Power control device, control method, and control program

Abstract

To provide a power supply control device with which it is possible to suppress the connection abnormality of a low-voltage battery from being erroneously determined in a technique that detects the charge / discharge currents of the low-voltage battery.SOLUTION: Provided is a power supply control device that controls a power converter that connects a high-voltage battery and a low-voltage battery. The power supply control device comprises an acquisition unit that acquires the charge / discharge current of the low-voltage battery, a detection unit that detects the prescribed operation having been executed regarding the high-voltage battery, and a determination unit that determines the presence of abnormality regarding the connection state of the low-voltage battery on the basis of the charge / discharge current. The determination unit determines whether or not the charge / discharge current continues to be smaller than or equal to a first threshold for a first duration when the prescribed operation is detected, and further determines, by controlling the power converter, whether or not the charge / discharge current continues to be smaller than or equal to the first threshold for a second duration that is longer than the first duration when the charge / discharge current continues to be smaller than or equal to the first threshold for the first duration, and determines that the connection state of the low-voltage battery is abnormal when the charge / discharge current continues to be smaller than or equal to the first threshold for the second duration.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a power supply control device that controls a power converter connecting a high-voltage battery and a low-voltage battery, etc.

Background Art

[0002] Patent Document 1 discloses an in-vehicle charging device that controls charging of a low-voltage battery by operating a step-down converter that steps down the voltage of a high-voltage battery and applies it to the low-voltage battery. In this in-vehicle charging device, based on the voltage difference generated between the output voltage of the step-down converter and the voltage of the low-voltage battery, it detects that a disconnection has occurred between the step-down converter and the low-voltage battery.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a connection abnormal state where the low-voltage battery is not properly connected to the step-down converter due to disconnection or terminal detachment, etc., the low-voltage battery cannot be charged or discharged. For this reason, it is conceivable to detect the charge and discharge current of the low-voltage battery and determine whether a connection abnormality has occurred in the low-voltage battery.

[0005] However, in the low-voltage battery mounted on a vehicle, there is a situation where, for example, when parked, the power of the high-voltage battery is controlled in a state where charging and discharging of the low-voltage battery are not intentionally performed. For this reason, simply detecting the presence or absence of the charge and discharge current of the low-voltage battery may result in an incorrect determination of the occurrence of a connection abnormality.

[0006] The present disclosure has been made in view of the above problems, and an object thereof is to provide a power control device or the like that can suppress an erroneous determination of an abnormal connection of a low-voltage battery in a method for detecting a charge and discharge current of the low-voltage battery.

Means for Solving the Problems

[0007] In order to solve the above problems, an aspect of the present disclosure technology is a power control device that controls a power converter connecting a high-voltage battery and a low-voltage battery, the power control device including: an acquisition unit that acquires a charge and discharge current of the low-voltage battery; and a control operation that causes a fluctuation in the power of the high-voltage battery Control and a detection unit that detects; and a determination unit that determines the presence or absence of an abnormality regarding the connection state of the low-voltage battery based on the charge and discharge current. The determination unit control when an operation is detected, determine that the state where the charge / discharge current is zero continues determines whether the charge and discharge current greater than the first threshold value continues in a state for a first time, by and when the charge and discharge current greater than the first threshold value continues in the state for the first time, performs control of the power converter to forcibly change the charge and discharge current. Further determines whether the charge and discharge current greater than the first threshold value continues in a state for a second time longer than the first time, and when the charge and discharge current greater than the first threshold value continues in the state for the second time, determines that the connection state of the low-voltage battery is abnormal.

Effects of the Invention

[0008] According to the power control device and the like of the present disclosure, it is possible to suppress an erroneous determination of an abnormal connection of the low-voltage battery in a method for detecting a charge and discharge current of the low-voltage battery.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0010] The power control device according to the present disclosure determines step by step while controlling the change in the charge and discharge current, the time during which the state where the charge and discharge current of the low-voltage battery becomes equal to or less than a predetermined threshold value continues. Thereby, even by simply detecting the charge and discharge current of the low-voltage battery, it is possible to accurately determine whether the connection state of the low-voltage battery is normal or abnormal. Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0011] <Embodiment> [Configuration] FIG. 1 is a functional block diagram of a power control device 60 according to an embodiment of the present disclosure and its peripheral parts. The functional blocks illustrated in FIG. 1 include a high-voltage battery 10, a low-voltage battery 20, a generator 30, a solar panel 40, a power converter 50, and a power control device 60. The high-voltage battery 10, the low-voltage battery 20, the generator 30, the solar panel 40, the power converter 50, and the power control device 60 can be mounted on a vehicle or the like.

