Wiring harness connection reliability detection device of fuel cell

Abstract

The utility model discloses a wire harness connection reliability detection device of a fuel cell, which comprises an alternating current signal generator, a shunt and a voltage inspection device, the alternating current signal generator, the shunt and a fuel cell stack to be detected are connected in series to form a loop, a first end of the voltage inspection device is electrically connected with the fuel cell stack, and a second end of the voltage inspection device is electrically connected with the fuel cell stack. And the second end of the voltage inspection device is electrically connected with the shunt. According to the utility model, wiring harness connection reliability detection can be carried out before the fuel cell runs, hydrogen is not involved, and the system safety can be improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of measurement and control of fuel cells, and more specifically relates to a wiring harness connection reliability detection device for fuel cells. Background Art

[0002] At present, the common hydrogen fuel cell stacks on the market are composed of hundreds of single cells connected in series, and the single cell voltage, impedance, etc. of the battery are detected by a voltage patroller. The voltage and impedance reflect the operating status of the fuel cell. If the collected voltage and impedance are abnormal, it means that the fuel cell is not operating normally. The single-cell voltage, impedance and connection of the sampling line are closely related. When the sampling harness connection is unreliable and a break occurs, the collected single-cell voltage data is also unreliable. Therefore, it is necessary to test the reliability of the fuel cell harness connection.

[0003] There are two main traditional methods for testing the reliability of wiring harness connections.

[0004] The first method is to use a multimeter to measure the wiring harness loop before the fuel cell is operated. This method is cumbersome and the measurement results must be recorded manually, which is time-consuming and laborious.

[0005] The second method is to measure the voltage during the operation of the fuel cell, and determine the disconnection based on the special phenomenon of the single cell voltage acquisition after the sampling line is disconnected and whether the voltage of the acquisition chip pin is connected to the battery. This test method is efficient and fast, and saves manpower. However, since it can only be detected after the fuel cell is started, the battery must be stopped before troubleshooting can be performed, and its reliability is not as good as testing before the battery is running. Utility Model Content

[0006] In response to at least one defect or improvement need in the prior art, the utility model provides a wiring harness connection reliability detection device for a fuel cell, which can perform wiring harness connection reliability detection before the fuel cell is operated, does not involve hydrogen, and can improve system safety.

[0007] To achieve the above-mentioned purpose, according to the first aspect of the utility model, a fuel cell wiring harness connection reliability detection device is provided, comprising: an AC signal generator, a shunt and a voltage patroller, wherein the AC signal generator, the shunt and the fuel cell stack to be detected are connected in series to form a loop, the first end of the voltage patroller is electrically connected to the fuel cell stack, and the second end of the voltage patroller is electrically connected to the shunt.

[0008] Furthermore, a controller is included, and the third end of the voltage patroller is electrically connected to the controller.

[0009] Furthermore, the controller is a host computer.

[0010] Furthermore, the voltage patroller includes a power supply, a signal gating unit, an AC voltage acquisition unit, an AC current acquisition unit, an analog-to-digital conversion unit, a microprocessor unit and a communication unit, one end of the signal gating unit is electrically connected to the fuel cell stack, the other end of the signal gating unit is electrically connected to one end of the AC voltage acquisition unit, the other end of the AC voltage acquisition unit is electrically connected to a first end of the analog-to-digital conversion unit, one end of the AC current acquisition unit is electrically connected to the shunt, the other end of the AC current acquisition unit is electrically connected to a second end of the analog-to-digital conversion unit, a third end of the analog-to-digital conversion unit is electrically connected to a first end of the microprocessor, and the second end of the microprocessor is electrically connected to a first end of the communication unit.

[0011] Furthermore, the AC voltage acquisition unit includes a high common-mode voltage-stabilizing amplifier U24, a first resistor R27, a second resistor R28, a first capacitor C24, a second capacitor C25 and a bandpass filter amplifier circuit, the non-inverting input terminal of the high common-mode voltage-stabilizing amplifier is electrically connected to the first resistor, the inverting input terminal of the high common-mode voltage-stabilizing amplifier is electrically connected to the second resistor, one end of the first capacitor is electrically connected to the non-inverting input terminal of the high common-mode voltage-stabilizing amplifier, the other end of the first capacitor is grounded, one end of the second capacitor is electrically connected to the inverting input terminal of the high common-mode voltage-stabilizing amplifier, the other end of the second capacitor is grounded, and the output terminal of the high common-mode voltage-stabilizing amplifier is electrically connected to the bandpass filter amplifier circuit.

