A control method for a high-voltage interlock control circuit of a fuel cell air compressor

Abstract

The present invention relates to a control method for a high-voltage interlock control circuit of a fuel cell air compressor. First, after the low-voltage power-on of the fuel cell system, the initialization of the HVIL signal source of the BMS and the initialization of the air compressor controller are completed, the air compressor controller detects the back electromotive force of the motor in real time through the motor current sensor, and continuously judges whether the back electromotive force is within the normal range. The high-voltage interlock error status of the air compressor is transmitted to the FCU through the communication bus. After receiving the high-voltage interlock error report, the FCU reports it to the PDCU, and the PDCU executes the high-voltage interlock error protection mechanism to prohibit high-voltage power-on or emergency power-off signals. This circuit solves the EMI electromagnetic interference problem caused by connecting the high-voltage interlock signal of the high-speed motor to the low-voltage circuit using connectors and wire harnesses. While solving the electromagnetic interference problem, it also reduces the material cost, improves the connection reliability and integration of the system.

Description

Technical Field

[0001] The present invention relates to a control circuit, specifically to a control method for a high-voltage interlock control circuit of a fuel cell air compressor. Background Art

[0002] The fuel cell air compressor uses high voltage as the power source, and the centrifugal rated speed is about 100,000 revolutions per minute or higher. The controller for driving the high-speed motor uses SiC (silicon carbide) power components, and its switching frequency is generally above 75 kHz and can reach up to 120 kHz at most. The high-voltage interlock plug and wiring harness inside the high-voltage AC interface of the high-speed motor are used to connect the interlock signals in series to the low-voltage signal loop of the high-voltage interlock for high-voltage interlock signal detection. Its disadvantage is that since the transmission path of the low-voltage signal of the high-voltage interlock is too close to the wiring harness and terminals carrying the high-voltage high-frequency electricity of the air compressor high-speed motor, the radiation emission and / or conduction emission effects bring high-energy electromagnetic interference into the low-voltage loop, making it difficult or impossible to meet the EMI limit requirements specified for new energy vehicles. Summary of the Invention

[0003] The control method for the high-voltage interlock control circuit of the fuel cell air compressor provided by the present invention is used to solve the EMI electromagnetic interference problem caused by using plugs and wiring harnesses to connect the high-voltage interlock signals of the high-speed motor to the low-voltage circuit in the prior art. While solving the electromagnetic interference problem, it reduces the material cost, improves the connection reliability and integration degree of the system.

[0004] The technical solution adopted by the present invention is: a control method for a high-voltage interlock control circuit of a fuel cell air compressor, characterized in that: its control circuit includes a BMS, an air compressor controller and a high-voltage AC plug at the motor end. The air compressor controller includes a low-voltage plug, a high-voltage DC plug, a motor current sensor and a high-voltage AC plug at the controller end. The motor current sensor is connected between the motor power supply and the high-voltage AC plug at the motor end. The HVIL signal source in the BMS is connected back to the HVIL signal detection device in the BMS through the first low-voltage plug, the high-voltage DC plug, the high-voltage AC plug at the controller end and the second low-voltage plug in sequence. The high-voltage AC plug at the controller end is plugged into the high-voltage AC plug at the motor end. First, the low-voltage power-on of the fuel cell system is carried out. After the initialization of the HVIL signal source of the BMS and the initialization of the air compressor controller are completed, the air compressor controller detects the back electromotive force of the motor in real time through the motor current sensor, and continuously judges whether the back electromotive force is within the normal range. If the back electromotive force is within the normal range, the air compressor controller transmits the normal state of the high-voltage interlock to the FCU through the communication bus. Otherwise, it transmits the high-voltage interlock error state of the air compressor to the FCU through the communication bus. After receiving the high-voltage interlock error report, the FCU reports it to the PDCU, and the PDCU executes the high-voltage interlock error protection mechanism to prohibit high-voltage power-on or emergency power-off and trigger a warning signal.

[0005] After the second low-voltage connector, there is also a high-voltage AC connector of other high-voltage devices, and the high-voltage AC connector of other high-voltage devices is connected back to the HVIL signal detection device in the BMS.

[0006] The second low-voltage connector and the first low-voltage connector are combined and installed in the same low-voltage connector.

[0007] The motor current sensor is connected to the FCU via a communication bus, the FCU is connected to the PDCU, and the PDCU controls the motor power supply.

[0008] The PDCU is connected to the relay or switch of the motor power supply.

[0009] The air compressor controller further includes a motor feedback speed sensor, which is arranged in the high-speed motor of the air compressor. The motor feedback speed sensor is connected to the FCU via a communication bus, the FCU is connected to the PDCU, and the PDCU controls the motor power supply.

[0010] The present invention can, while using the high-voltage AC high-voltage interlock of the motor and physically connecting the plug-in connector to the low-voltage signal circuit to solve the EMI problem of electromagnetic interference introduced into the low-voltage circuit, realize the transmission of the high-voltage interlock signal to the FCU through the communication bus, without the need to additionally increase independent low-voltage wiring harnesses and plug-in connectors, and reduce the cost. Description of the Drawings

[0011] Figure 1 : Schematic diagram of the high-voltage interlock circuit of the fuel cell air compressor in the present invention.

[0012] Figure 2 : Flowchart of the establishment of the high-voltage interlock control strategy and the fault detection method of the fuel cell air compressor in the present invention.

[0013] In the figure: 1 - BMS; 2 - HVIL signal source; 3 - HVIL signal detection device; 4 - other high-voltage devices; 5 - low-voltage connector; 6 - high-voltage DC connector; 7 - air compressor controller; I - motor current sensor; ω - motor feedback speed signal sensor; 8 - high-voltage AC connector at the controller end; 9 - high-voltage AC connector at the motor end; 10 - high-speed motor of the air compressor. Embodiment

[0014] The following is further described with reference to the drawings.

