, that is, is connected between the commutator 8b and the control unit 7, so that the output voltage V _out can be reliably supplied to the control unit 7.

The circulation path 11, by being disposed at the output portion, which is the output side of the capacitor 6 in the output path 10, it is possible to recirculate the voltage smoothed, the control unit 7 a certain input voltage V _in You can enter it.

Further, the power supply control device 2 does not need to newly develop and provide a complicated control mechanism in response to a drop in the power supply voltage, and provides a return path 11, a commutator 8b and 8c to the conventional power supply control device 21. The boost function can be stabilized just by arranging it. Therefore, the power supply control device 2 can improve the circuit characteristics at low cost.

Further, when the power supply voltage drops, the control unit 7 automatically inputs the voltage boosted by the boost coil 4 by the return path 11, so that the boost function is stable without complicating the control configuration. You can continue.

FIGS. 5A and 5B show changes in _{the output voltage V out} when the power supply voltage of the power supply 1 is actually lowered from the specification value of the control unit 7 in the power supply control device 2. Here, the specification value of the control unit 7 is 4V.

As shown in FIG. 5A, it was found that the _{output voltage V out} is maintained at 12V even when the power supply voltage is lowered to 3.0V, which is smaller than the specification value of the control unit 7. The 12V was the same value as the output voltage V _out when actuating the control unit 7 in Specification Verification value above the input voltage V _{in. That is, the output voltage V out} could be maintained at 12V while the power supply voltage of the power supply 1 was lowered from the nominal voltage to 3.0V. Therefore, the input voltage V _in of the control unit 7 is prevented from being unstable the operation of the control unit 7 by being maintained at 12V, the boost function is suggested to be stably continued.

_{Further, as shown in FIG. 5B, it was found that the output voltage V out} is maintained at 5V, which is higher than the specification value of the control unit 7, even when the power supply voltage is lowered to 1.1V. .. Therefore, operation of the control unit 7 is prevented from being destabilized by the input voltage V _in of the control unit 7 is maintained at a value higher than the Specification Verification value, suggesting that booster function is continued Was done. Further, since the output voltage V _out gradually decreases as the power supply voltage drops, the boosting function can be maintained even if the power supply voltage drops until immediately before the operation of the control unit 7 becomes unstable. Therefore, the boosting function can be maintained until the power supply voltage becomes almost 0 V.

In this way, the control unit 7 can stably maintain the boosting function even when the power supply voltage of the power supply unit 1 drops more than the specification value of the control unit 7, and continuously supplies power to the load 3. Can be supplied.

According to the present embodiment, the current of the output path 10 connecting between the boost coil 4 and the load 3 is returned to the input paths 9b and 9c connecting between the power supply 1 and the control unit 7. The path 11 connects the output path 10 and the input path 9c. As a result, even when the power supply voltage of the power supply 1 drops significantly, the control unit 7 can be operated stably, and the boosting function can be stably continued.

In the above embodiment, the power supply control device 2 controls the voltage input to the load 3 composed of electronic devices for the engine, but the power supply voltage of the power supply 1 is boosted by the boost coil 4 and output to the load. It is good if it can be done, and it is not limited to the engine. That is, the power supply control device 2 can be applied to all systems and devices in which a voltage drop occurs.

Further, in the above embodiment, the power supply control device 2 controls only the boosting of the power supply voltage, but other controls can also be incorporated. For example, the power supply control device 2 can incorporate control for stepping down the power supply voltage.

Further, in the above embodiment, the control unit 7 _{switches the switch 5 based on the reference voltage V ref} input from the return path 11, but the power supply voltage of the power supply 1 is boosted by the boost coil 4. It suffices if the switch 5 can be switched, and the present invention is not limited to this.

In addition, the above embodiments are merely examples of embodiment of the present invention, and the technical scope of the present invention should not be construed in a limited manner by these. be. That is, the present invention can be implemented in various forms without departing from its gist or its main features. For example, the disclosure of the shape, number, and the like of each part described in the above embodiment is merely an example, and can be appropriately modified and carried out.

The power supply control device according to the present disclosure can be used as a device for controlling the power supply voltage to be boosted.

1 Power supply 2 Power supply controller 3 Load 4 Boost coil 5 Switch 6 Capacitor 7 Control unit 8a, 8b, 8c Commutator 9a, 9b, 9c Input path 10 Output path 11 Reflux path 12 Reference path V _in Input voltage V _out Output voltage V _ref reference voltage

Claims (3)

The boost coil connected between the vehicle power supply and the load,
A switch connected in parallel with the load in the output path connecting the boost coil and the load,
A control unit that controls switching of the switch so that the power supply voltage of the power supply is boosted by the step-up coil and output to the load.
An input path that connects between the power supply and the control unit and inputs an input voltage for operating the control unit.
A power supply control device including a recirculation path connecting the output path and the input path so that the current of the output path recirculates to the input path. A first commutator arranged in the return path so that a current flows from the output path to the input path,
Further, it has a second commutator arranged in the input path so as to allow a current to flow from the power source to the control unit.
The power supply control device according to claim 1, wherein the return path is connected between the second commutator and the control unit in the input path. Further having a capacitor connected in parallel with the switch between the switch and the load
The power supply control device according to claim 1 or 2, wherein the return path is connected between the capacitor and the load in the output path.

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