Power Control Device

Abstract

To provide a power controller that even when a load at a supply destination needs current exceeding an output limit of a DCDC converter, is capable of supplying necessary power to the load.SOLUTION: A power controller for controlling a power supply system having a structure including a DCDC converter for supplying a load with power of a battery and an alternator connected in parallel with the DCDC converter so as to ba capable of supplying the load with generated power comprises: a monitoring unit for monitoring current output to the load by the DCDC converter; and a control unit for controlling operation of the DCDC converter and the alternator. The control unit controls the alternator so as to generate power when the DCDC converter's output current monitored by the monitoring unit is equal to or larger than a first threshold, and controls the alternator so as not to generate power when the DCDC converter's output current monitored by the monitoring unit is equal to or smaller than a second threshold smaller than the first threshold.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a power control device for controlling output power of a power supply system. [Background technology]

[0002] Patent Document 1 discloses a control device that can more reliably start a vehicle engine. This patent document describes a method of using a DC-DC converter that limits output current by reducing output voltage when the output current exceeds a threshold, and performing boost control to increase the threshold value above normal when supplying power to an engine starting motor to start the engine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-157861 Summary of the Invention [Problem to be solved by the invention]

[0004] Normally, a DC-DC converter has an upper limit (output limit) for the allowable output current. Therefore, if the power output from the DC-DC converter is less than the power required by the load to which it is supplied, even if the boost control described in Patent Document 1 is performed to raise the threshold, there is a risk that the current from the DC-DC converter will be insufficient and the required power will not be supplied to the load.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a power control device that can supply the necessary power to a load even when the load requires a current that exceeds the output limit of the DC-DC converter. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the disclosed technology is a power control device that controls a power supply system, which includes a DC-DC converter that supplies battery power to a load and an alternator connected in parallel to the DC-DC converter so that the generated power can be supplied to the load, and which is equipped with a monitoring unit that monitors the current output by the DC-DC converter to the load, and a control unit that controls the operation of the DC-DC converter and the alternator, and the control unit controls the alternator to generate power when the output current of the DC-DC converter monitored by the monitoring unit is equal to or greater than a first threshold, and controls the alternator not to generate power when the output current of the DC-DC converter monitored by the monitoring unit is equal to or less than a second threshold that is smaller than the first threshold. [Effects of the Invention]

[0007] According to the power control device disclosed herein, when the load to which the DC-DC converter is supplied requires a current that exceeds the output limit of the DC-DC converter, the DC-DC converter and the alternator output power to the load in parallel, so that the required power can be supplied to the load. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram of a power control device according to an embodiment of the present disclosure and its peripheral components; [Figure 2] 1 is a flowchart of a power control process executed by a power control device. DETAILED DESCRIPTION OF THE INVENTION

[0009] The power control device disclosed herein controls a power supply system that includes a DC-DC converter that supplies power from a battery to a load and an alternator connected in parallel to the DC-DC converter. If the DC-DC converter's power supply to the load exceeds its output limit when only the DC-DC converter supplies power to the load, the power control device supplies power to the load in parallel from both the DC-DC converter and the alternator. This parallel supply control allows the required power to be supplied to the load. Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0010] [Embodiment] <Configuration> 1 is a functional block diagram showing a schematic configuration of a power control device 300 and its peripheral components according to an embodiment of the present disclosure. The functional block shown in FIG. 1 includes a power supply system 100, a load 200, the power control device 300, and an engine 400.

[0011] The power control device 300 is mounted on a vehicle such as a hybrid electric vehicle (HEV) or a plug-in hybrid electric vehicle (PHEV) that uses an internal combustion engine 400 as a power source.

[0012] The power supply system 100 is configured to supply power to a load 200. The power supply system 100 includes a battery 110, a DC-DC converter 120, and an alternator .

[0013] The battery 110 is a secondary battery configured to be rechargeable, such as a lithium-ion battery or a nickel-metal hydride battery. The battery 110 can output stored power to the DC-DC converter 120. An example of this battery 110 is a drive battery used to drive a vehicle.

