JP2022110434A - vehicle structure - Google Patents

Abstract

To provide a drive control method for a vehicle, capable of properly continuing to drive the vehicle by selecting a driving mode according to a failure location, even if an OVL circuit failure occurs.SOLUTION: In a drive control method for a vehicle equipped with a fuel cell system according to the present disclosure, a control unit detects whether or not a circuit failure (OVL circuit failure) of an overvoltage detection mechanism to monitor an input voltage of a secondary battery converter occurs, stops an air compressor, a drive motor and the secondary battery converter when detecting the occurrence of the OVL circuit failure, then sends a drive command to these apparatuses, and, if all of these apparatuses are driven according to the drive command, drives the vehicle in a normal driving mode, while, if all of these apparatuses are not driven according to the drive command, drives the vehicle in an evacuation traveling mode.SELECTED DRAWING: Figure 3

Description

The present invention relates to a vehicle operation control method, and more particularly to a novel operation control method when a circuit failure occurs in a vehicle equipped with a fuel cell system.

In general, a fuel cell vehicle (FCV) is equipped with an overvoltage detection mechanism for detecting an overvoltage (OVL) of the input voltage VL to a secondary battery converter connected to a secondary battery (battery) by hardware configuration. there is When a circuit failure of the OVL detection mechanism (hereinafter referred to as "OVL circuit failure") occurs, control is normally performed to shift the driving mode of the vehicle from the normal driving mode to the evacuation driving mode. This evacuation driving mode is called an MD (Motor Drive) discharging driving mode (hereinafter referred to as "MD discharging driving mode"). Stop the inverter connected to the drive motor of the vehicle. In this state, the electric power of the secondary battery is discharged and supplied to the inverter for power division, so that the generator can be operated as an electric motor, and the vehicle can be kept running for several kilometers (for example, Patent Document 1). reference.).

JP 2016-215675 A

Here, the input voltage VL to the secondary battery converter is monitored, for example, by an OVL detector provided in an IPM (Intelligent Power Module) incorporated in the secondary battery converter. The voltage detection signal is input from the latch circuit section through the CPU port to the CPU of the MG ECU (motor/generator electronic control unit for controlling the inverter connected to the drive motor). It is determined whether or not it is OVL. When OVL is detected, a shutdown system provided in the MGECU functions to stop various inverters and the like. Therefore, the places where the OVL circuit failure can occur are usually assumed to be (1) the OVL detection section, (2) the latch circuit section, (3) the input to the CPU port, and (4) the shutdown system. be.

However, the self-diagnosis function (diagnosis) of a normal vehicle does not discriminate between the failure locations and failure patterns. Thus, the vehicle can only run in the MD discharge running mode. However, if (3) the input to the CPU port fails among the above failure points, various devices such as inverters can operate, so it is possible to continue driving the vehicle in normal driving mode. Practically, there is no need to shift to the MD discharge running mode with a short running duration.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above problems. It is an object of the present invention to provide a vehicle operation control method capable of

In order to solve the above problems, the present invention employs the following configurations. That is, one example of the vehicle operation control method according to the present disclosure includes a fuel cell stack, an air system having an air compressor that supplies air to the fuel cell stack, and a fuel gas system that supplies fuel gas to the fuel cell stack. a cooling system that cools the fuel cell stack; a high voltage system that is connected to the fuel cell stack and has a fuel cell boost converter, a secondary battery, a secondary battery converter, and a drive motor; connected to the fuel cell stack, the air system, the fuel gas system, the cooling system, and the high voltage system, and detects an overvoltage (OVL) of the input voltage VL to the secondary battery converter; and a control unit having an OVL detection mechanism.

The control unit detects whether or not an OVL circuit failure has occurred, and temporarily stops the air compressor, the drive motor, and the secondary battery converter when the occurrence of the OVL circuit failure is detected. Then, a drive command was sent to the air compressor, the drive motor, and the secondary battery converter, and the air compressor, the drive motor, and the secondary battery converter were all driven according to the drive command. In this case, the vehicle is driven in the normal driving mode, and if any one of the air compressor, the drive motor, and the secondary battery converter does not drive according to the driving command, the vehicle is driven in the evacuation driving mode ( run in the MD discharge running mode).