[0012] Further, the bandpass filter amplifier circuit includes an amplifier U23, a third capacitor C22, a third resistor R23, a fourth resistor R26, a fifth resistor R24, a sixth resistor R25, a seventh resistor R21 and a low-pass filter circuit, one end of the fourth resistor is electrically connected to the output end of the high common-mode voltage regulator amplifier, the other end of the fourth resistor is electrically connected to the input end of the low-pass filter circuit, the output end of the low-pass filter circuit is electrically connected to one end of the third capacitor, the other end of the third capacitor is electrically connected to the in-phase input end of the amplifier, the in-phase input end of the amplifier is also electrically connected to one end of the third resistor, the other end of the third resistor is grounded, one end of the seventh resistor is electrically connected to the inverting input end of the amplifier, the other end of the seventh resistor is grounded, one end of the fifth resistor is electrically connected to the inverting input end of the amplifier, the other end of the fifth resistor is electrically connected to the output end of the amplifier, one end of the sixth resistor is electrically connected to the in-phase input end of the amplifier, and the other end of the sixth resistor is electrically connected to the output end of the amplifier.

[0013] Further, the low-pass filter circuit includes an eighth resistor R22, a fourth capacitor C21 and a fifth capacitor C23, the other end of the fourth resistor is electrically connected to one end of the eighth resistor, the other end of the eighth resistor is electrically connected to one end of the third capacitor, the common end of the fourth resistor and the eighth resistor is also electrically connected to one end of the fourth capacitor, the other end of the fourth capacitor is grounded, the common end of the eighth resistor and the third capacitor is also electrically connected to one end of the fifth capacitor, and the other end of the fifth capacitor is grounded.

[0014] Furthermore, the structure of the AC current acquisition unit is the same as that of the AC voltage acquisition unit.

[0015] In general, compared with the prior art, the present invention has the following advantages:

[0016] (1) The utility model adopts an AC signal generator, which can provide an AC signal to the fuel cell stack before the fuel cell is operated, so that the reliability of the wiring harness connection can be tested before the fuel cell is operated. It does not involve hydrogen, improves the safety of the system, and because the fuel cell is not running during the test, any problems found can be confirmed and repaired in time.

[0017] (2) This solution can observe the measurement results through the host computer, which can save the work of manually using a multimeter to measure the connectivity of the wiring harness, saving time and effort. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of a wiring harness connection reliability detection device for a fuel cell according to an embodiment of the utility model;

[0019] Figure 2 It is a schematic diagram of the composition of the voltage patrol device of an embodiment of the utility model;

[0020] Figure 3 It is a circuit schematic diagram of a signal gating unit of an embodiment of the utility model;

[0021] Figure 4 It is a circuit schematic diagram of the AC voltage acquisition unit of the embodiment of the utility model;

[0022] Figure 5 It is a circuit schematic diagram of an AC current acquisition unit of an embodiment of the utility model;

[0023] Figure 6 It is a circuit principle diagram of the analog-to-digital conversion unit of an embodiment of the utility model. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model. In addition, the technical features involved in each embodiment of the utility model described below can be combined with each other as long as they do not conflict with each other.

[0025] like Figure 1 As shown, a fuel cell wiring harness connection reliability detection device of this embodiment can detect whether a wire break occurs before the fuel cell is operated based on the internal resistance detection function of the voltage patroller. The fuel cell wiring harness connection reliability detection device includes: an AC signal generator, a shunt and a voltage patroller. The AC signal generator, the shunt and the fuel cell stack to be detected are connected in series to form a loop, the first end of the voltage patroller is electrically connected to the fuel cell stack, and the second end of the voltage patroller is electrically connected to the shunt. The shunt is an instrument for measuring current, which is made based on the principle that a voltage is generated at both ends of a resistor when current passes through the resistor.

