Power Circuit Connection Diagnostic Device

Abstract

To provide a connection diagnosis device that, without using complicated control, can perform connection diagnosis of a power circuit including a DC / DC converter and a storage battery as a power supply source to a load.SOLUTION: A diagnosis device performs diagnosis of a power circuit including a DC / DC converter and a storage battery as a power supply source to a load, and comprises: a control unit that controls output from the DC / DC converter to control the operation of the load; an acquisition unit that acquires a current value of the storage battery; and a diagnosis unit that performs diagnosis of the power circuit on the basis of the current value. When the current value is equal to or less than a predetermined threshold in a diagnostic mode in which the DC / DC converter is controlled in a first state and the load is controlled in a second state, the diagnosis unit determines that there is an abnormality in the connection of the power circuit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an apparatus for diagnosing the connection of a power supply circuit including a DC-DC converter and a storage battery as a power supply source to a load.

Background Art

[0002] Patent Document 1 discloses a method for detecting disconnection of an electric battery in a system in which electric circuits interconnected by a DC-DC converter are mounted. In the method described in this Patent Document 1, by using a periodic control signal generated by an oscillation circuit to intentionally increase and decrease the output voltage of the DC-DC converter to detect the charge and discharge current of the storage battery, it is determined that the circuit network of the storage battery is normal.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the method described in Patent Document 1 above, it is necessary to periodically search for a current intensity signal with respect to a voltage signal, and when the current intensity signal is less than a threshold value, it is necessary to increase the amplitude of the voltage signal and search again. Therefore, the method described in Patent Document 1 has a problem that the control is complicated and the circuit network of the storage battery cannot be accurately diagnosed when there is an upper limit to the amplitude of the voltage signal changed by the DC-DC converter. Thus, there is room for further study on a method for diagnosing the connection of a power supply circuit including a DC-DC converter and a storage battery as a power supply source to a load.

[0005] <0000This disclosure was made in view of the above-mentioned problems, and aims to provide a device that can diagnose the connection of a power supply circuit, including a DC-DC converter and a battery, as a power supply source to a load, without using complex control. [Means for solving the problem]

[0006] To solve the above problems, one aspect of the disclosed technology is a connection diagnostic device for diagnosing a power supply circuit including a DC-DC converter and a battery as a power supply source to a load, comprising: a control unit that controls the output of the DC-DC converter and controls the operation of the load; an acquisition unit that acquires the current value of the battery; and a diagnostic unit that diagnoses the power supply circuit based on the current value. The control unit controls the DC-DC converter to a first state in which the power output of the DC-DC converter is limited to a first power that is less than a specified power, and controls the load to a second state in which the power consumed by the operation of the load is greater than the first power, thereby switching the power supply circuit to diagnostic mode. In diagnostic mode, if the current value is below a predetermined threshold, the diagnostic unit will... Battery storage There is a problem with the connection. There is a possibility This is a power supply circuit connection diagnostic device that makes such a determination. [Effects of the Invention]

[0007] According to the power supply circuit connection diagnostic device of the present disclosure, connection diagnostics of a power supply circuit including a DC-DC converter and a storage battery as a power supply source to a load can be easily performed without using complex control. [Brief explanation of the drawing]

[0008] [Figure 1] Functional block diagram of a power supply circuit and its peripheral parts, including a connection diagnostic device according to one embodiment of the present disclosure. [Figure 2A] Flowchart of the power supply control process performed by the power circuit connection diagnostic device. [Figure 2B] Flowchart of the power supply control process performed by the power circuit connection diagnostic device. [Figure 3] A diagram illustrating the relationship between load current consumption in normal mode and the output current and actual output current of the DC-DC converter. [Figure 4] A diagram illustrating the relationship between the normal current consumption of the load in diagnostic mode and the available output current and actual output current when the DC-DC converter's output is limited. [Figure 5] A diagram illustrating the relationship between current consumption during increased load in diagnostic mode, the available output current and actual output current when the DC-DC converter's output is limited, and the discharge current of the Li-battery. [Modes for carrying out the invention]

[0009] The power supply circuit connection diagnostic device disclosed herein controls the load and the DC-DC converter so that the load's current consumption exceeds the DC-DC converter's output current, thereby forcing a current draw from the battery to the load. This state control allows for the detection of any battery connection abnormalities in the power supply circuit through a simple diagnosis that only monitors the battery's discharge current. Possibility It is possible to make that determination. The embodiments of this disclosure will be described in detail below with reference to the drawings.

