Detection device with high precision and high common mode monomer voltage

Abstract

The utility model relates to a high-precision and high-common-mode monomer voltage detection device, which comprises a power supply unit, a voltage detection unit and a control unit, the detection unit is used for inspecting and sampling voltage values of the fuel cell stack and the electrolytic cell monomer in a floating manner; the self-inspection calibration unit is used for judging the enabling state of a multiplexer in a routing inspection switching channel in the detection unit and the driving IO output state of the MCU; the main control unit MCU is used for performing logic control and data interaction processing on each integrated chip; the device performs CAN communication processing through an external CAN bus network so as to realize detection processing of a fuel cell system test board or an electrolytic cell test board. By adopting the detection device provided by the utility model, the requirements of positive and negative voltage sampling of a fuel cell stack and an electrolytic cell can be met only by conditioning a signal through one operational amplifier, and the requirements of + / -1mV sampling error, + / -0.02% rdg precision and 0.1 mV resolution can also be met.

Description

Technical Field

[0001] The utility model relates to the technical field of fuel cells, in particular to the technical field of electrolytic cell single cell voltage detection, and specifically refers to a detection device with high-precision and high common-mode single cell voltage. Background Art

[0002] The traditional multi-channel optocoupler polling analog acquisition solution has low accuracy, and can only meet the sampling error of about ±5mV. It cannot restore the current voltage value better and with high accuracy in the application scenarios of fuel cell stacks and electrolyzer test benches. At present, the LTC6806 solution based on ADI can meet the requirements of vehicle-mounted accuracy. It cannot restore the current voltage value better and with high accuracy in the application scenarios of fuel cell stacks and electrolyzer test benches. At the same time, the price of ADI's LTC6806 chip is too high, and it also needs to be used with ADI's isolated SPI communication chip, and the overall R&D cost is too high. In addition, traditional solutions often use a single acquisition board with multiple signal conditioning circuits. Because the actual operational amplifier has parameter consistency problems, the actual signal conditioning process has differences in each operational amplifier, resulting in poor actual data accuracy. In the application scenarios of high-power multi-chip fuel cell stacks and electrolyzers, a more conventional grounding solution is used, and multiple acquisition boards will also have common-mode voltage limitation problems when cascading. Utility Model Content

[0003] The purpose of the utility model is to overcome the disadvantages of the prior art and provide a detection device with high precision and high common mode monomer voltage.

[0004] In order to achieve the above-mentioned purpose, the detection device with high precision and high common mode monomer voltage of the utility model is as follows:

[0005] The detection device with high-precision and high common-mode monomer voltage has the following main features: the device comprises: a power supply unit, a detection unit, a self-test calibration unit, a main control unit MCU and a CAN communication unit, wherein:

[0006] The power supply unit is used to input 9V to 32V DC power from the outside, and performs power filtering, reverse connection protection, overvoltage protection, overcurrent protection, undervoltage protection and overtemperature protection on the input current through the dual power isolation module integrated inside the device, and at the same time provides ±15V power rails for the fuel cell single-chip voltage patrol meter CVM;

[0007] The detection unit is connected to the power supply unit and is used to inspect and sample voltage values ​​of the fuel cell stack and the electrolyzer monomer in a floating manner;

[0008] The self-checking and calibration unit is connected to the detection unit, and is used to control the execution of the self-checking and calibration task by judging the enabling state of the multiplexer in the inspection switching channel inside the detection unit and the driving IO output state of the main control unit MCU;

[0009] The main control unit MCU is connected to the detection unit and the self-test calibration unit, and is used to perform logic control and data interaction processing on each integrated chip;

[0010] The CAN communication unit is connected to the power supply unit, the detection unit and the main control unit MCU. The device performs CAN communication processing through an external CAN bus network, thereby realizing detection processing for a fuel cell system test bench or an electrolyzer test bench.

[0011] Preferably, the power supply unit specifically includes:

[0012] An external DC power supply is used to provide a 9 to 32V DC power supply to the fuel cell single-chip voltage monitor CVM;

[0013] The CVM internal power supply integrates a dual power isolation module URA2415S-6WR3 and corresponding peripheral circuits, one end of the peripheral circuit is connected to the external DC power supply, and the other end is connected to the dual power isolation module URA2415S-6WR3, and the peripheral circuit includes an EMI filter circuit and a reverse connection protection circuit; the dual power isolation module URA2415S-6WR3 and the peripheral circuit are used to provide ±15V power rails.