[0026] An AC disturbance signal is applied to the fuel cell stack system through an external AC signal generator, and the single-chip AC voltage is detected through a voltage patroller. At the same time, the current is converted into a voltage through a shunt and input into the voltage patroller. The reliability of the wiring harness connection can be judged by combining the collected AC current and AC voltage. If a certain battery cannot collect the AC disturbance signal at all or the collected AC voltage value is abnormal, it means that the sampling line of the battery may be broken. Since the fuel cell is not running at this time, the user can directly measure the wiring harness connection with a multimeter to confirm it. If each battery can collect the AC disturbance signal, the battery impedance can be judged whether it is normal by combining the applied AC disturbance current and the fuel cell specifications.

[0027] Furthermore, a controller is included, and the third end of the voltage patroller is electrically connected to the controller.

[0028] Furthermore, the controller is a host computer. In this way, the measurement results can be observed through the host computer, which can save the manual work of using a multimeter to measure the connectivity of the wiring harness, saving time and effort.

[0029] like Figure 2As shown, further, the voltage patroller includes a power supply, a signal gating unit, an AC voltage acquisition unit, an AC current acquisition unit, an analog-to-digital conversion unit, a microprocessor unit and a communication unit. One end of the signal gating unit is electrically connected to the fuel cell stack, the other end of the signal gating unit is electrically connected to one end of the AC voltage acquisition unit, the other end of the AC voltage acquisition unit is electrically connected to the first end of the analog-to-digital conversion unit, one end of the AC current acquisition unit is electrically connected to the shunt, the other end of the AC current acquisition unit is electrically connected to the second end of the analog-to-digital conversion unit, the third end of the analog-to-digital conversion unit is electrically connected to the first end of the microprocessor, and the second end of the microprocessor is electrically connected to the first end of the communication unit. The signal gating unit is used to control the isolation optocoupler to gating the battery voltage signal. The AC voltage acquisition unit performs a series of processing such as voltage stabilization, filtering, and amplification on the isolated voltage signal. The AC current acquisition unit performs a series of processing such as voltage stabilization, filtering, and amplification on the voltage signals at both ends of the shunt. The signal processed by the acquisition unit is converted into a digital signal through an analog-to-digital converter, and then the microprocessor processes and calculates the converted data and communicates with the external controller through the communication unit.

[0030] Furthermore, the voltage patroller also includes a power supply, which is electrically connected to the signal selection unit, the AC voltage acquisition unit, the AC current acquisition unit, the analog-to-digital conversion unit, the microprocessor and the communication unit respectively. The power supply unit converts the external power supply to power the circuits of each module.

[0031] like Figure 3 As shown, the signal gating unit of this embodiment includes a 38 decoder and its input and output signals. The signal gating unit is enabled by a microprocessor and controls the output of the 38 decoder, and then the 38 decoder output controls the on and off of the optocoupler. Pin 6 of the 38 decoder U21 is an enable pin, which is valid at a low level. Pins 9 to 11 are digital inputs, which receive high and low level signals from the microprocessor to control the output and perform optocoupler gating.

[0032] like Figure 4 As shown, further, the AC voltage acquisition unit includes a high common-mode voltage-stabilizing amplifier U24, a first resistor R27, a second resistor R28, a first capacitor C24, a second capacitor C25 and a bandpass filter amplifier circuit, the non-inverting input terminal of the high common-mode voltage-stabilizing amplifier is electrically connected to the first resistor, the inverting input terminal of the high common-mode voltage-stabilizing amplifier is electrically connected to the second resistor, one end of the first capacitor is electrically connected to the non-inverting input terminal of the high common-mode voltage-stabilizing amplifier, the other end of the first capacitor is grounded, one end of the second capacitor is electrically connected to the inverting input terminal of the high common-mode voltage-stabilizing amplifier, the other end of the second capacitor is grounded, and the output terminal of the high common-mode voltage-stabilizing amplifier is electrically connected to the bandpass filter amplifier circuit.