[0010] <Embodiment> [composition] Figure 1 is a functional block diagram of a power supply circuit 40 and its surrounding components, including a connection diagnostic device 45 according to one embodiment of the present disclosure. The functional block illustrated in Figure 1 includes a power supply 10, an electronic system 20, a plurality of loads 31, 32, and 33, and the power supply circuit 40. These components can be mounted in a vehicle, for example.

[0011] In the following embodiment, the connection diagnostic device 45 will be described as an example where the power supply circuit 40 is a redundant power supply that provides backup power to multiple loads 31, 32, and 33 in place of the power supply 10 when the power supply 10 fails.

[0012] Power source 10 is a power source (primary power system) that supplies power to the electronic system 20 and multiple loads 31, 32, and 33. This power source 10 is, for example, a rechargeable battery such as a lithium-ion battery. In the case of a vehicle, an auxiliary battery can be used as an example of a rechargeable battery power source 10. This power source 10 may also include a DC-DC converter that converts the power output from the rechargeable battery to an appropriate voltage and outputs it.

[0013] The electronic system 20 is a predetermined device (load) that is powered and driven by power supplied from the power source 10. Examples of the electronic system 20 include in-vehicle equipment not related to the vehicle's drive (such as air conditioners and lighting equipment) when the power source 10 is an auxiliary battery mounted on the vehicle. The number of electronic systems 20 is not limited to those shown in Figure 1.

[0014] The multiple loads 31, 32, and 33 are predetermined devices that are driven by power supplied from the primary power supply system, the power supply 10, and from the secondary power supply system, the power supply circuit 40. Examples of these multiple loads 31, 32, and 33 include loads subject to backup control that require a redundant power supply configuration using the power supply circuit 40 (for example, an autonomous driving system in a vehicle). Furthermore, at least one of the multiple loads 31, 32, and 33 is a load (hereinafter referred to as the "target load") that can perform an operation to intentionally increase the power it consumes (such as driving an actuator) based on a request from the power supply circuit 40. In this embodiment, load 33 is described as the target load. Note that the number of multiple loads 31, 32, and 33 and the number of target loads are not limited to those shown in Figure 1.

[0015] The power supply circuit 40 is a redundant power supply (secondary power supply system) that provides backup power to the multiple loads 31, 32, and 33 in place of the power supply 10 when an abnormality (such as power loss) occurs in the power supply 10 to the multiple loads 31, 32, and 33 due to a failure of the power supply 10. The power supply circuit 40 illustrated in Figure 1 includes a Li battery 41, a current sensor 42, a DC-DC converter 43, a communication device 44, and a connection diagnostic device 45. Note that the communication device 44 and the connection diagnostic device 45 may be provided in a different configuration from the power supply circuit 40.

[0016] The Li battery 41 is a storage battery such as a rechargeable lithium-ion battery. This Li battery 41 is connected to the DCDC converter 43 so that it can charge the power of the power supply 10 and discharge the power it stores to the power supply 10 and the electronic system 20. Also, the Li battery 41 is connected to a plurality of loads 31, 32, and 33 so that it can supply the power it stores. When the power supply circuit 40 is a redundant power supply, this Li battery 41 is for maintaining the driving states of the loads 31, 32, and 33 and performing the necessary minimum fail-safe measures in case of a failure of the power supply 10.

[0017] The current sensor 42 is a configuration for detecting the states of the current flowing into the Li battery 41 (charging current) and the current flowing out of the Li battery 41 (discharging current). Note that various sensors capable of detecting the voltage, temperature, etc. of the Li battery 41 may be provided in the power supply circuit 40.

[0018] The DCDC converter 43 is a configuration for converting the power input from the power supply 10 into power of a predetermined voltage and outputting it to the Li battery 41 and a plurality of loads 31, 32, and 33 based on an instruction from the connection diagnostic device 45. Also, the DCDC converter 43 can input the power stored in the Li battery 41 based on an instruction from the connection diagnostic device 45, convert it into power of a predetermined voltage, and output it to the power supply 10 and the electronic system 20.

[0019] The communication device 44 is a communication interface for performing information transmission between the connection diagnostic device 45 and a plurality of loads 31, 32, and / or 33. This communication device 44 transmits a request (operation request) to increase the power consumption to the target load 33 based on an instruction from the connection diagnostic device 45. Also, the communication device 44 outputs a response to the operation request received from the target load 33 to the connection diagnostic device 45. Note that this communication device 44 may be configured inside the connection diagnostic device 45.

[0020] The connection diagnostic device 45 performs a connection diagnosis of the power supply circuit 40 based on the state of the Li battery 41 obtained by controlling the DC-DC converter 43 and the target load 33. This connection diagnostic device 45 includes a control unit 451, an acquisition unit 452, and a diagnostic unit 453.