[0012] The high-voltage battery 10 is a secondary battery configured to be chargeable and dischargeable, such as a lithium-ion battery or a nickel-metal hydride battery. The high-voltage battery 10 is connected to the power converter 50 so as to be chargeable by the electric power generated by the generator 30 or the solar panel 40. Further, the high-voltage battery 10 is connected to the power converter 50 so as to be able to output electric power (pumping control) to a low-voltage system load (not shown) that is driven exclusively by the electric power of the low-voltage battery 20. As the high-voltage battery 10 mounted on a vehicle, an example can be a so-called driving battery that can supply the electric power necessary for the operation of a high-voltage system load (not shown) such as a starter motor or an electric motor.

[0013] The low-voltage battery 20 is a rechargeable secondary battery such as a lithium-ion battery or a lead-acid battery. This low-voltage battery 20 is connected to a power converter 50 so as to be rechargeable by the electric power generated by a generator 30 or a solar panel 40. Further, the low-voltage battery 20 is connected to the power converter 50 so as to be able to charge the high-voltage battery 10. The low-voltage battery 20 mounted on a vehicle can be exemplified by a so-called accessory battery that can supply the electric power necessary for the operation of low-voltage loads such as lights such as headlamps and interior lights, and air conditioners such as heaters and coolers.

[0014] The generator 30 is a device that can generate predetermined electric power such as an alternator, and is connected to the power converter 50 so as to be able to output the generated electric power. The electric power output by this generator 30 is controlled by the power converter 50.

[0015] The solar panel 40 is a device that can generate predetermined electric power by receiving sunlight such as a solar cell module, and is connected to the power converter 50 so as to be able to output the generated electric power. This solar panel 40 can be installed, for example, on the roof of a vehicle. The electric power output by this solar panel 40 is controlled by the power converter 50.

[0016] The power converter 50 is a device that can input the electric power generated by the generator 30 or the solar panel 40, convert (step up / step down) it to a predetermined voltage, and output it to the high-voltage battery 10 or the low-voltage battery 20. Further, the power converter 50 can input the electric power stored in the high-voltage battery 10, step it down to a predetermined voltage, and output it to the low-voltage battery 20. This power converter 50 has a configuration including a DC-DC converter or the like.

[0017] The power control device 60 is configured to control the power converter 50 to control the power transfer among the high-voltage battery 10, the low-voltage battery 20, the generator 30, and the solar panel 40. In particular, the power control device 60 according to the present embodiment performs control to determine the presence or absence of an abnormality in the connection state of the low-voltage battery 20. To perform this determination control, the power control device 60 includes an acquisition unit 61, a detection unit 62, and a determination unit 63.

[0018] The acquisition unit 61 acquires the charge and discharge current, which is the charging current flowing into the low-voltage battery 20 and the discharging current flowing out of the low-voltage battery 20. For acquiring this charge and discharge current, a current sensor provided in the power converter 50 or the low-voltage battery 20 can be used.

[0019] The detection unit 62 detects a predetermined operation executed on the high-voltage battery 10. The predetermined operation is a control operation that causes a change in the power of the high-voltage battery 10 while maintaining the state of charge (SOC) of the low-voltage battery 20, that is, in a state where the low-voltage battery 20 neither charges nor discharges (charge and discharge current = 0). Examples of this predetermined operation include control (pumping control) for supplying power from the high-voltage battery 10 to a low-voltage system load connected to the low-voltage battery 20 via the power converter 50, and control (solar high-voltage charging control) for charging the high-voltage battery 10 with the power generated by the solar panel 40 via the power converter 50.

[0020] The pumping control is a control for suppressing the deterioration of the low-voltage battery 20 by starting the high-voltage system including the high-voltage battery 10 and supplying power from the high-voltage battery 10 to necessary equipment when boarding before the vehicle state becomes READY-ON and when getting off after the vehicle state becomes READY-OFF. Since the purpose of this pumping control is to supply power to the equipment operating during boarding and alighting while suppressing the consumption of the high-voltage battery 10, the DCDC converter is controlled so that the low-voltage battery 20 reaches a voltage at which it neither charges nor discharges.

[0021] Furthermore, the solar high-voltage charging control is a control aimed at charging the high-voltage battery 10 with the electric power generated by the solar panel 40 to extend the driving range. This solar high-voltage charging control automatically starts when the solar panel 40 is irradiated with sunlight after the ignition of the vehicle is turned off (IG-OFF), and charging of the high-voltage battery 10 is started. Since charging of the high-voltage battery 10 is prioritized in the solar high-voltage charging control, the power by which the low-voltage battery 20 neither charges nor discharges is required for the solar panel 40 by feedback control.

