Control device, control method, and control program

Abstract

To provide a control device, a control method, and a control program capable of determining failure in a connecting portion even when an abnormality occurs in a high-voltage battery at startup.SOLUTION: A control device according to an embodiment includes a DCDC converter connected between a high-voltage system including a high-voltage battery and a low-voltage system including a low-voltage battery; a converter connecting portion connected between the DCDC converter and the high-voltage system; a bypass circuit bypassing the DCDC converter, and a controller. The controller controls the DCDC converter, determines a failure in the converter connecting portion by comparing the voltage applied to the converter connecting portion and a first threshold when the high-voltage battery is normal, connects the low-voltage system and the high-voltage system through the bypass circuit when the high-voltage battery is abnormal, and determines a failure in the converter connecting portion by comparing the voltage applied to the converter connecting portion and a second threshold lower than the first threshold.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The disclosed embodiments relate to a control device, a control method, and a control program. [Background technology]

[0002] Conventionally, there is a vehicle equipped with a high-voltage system including a high-voltage battery and a motor generator that output a voltage of, for example, 48 V, a low-voltage system including a low-voltage battery that output a voltage of, for example, 12 V, and a DC-DC converter connected between the high-voltage system and the low-voltage system.

[0003] Vehicles equipped with a DCDC converter connected between a high-voltage system and a low-voltage system are provided with a connection part such as a relay that cuts off the electrical connection between the DCDC converter and the high-voltage system in order to protect the DCDC converter in the event of an electrical abnormality.

[0004] When a high-voltage battery fails, a control device that controls the DCDC converter boosts the output voltage of the low-voltage battery using the DCDC converter, charges a smoothing capacitor, and supplies the voltage to a motor (see, for example, Patent Document 1).

[0005] In addition, in order to ensure safety when an electrical abnormality occurs in the vehicle, the control device performs a fault determination for the connection part, for example, when the vehicle is started. Then, when the control device confirms that the connection part is operating normally, it starts controlling the DCDC converter.

[0006] For example, when the vehicle is started, the control device controls the connection part to be in a disconnected state before starting the operation of the DCDC converter.Then, if the difference in the voltage across the connection part is equal to or greater than a threshold, the control device determines that the connection part is normal.Also, if the voltage across the connection part is less than the threshold, the control device determines that the connection part has an ON-stuck fault.

[0007] Furthermore, the control device controls the connection part to a connected state before starting the operation of the DC-DC converter.Then, if the difference in the voltage across the connection part is equal to or greater than a threshold, the control device determines that the connection part has a stuck-off fault.Also, if the voltage across the connection part is less than the threshold, the control device determines that the connection part is normal. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2007-255294 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, if an abnormality occurs in the high-voltage battery when the control device is started, the difference in voltage across the connection part falls below the threshold regardless of the control state, and therefore the control device cannot determine whether the connection part is faulty.

[0010] One aspect of the embodiment has been made in consideration of the above, and aims to provide a control device, control method, and control program that can determine a failure in a connection even if an abnormality occurs in the high-voltage battery at startup. [Means for solving the problem]

[0011] A control device according to an embodiment includes a DC-DC converter, a converter connection unit, a bypass circuit, and a controller. The DC-DC converter is connected between a high-voltage system including a generator and a high-voltage battery capable of outputting a first voltage, and a low-voltage system including a low-voltage battery capable of outputting a second voltage lower than the first voltage. The converter connection unit is connected between the DC-DC converter and the high-voltage system. The bypass circuit connects the low-voltage system and the high-voltage system by bypassing the DC-DC converter. The controller controls the DC-DC converter and determines a fault in the converter connection unit. When the high-voltage battery is normal, the controller compares a voltage applied to the converter connection unit with a first threshold value to determine a fault in the converter connection unit. When the high-voltage battery is abnormal, the controller connects the low-voltage system and the high-voltage system by the bypass circuit, and compares a voltage applied to the converter connection unit with a second threshold value lower than the first threshold value to determine a fault in the converter connection unit. Effect of the Invention

[0012] A control device, a control method, and a control program according to an aspect of the embodiment have an effect of being able to determine a failure in a connection even if an abnormality occurs in the high-voltage battery at start-up. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is an explanatory diagram showing a power supply system according to an embodiment. [Diagram 2] FIG. 2 is an explanatory diagram of a connection portion and a voltage sensor according to the embodiment. [Diagram 3] FIG. 3 is an explanatory diagram illustrating an example of the operation of the control device according to the embodiment. [Figure 4] FIG. 4 is an explanatory diagram illustrating an example of the operation of the control device according to the embodiment. [Diagram 5] FIG. 5 is a flowchart illustrating an example of processing executed by the controller according to the embodiment. [Figure 6]FIG. 6 is a flowchart illustrating an example of processing executed by the controller according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of a control device, a control method, and a control program will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following embodiment.