[0021] The control unit 451 controls the output of the DC-DC converter 43. Specifically, when the power supply 10 is supplying power to multiple loads 31, 32, and 33 in normal mode, the control unit 451 controls the power that can be output from the DC-DC converter 43 to a specified value. When the power supply circuit 40 is being diagnosed, the control unit 451 controls the DC-DC converter 43 to a "first state" in which the power that can be output from the DC-DC converter 43 is limited to a first power that is smaller than the specified value.

[0022] Furthermore, the control unit 451 controls the operation of the target load 33. Specifically, when the control unit 451 is in normal mode, supplying power to multiple loads 31, 32, and 33 from the power supply 10, it does not control the operation of the target load 33. However, when the control unit 451 is in diagnostic mode, which diagnoses the power supply circuit 40, it controls the target load 33 to a "second state" that forces it to operate so that the sum of the power consumption of the multiple loads 31, 32, and 33 equals the second power. The second power when the target load 33 is controlled to the second state is set to any power greater than the first power when the DC-DC converter 43 is controlled to the first state (second power > first power).

[0023] The acquisition unit 452 acquires the value of the current flowing through the Li battery 41. Specifically, the acquisition unit 452 acquires the discharge current value when the Li battery 41 discharges to multiple loads 31, 32, and 33 in diagnostic mode. This discharge current value can be obtained from the current sensor 42.

[0024] In a diagnostic mode in which the DCDC converter 43 is controlled to a first state by the control unit 451 and the target load 33 is controlled to a second state, the diagnostic unit 453 uses the power supply circuit 40 based on the discharge current value of the Li battery 41 acquired by the acquisition unit 452. Li battery 41 There is a problem with the connection. There is a possibility The diagnostic unit 453 determines whether or not the discharge current value of the Li battery 41 in diagnostic mode is below a predetermined threshold, and then the power supply circuit 40 Li battery 41 There is a problem with the connection. There is a possibility This is the determination made. This predetermined threshold can be set based on the difference between the first power and the second power.

[0025] The configuration of some or all of the above-described connection diagnostic device 45 may typically be configured as an MCU (microcontroller unit) including a processor, memory, and input / output interfaces. This MCU can realize some or all of the functions of the control unit 451, acquisition unit 452, and diagnostic unit 453 described above by having the processor read and execute a program stored in memory.

[0026] [control] Next, the control performed by the connection diagnostic device 45 according to this embodiment will be described with further reference to Figures 2A, 2B, 3, 4, and 5.

[0027] Figures 2A and 2B are flowcharts illustrating the processing procedure for the connection diagnostic control of the power supply circuit 40 performed by each component of the connection diagnostic device 45. The processing in Figure 2A and the processing in Figure 2B are connected by connectors X, Y, and Z, respectively. The connection diagnostic control of the power supply circuit 40 illustrated in Figures 2A and 2B is initiated by transitioning from a normal mode in which power is supplied from the power supply 10 to multiple loads 31, 32, and 33 via the power supply circuit 40 to a diagnostic mode in which the power supply circuit 40 is diagnosed.

[0028] Figure 3 shows an illustrative diagram illustrating the current consumption of multiple loads 31, 32, and 33 (shaded arrows), the current that can be output from the DC-DC converter 43 (dotted arrows), and the actual output current (white arrows) in normal mode. As shown in Figure 3, in normal mode, the current consumption of the multiple loads 31, 32, and 33 is all supplied by the output current of the DC-DC converter 43.

[0029] (Step S201) The control unit 451 of the connection diagnostic device 45 implements output limiting (current limiting) on ​​the DC-DC converter (DDC) 43. Specifically, the control unit 451 controls the DC-DC converter 43 to a first state, thereby limiting the power that can be output from the DC-DC converter 43 to a first power. Figure 4 is an illustrative diagram showing the normal current consumption (shaded arrows) of multiple loads 31, 32, and 33 in diagnostic mode, the outputable current (dotted arrows) and actual output current (white arrows) of the DC-DC converter 43 when its output is limited. In the example in Figure 4, the total current consumption of the multiple loads 31, 32, and 33 is less than or equal to the upper limit current of the DC-DC converter 43 after limiting, so no discharge current is generated in the Li battery 41. Once the control unit 451 implements output limiting of the DC-DC converter 43, the process proceeds to step S202.