[0015] Figure 1 、 2As shown in the figure: A high-voltage interlock control circuit method for a fuel cell air compressor. The circuit uses the HVIL signal source 2 in the BMS 1 to generate a high-voltage interlock signal source, which is connected in series with the high-voltage interlock contacts HV1 in the low-voltage connector 5 and the high-voltage DC connector 6 on the air compressor controller 7, the high-voltage interlock contacts HV2 in the high-voltage AC connector 8 at the controller end, the low-voltage connector, and the high-voltage interlock contacts HVn in other high-voltage devices 4, and then returns to the HVIL signal detection device 3 in the BMS to form a high-voltage interlock detection loop. To avoid EMI problems caused by the introduction of high-voltage and high-frequency electromagnetic interference from the high-speed motor 10 of the air compressor into the low-voltage circuit, the high-voltage interlock contact HV3 in the high-voltage AC connector 9 at the motor end is not connected to the above high-voltage interlock detection loop, and the high-voltage AC connectors 8 at the controller end and 9 at the motor end are plugged with U, V, W, and PE; during control, after the fuel cell first performs system low-voltage power-on (S21), HVIL initialization of the BMS (S22), and air compressor control initialization (S23), the air compressor controller will detect the back electromotive force of the motor in real time through the motor current sensor I and the motor feedback speed signal sensor ω (S24), and continuously judge whether the back electromotive force is within the normal range (S25). If the back electromotive force is within the normal range, the controller will transmit the normal state of the high-voltage interlock to the FCU through the communication bus (S26); otherwise, it will transmit the high-voltage interlock error state of the air compressor to the FCU through the communication bus (S29) and stop the operation of the air compressor. After receiving the high-voltage interlock error report, the FCU reports it to the PDCU, and the PDCU executes the high-voltage interlock error protection mechanism to prohibit high-voltage power-on or emergency power-off and trigger a warning signal (S28). The entire fault detection process is completed within one communication cycle.

Claims

1. A control method for a high-voltage interlock control circuit of a fuel cell air compressor, characterized in that: Its control circuit includes a BMS, an air compressor controller, and a high-voltage AC connector at the motor end. The air compressor controller includes a low-voltage connector, a high-voltage DC connector, a motor current sensor, and a high-voltage AC connector at the controller end. The motor current sensor is connected between the motor power supply and the high-voltage AC connector at the motor end. The HVIL signal source in the BMS is sequentially connected back to the HVIL signal detection device in the BMS through the first low-voltage connector, the high-voltage DC connector, the high-voltage AC connector at the controller end, and the second low-voltage connector. The high-voltage AC connector at the controller end is plugged into the high-voltage AC connector at the motor end. First, the fuel cell system is powered on at low voltage. After the HVIL signal source of the BMS and the initialization of the air compressor controller are completed, the air compressor controller detects the back electromotive force of the motor in real time through the motor current sensor, and continuously judges whether the back electromotive force is within the normal range. If the back electromotive force is within the normal range, the air compressor controller transmits the normal state of the high-voltage interlock to the FCU through the communication bus. Otherwise, it transmits the high-voltage interlock error state of the air compressor to the FCU through the communication bus. After receiving the high-voltage interlock error report, the FCU reports it to the PDCU, and the PDCU executes the high-voltage interlock error protection mechanism to prohibit high-voltage power-on or emergency power-off and trigger a warning signal. The circuit uses the HVIL signal source in the BMS to generate a high-voltage interlock signal source, which is connected in series with the high-voltage interlock contacts HV1 in the low-voltage connector and the high-voltage DC connector on the air compressor controller, the high-voltage interlock contacts HV2 in the high-voltage AC connector at the controller end, the low-voltage connector, and the high-voltage interlock contacts HVn in other high-voltage devices, and then returns to the HVIL signal detection device in the BMS to form a high-voltage interlock detection circuit. To avoid EMI problems caused by the introduction of high-voltage high-frequency electromagnetic interference from the high-speed motor of the air compressor into the low-voltage circuit, the high-voltage interlock contact HV3 in the high-voltage AC connector at the motor end is not connected to the above high-voltage interlock detection circuit, and the high-voltage AC connectors at the controller end and the motor end are plugged with U, V, W, and PE.

2. The control method of the high-voltage interlock control circuit of a fuel cell air compressor according to claim 1, characterized in that: After the second low-voltage connector, there is also a high-voltage AC connector of other high-voltage devices, and the high-voltage AC connector of other high-voltage devices is connected back to the HVIL signal detection device in the BMS.

3. A control method for a high-voltage interlock control circuit of a fuel cell air compressor according to claim 1 or 2, characterized in that: The second low-voltage connector and the first low-voltage connector are combined and installed in the same low-voltage connector.

4. A control method for a high-voltage interlock control circuit of a fuel cell air compressor according to claim 1, characterized in that: The motor current sensor is connected to the FCU through the communication bus, the FCU is connected to the PDCU, and the PDCU controls the motor power supply.

5. A control method for a high-voltage interlock control circuit of a fuel cell air compressor according to claim 4, characterized in that: The PDCU is connected to the relay of the motor power supply.

6. A control method for a high-voltage interlock control circuit of a fuel cell air compressor according to claim 1, characterized in that: The air compressor controller also includes a motor feedback speed sensor, which is set in the high-speed motor of the air compressor. The motor feedback speed sensor is connected to the FCU through the communication bus, the FCU is connected to the PDCU, and the PDCU controls the motor power supply.

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