JP7437231B2 - Power system control device and control method - Google Patents

Description

The present invention relates to a control device and a control method for a power supply system.

Conventionally, a technique has been proposed in which when a short-circuit failure occurs in a relay connected to a battery, the relay is controlled on and off to avoid a welding failure in the relay (for example, see Patent Document 1) ).

International Publication No. 2010/122648

However, the conventional technology has room for further improvement in terms of preventing abnormalities from occurring in the relay when an overcurrent occurs in the current path in which the relay is inserted.

The present invention has been made in view of the above, and includes a control device and a control device for a power supply system that can prevent abnormalities from occurring in a relay when an overcurrent occurs in a current path in which the relay is inserted. The purpose is to provide a control method.

In order to solve the above problems and achieve the objects, the present invention provides a control device for a power supply system that includes a detection section, a relay control section, and a power generation control section. The detection unit detects overcurrent in a current path connecting the generator and the battery. The relay control section maintains an on state of a relay inserted in the current path between the generator and the battery when the overcurrent is detected by the detection section. The power generation control section causes the generator to stop power generation while the relay is maintained in an on state by the relay control section.

According to the present invention, it is possible to prevent an abnormality from occurring in a relay when an overcurrent occurs in a current path in which a relay is inserted.

FIG. 1 is a block diagram showing a configuration example of a power supply system including a control device according to an embodiment. FIG. 2 is a block diagram showing the configuration of a power supply system including a control device. FIG. 3 is a flowchart showing the processing procedure executed by the control device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a control device and a control method for a power supply system disclosed in the present application will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments described below.

Furthermore, in the following, an example will be given in which the control device controls a power supply system installed in a vehicle such as a HEV (Hybrid Electric Vehicle), μHEV (Micro Hybrid Electric Vehicle), or PHEV (Plug-in Hybrid Electric Vehicle). I will explain. Note that the object to be controlled by the control device is not limited to a power supply system mounted on a vehicle, but may be a power supply system mounted on any device.

(Overall configuration of power supply system including control device)
First, a power supply system including a control device according to an embodiment will be described using FIG. 1. FIG. 1 is a block diagram showing a configuration example of a power supply system including a control device according to an embodiment.

As shown in FIG. 1, power supply system 1 includes a generator 11, a lead battery 12, an auxiliary machine 13, a relay 14, and a control device 20.

In addition, in the example shown in FIG. 1, the power supply system 1 was equipped with one lead battery 12, but it is not limited to this. That is, for example, the power supply system 1 may include a LIB (Lithium-Ion rechargeable battery) and may be a two-power supply system with dual batteries. Furthermore, the power supply system 1 may include three or more batteries.

The generator 11 is a device that generates electric power using the rotation of an engine (not shown) as a power source. Additionally, when the vehicle is decelerating, regenerative braking generates regenerative power. Note that the generator 11 is also called an alternator or a generator. Further, the generator 11 may function as a starter that starts the engine. That is, the generator 11 may be an ISG (Integrated Starter Generator).

Further, the generator 11 may generate electric power according to an instruction from the control device 20, for example. Then, the lead battery 12 is charged by supplying the generated power to the lead battery 12, for example.

The lead battery 12 is a secondary battery using lead as an electrode. The lead battery 12 serves as a power source for an auxiliary device 13 mounted on a vehicle, for example. Note that the lead battery 12 is an example of a battery. Further, the lead battery 12 may be another type of secondary battery such as LIB.

The auxiliary machine 13 is an electrical device (load) mounted on the vehicle. For example, the auxiliary equipment 13 is a navigation device, an audio device, an air conditioner, etc., but these are examples and are not limited. The auxiliary machine 13 can receive power from the lead battery 12 .

The lead battery 12, generator 11, and auxiliary machine 13 described above are connected in parallel. For example, the generator 11 and the lead battery 12 are connected via a first path (current path) L1. The auxiliary machine 13 is connected to the lead battery 12 via a second path (current path) L2 connected to the first path L1 and the first path L1.

Relay 14 is a switch that controls shorting and opening of the circuit. Relay 14 is inserted between lead battery 12 and generator 11 . Specifically, the relay 14 is inserted in the first path L1 between the generator 11 and the lead battery 12. Specifically, the relay 14 is inserted between the generator 11 and the position where the second path L2 is connected in the first path L1.

Relay 14 includes a pair of transistors 151 and 152 and a shunt resistor 153. Note that as the transistors 151 and 152, for example, MOSFETs (Metal-Oxide-Semiconductor Field Effect Transistors) can be used, but the present invention is not limited thereto.

A pair of transistors 151 and 152 are connected in series. For example, the transistor 151 has one end connected to the generator 11 and the other end connected to the transistor 152. The transistor 152 has one end connected to the transistor 151 and the other end connected to the lead battery 12.