With such a configuration, when the occurrence of an OVL circuit failure is detected, by attempting to drive the temporarily stopped air compressor, drive motor, and secondary battery converter, if all of these devices are driven according to the drive command, can be determined to be the failure of (3) the CPU port among the failure locations (1) to (4) described above. In this case, the temporarily stopped air compressor, drive motor, and secondary battery converter can be operated in normal operation, and the vehicle can be driven in the normal driving mode. On the other hand, if at least one of the air compressor, the drive motor, and the secondary battery converter that receives the drive command does not drive according to the drive command, one of the failure locations (1) to (4) described above ( 3) Since it is possible to determine that the failure is at a location other than the input to the CPU port, in this case, the vehicle can be run in the evacuation mode.

From the above, according to the present disclosure, even when an OVL circuit failure occurs, it is possible to select an operation mode according to the location of the failure and appropriately continue driving the vehicle. , it can contribute to the improvement of driving reliability and economic efficiency of the vehicle.

1 is a schematic configuration diagram of a fuel cell system mounted in a vehicle to which a vehicle operation control method according to an embodiment of the present disclosure is effectively applied; FIG. 1 is a block diagram schematically illustrating the concept of OVL detection and where OVL circuit failures can occur; FIG. 4 is a flow chart showing an example of a processing procedure when an OVL circuit failure occurs;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same reference numerals are given to the same elements, and overlapping explanations are omitted.

[Embodiment]
FIG. 1 is a schematic configuration diagram of a fuel cell system mounted on a vehicle to which a vehicle operation control method according to an embodiment of the present disclosure is effectively applied. The fuel cell system 100 includes a fuel cell (FC) stack 10, an air system 20, a fuel gas system 30, a cooling system 40, and a high voltage system 50 connected to the fuel cell stack 10, respectively. and a control unit 60 connected thereto.

The fuel cell stack 10 is formed by stacking a plurality of single cells, and generates power through an electrochemical reaction between a fuel gas (hydrogen or the like) and an oxidant gas (air). Each single cell is a power generating element capable of generating power by itself, and includes a membrane electrode assembly (MEA), which is a power generating body in which electrodes are arranged on both sides of an electrolyte membrane, and separators arranged on both sides thereof.

The air system 20 is a circuit that supplies and discharges oxygen in the air to the fuel cell stack 10 . Further, the fuel gas system 30 is a circuit that supplies hydrogen to the fuel cell stack 10 and discharges it. As a result, electric energy and heat are generated in the fuel cell stack 10 by the reaction between hydrogen and oxygen. Also, the cooling system 40 cools and removes heat generated in the fuel cell stack 10 . Further, the high voltage system 50 is a circuit that mainly drives the vehicle using the electrical energy generated by the fuel cell stack 10 . The control unit 60 also controls the air system 20, the fuel gas system 30, the cooling system 40, and the high voltage system 50, respectively.

The high voltage system 50 includes a fuel cell boost converter (FDC) 51, a secondary battery (BAT) 52, a secondary battery converter (BDC) 53, an air compressor (MG1) 54, and a drive motor (MG2) 55. , and accessories 56 .

The fuel cell boost converter 51 is connected to the fuel cell stack 10, boosts the voltage output from the fuel cell stack 10, and outputs the boosted voltage to the high voltage wiring. If the output voltage of the fuel cell stack 10 is not boosted, the fuel cell boost converter 51 can be omitted. A secondary battery 52 is connected to this high-voltage wiring via a secondary battery converter 53 . The secondary battery converter 53 in this embodiment has the function of stepping down the high voltage input from the high voltage wiring and outputting it to the secondary battery 52, and the function of stepping up the voltage input from the secondary battery 52 to high voltage It is a bi-directional DC-DC converter with a function of outputting to wiring.