[0015] [1. Power supply system configuration] First, a power supply system 100 of a vehicle equipped with a control device 1 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is an explanatory diagram showing the power supply system 100 according to an embodiment.

[0016] 1 does not show a plurality of voltage sensors and a plurality of connection parts included in the power supply system 100. The plurality of voltage sensors and a plurality of connection parts included in the power supply system 100 will be described with reference to FIG.

[0017] 1, the vehicle in which the control device 1 is installed includes an engine 10, a transmission (hereinafter referred to as "T / M 11"), a starter 12, and a high-voltage battery B1. The vehicle also includes a low-voltage battery B2, a plurality of electric loads 13, and a generator (hereinafter referred to as "MG (motor generator) 14").

[0018] The vehicle also includes an inverter (hereinafter, referred to as "INV15"), a smoothing capacitor 16, a DCDC converter (hereinafter, referred to as "DCDC17"), a battery monitoring device 18, and an ignition switch (hereinafter, referred to as "IG19"). The smoothing capacitor 16 smoothes the input voltage to the INV15.

[0019] The engine 10 is an internal combustion engine that drives the vehicle. The T / M 11 is a device that transmits the driving force of the engine 10 to a propeller shaft 21. The starter 12 is a starter motor that starts the engine 10.

[0020] The electric load 13 is various on-board electrical equipment mounted on the vehicle. The high-voltage battery B1 is, for example, a lithium-ion battery, and is a secondary battery capable of outputting a voltage of 48 V. 48 V is an example of a maximum first voltage that the high-voltage battery B1 can output. The high-voltage battery B1 is connected to the INV 15, the smoothing capacitor 16, and the DCDC 17 via the high-voltage battery connection unit SW1.

[0021] When the high-voltage battery connection unit SW1 is turned on, it electrically connects the high-voltage battery B1 to the INV15, the smoothing capacitor 16, and the DCDC 17. When the high-voltage battery connection unit SW1 is turned off, it cuts off the electrical connection between the high-voltage battery B1 and the INV15, the smoothing capacitor 16, and the DCDC 17.

[0022] The high-voltage battery B1 supplies electric power to the MG 14 via the high-voltage battery connector SW1, the smoothing capacitor 16, and the INV 15. The high-voltage battery B1 also stores the electric power generated by the MG 14.

[0023] The high-voltage battery B1 can also supply power to the low-voltage battery B2, the electrical load 13, and the starter 12 via the high-voltage battery connection unit SW1 and the DCDC 17. In this case, the DCDC 17 steps down the voltage of the high-voltage battery B1 and outputs it to the low-voltage battery B2, the electrical load 13, and the starter 12.

[0024] The low-voltage battery B2 is, for example, a lead battery, and is a secondary battery capable of outputting a lower voltage than the high-voltage battery B1, for example, a voltage of 12 V. 12 V is an example of a maximum second voltage that the low-voltage battery B2 can output. The low-voltage battery B2 supplies power to the starter 12 and the electrical load 13. The low-voltage battery B2 stores the power generated by the MG 14.

[0025] The low-voltage battery B2 can also supply power to the high-voltage battery B1 and the smoothing capacitor 16 via the DCDC 17. The low-voltage battery B2 can also supply power to the MG 14 via the DCDC 17 and the INV 15. In this case, the DCDC 17 boosts the voltage of the low-voltage battery B2 and supplies power to the high-voltage battery B1, the smoothing capacitor 16, and the MG 14.

[0026] The MG 14 is, for example, a motor generator. The MG 14 has a function as an electric motor that assists the driving force of the engine 10 when the engine 10 of the vehicle is started or when the vehicle is running, and a function as a generator that generates electricity using regenerative energy generated when the vehicle decelerates.

[0027] A pulley 22 is attached to a propeller shaft 21 of the engine 10, and a pulley 24 is attached to a rotating shaft 23 of the MG 14. A belt 25 is wound around the pulleys 22 and 24.

[0028] As a result, MG 14 can assist the driving force of engine 10 when engine 10 is started or when the vehicle is running by rotating rotating shaft 23. In addition, MG 14 can generate electricity using the rotational energy of engine 10 and regenerative energy generated when the vehicle decelerates.

[0029] The battery monitoring device 18 detects, for example, the voltage, temperature, and SOC (State Of Charge) of the high voltage battery B1. The battery monitoring device 18 outputs the detection results of the voltage and SOC of the high voltage battery B1 to the control device 1.

[0030] 1, the MG 14, the INV 15, the smoothing capacitor 16, and the high-voltage battery B1 are included in a high-voltage system 101. The low-voltage battery B2 and the electric load 13 are included in a low-voltage system 102. The DCDC 17 is connected between the high-voltage system 101 and the low-voltage system 102. The DCDC 17 is connected between the high-voltage system 101 and the low-voltage system 102, and is controlled by the control device 1.