[0014] The DCDC converter 120 is a voltage converter that is provided to connect the battery 110 and the load 200, converts the power of the battery 110 into power with a voltage suitable for the load 200, and outputs the power to the load 200. This DCDC converter 120 is connected to the power control device 300 via a signal line (dotted line in FIG. 1), and its operation is controlled by instructions from the power control device 300 in response to requests from the load 200, etc. An example of this DCDC converter 120 is a step-down DCDC converter that steps down the voltage of the battery 110 and outputs it to the load 200.

[0015] The alternator 130 is a generator that can generate electricity in response to the driving of the engine 400. The alternator 130 is connected in parallel with the DC-DC converter 120 so that it can output its own generated power to the load 200 together with the power of the DC-DC converter 120. The power control device 300 controls whether the alternator 130 is allowed to output the generated power.

[0016] The power control device 300 is configured to control the power supply from the DC-DC converter 120 and / or the alternator 130 to the load 200. The power control device 300 includes a monitoring unit 310 and a control unit 320.

[0017] The monitoring unit 310 monitors the current that the DC-DC converter 120 outputs to the load 200 for power supply. The output current of the DC-DC converter 120 can be acquired using a current sensor (not shown) provided in the power supply system 100 or the like.

[0018] The control unit 320 controls the operations of the DC-DC converter 120 and the alternator 130. More specifically, the control unit 320 instructs the DC-DC converter 120 to supply power from the battery 110 to the load 200 in accordance with the power request of the load 200. The control unit 320 also controls the operation (power generation state) of the alternator 130 based on the output current of the DC-DC converter 120 monitored by the monitoring unit 310. The control related to the operation of the alternator 130 will be described later.

[0019] A part or all of the above-described power control device 300 may be configured by an electronic control unit (HV_ECU, EFI_ECU, etc.) that typically includes a processor such as a microcomputer, a memory, an input / output interface, etc. This electronic control unit can realize a part or all of the functions performed by the above-described monitoring unit 310 and control unit 320 by having the processor read and execute a program stored in the memory.

[0020] The load 200 is an electronic device or equipment mounted on the vehicle that consumes power. The load 200 is configured to operate using power from the battery 110 supplied via the DC-DC converter 120 and / or power generated by the alternator 130. Note that the load 200 may also operate using power from another battery (such as an auxiliary battery) not shown.

[0021] <Control> Next, the control performed by the power control device 300 according to this embodiment will be described with further reference to Fig. 2. Fig. 2 is a flowchart illustrating the procedure of power control executed by the control unit 320 of the power control device 300. The power control illustrated in Fig. 2 is started, for example, when a power supply is requested by the load 200 (or when power consumption occurs).

[0022] (Step S201) The control unit 320 instructs the DC-DC converter 120 to supply power to the load 200. The supplied power is controlled by a voltage command value determined according to the request of the load 200 and the physical quantities (voltage, current) of another battery (not shown) connected to the load 200. When the control unit 320 instructs the DC-DC converter 120 to supply power, the process proceeds to step S202.

[0023] (Step S202) The control unit 320 acquires the output current of the DC-DC converter 120 monitored by the monitoring unit 310 and determines whether the output current of the DC-DC converter 120 is equal to or greater than a first threshold. This determination is made to confirm whether the output current of the DC-DC converter 120 exceeds its own output limit. Therefore, the first threshold can be set to any value lower than the upper limit of the current that the DC-DC converter 120 is allowed to output, based on this upper limit.

[0024] If the control unit 320 determines that the output current of the DC-DC converter 120 is equal to or greater than the first threshold (step S202, Yes), the process proceeds to step S204. On the other hand, if the control unit 320 determines that the output current of the DC-DC converter 120 is less than the first threshold (step S202, No), the process proceeds to step S203.

[0025] (Step S203) The control unit 320 acquires the output current of the DC-DC converter 120 monitored by the monitoring unit 310 and determines whether the output current of the DC-DC converter 120 is equal to or less than the second threshold. This determination is made to avoid the influence of control caused by the output current of the DC-DC converter 120 being determined to be equal to or greater than the first threshold in step S202 immediately changing to less than the first threshold. In other words, this determination is made to provide hysteresis so that transitions between the first state in step S204 and the second state in step S205, which will be described later, do not occur frequently. Therefore, the second threshold can be set to any value smaller than the first threshold so that frequent switching between the first state and the second state does not occur in a short period of time even if the output current of the DC-DC converter 120 fluctuates slightly.