[0030] (Step S202) The control unit 451 of the connection diagnostic device 45 requests a forced operation from the target load 33 via the communication device 44. Specifically, the control unit 451 controls the target load 33 so that the sum of the power consumption of the multiple loads 31, 32, and 33 becomes the second power by requesting that the target load 33 be controlled to a second state in which a predetermined function (such as an actuator) is activated. This makes it possible to intentionally operate loads that exceed the output capacity of the DC-DC converter 43 in the multiple loads 31, 32, and 33. Figure 5 is an illustrative diagram showing the current consumption (shaded arrows) when the multiple loads 31, 32, and 33 increase, the outputable current (dotted arrows) and actual output current (white arrows) when the output of the DC-DC converter 43 is limited, and the discharge current of the Li battery 41 (black arrow) in the diagnostic mode. In the example in Figure 5, the total current consumption of the multiple loads 31, 32, and 33 exceeds the upper limit current after the DC-DC converter 43 is limited, resulting in a discharge current in the Li battery 41. When the control unit 451 requests a forced operation from the target load 33, the process proceeds to step S203.

[0031] (Step S203) The control unit 451 of the connection diagnostic device 45 determines the response received from the target load 33 via the communication device 44. Specifically, the control unit 451 determines whether the target load 33 accepts the forced operation it has requested. Examples of situations in which the target load 33 cannot accept the request for forced operation include cases where a predetermined function cannot be activated or where a predetermined function has already been activated (in which case power consumption does not increase). If the control unit 451 determines that the target load 33 has accepted the requested forced operation (step S203, affirmative), the process proceeds to step S204. As a result, the total power consumption of the multiple loads 31, 32, and 33 increases to the second power. On the other hand, if the control unit 451 determines that the target load 33 has not accepted the requested forced operation (step S203, negative), the process proceeds to step S207.

[0032] (Step S204) The acquisition unit 452 of the connection diagnostic device 45 acquires the discharge current value of the Li battery 41 after the sum of the power consumption of the multiple loads 31, 32, and 33 has reached the second power. At this time, the acquisition unit 452 may also acquire the output voltage value of the DC-DC converter 43 for use in connection diagnostics. Once the acquisition unit 452 has acquired the discharge current value of the Li battery 41, the process proceeds to step S205.

[0033] (Step S205) The control unit 451 of the connection diagnostic device 45 has obtained the discharge current value of the Li battery 41 used for connection diagnostics of the power supply circuit 40, and has made a request to the target load 33 via the communication device 44 to cancel the forced operation (second state) of a predetermined function that is being performed based on the request in step S202. Once the forced operation of the target load 33 is canceled by the control unit 451, the process proceeds to step S206.

[0034] (Step S206) The control unit 451 of the connection diagnostic device 45 has obtained the discharge current value of the Li battery 41 used for connection diagnostics of the power supply circuit 40, and therefore releases the output limit (first state) applied to the DC-DC converter (DDC) 43. Once the control unit 451 releases the output limit of the DC-DC converter 43, the process proceeds to step S208.

[0035] (Step S207) The control unit 451 of the connection diagnostic device 45 cannot obtain the discharge current value of the Li battery 41 used for connection diagnostics of the power supply circuit 40, so it releases the output limit (first state) applied to the DC-DC converter (DDC) 43. When the output limit of the DC-DC converter 43 is released by the control unit 451, the connection diagnostic control of the power supply circuit 40 is terminated.

[0036] (Step S208) The diagnostic unit 453 of the connection diagnostic device 45 determines whether the discharge current value of the Li battery 41 acquired by the acquisition unit 452 is above a predetermined threshold. The second power consumed by the multiple loads 31, 32, and 33 is the sum of the first power that the DC-DC converter 43 controlled to the first state can output and the power discharged from the Li battery 41. Therefore, the predetermined threshold is set based on the difference between the first power and the second power. If the diagnostic unit 453 determines that the discharge current value of the Li battery 41 is above the predetermined threshold (step S208, yes), the process proceeds to step S209. On the other hand, if the diagnostic unit 453 determines that the discharge current value of the Li battery 41 is below the predetermined threshold (step S208, no), the process proceeds to step S210.

[0037] (Step S209) The diagnostic unit 453 of the connection diagnostic device 45 determined that the power supply circuit 40 Li battery 41 The connection is determined to be normal (OK determination). When the diagnostic unit 453 determines the connection diagnosis result to be OK, the connection diagnostic control of this power supply circuit 40 is terminated.

[0038] (Step S210) The diagnostic unit 453 of the connection diagnostic device 45 counts the number of times in step S208 that it is determined that the discharge current value of the Li battery 41 is below a predetermined threshold. This count can be performed using a predetermined counter (retry counter). The counter's count is reset to zero, for example, at the start or end of the connection diagnostic control of the power supply circuit 40. Once the number of counts has been reached by the diagnostic unit 453, the process proceeds to step S211.