[0031] The control device 1 includes a DCDC 17 and a controller 3. The controller 3 is an ECU (Electronic Control Unit) that controls the power supply system 100. For example, when the controller 3 receives a start request from the IG 19 at the start of the engine 10, the controller 3 starts the MG 14. In addition, for example, when the controller 3 receives a start request from a higher-level ECU during an idling stop at a temporary stop such as at a traffic light, the controller 3 starts the MG 14.

[0032] Furthermore, when the high-voltage battery B1 is abnormal, the controller 3 boosts the output voltage of the low-voltage battery by the DCDC 17 and charges the smoothing capacitor 16. Then, the controller 3 supplies the power charged in the smoothing capacitor 16 to the MG 14 via the INV 15.

[0033] Furthermore, when the amount of stored electricity in the low-voltage battery B2 is insufficient, the controller 3 steps down the voltage of the high-voltage system 101 using the DCDC 17 and supplies the voltage to the low-voltage system 102. This allows the controller 3 to charge the low-voltage battery B2 when the amount of stored electricity in the low-voltage battery B2 is insufficient. Furthermore, the controller 3 can compensate for the operation of the electric load 13 when the amount of stored electricity in the low-voltage battery B2 is insufficient.

[0034] [2. Connections and voltage sensors in the power supply system] Next, a plurality of connection parts and a plurality of voltage sensors included in the power supply system 100 according to the embodiment will be described with reference to Fig. 2. Fig. 2 is an explanatory diagram of the connection parts and the voltage sensors according to the embodiment.

[0035] 2, the power supply system 100 includes a high-voltage battery connection unit SW1, a converter connection unit SW2, and a pre-charge connection unit SW3. The high-voltage battery connection unit SW1, the converter connection unit SW2, and the pre-charge connection unit SW3 are, for example, semiconductor relays.

[0036] The high-voltage battery connection unit SW1 electrically connects the high-voltage battery B1 to the smoothing capacitor 16 and the converter connection unit SW2. The converter connection unit SW2 electrically connects the high-voltage system 101 to the DCDC 17. The pre-charge connection unit SW3 is included in a bypass circuit 31 that bypasses the DCDC 17 and connects the low-voltage system 102 to the high-voltage system 101.

[0037] The precharge connection unit SW3 is an example of a limiting circuit that limits the connection between the low-voltage system 102 and the high-voltage system 101. The precharge connection unit SW3 is, for example, a switch such as a semiconductor relay. The bypass circuit 31 also includes a diode D1. The diode D1 is connected in series with the precharge connection unit SW3. The diode D1 prevents a high-voltage current from flowing from the high-voltage system 101 to the low-voltage system 102 when the precharge connection unit SW3 is in a conductive state.

[0038] The limiting circuit is not limited to a switch, and any circuit capable of switching between conductive and cut-off of the bypass circuit 31 may be used. For example, the precharge connection unit SW3 may be eliminated, and the diode D1 may be used as the limiting circuit. In this case, if the high-voltage battery B1 is normal, the diode D1 can automatically prevent high-voltage current from flowing from the high-voltage system 101 to the low-voltage system 102. Also, if the high-voltage battery B1 is abnormal, a current automatically flows from the low-voltage system 102 to the high-voltage system 101 via the diode D1.

[0039] The high-voltage battery connection part SW1, the converter connection part SW2, and the pre-charge connection part SW3 are controlled by a controller 3 included in the control device 1 so as to be in a conductive state or a cut-off state.

[0040] The controller 3 includes a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and the like, and various other circuits.

[0041] The controller 3 controls the states of the high-voltage battery connection unit SW1, the converter connection unit SW2, and the pre-charge connection unit SW3, and the operation of the DCDC 17, by the CPU executing a program stored in the ROM using the RAM as a working area.

[0042] The controller 3 may be configured in part or in whole using hardware such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA).

[0043] The power supply system 100 also includes a first voltage sensor V1 and a second voltage sensor V2. The first voltage sensor V1 is connected between the high-voltage system 101 and the converter connection unit SW2. The first voltage sensor V1 detects a voltage of a connection line electrically connecting the high-voltage system 101 and the converter connection unit SW2 (hereinafter, referred to as a "first voltage sensor voltage"). The first voltage sensor V1 outputs the first voltage sensor voltage to the controller 3.

[0044] The second voltage sensor V2 is connected between the converter connection unit SW2 and the DCDC 17. The second voltage sensor V2 detects the voltage of a connection line electrically connecting the converter connection unit SW2 and the DCDC 17 (hereinafter, referred to as the "second voltage sensor voltage"). The second voltage sensor V2 outputs the second voltage sensor voltage to the controller 3.

[0045] In order to ensure safety when an electrical abnormality occurs in the vehicle, the control device 1 performs a fault determination for the converter connection unit SW2, for example, when the vehicle is started. Then, when the control device 1 confirms that the converter connection unit SW2 operates normally, it starts controlling the DCDC 17.