[0026] If the control unit 320 determines that the output current of the DC-DC converter 120 is equal to or less than the second threshold (step S203, Yes), the process proceeds to step S205. On the other hand, if the control unit 320 determines that the output current of the DC-DC converter 120 exceeds the second threshold (step S203, No), the power control ends.

[0027] (Step S204) Control unit 320 sets ON a flag requesting the start of engine 400. In response to this flag being set ON, engine 400 is started under the control of a predetermined electronic control unit (if engine 400 is already running, that operation continues). When control unit 320 sets ON the engine start request flag, the process proceeds to step S206.

[0028] (Step S205) Control unit 320 sets OFF a flag requesting the start of engine 400. In response to this flag being set OFF, engine 400 that is running is stopped by control of a predetermined electronic control unit (if engine 400 is already stopped, its operation continues). When control unit 320 sets the engine start request flag OFF, the process proceeds to step S207.

[0029] (Step S206) The control unit 320 controls the alternator 130 to supply the electric power generated by the alternator 130 in conjunction with the operation of the engine 400 to the load 200. This allows the DC-DC converter 120 and the alternator 130 to supply electric power in parallel to the load 200. When the control unit 320 has supplied the electric power generated by the alternator 130 to the load 200, this power control ends.

[0030] (Step S207) When the engine 400 is stopped, the control unit 320 stops the power generation of the alternator 130 and stops the power supply from the alternator 130 to the load 200. This returns to the initial state in which power is supplied to the load 200 only from the DC-DC converter 120. When the control unit 320 stops the power supply from the alternator 130 to the load 200, this power control ends.

[0031] [Actions and Effects] As described above, according to the power control device 300 of one embodiment of the present disclosure, in the power supply system 100 including the DCDC converter 120 that supplies the power of the battery 110 to the load 200 and the alternator 130 that is connected in parallel with the DCDC converter 120 so that the generated power can be supplied to the load 200, when the output current of the DCDC converter 120 that supplies the power of the battery 110 to the load 200 is equal to or greater than a first threshold, the engine 400 is started and the alternator 130 is controlled to generate power, and when the output current of the DCDC converter 120 is equal to or less than a second threshold, the alternator 130 is controlled not to generate power.

[0032] With this control, when the load 200 to which the power is being supplied requires a current that exceeds the output limit of the DCDC converter 120, the DCDC converter 120 and the alternator 130 output power to the load 200 in parallel, so that the required power can be supplied to the load 200.

[0033] The above describes one embodiment of the present disclosure, but the present disclosure can be understood as not only a power control device, but also a method executed by a power control device equipped with a processor, memory, etc., a program for executing this method, a computer-readable non-transitory storage medium storing the program, and a vehicle equipped with a power control device. [Industrial Applicability]

[0034] The power control device of the present disclosure can be used in vehicles and the like that are equipped with a power supply system that includes a DC-DC converter and an alternator. [Explanation of symbols]

[0035] 100 Power System 110 Battery 120 DC-DC converter 130 Alternator 200 load 300 Power control device 310 Monitoring Department 320 Control Unit 400 Engine

Claims

1. A power control device for controlling a power supply system including a DC-DC converter that supplies power from a battery to a load, and an alternator that is connected in parallel with the DC-DC converter so as to be able to supply generated power to the load, a monitoring unit that monitors a current output from the DC-DC converter to the load; a control unit that controls operations of the DC-DC converter and the alternator, In a state in which the control unit instructs the operation of the DC-DC converter in response to a power request from the load, When the output current of the DC-DC converter monitored by the monitoring unit is equal to or greater than a first threshold, the alternator is controlled to generate power; When the output current of the DC-DC converter monitored by the monitoring unit is equal to or less than a second threshold value that is smaller than the first threshold value, the alternator is controlled not to generate power. Power control device.

2. the first threshold is set based on an upper limit value of a current that is allowed to be output from the DC-DC converter; The power control device according to claim 1 .

3. The power supply system is mounted on a vehicle, The control unit controls the power generation state of the alternator by starting or stopping the engine of the vehicle. The power control device according to claim 1 or 2.

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