The transistors 151 and 152 have a switching element and a body diode, and the switching element and the body diode are connected in parallel. Body diodes of transistors 151 and 152 are provided in opposite directions. For example, the body diode of transistor 151 has an anode connected to transistor 152 and a cathode connected to generator 11 . Further, the body diode of the transistor 152 has an anode connected to the transistor 151 and a cathode connected to the lead battery 12. Thereby, for example, the relay 14 is configured such that no current flows between the pair of transistors 151 and 152 when the relay 14 is turned off (more precisely, when the switching elements of the transistors 151 and 152 are turned off).

Shunt resistor 153 is connected in series between transistor 151 and transistor 152. For example, in the shunt resistor 153, a potential difference occurring between both ends is detected by the control device 20, and a current flowing through the shunt resistor 153 is measured from a voltage value based on the detected potential difference. Note that the shunt resistor 153 may be connected to a pull-down resistor. Further, the shunt resistor 153 may be connected to the generator 11 side of the transistor 151 or to the lead battery 12 side of the transistor 152. Note that in the above, the current is detected using the shunt resistor 153, but the present invention is not limited to this, and the current may be detected using other types of current sensors such as a Hall type current sensor.

A fuse 16 is inserted in the first path L1 between the relay 14 and the lead battery 12 described above. Specifically, the fuse 16 is inserted in the first path L1 between the lead battery 12 and the position where the second path L2 is connected.

In the power supply system 1 configured as described above, an overcurrent may flow in the first path (current path) L1 connecting the generator 11 and the lead battery 12. For example, when the relay 14 is in the on (conducting) state, if a ground fault occurs at point A on the lead battery 12 side of the relay 14 in the first path L1, as shown by the two-dot chain line in FIG. An overcurrent flows through the path L1 from the generator 11 to the ground fault location (see arrow B1). Specifically, if the harness connecting the relay 14 and the lead battery 12 is grounded for some reason, the above-mentioned overcurrent flows to the first path L1.

If the overcurrent continues to flow through the relay 14, the amount of heat generated will increase, and there is a risk that the relay 14 will malfunction due to the heat generation. Here, for example, if the relay 14 is turned off with an overcurrent flowing, the switching loss in the transistors 151 and 152 of the relay 14 will increase excessively, and there is a possibility that an abnormality of the relay such as damage may occur.

Therefore, the control device 20 according to the present embodiment is configured to be able to prevent an abnormality from occurring in the relay 14 when an overcurrent occurs in the first path L1.

Note that when a ground fault occurs at point A on the first path L1, an overcurrent also flows from the lead battery 12 to the ground fault location in the first path L1 (see arrow B2). In such a case, the fuse 16 provided between the lead battery 12 and the ground fault location in the first path L1 is blown, and the lead battery 12 and the like are protected.

(Configuration of control device)
Next, with reference to FIG. 2, the configuration of the power supply system 1 including the control device 20 according to the embodiment will be described in detail. FIG. 2 is a block diagram showing the configuration of the power supply system 1 including the control device 20 according to the embodiment. Note that in FIG. 2, only the components necessary to explain the features of this embodiment are shown as functional blocks, and descriptions of general components are omitted.

In other words, each component illustrated in FIG. 2 is functionally conceptual, and does not necessarily need to be physically configured as illustrated. For example, the specific form of distributing and integrating each functional block is not limited to what is shown in the diagram, and all or part of it can be functionally or physically distributed in arbitrary units depending on various loads and usage conditions. - Can be configured in an integrated manner.

As shown in FIG. 2, the control device 20 of the power supply system 1 includes an input section 31, an output section 32, a control section 40, and a storage section 50. The control section 40 includes a detection section 41, a relay control section 42, and a power generation control section 43.

The input section 31 receives a signal indicating the current flowing through the shunt resistor 153 (see FIG. 1) from the relay 14, and outputs this signal to the control section 40.

The output unit 32 outputs a signal for turning on (conducting) or off (blocking) the relay 14. For example, the on signal for turning on the relay 14 is a signal that turns on the transistors 151 and 152 of the relay 14. Further, the off signal for turning off the relay 14 is a signal that turns off the transistors 151 and 152 of the relay 14.

The output unit 32 outputs a signal for controlling the generator 11. For example, the output unit 32 can output a stop signal that causes the generator 11 to stop generating electricity.

The storage unit 50 is, for example, a storage device such as a data flash, a nonvolatile memory, or a register, and stores various programs and information.

The control unit 40 includes, for example, a computer and various circuits having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an HDD (Hard Disk Drive), an input/output port, and the like.

The CPU of the computer functions as the detection section 41, relay control section 42, and power generation control section 43 of the control section 40, for example, by reading and executing a program stored in the ROM.

Furthermore, at least a part or all of the detection unit 41, relay control unit 42, and power generation control unit 43 of the control unit 40 is configured with hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). You can also do that.

The detection unit 41 can detect an overcurrent in the first path (current path) L1 connecting the generator 11 and the lead battery 12. For example, the detection unit 41 detects an overcurrent in the first path L1 when the current flowing through the shunt resistor 153 of the relay 14 exceeds the rated current of the relay 14. Note that the relay 14 at this time is turned on (conducted).

When an overcurrent is detected, the detection unit 41 outputs an overcurrent detection signal indicating that an overcurrent has been detected to the relay control unit 42 and the power generation control unit 43.