[0046] [3. Fault detection operation of converter connection part by the control device] Next, the operation of the control device 1 to determine whether or not there is a fault in the converter connection unit SW2 will be described with reference to Fig. 3 and Fig. 4. Fig. 3 and Fig. 4 are explanatory diagrams showing an example of the operation of the control device according to the embodiment. First, the case where the high-voltage battery B1 is in a normal state will be described, and then the case where the high-voltage battery B1 is in an abnormal state will be described.

[0047] Examples of cases where the high-voltage battery B1 is abnormal include cases where the high-voltage battery B1 has broken down and is unable to output sufficient voltage (e.g., 40 V or more), where the high-voltage battery B1 is abnormally high or low temperature, and where the high-voltage battery connection part SW1 is stuck in the disconnected state (off stuck).

[0048] A high-voltage battery is normal when the high-voltage battery B1 is not faulty, can output sufficient voltage (e.g., 40 V or more), the temperature of the high-voltage battery B1 is within the normal temperature range, and the high-voltage battery connection unit SW1 can normally switch between conductive and cut-off states.

[0049] Before startup, the power supply system 100 has the high-voltage battery connection SW1, the converter connection SW2, and the pre-charge connection SW3 disconnected (see FIG. 2). When started up, the controller 3 starts determining whether or not there is a failure in the converter connection SW2.

[0050] 3, the controller 3 maintains the converter connection SW2 and the precharge connection SW3 in a cut-off state, and then turns on the high-voltage battery connection SW1. Then, the controller 3 determines whether the high-voltage battery B1 is normal.

[0051] The controller 3 determines that the high-voltage battery B1 is normal if the first voltage sensor voltage input from the first voltage sensor V1 is a normal voltage, the SOC of the high-voltage battery B1 obtained from the battery monitoring device 18 is above a predetermined value, and the temperature of the high-voltage battery is within the normal range.

[0052] Here, the voltage of the high voltage battery B1 in the normal state is, for example, 40 V or more. The SOC of the high voltage battery B1 in the normal state is, for example, 80% or more. The temperature range of the high voltage battery B1 in the normal state is, for example, 10° C. to 30° C.

[0053] When the high-voltage battery B1 is normal, a voltage of at least 40 V is applied from the high-voltage system to the first voltage sensor V1 when the high-voltage battery connection unit SW1 is conductive. At this time, when the converter connection unit SW2 is normally disconnected, no voltage is applied from the high-voltage battery B1 to the second voltage sensor V2.

[0054] In contrast, when converter connection unit SW2 is stuck in a conductive state, that is, stuck on, a voltage equivalent to the voltage of high voltage battery B1 is applied from high voltage battery B1 to second voltage sensor V2.

[0055] Therefore, when the high-voltage battery B1 is normal, the controller 3 turns off the precharge connection part SW3 and turns on the high-voltage battery connection part SW1, and compares the voltage applied to the converter connection part SW2 with the first threshold value to determine whether the converter connection part SW2 is faulty. The first threshold value is, for example, 24 V. Note that the first threshold value is not limited to 24 V as long as it is higher than 12 V, which is the voltage of the low-voltage battery B2.

[0056] Specifically, the controller 3 turns off the converter connection SW2 and the precharge connection SW3, turns on the high-voltage battery connection SW1, and determines that the converter connection SW2 is stuck on if the second voltage sensor voltage is equal to or higher than the first threshold value. Also, the controller 3 determines that the converter connection SW2 is not stuck on if the second voltage sensor voltage is lower than the first threshold value.

[0057] Thereafter, if the converter connection unit SW2 is not stuck on, the controller 3 determines whether the converter connection unit SW2 is stuck in a disconnected state, that is, stuck off. Specifically, the controller 3 sets the converter connection unit SW2 to a conductive state, sets the pre-charge connection unit SW3 to a disconnected state, and then sets the high-voltage battery connection unit SW1 to a conductive state.

[0058] At this time, if the converter connection unit SW2 is normally conductive, the second voltage sensor voltage will be equal to the voltage of the high-voltage battery B1. On the other hand, if the converter connection unit SW2 is stuck off, the second voltage sensor voltage will be 0 V.

[0059] Therefore, when the controller 3 brings the converter connection unit SW2 into a conductive state and makes the high-voltage battery connection unit SW1 conductive, if the second voltage sensor voltage is greater than or equal to the first threshold value, the controller 3 determines that the converter connection unit SW2 is not stuck off.

[0060] In addition, when the controller 3 brings the converter connection unit SW2 into a conductive state and makes the high-voltage battery connection unit SW1 conductive, if the second voltage sensor voltage is less than the first threshold value, the controller 3 determines that the converter connection unit SW2 is stuck off.

[0061] In this way, when the high-voltage battery B1 is normal, the controller 3 can accurately determine whether the converter connection unit SW2 is stuck on or off by turning on the high-voltage battery connection unit SW1 and comparing the voltage applied to the converter connection unit SW2 with the first threshold value.