[0033] Further, the bandpass filter amplifier circuit includes an amplifier U23, a third capacitor C22, a third resistor R23, a fourth resistor R26, a fifth resistor R24, a sixth resistor R25, a seventh resistor R21 and a low-pass filter circuit, one end of the fourth resistor is electrically connected to the output end of the high common-mode voltage regulator amplifier, the other end of the fourth resistor is electrically connected to the input end of the low-pass filter circuit, the output end of the low-pass filter circuit is electrically connected to one end of the third capacitor, the other end of the third capacitor is electrically connected to the in-phase input end of the amplifier, the in-phase input end of the amplifier is also electrically connected to one end of the third resistor, the other end of the third resistor is grounded, one end of the seventh resistor is electrically connected to the inverting input end of the amplifier, the other end of the seventh resistor is grounded, one end of the fifth resistor is electrically connected to the inverting input end of the amplifier, the other end of the fifth resistor is electrically connected to the output end of the amplifier, one end of the sixth resistor is electrically connected to the in-phase input end of the amplifier, and the other end of the sixth resistor is electrically connected to the output end of the amplifier.

[0034] Further, the low-pass filter circuit includes an eighth resistor R22, a fourth capacitor C21 and a fifth capacitor C23, the other end of the fourth resistor is electrically connected to one end of the eighth resistor, the other end of the eighth resistor is electrically connected to one end of the third capacitor, the common end of the fourth resistor and the eighth resistor is also electrically connected to one end of the fourth capacitor, the other end of the fourth capacitor is grounded, the common end of the eighth resistor and the third capacitor is also electrically connected to one end of the fifth capacitor, and the other end of the fifth capacitor is grounded.

[0035] The AC voltage acquisition unit can extract and amplify weak AC voltage signals for conversion by the analog-to-digital converter.

[0036] Since the internal resistance of the single chip is between 0.4mΩ and 1.4mΩ before the fuel cell is operated, and the amplitude of the applied AC disturbance signal is about 5A, the AC voltage amplitude on both sides of the single fuel cell is at the mV level. The voltage acquisition unit needs to amplify this weak voltage to the range that the analog-to-digital converter can detect. In the figure, U24 is a high common-mode voltage-stabilizing amplifier, and its amplification factor can be set to 1:1 to stabilize the input signal to prevent distortion caused by the subsequent circuit. R22, C21, and C23 are low-pass filter circuits. Since the frequency of the AC disturbance signal is 512Hz, it is necessary to filter out signals with higher frequencies to prevent interference with the target signal. C22 and R23 can filter out DC signals and low-frequency signals, and together with the previous low-pass filter circuit and the subsequent amplifier circuit, they form a bandpass filter amplifier circuit. By configuring the resistance and capacitance parameters, a passband frequency of 50Hz to 1kHz and a magnification factor of 100 can be achieved to extract and amplify the weak 512Hz AC voltage signal.

[0037] like Figure 5 As shown, further, the structure of the AC current acquisition unit is the same as that of the AC voltage acquisition unit. The same structure means that the components are the same, but the parameter values ​​such as capacitance and resistance in the circuit are not necessarily the same. The AC current unit is used to extract the mV-level voltage signal on the shunt for use in the calculation of the battery impedance, and the shunt resistance is selected to be 0.1mΩ. Since the calculation is based on the AC impedance method, it is necessary to convert the time domain signal into a frequency domain signal. The phase angle of the AC impedance is the difference between the phase angles of the AC voltage and the AC current. Therefore, the signal conditioning circuit must have good consistency, that is, the phase difference between the voltage signal and the current signal should not change too much before and after passing through their respective signal conditioning circuits, otherwise the calculation accuracy of the AC impedance will be significantly reduced. In order to reduce the influence of the signal processing circuit on the amplitude and phase of the weak AC signal, the AC current unit circuit adopts the same filter amplifier circuit as the AC voltage unit.

[0038] like Figure 6 As shown, due to the limited analog-to-digital conversion function of the microprocessor, the voltage patroller uses an external analog-to-digital conversion unit to convert analog signals into digital signals. Pins 9 and 10 of the analog-to-digital conversion chip U39 are the data line and clock line of the IIC, respectively, which are used to transmit information to the microprocessor. R88 and R89 are pull-up resistors. Pin 4 is the output of the AC voltage acquisition unit 1, and pin 6 is the output of the AC current acquisition unit. R87 and R90 are used to limit current.