[0022] When the detection unit 62 detects a predetermined operation, the determination unit 63 determines the presence or absence of an abnormality regarding the connection state of the low-voltage battery 20 by appropriately changing the output voltage of the power converter 50 or the like based on the charge and discharge current acquired by the acquisition unit 61. Examples of the abnormality regarding the connection state of the low-voltage battery 20 include a state where the terminals of the low-voltage battery 20 are disconnected and a state where the wiring connecting the low-voltage battery 20 to the power converter 50 is disconnected. Details of the control performed by this determination unit 63 will be described later.

[0023] Part or all of the above-described power supply control device 60 can typically be configured as an electronic control unit (ECU) including a processor, a memory, an input / output interface, and the like. This electronic control unit can realize part or all of the acquisition unit 61, the detection unit 62, and the determination unit 63 by the processor reading and executing a program stored in the memory.

[0024] [Control] Next, with further reference to FIG. 2, the control executed by the power supply control device 60 will be described. FIG. 2 is a flowchart for explaining the processing procedure of the connection state determination control executed by each component of the power supply control device 60.

[0025] The connection state determination control illustrated in FIG. 2 starts when the ignition of the vehicle is turned off (IG-OFF) while the vehicle is parked or stopped, and is repeatedly executed until the ignition is turned on (IG-ON) when no abnormality determination is made.

[0026] (Step S201) The detection unit 62 determines whether or not a predetermined operation executed on the high-voltage battery 10 has been detected. More specifically, the detection unit 62 determines whether or not an operation of intentionally controlling the charge / discharge current of the low-voltage battery 20 to zero and operating the high-voltage system including the high-voltage battery 10 has been started. If the detection unit 62 determines that a predetermined operation has been detected (Step S201, Yes), the process proceeds to Step S202.

[0027] (Step S202) The power control device 60 changes the state of "normal control" for controlling the power transfer between the high-voltage battery 10, the low-voltage battery 20, the generator 30, and the solar panel 40 to the state of "diagnostic control" for determining the connection state of the low-voltage battery 20. When the state transitions to the diagnostic control, the process proceeds to Step S203.

[0028] (Step S203) The determination unit 63 determines whether or not the charge / discharge current of the low-voltage battery 20 has greater than the first threshold value continued in a state for the first period of time. This determination is made to preliminarily determine whether or not the low-voltage battery 20 is in a state where it is neither charging nor discharging. The first period of time can be set based on factors such as determination accuracy and detection ability, and can be, for example, 1 second. If the determination unit 63 determines that the charge / discharge current of the low-voltage battery 20 has greater than the first threshold value continued in a state for the first period of time (Step S203, Yes), the process proceeds to Step S204. On the other hand, if the determination unit 63 determines that the charge / discharge current of the low-voltage battery 20 has greater than the first threshold value not continued in a state for the first period of time (Step S203, No), the process proceeds to Step S206.

[0029] (Step S204) The determination unit 63 controls the power converter 50 to forcibly change or generate the charge and discharge current of the low-voltage battery 20. The current to be changed or generated may be in the charging direction or the discharging direction. As an example, when the predetermined operation detected in step S201 is pumping control, it is conceivable to increase or decrease the command voltage of the DCDC converter that steps down and outputs the power of the high-voltage battery 10. Further, when the predetermined operation detected in step S201 is solar high-voltage charging control, it is conceivable to decrease the power generation required power to the solar panel 40. When the power converter 50 is controlled by the determination unit 63, the process proceeds to step S205.

[0030] (Step S205) After the determination unit 63 controls the power converter 50, it determines whether the charge and discharge current of the low-voltage battery 20 greater than the first threshold value has continued in the state for a further second period of time. This determination is made to determine whether the low-voltage battery 20 is in a state where it is neither charging nor discharging. The second period is set longer than the first period and can be, for example, 3 seconds. When the determination unit 63 determines that the charge and discharge current of the low-voltage battery 20 greater than the first threshold value has continued in the state for the second period of time (step S205, yes), the process proceeds to step S207. On the other hand, when the determination unit 63 determines that the charge and discharge current of the low-voltage battery 20 greater than the first threshold value has not continued in the state for the second period of time (step S205, no), the process proceeds to step S206.