[0062] However, if the high voltage battery B1 is abnormal, the voltage of the high voltage system 101 may fall below the minimum voltage required for the controller 3 to determine whether or not there is a fault in the converter connection unit SW2, for example, below 24 V which is the first threshold value.

[0063] In this case, when the controller 3 performs a fault determination by comparing the voltage applied to the converter connection unit SW2 with the first threshold value, there is a risk that the controller 3 may erroneously determine that the converter connection unit SW2 is stuck on or off even if it is not stuck on or off.

[0064] However, even if the high-voltage battery B1 is abnormal, if the precharge connection part SW3 is conductive, the voltage of the low-voltage battery B2, 12V, is applied to the converter connection part SW2, bypassing the DCDC17 from the low-voltage battery B2.

[0065] Therefore, when the controller 3 determines that the high-voltage battery B1 is abnormal, as shown in FIG. 4, it cuts off the high-voltage battery connection part SW1 and the converter connection part SW2, and makes the pre-charge connection part SW3 conductive.

[0066] In other words, when the high-voltage battery B1 is normal, the controller 3 cuts off the connection between the low-voltage system 102 and the high-voltage system 101, but when the high-voltage battery B1 is abnormal, the controller 3 controls the limiting circuit to connect the low-voltage system 102 and the high-voltage system 101.

[0067] Specifically, when the high-voltage battery B1 is normal, the controller 3 turns the pre-charge connection unit SW3 (switch) to a cut-off state, but when the high-voltage battery B1 is abnormal, the controller 3 turns the pre-charge connection unit SW3 (switch) to a conductive state.

[0068] This allows the controller 3 to apply the inspection voltage of 12V from the low-voltage battery B2 to the converter connection part SW2 when the high-voltage battery B1 is abnormal.

[0069] When the high-voltage battery B1 is abnormal, the controller 3 compares the voltage at the converter connection unit SW2 with a second threshold value lower than the first threshold value to determine whether the converter connection unit SW2 is faulty. The second threshold value is, for example, 10 V. Note that the second threshold value is not limited to 10 V as long as it is a voltage that the low-voltage battery B2 can output in a normal state.

[0070] For example, when the high-voltage battery connection unit SW1 cannot be made conductive with the precharge connection unit SW3 cut off and the first voltage sensor voltage input from the first voltage sensor V1 is 0 V, the controller 3 determines that the high-voltage battery B1 is abnormal. In addition, when the SOC of the high-voltage battery B1 acquired from the battery monitoring device 18 is less than a predetermined value or when the temperature of the high-voltage battery is outside the normal range, the controller 3 determines that the high-voltage battery B1 is abnormal.

[0071] When the controller 3 determines that the high-voltage battery B1 is abnormal, it controls the high-voltage battery connection SW1 and the converter connection SW2 to be in a cut-off state, and then turns on the pre-charge connection SW3. At this time, if the second voltage sensor voltage is equal to or higher than the second threshold, the controller 3 determines that the converter connection SW2 is stuck on. Also, if the second voltage sensor voltage is less than the second threshold, the controller 3 determines that the converter connection SW2 is not stuck on.

[0072] Thereafter, if the converter connection unit SW2 is not stuck on, the controller 3 determines whether or not the converter connection unit SW2 is stuck off. Specifically, the controller 3 cuts off the high-voltage battery connection unit SW1, controls the converter connection unit SW2 to be in a conductive state, and then puts the pre-charge connection unit SW3 in a conductive state.

[0073] At this time, if the second voltage sensor voltage is equal to or higher than the second threshold, the controller 3 determines that the converter connection unit SW2 is not stuck off. Also, if the second voltage sensor voltage is lower than the second threshold, the controller 3 determines that the converter connection unit SW2 is stuck off.

[0074] In this way, when the high voltage battery B1 is abnormal, the controller 3 applies the voltage of the low voltage battery B2 to the converter connection unit SW2, and compares the voltage applied to the converter connection unit SW2 with a second threshold value lower than the first threshold value to determine whether the converter connection unit SW2 is faulty. This allows the controller 3 to accurately determine whether the converter connection unit SW2 is faulty, even if an abnormality occurs in the high voltage battery B1.

[0075] [4. Processing performed by the controller of the control device] Next, a process executed by the controller 3 of the control device 1 when determining whether or not there is a malfunction in the converter connection unit SW2 will be described with reference to Fig. 5 and Fig. 6. Fig. 5 and Fig. 6 are flowcharts showing an example of a process executed by the controller according to the embodiment.

[0076] When IG19 is turned on, the controller 3 executes the process of determining whether the converter connection part SW2 is stuck on shown in FIG. 5, and if it is determined that the converter connection part SW2 is not stuck on, it executes the process of determining whether the converter connection part SW2 is stuck off shown in FIG. 6.