[0039] It is easy for those skilled in the art to understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A fuel cell wiring harness connection reliability detection device, characterized in that: include: An AC signal generator, a shunt and a voltage patroller, wherein the AC signal generator, the shunt and the fuel cell stack to be detected are connected in series to form a loop, and the voltage patroller comprises a signal gating unit, an AC voltage acquisition unit, an AC current acquisition unit, an analog-to-digital conversion unit, a microprocessor and a communication unit, wherein one end of the signal gating unit is electrically connected to the fuel cell stack, the other end of the signal gating unit is electrically connected to one end of the AC voltage acquisition unit, the other end of the AC voltage acquisition unit is electrically connected to a first end of the analog-to-digital conversion unit, one end of the AC current acquisition unit is electrically connected to the shunt, the other end of the AC current acquisition unit is electrically connected to a second end of the analog-to-digital conversion unit, a third end of the analog-to-digital conversion unit is electrically connected to a first end of the microprocessor, and the second end of the microprocessor is electrically connected to a first end of the communication unit; The AC voltage acquisition unit includes a high common-mode voltage-stabilizing amplifier, a first resistor, a second resistor, a first capacitor, a second capacitor and a band-pass filter amplifier circuit. The non-inverting input terminal of the high common-mode voltage-stabilizing amplifier is electrically connected to the first resistor, the inverting input terminal of the high common-mode voltage-stabilizing amplifier is electrically connected to the second resistor, one end of the first capacitor is electrically connected to the non-inverting input terminal of the high common-mode voltage-stabilizing amplifier, the other end of the first capacitor is grounded, one end of the second capacitor is electrically connected to the inverting input terminal of the high common-mode voltage-stabilizing amplifier, the other end of the second capacitor is grounded, and the output terminal of the high common-mode voltage-stabilizing amplifier is electrically connected to the band-pass filter amplifier circuit.

2. The fuel cell wiring harness connection reliability detection device according to claim 1, characterized in that: A controller is also included, and the second end of the communication unit is electrically connected to the controller.

3. The fuel cell wiring harness connection reliability detection device according to claim 2, characterized in that: The controller is a host computer.

4. The fuel cell wiring harness connection reliability detection device according to claim 1, characterized in that: The bandpass filter amplifier circuit includes an amplifier, a third capacitor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and a low-pass filter circuit, one end of the fourth resistor is electrically connected to the output end of the high common-mode voltage regulator amplifier, the other end of the fourth resistor is electrically connected to the input end of the low-pass filter circuit, the output end of the low-pass filter circuit is electrically connected to one end of the third capacitor, the other end of the third capacitor is electrically connected to the non-inverting input end of the amplifier, the non-inverting input end of the amplifier is also electrically connected to one end of the third resistor, the other end of the third resistor is grounded, one end of the seventh resistor is electrically connected to the inverting input end of the amplifier, the other end of the seventh resistor is grounded, one end of the fifth resistor is electrically connected to the inverting input end of the amplifier, the other end of the fifth resistor is electrically connected to the output end of the amplifier, one end of the sixth resistor is electrically connected to the non-inverting input end of the amplifier, and the other end of the sixth resistor is electrically connected to the output end of the amplifier.

5. The fuel cell wiring harness connection reliability detection device according to claim 4, characterized in that: The low-pass filter circuit includes an eighth resistor, a fourth capacitor and a fifth capacitor. The other end of the fourth resistor is electrically connected to one end of the eighth resistor, the other end of the eighth resistor is electrically connected to one end of the third capacitor, the common end of the fourth resistor and the eighth resistor is also electrically connected to one end of the fourth capacitor, the other end of the fourth capacitor is grounded, the common end of the eighth resistor and the third capacitor is also electrically connected to one end of the fifth capacitor, and the other end of the fifth capacitor is grounded.

6. The fuel cell wiring harness connection reliability detection device according to claim 1, characterized in that: The structure of the AC current acquisition unit is the same as that of the AC voltage acquisition unit.

7. The fuel cell wiring harness connection reliability detection device according to claim 1, characterized in that: The voltage patroller also includes a power supply, which is electrically connected to the signal selection unit, the AC voltage acquisition unit, the AC current acquisition unit, the analog-to-digital conversion unit, the microprocessor and the communication unit respectively.

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