[0031] (Step S206) The power control device 60 returns the state of "diagnostic control" for determining the connection state of the low-voltage battery 20 to the state of "normal control" for controlling the power transfer between the high-voltage battery 10, the low-voltage battery 20, the generator 30, and the solar panel 40. When the state returns to normal control, the process proceeds to step S201.

[0032] (Step S207) The determination unit 63 determines (confirms) that an abnormality has occurred in the connection state of the low-voltage battery 20. When the determination unit 63 determines that there is an abnormality, it may stop the operation of the power converter 50. By stopping this operation, the safety during service work and the like is further ensured. When the determination unit 63 determines that the connection state of the low-voltage battery 20 is abnormal, the connection state determination control ends.

[0033] [Example of operation timing] FIG. 3 shows an example of a timing chart of each state when the connection state of the low-voltage battery 20 is normal.

[0034] At time T1, the execution of a predetermined operation is detected for the high-voltage battery 10. When a predetermined operation is detected, the charge and discharge current of the low-voltage battery 20 greater than the first threshold value The measurement of the time for which the state continues is started using a timer or the like. Thereafter, at time T2, the charge and discharge current of the low-voltage battery 20 greater than the first threshold value When the state continues for the first hour (for example, 1 second), the flag for provisional determination of abnormality is turned on, and the power converter 50 performs control to cause a change in the charge and discharge current of the low-voltage battery 20. For example, when the predetermined operation is draw control, the command voltage of the DCDC converter that steps down and outputs the power of the high-voltage battery 10 is lowered by 0.5 V, or when the predetermined operation is solar high-voltage charging control, the power generation request power to the solar panel 40 is lowered by 5 W. When the connection state of the low-voltage battery 20 is normal as shown in FIG. 3, the charge and discharge current of the low-voltage battery 20 changes decrease and at time T3 equal to or less than the first threshold value becomes. Therefore, this At this timing, the flag for provisional determination of abnormality is turned off, and it is confirmed that the connection state of the low-voltage battery 20 is normal.

[0035] FIG. 4 shows an example of a timing chart of each state when the connection state of the low-voltage battery 20 is abnormal.

[0036] At time T1, the execution of a predetermined operation is detected for the high-voltage battery 10. When the predetermined operation is detected, the charge and discharge current of the low-voltage battery 20 is greater than the first threshold value The measurement of the time for which the state continues is started using a timer or the like. Then, at time T2, the charge and discharge current of the low-voltage battery 20 is greater than the first threshold value When the state continues for the first time (for example, 1 second), the flag for abnormal provisional determination becomes ON, and the power converter 50 performs control to cause a change in the charge and discharge current of the low-voltage battery 20. When the connection state of the low-voltage battery 20 is abnormal as shown in FIG. 4, the charge and discharge current of the low-voltage battery 20 is decrease Since it does not occur, equal to or less than the first threshold value The charge and discharge current of the low-voltage battery 20 at time T4 does not become greater than the first threshold value The state will continue for the second time (for example, 3 seconds). Therefore, at the timing when this second time is reached, the flag for abnormal final determination becomes ON, and it is determined that the connection state of the low-voltage battery 20 is abnormal.

[0037] <Operation and Effect> As described above, in the power control device 60 according to an embodiment of the present disclosure, in the method of determining the connection abnormality of the low-voltage battery 20 based on the charge and discharge current of the low-voltage battery 20, when the execution of a predetermined operation is detected for the high-voltage battery 10, first, the charge and discharge current is greater than the first threshold value It is determined whether or not the state continues for the first time (provisional determination). Here, when the charge and discharge current is greater than the first threshold value When the state continues for the first time, next, the power converter 50 is controlled to further determine whether or not the charge and discharge current is greater than the first threshold value The state continues for a second time longer than the first time (final determination). Then, when the charge and discharge current is greater than the first threshold value When the state continues for the second time, it is determined that the connection state of the low-voltage battery 20 is abnormal.

[0038] By determining the connection state of the low-voltage battery 20 through such step-by-step determination, even in a situation where, for example, during parking, the power of the high-voltage battery 10 is controlled without intentionally charging and discharging the low-voltage battery 20, it is possible to suppress false determination of connection abnormality of the low-voltage battery 20 only by detecting the charge and discharge current of the low-voltage battery 20. Further, when the low-voltage battery 20 is in a fully charged state, it is difficult to detect the charge and discharge current. Therefore, by controlling the power converter 50 on the discharge side, it is possible to suppress false determination of connection abnormality of the low-voltage battery 20.