[0077] In addition, the controller 3 can also execute the process of determining whether the converter connection unit SW2 is stuck off shown in Figure 6, and if it is determined that the converter connection unit SW2 is not stuck off, execute the process of determining whether the converter connection unit SW2 is stuck on shown in Figure 5.

[0078] As shown in FIG. 5, when the controller 3 starts the process of determining whether the converter connection unit SW2 is stuck on, it first controls the converter connection unit SW2 to be cut off, cuts off the precharge connection unit SW3, and makes the high-voltage battery connection unit SW1 conductive (step S101).

[0079] Then, the controller 3 determines whether the high voltage battery B1 is normal or not (step S102). If the controller 3 determines that the high voltage battery B1 is normal (step S102, Yes), the controller 3 determines whether the second voltage sensor voltage is equal to or higher than the first threshold value (step S103).

[0080] If the controller 3 determines that the second voltage sensor voltage is equal to or higher than the first threshold value (Yes at step S103), it determines that converter connection unit SW2 is stuck on (step S104) and ends the process of determining whether converter connection unit SW2 is stuck on.

[0081] Furthermore, when the controller 3 determines that the second voltage sensor voltage is not equal to or higher than the first threshold, that is, the second voltage sensor voltage is less than the first threshold (step S103, No), the controller 3 determines that the converter connection unit SW2 is not stuck on (step S105). After that, the controller 3 ends the process of determining whether the converter connection unit SW2 is stuck on.

[0082] Furthermore, when the controller 3 determines that the high voltage battery B1 is not normal, that is, that the high voltage battery B1 is abnormal (step S102, No), it cuts off the high voltage battery connection part SW1 and makes the pre-charge connection part SW3 conductive.

[0083] Specifically, the high-voltage battery connection SW1 is disconnected, and the pre-charge connection SW3 is made conductive while controlling the converter connection SW2 to be disconnected (step S106).Then, the controller 3 determines whether the second voltage sensor voltage is equal to or higher than the second threshold (step S107).

[0084] If the controller 3 determines that the second voltage sensor voltage is equal to or higher than the second threshold value (step S107, Yes), it determines that converter connection unit SW2 is stuck on (step S108) and ends the process of determining whether converter connection unit SW2 is stuck on.

[0085] On the other hand, if it is determined that the second voltage sensor voltage is not equal to or higher than the second threshold, that is, the second voltage sensor voltage is less than the second threshold (step S107, No), it is determined that the converter connection unit SW2 is not stuck on (step S109). After that, the controller 3 ends the process of determining whether the converter connection unit SW2 is stuck on.

[0086] Thereafter, when the controller 3 determines that the converter connection unit SW2 is not stuck on, the controller 3 starts the process of determining whether the converter connection unit SW2 is stuck off, which is shown in FIG.

[0087] As shown in FIG. 6, when the controller 3 starts the process of determining whether the converter connection unit SW2 is stuck off, it first controls the converter connection unit SW2 to be conductive, cuts off the precharge connection unit SW3, and makes the high-voltage battery connection unit SW1 conductive (step S201).

[0088] Then, the controller 3 determines whether the high voltage battery B1 is normal or not (step S202). If the controller 3 determines that the high voltage battery B1 is normal (step S202, Yes), the controller 3 determines whether the second voltage sensor voltage is equal to or higher than the first threshold value (step S203).

[0089] If the controller 3 determines that the second voltage sensor voltage is equal to or higher than the first threshold value (step S203, Yes), it determines that converter connection unit SW2 is not stuck off (step S204) and ends the process of determining whether converter connection unit SW2 is stuck on.

[0090] Furthermore, when the controller 3 determines that the second voltage sensor voltage is not equal to or higher than the first threshold, that is, the second voltage sensor voltage is less than the first threshold (step S203, No), the controller 3 determines that the converter connection unit SW2 is stuck off (step S205). After that, the controller 3 ends the process of determining whether the converter connection unit SW2 is stuck off.

[0091] Furthermore, when the controller 3 determines that the high voltage battery B1 is not normal, that is, that the high voltage battery B1 is abnormal (step S202, No), it cuts off the high voltage battery connection part SW1 and makes the pre-charge connection part SW3 conductive.

[0092] Specifically, the high-voltage battery connection SW1 is cut off, the converter connection SW2 is controlled to be conductive, and the pre-charge connection SW3 is made conductive (step S206). Then, the controller 3 determines whether the second voltage sensor voltage is equal to or higher than the second threshold (step S207).

[0093] If the controller 3 determines that the second voltage sensor voltage is equal to or higher than the second threshold value (step S207, Yes), it determines that converter connection unit SW2 is not stuck off (step S208) and ends the process of determining whether converter connection unit SW2 is stuck off.

[0094] On the other hand, if it is determined that the second voltage sensor voltage is not equal to or higher than the second threshold, that is, the second voltage sensor voltage is less than the second threshold (step S207, No), it is determined that the converter connection unit SW2 is stuck off (step S209). After that, the controller 3 ends the process of determining whether the converter connection unit SW2 is stuck off.