An air compressor 54 and a drive motor 55 are connected to the high voltage wiring of the high voltage system 50 via an inverter (not shown). The inverter converts the DC voltage input from the fuel cell stack 10 and the secondary battery 52 into a three-phase AC voltage, which is output to the operating motor of the air compressor 54 and the drive motor 55 of the vehicle. Thereby, the air compressor 54 can compress air in the atmosphere and supply it to the fuel cell stack 10, and the drive motor 55 can drive the wheels of the vehicle (not shown). Note that the air compressor 54 itself is provided in the air system 20 . Also, the inverter connected to the air compressor 54 and the drive motor 55 may have a regeneration function of regenerating the kinetic energy of the vehicle as electrical energy, and the regenerated power can charge the secondary battery 52 .

Further, various accessories 56 for operating the vehicle are connected to the high voltage wiring of the high voltage system 50 . Such accessories 56 include various high-voltage accessories such as an inverter for driving various pumps used in the air system 20, the fuel gas system 30, and the cooling system 40, a hydrogen pump (H/P ), cooling water pump (W/P), air conditioning compressor (A/C), water heater, low voltage (12V) converter, and the like. These high voltage auxiliaries are connected to a high voltage wiring through a step-up DC/DC converter, and are supplied with electric power having a voltage raised to about 300V.

Here, FIG. 2 is a block diagram schematically showing the concept of OVL detection and locations where OVL circuit failures may occur. As described above, the input voltage to the secondary battery converter 53 is monitored by (1) the OVL detector 211 provided in the IPM 210 incorporated in the secondary battery converter 53, for example. The voltage detection signal is input to the CPU 222 of the MGECU 220 from (2) the latch circuit unit 212 through the (3) CPU port 221 in the MGECU 220, where it is compared with OVL to determine whether the input voltage is OVL. is determined. When OVL is detected, a shutdown command signal for stopping various inverters etc. is sent from a shutdown (SDOWN) system 223 provided in the MGECU 220 to the high voltage system 50 through an appropriate logic circuit 224. It is output to the IPM 230, and the driving of the air compressor 54, the drive motor 55, the secondary battery converter 53, etc. is controlled to shut down.

Here, FIG. 3 is a flow chart showing an example of a processing procedure when an OVL circuit failure occurs. First, when the control unit 60 detects the occurrence of an OVL circuit failure using, for example, sensors provided in the MGECU 220 (step S1), the control unit 60 controls the air compressor 54 (MG1), the drive motor 55 (MG2), and the A stop command is sent to the secondary battery converter 53 (BDC) to stop these devices (step S2). In this state, the control unit 60 determines whether the input voltage VL to the secondary battery converter 53 monitored by the OVL detection unit 211 is not OVL (overvoltage) (VL<OVL) ( step S3).

If the input voltage VL is equal to or higher than OVL (No in step S3), it can be determined that the OVL circuit failure is caused by (1) the failure of the OVL detector. With the vehicle stopped, the control unit 60 causes the vehicle to travel in an evacuation travel mode (MD discharge travel mode) similar to the conventional one (step S31). On the other hand, if the input voltage VL is not OVL (Yes in step S3), the control unit 60 sends a drive command to each of the air compressor 54 (MG1) and the drive motor 55 (MG2). The drive command in this case is a command for instructing discharge (discharge command) so as not to generate the driving force of the air compressor 54 and the drive motor 55 .

Next, the control unit 60 determines whether the inverter current INV (actual current) output from the air compressor 54 and the drive motor 55 by the discharge command rises to the target current (command target value) based on the command. (Step S5).

If the inverter current INV at this time does not reach the command target value (No in step S5), it can be determined that the OVL circuit failure is due to (1) the OVL detection unit 211 or (2) the latch circuit unit 212 failure. 60 drives the vehicle in the same evacuation driving mode (MD discharging driving mode) as in the conventional art, with the air compressor 54, drive motor 55, and secondary battery converter 53 stopped (step S32). On the other hand, if the inverter current INV at this time matches or substantially matches the command target value (Yes in step S5), the control unit 60 cancels the discharge command to the air compressor 54 and the drive motor 55 (step S6), Subsequently, the drive command is sent to the secondary battery converter 53 (BDC) (step S7). The drive command in this case is a command (boost command) to continuously or intermittently boost the output voltage of the secondary battery converter 53 from the minimum value to the maximum value.