Note that in the above description, the detection unit 41 detects an overcurrent when the current flowing through the relay 14 exceeds the rated current, but the present invention is not limited to this. That is, for example, the detection unit 41 may detect an overcurrent using other methods, such as detecting an overcurrent when the current flowing through the relay 14 exceeds an arbitrary current value set in advance. Furthermore, the detection unit 41 may provide a current sensor different from the shunt resistor 153 at an arbitrary position on the first path L1, and detect an overcurrent based on the output of the current sensor.

The relay control unit 42 maintains the ON state of the relay 14 when the detection unit 41 detects an overcurrent, in other words, when the above-described overcurrent detection signal is input. That is, the relay control section 42 continues to output the ON signal from the output section 32 to the relay 14 in which the overcurrent flows.

The power generation control unit 43 stops the power generation of the generator 11 while the relay 14 is maintained in the on state. For example, the power generation control unit 43 outputs a stop signal to the generator 11 via the output unit 32. As a result, the generator 11 stops generating electricity, and therefore the current flowing through the relay 14 decreases, and eventually the relay 14 can be in a state where no current flows.

In this way, in this embodiment, the power generation of the generator 11 is stopped while the relay 14 is maintained in the ON state, so that, for example, an overcurrent continues to flow through the relay 14 and the amount of heat generated increases. Therefore, it is possible to prevent an abnormality in the relay 14 from occurring due to heat generation.

Subsequently, the relay control unit 42 turns off the relay 14 after the generator 11 stops generating electricity. For example, the relay control unit 42 outputs an off signal to the relay 14 via the output unit 32 when the current does not flow through the relay 14 due to the stoppage of power generation by the generator 11 . This turns off the relay 14.

Note that in the above description, the relay control unit 42 turns off the relay 14 when no current flows through the relay 14, but the present invention is not limited to this. That is, for example, if the current flowing through the relay 14 decreases and becomes less than the rated current due to the stoppage of power generation by the generator 11, the relay control unit 42 may turn off the relay 14 at any timing after the power generation stops. The relay 14 may be turned off.

In this way, in this embodiment, the relay 14 is turned off after the power generation of the generator 11 is stopped, so that, for example, when the relay 14 is turned off in an overcurrent state, the transistor 151 of the relay 14 is turned off. , 152 does not increase excessively. Therefore, it is possible to prevent relay abnormalities such as damage due to increased switching loss from occurring.

Moreover, in this embodiment, by configuring as described above, it becomes possible to safely release an overcurrent state that occurs in the power supply system 1.

(Processing procedure of control device)
Next, the processing procedure executed by the control device 20 according to the embodiment will be described using FIG. 3. FIG. 3 is a flowchart showing the processing procedure executed by the control device 20.

As shown in FIG. 3, the control unit 40 of the control device 20 determines whether an overcurrent is detected in the first path L1 connecting the generator 11 and the lead battery 12 (step S100). If it is determined that no overcurrent is detected in the first path L1 (step S100, No), the control unit 40 ends the process.

On the other hand, if it is determined that an overcurrent in the first path L1 has been detected (Step S100, Yes), the control unit 40 maintains the ON state of the relay 14 (Step S101), and then stops the generator 11 from generating power. It is stopped (step S102). After the generator 11 stops generating electricity, the control unit 40 turns off the relay 14 (step S103).

As described above, the control device 20 according to the embodiment includes the detection section 41, the relay control section 42, and the power generation control section 43. The detection unit 41 detects an overcurrent in a first path (current path) L1 connecting the generator 11 and the lead battery 12. When the detection unit 41 detects an overcurrent, the relay control unit 42 maintains the relay 14 inserted in the first path L1 between the generator 11 and the lead battery 12 in an on state. The power generation control section 43 stops the power generation of the generator 11 while the relay control section 42 maintains the on state of the relay 14 . Thereby, when an overcurrent occurs in the first path L1 in which the relay 14 is inserted, it is possible to prevent an abnormality from occurring in the relay 14, in other words, it is possible to protect the relay 14.

Further advantages and modifications can be easily deduced by those skilled in the art. Therefore, the broader aspects of the invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various changes may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

1 power supply system 11 generator 12 lead battery 14 relay 20 control device 40 control section 41 detection section 42 relay control section 43 power generation control section

Claims (3)

a detection unit that detects overcurrent in a current path connecting the generator and the battery;
a relay control unit that maintains an on state of a relay inserted in the current path between the generator and the battery when the overcurrent is detected by the detection unit;
A power generation control unit for stopping power generation of the generator while the relay is maintained in an on state by the relay control unit. A control device for a power supply system. The relay control section includes:
The control device for a power supply system according to claim 1, wherein the relay is turned off after the power generation control unit stops power generation of the generator. a detection step of detecting overcurrent in a current path connecting the generator and the battery;
a relay control step of maintaining an on state of a relay inserted in the current path between the generator and the battery when the overcurrent is detected in the detection step;
A method for controlling a power supply system, comprising: a power generation control step of stopping power generation of the generator while the relay is maintained in an on state by the relay control step.

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