[0095] After that, if the controller 3 determines that the converter connection unit SW2 is not stuck on or stuck off, it starts normal control of the DCDC 17. Also, if the controller 3 determines that the converter connection unit SW2 is stuck on or stuck off, it prohibits the start of the vehicle.

[0096] In the above embodiment, the controller 3 performs the stuck-on check and stuck-off check of the converter connection unit SW2 using the second voltage sensor voltage, but this is not limited to the above. For example, the controller 3 may compare the difference voltage between the first voltage sensor voltage and the second voltage sensor voltage with the first threshold value or the second threshold value to perform the stuck-on check and stuck-off check of the converter connection unit SW2.

[0097] [5. Notes] As an appendix, the features of the present invention are as follows: (1) a DC-DC converter connected between a high-voltage system including a generator and a high-voltage battery capable of outputting a first voltage, and a low-voltage system including a low-voltage battery capable of outputting a second voltage lower than the first voltage; A converter connection unit connected between the DC-DC converter and the high-voltage system; A bypass circuit that bypasses the DC-DC converter and connects the low-voltage system and the high-voltage system; A controller that controls the DC-DC converter and determines whether a fault has occurred in the converter connection portion, The controller: When the high-voltage battery is normal, a voltage applied to the converter connection part is compared with a first threshold value to determine whether the converter connection part has a fault; When the high-voltage battery is abnormal, the low-voltage system and the high-voltage system are connected by the bypass circuit, and a fault in the converter connection part is determined by comparing a voltage applied to the converter connection part with a second threshold value lower than the first threshold value. Control device. (2) The bypass circuit includes: a limiting circuit that limits a connection between the low-voltage system and the high-voltage system; The controller: When the high-voltage battery is normal, the limiting circuit is controlled to cut off the connection between the low-voltage system and the high-voltage system, and when the high-voltage battery is abnormal, the limiting circuit is controlled to connect the low-voltage system and the high-voltage system. The control device described in (1). (3) The limiting circuit is a switch. The controller: When the high voltage battery is normal, the switch is turned off, and when the high voltage battery is abnormal, the switch is turned on. The control device described in (2). (4) a DC-DC converter connected between a high-voltage system including a generator and a high-voltage battery capable of outputting a first voltage, and a low-voltage system including a low-voltage battery capable of outputting a second voltage lower than the first voltage; A converter connection unit connected between the DC-DC converter and the high-voltage system; A bypass circuit that bypasses the DC-DC converter and connects the low-voltage system and the high-voltage system; A control device including a controller that controls the DC-DC converter and determines a fault in the converter connection portion, When the high-voltage battery is normal, a voltage applied to the converter connection part is compared with a first threshold value to determine whether the converter connection part has a fault; When the high-voltage battery is abnormal, the low-voltage system and the high-voltage system are connected by the bypass circuit, and a fault in the converter connection part is determined by comparing a voltage applied to the converter connection part with a second threshold value lower than the first threshold value. The control method includes: (5) The bypass circuit includes: a limiting circuit that limits a connection between the low-voltage system and the high-voltage system; The controller: When the high-voltage battery is normal, the limiting circuit is controlled to cut off the connection between the low-voltage system and the high-voltage system, and when the high-voltage battery is abnormal, the limiting circuit is controlled to connect the low-voltage system and the high-voltage system. The control method according to (4) above, (6) The limiting circuit is a switch. The controller: When the high voltage battery is normal, the switch is turned off, and when the high voltage battery is abnormal, the switch is turned on. The control method according to (5) above, (7) a DC-DC converter connected between a high-voltage system including a generator and a high-voltage battery capable of outputting a first voltage, and a low-voltage system including a low-voltage battery capable of outputting a second voltage lower than the first voltage; A converter connection unit connected between the DC-DC converter and the high-voltage system; A bypass circuit that bypasses the DC-DC converter and connects the low-voltage system and the high-voltage system; A controller of a control device including a controller that controls the DC-DC converter and determines a fault in the converter connection portion, If the high voltage battery is normal, a step of comparing a voltage applied to the converter connection part with a first threshold value to determine whether the converter connection part has a fault; a step of connecting the low voltage system and the high voltage system by the bypass circuit when the high voltage battery is abnormal, and determining whether the converter connection part has a fault by comparing a voltage applied to the converter connection part with a second threshold value lower than the first threshold value; A control program that executes the above. (8) The bypass circuit includes: a limiting circuit that limits a connection between the low-voltage system and the high-voltage system; The controller, a step of controlling the limiting circuit so as to cut off a connection between the low voltage system and the high voltage system when the high voltage battery is normal, and to connect the low voltage system and the high voltage system when the high voltage battery is abnormal; The control program according to (7) above. (9) The limiting circuit is a switch. The controller, a step of turning on the switch when the high voltage battery is normal and turning on the switch when the high voltage battery is abnormal; The control program according to (8) above. [Explanation of symbols]