[0039] (Step S211) The diagnostic unit 453 of the connection diagnostic device 45 determines whether the number of counts in step S210 has reached a predetermined number. The predetermined number is the number of times the connection diagnosis will be retried, and is set appropriately according to the diagnostic accuracy required of the connection diagnostic device 45. If the diagnostic unit 453 determines that the count has reached the predetermined number (step S211, yes), the process proceeds to step S212. On the other hand, if the diagnostic unit 453 determines that the count has not reached the predetermined number (step S211, no), the process proceeds to step S201.

[0040] (Step S212) The diagnostic unit 453 of the connection diagnostic device 45 determined that the power supply circuit 40 Li battery 41 There is a problem with the connection. There is a possibility The diagnostic unit 453 determines that the connection is not working (NG). If the diagnostic unit 453 determines that the connection diagnostic result is NG, the connection diagnostic control of the power supply circuit 40 is terminated.

[0041] In the flowchart described above, if it is determined in step S208 that the discharge current value of the Li battery 41 is below a predetermined threshold, the connection diagnosis result is determined as NG only after waiting for the number of times this determination has been made to reach a predetermined number (after performing a predetermined retry process). However, if it is determined in step S208 that the discharge current value of the Li battery 41 is below a predetermined threshold, the connection diagnosis result may be determined as NG in a single determination without performing the predetermined retry process (steps S210 and S211 are deleted in Figure 2B).

[0042] <Effects and Actions> As described above, according to the connection diagnostic device 45 for the power supply circuit 40 as an embodiment of the present disclosure, when performing a diagnosis, the output current of the DC-DC converter 43 is limited to a small amount, and functions such as actuators are forcibly operated to increase the total current consumption of the multiple loads 31, 32, and 33 to a current value that exceeds the output current of the DC-DC converter 43.

[0043] This control ensures that the current consumed by loads 31, 32, and 33, which the DC-DC converter 43 cannot output, is drawn from the Li battery 41. Therefore, by monitoring the discharge current of the Li battery 41, it is possible to determine whether the Li battery 41 is connected to the multiple loads 31, 32, and 33 (and the DC-DC converter 43) (i.e., whether there are any disconnections), i.e., the power supply circuit 40 Li battery 41 Is the connection normal or abnormal? Possibility assessment This can be easily done without using complex control systems.

[0044] Although one embodiment of the disclosed technology has been described above, the disclosed technology can be understood not only as a power supply circuit connection diagnostic device, but also as a control method executed by a connection diagnostic device equipped with a processor and memory, a control program for executing the control method, a computer-readable non-temporary storage medium storing the control program, and a vehicle equipped with the connection diagnostic device. [Industrial applicability]

[0045] The power supply circuit connection diagnostic device disclosed herein can be used in systems employing redundant power supply configurations, etc. [Explanation of symbols]

[0046] 10 Power supply 20 Electronic Systems 31, 32, 33 Load 40 Power circuit 41 Li battery 42 Current Sensor 43 DC-DC converters 44 Communication equipment 45 Connection Diagnostic Device 451 Control Unit 452 Acquisition Department 453 Diagnostic Department

Claims

1. A connection diagnostic device for diagnosing a power supply circuit that includes a DC-DC converter and a storage battery as a power supply source to a load, A control unit that controls the output of the DCDC converter and controls the operation of the load, An acquisition unit for acquiring the current value of the aforementioned storage battery, The system includes a diagnostic unit that diagnoses the power supply circuit based on the current value, The control unit controls the DC-DC converter to a first state in which the power output of the DC-DC converter is limited to a first power less than a specified power, and controls the load to a second state in which the power consumed by the operation of the load is a second power greater than the first power, thereby causing the power supply circuit to switch to diagnostic mode. The diagnostic unit determines, in the diagnostic mode, that if the current value is below a predetermined threshold, there may be an abnormality in the connection of the battery in the power supply circuit. Power supply circuit connection diagnostic device.

2. The predetermined threshold is set based on the difference between the first power and the second power. A power supply circuit connection diagnostic device according to claim 1.

3. The control unit performs the control according to the diagnostic mode multiple times, The diagnostic unit determines that there may be an abnormality in the battery connection in the power supply circuit when the number of times it has determined that the current value is below a predetermined threshold in the diagnostic mode reaches a specified number of times. A power supply circuit connection diagnostic device according to claim 1 or 2.

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