[0039] By appropriately determining the connection abnormality of the low-voltage battery 20, for example, in a situation where the connection terminal of the low-voltage battery 20 is removed during a service operation such as vehicle maintenance, even if the high-voltage system attempts to start without the operator noticing, the control of this embodiment determines that the connection state of the low-voltage battery 20 is abnormal and stops the operation of the power converter 50. Therefore, the safety and peace of mind of the operator during service operations can be ensured.

[0040] As described above, one embodiment of the disclosed technology has been explained. However, the present disclosure can be understood not only as a power control device, but also as a method performed by the power control device, a program of the method, a computer-readable non-transitory storage medium storing the program, a vehicle equipped with the power control device, and the like.

Industrial Applicability

[0041] The power control device and the like of the present disclosure can be used in vehicles equipped with a high-voltage battery and a low-voltage battery.

Explanation of Reference Numerals

[0042] 10 High-voltage battery 20 Low-voltage battery 30 Generator 40 Solar panel 50 Power converter 60 Power control device 61 Acquisition unit 62 Detection unit 63 Determination unit

Claims

1. A power supply control device for controlling a power converter that connects a high-voltage battery and a low-voltage battery, an acquisition unit that acquires the charge and discharge current of the low-voltage battery, a detection unit that controls the charge and discharge current of the low-voltage battery to a zero state and detects a control operation that causes fluctuations in the power of the high-voltage battery, a determination unit that determines whether there is an abnormality regarding the connection state of the low-voltage battery based on the charge and discharge current, and includes: when the control operation is detected, the determination unit determines whether the state where the charge and discharge current is zero continues based on whether the state where the charge and discharge current is greater than a first threshold value continues for a first time, when the state where the charge and discharge current is greater than the first threshold value continues for the first time, controls the power converter to forcibly change the charge and discharge current, and further determines whether the state where the charge and discharge current is greater than the first threshold value continues for a second time longer than the first time, a power supply control device that determines that the connection state of the low-voltage battery is abnormal when the state where the charge and discharge current is greater than the first threshold value continues for the second time.

2. The control operation is an operation of supplying power from the high-voltage battery to a load connected to the low-voltage battery via the power converter, when the state where the charge and discharge current is greater than the first threshold value continues for the first time, the determination unit controls the power converter to change the output voltage of the power converter, according to the power supply control device of claim 1.

3. The control operation is an operation of charging the high-voltage battery with the power generated by a solar panel via the power converter, when the state where the charge and discharge current is greater than the first threshold value continues for the first time, the determination unit controls the power converter to change the power input from the solar panel by the power converter, according to the power supply control device of claim 1.

4. The abnormal connection state of the low-voltage battery includes a state where the terminals of the low-voltage battery are disconnected or a state where the wiring connecting the low-voltage battery to the power converter is disconnected, according to any one of claims 1 to 3. The power supply control device described in the item.

5. when the determination unit determines that the connection state of the low-voltage battery is abnormal, the power supply control device according to claim 4 stops the operation of the power converter.

6. A control method executed by a power supply control device that controls a power converter that connects a high-voltage battery and a low-voltage battery, A step of controlling the charge and discharge current of the low-voltage battery to a zero state and detecting a control operation that causes a fluctuation in the power of the high-voltage battery; When the control operation is detected, obtaining the charge and discharge current of the low-voltage battery, and determining whether the state where the charge and discharge current is zero continues based on whether the state where the charge and discharge current is greater than the first threshold continues for a first time; When the state where the charge and discharge current is greater than the first threshold continues for the first time, controlling the power converter to forcibly change the charge and discharge current, and further determining whether the state where the charge and discharge current is greater than the first threshold continues for a second time that is longer than the first time; When the state where the charge and discharge current is greater than the first threshold continues for the second time, determining that the connection state of the low-voltage battery is abnormal. A control method including the above steps.

7. A control program executed by a computer of a power control device that controls a power converter connecting a high-voltage battery and a low-voltage battery, A step of controlling the charge and discharge current of the low-voltage battery to a zero state and detecting a control operation that causes a fluctuation in the power of the high-voltage battery; When the control operation is detected, obtaining the charge and discharge current of the low-voltage battery, and determining whether the state where the charge and discharge current is zero continues based on whether the state where the charge and discharge current is greater than the first threshold continues for a first time; When the state where the charge and discharge current is greater than the first threshold continues for the first time, controlling the power converter to forcibly change the charge and discharge current, and further determining whether the state where the charge and discharge current is greater than the first threshold continues for a second time that is longer than the first time; When the state where the charge and discharge current is greater than the first threshold continues for the second time, determining that the connection state of the low-voltage battery is abnormal. A control program including the above steps.

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