[0098] 1 Control device 3. Controller 10 Engine 11 T / M 12 Starter 13 Electrical Load 14MG 15 INV 16 Smoothing capacitor 17 DCDC 18 Battery monitoring device 19IG 21 Propeller shaft 22 Pulley 23 Rotation axis 24 Pulley 25 Belt 100 Power Supply System 101 High Voltage System 102 Low voltage system B1 High voltage battery B2 Low voltage battery SW1 High voltage battery connection SW2 Converter connection SW3 Precharge connection V1 First voltage sensor V2 Second voltage sensor

Claims

1. a DC-DC converter connected between a high-voltage system including a generator and a high-voltage battery capable of outputting a first voltage, and a low-voltage system including a low-voltage battery capable of outputting a second voltage lower than the first voltage; A converter connection unit connected between the DC-DC converter and the high voltage system; a bypass circuit that bypasses the DC-DC converter and connects the low-voltage system and the high-voltage system; A controller that controls the DC-DC converter and determines whether a fault has occurred in the converter connection portion, The controller: When the high voltage battery is normal, a voltage applied to the converter connection part is compared with a first threshold value to determine whether or not the converter connection part has a fault; When the high-voltage battery is abnormal, the low-voltage system and the high-voltage system are connected by the bypass circuit, and a voltage applied to the converter connection part is compared with a second threshold value lower than the first threshold value to determine whether the converter connection part has a fault. Control device.

2. The bypass circuit includes: a limiting circuit that limits a connection between the low-voltage system and the high-voltage system, The controller: When the high-voltage battery is normal, the limiting circuit is controlled to cut off the connection between the low-voltage system and the high-voltage system, and when the high-voltage battery is abnormal, the limiting circuit is controlled to connect the low-voltage system and the high-voltage system. The control device according to claim 1 .

3. The limiting circuit is a switch. The controller: When the high voltage battery is normal, the switch is turned off, and when the high voltage battery is abnormal, the switch is turned on. The control device according to claim 2.

4. a DC-DC converter connected between a high-voltage system including a generator and a high-voltage battery capable of outputting a first voltage, and a low-voltage system including a low-voltage battery capable of outputting a second voltage lower than the first voltage; A converter connection unit connected between the DC-DC converter and the high voltage system; a bypass circuit that bypasses the DC-DC converter and connects the low-voltage system and the high-voltage system; A control device including a controller that controls the DC-DC converter and determines a fault in the converter connection portion, When the high voltage battery is normal, a voltage applied to the converter connection part is compared with a first threshold value to determine whether or not the converter connection part has a fault; When the high-voltage battery is abnormal, the low-voltage system and the high-voltage system are connected by the bypass circuit, and a voltage applied to the converter connection part is compared with a second threshold value lower than the first threshold value to determine whether the converter connection part has a fault. The control method includes:

5. The bypass circuit includes: a limiting circuit that limits a connection between the low-voltage system and the high-voltage system; The controller: When the high-voltage battery is normal, the limiting circuit is controlled to cut off the connection between the low-voltage system and the high-voltage system, and when the high-voltage battery is abnormal, the limiting circuit is controlled to connect the low-voltage system and the high-voltage system. The control method according to claim 4, comprising:

6. The limiting circuit is a switch. The controller: When the high voltage battery is normal, the switch is turned off, and when the high voltage battery is abnormal, the switch is turned on. The control method according to claim 5 , comprising:

7. a DC-DC converter connected between a high-voltage system including a generator and a high-voltage battery capable of outputting a first voltage, and a low-voltage system including a low-voltage battery capable of outputting a second voltage lower than the first voltage; A converter connection unit connected between the DC-DC converter and the high voltage system; a bypass circuit that bypasses the DC-DC converter and connects the low-voltage system and the high-voltage system; A controller of a control device including a controller that controls the DC-DC converter and determines a fault in the converter connection portion, If the high voltage battery is normal, a step of comparing a voltage applied to the converter connection part with a first threshold value to determine whether the converter connection part has a fault; a step of connecting the low voltage system and the high voltage system by the bypass circuit when the high voltage battery is abnormal, and determining whether the converter connection part has a fault by comparing a voltage applied to the converter connection part with a second threshold value lower than the first threshold value; A control program that executes the above.

8. The bypass circuit includes: a limiting circuit that limits a connection between the low-voltage system and the high-voltage system; The controller, a step of controlling the limiting circuit so as to cut off a connection between the low voltage system and the high voltage system when the high voltage battery is normal, and to connect the low voltage system and the high voltage system when the high voltage battery is abnormal; The control program according to claim 7, which causes the control program to execute the following:

9. The limiting circuit is a switch. The controller, a step of turning on the switch when the high voltage battery is normal and turning on the switch when the high voltage battery is abnormal; 9. The control program according to claim 8, which causes the control program to execute the following:

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