Next, control unit 60 determines whether or not voltage VH (actual voltage) output from secondary battery converter 53 according to the boost command follows the change in target voltage based on the command (step S8).

If the output voltage VH at this time does not change following the command target value (No in step S8), it can be determined that the OVL circuit failure is caused by (1) the OVL detector 211 or (2) the latch circuit 212. , the control unit 60 causes the vehicle to run in the same evacuation mode (MD discharge mode) as in the conventional art, with the air compressor 54, the drive motor 55, and the secondary battery converter 53 stopped (step S32). On the other hand, if the output voltage VH at this time changes following the instruction target value (Yes in step S8), it can be determined that the OVL circuit failure is caused only by (3) the failure of the input to the CPU port 221. , the control unit 60 sends a drive command to the air compressor 54, the drive motor 55, and the secondary battery converter 53 to cancel their stoppages and restart the operation, thereby causing the vehicle to travel in the normal operation mode. and returns (step S33).

According to the processing procedure of this embodiment configured in this manner, as described above, the air compressor 54, the drive motor 55, and the secondary battery converter 53, which have been temporarily stopped due to the occurrence of the OVL circuit failure, , and determines whether they operate normally. As a result, even if an OVL circuit failure is detected, instead of running the vehicle only in the evacuation running mode (MD discharge running mode) regardless of the location of the failure, as in the conventional case, the circuit failure is (3) connected to the CPU port. If it can be determined that the input failure is the only cause, the vehicle can be returned to the normal running mode. Therefore, according to the vehicle operation control method of the present disclosure, it is possible to discriminate and identify the failure location that is the cause of the OVL circuit failure, and select the operation mode according to the actual and detailed determination result of the failure location. As a result, it is possible to continue the operation of the vehicle appropriately, and as a result, it is possible to improve the operation reliability and economic efficiency of the vehicle.

Although the above embodiment has been described in detail as an example of the present disclosure, the above description merely shows an example of the present disclosure in all respects, and various improvements and modifications can be made without departing from the scope of the present disclosure. It goes without saying that Moreover, the above-described embodiments may be partially replaced, and can be configured by combining them as appropriate.

DESCRIPTION OF SYMBOLS 10... Fuel cell stack 20... Air system 30... Fuel gas system 40... Cooling system 50... High voltage system 51... Fuel cell step-up converter (FDC) 52... Secondary battery (BAT) 53... Two Secondary battery converter (BDC) 54 Air compressor (MG1) 55 Drive motor (MG2) 56 Auxiliaries 60 Control unit 100 Fuel cell system 211 OVL detector 212 Latch circuit Part 221...CPU port 222...CPU 223...Shutdown system 224...Logic circuit.

Claims (1)

a fuel cell stack;
an air system having an air compressor that supplies air to the fuel cell stack;
a fuel gas system that supplies fuel gas to the fuel cell stack;
a cooling system for cooling the fuel cell stack;
a high voltage system connected to the fuel cell stack and having a fuel cell boost converter, a secondary battery, a secondary battery converter, and a drive motor;
an overvoltage detection mechanism that is connected to the fuel cell stack, the air system, the fuel gas system, the cooling system, and the high voltage system and detects an overvoltage of the input voltage to the secondary battery converter; a control unit having
An operation control method for a vehicle equipped with a fuel cell system comprising:
detecting whether or not a circuit failure of the overvoltage detection mechanism has occurred;
temporarily stopping the air compressor, the drive motor, and the secondary battery converter when a circuit failure of the overvoltage detection mechanism is detected;
sending a drive command to the air compressor, the drive motor, and the secondary battery converter;
When all of the air compressor, the drive motor, and the secondary battery converter are driven according to the drive command, the vehicle is driven in a normal driving mode,
When any one of the air compressor, the drive motor, and the secondary battery converter does not drive according to the drive command, the vehicle is driven in an evacuation mode.
Vehicle driving control method.

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