[0014] Preferably, the detection unit includes several solid-state relays AQW210, two 16:1 single-channel analog multiplexers CD74HC4067, a signal conditioning circuit, a first high-precision voltage reference source ADR4550, a second high-precision voltage reference source ADR4525 and an analog-to-digital converter SAR ADC chip ADS8353, wherein:

[0015] The first input terminal of the first solid-state relay AQW210 is connected to the even-numbered cells of the fuel cell, and the second input terminal is connected to the non-inverting input terminal +IN terminal of the differential operational amplifier AD629 in the signal conditioning circuit; the first input terminal of another adjacent solid-state relay AQW210 is connected to the odd-numbered cells of the fuel cell, and the second input terminal is connected to the inverting input terminal -IN terminal of the differential operational amplifier AD629 in the signal conditioning circuit; and a plurality of adjacent solid-state relays AQW210 are grouped in pairs, and both input terminals are connected to the differential operational amplifier AD629 in the above manner;

[0016] The control end of each of the solid-state relays AQW210 is alternately connected to the input end of two 16:1 single-channel analog multiplexers, and the output end and control end of the two 16:1 single-channel analog multiplexers are connected to the GPIO port of the main control unit MCU, and the main control unit MCU controls the polling of the corresponding channel switching;

[0017] Through the polling switching between the solid-state relay AQW210 and the main control unit MCU, the detection unit inputs the measured voltage to the analog front end of the signal conditioning circuit. The analog front end further processes the measured voltage through the differential operational amplifier AD629 and the first high-precision voltage reference source ADR4550, and outputs the measured voltage to the input end of the analog-to-digital converter SAR ADC chip ADS8353 through a filtering buffer.

[0018] Preferably, the CVM internal power supply further includes: a BUCK conversion chip LMR14010, a first LDO chip TPS7A4901, a second LDO chip TPS7A3001, and a third LDO chip TPS74650, wherein:

[0019] The BUCK conversion chip LMR14010 and the first LDO chip TPS7A4901 are both connected to the +15V power rail of the dual power isolation module URA2415S-6WR3, and the second LDO chip TPS7A3001 is connected to the -15V power rail of the dual power isolation module URA2415S-6WR3;

[0020] The first LDO chip TPS7A4901 and the second LDO chip TPS7A3001 are used to provide positive and negative 12V dual-rail power supply requirements for the differential operational amplifier AD629;

[0021] The BUCK conversion chip LMR14010 is used to provide a 5.5V power rail and to supply power to the first high-precision voltage reference source ADR4550 and the third LDO chip TPS74650;

[0022] The first high-precision voltage reference source ADR4550 is used to provide a 5V reference power supply for the differential operational amplifier AD629;

[0023] The third LDO chip TPS74650 is used to provide a 5V power rail and provide power supply requirements for the main control chip, the digital circuit chip, the analog-to-digital converter ADC ADS8353, the second high-precision voltage reference source ADR4525 and the CAN communication unit.

[0024] Preferably, the output end of the signal conditioning circuit is connected to the positive polarity analog input end of the analog-to-digital converter SAR ADC chip ADS8353, and the negative polarity analog input end of the analog-to-digital converter SAR ADC chip ADS8353 is connected to the output end of the second high-precision voltage reference source ADR4525; the analog-to-digital converter SAR ADC chip ADS8353 is also provided with ADC_channel A, ADC_channel B, ADC analog-to-digital conversion module, ADC power supply module and digital SPI interface; wherein,

[0025] The ADC_channel A, ADC_channel B and ADC analog-to-digital conversion module are connected to each other, and the digital SPI interface exchanges data with the main control unit MCU through the SPI bus;

[0026] The signal conditioning circuit is connected to the ADC_channel A via an ADC input filter driving circuit;

[0027] The second high-precision voltage reference source ADR4525 is connected to the ADC_channel B via a reference voltage source driving circuit, and is used to detect the acquired voltage value;

[0028] The digital SPI interface communicates with the main control unit MCU via the SPI bus to perform data exchange.

[0029] Preferably, the self-test calibration unit specifically includes: a mechanical relay EB2-5NU and a relay drive circuit, wherein the output end of the mechanical relay EB2-5NU is respectively connected to the in-phase input end and the inverting input end of the differential operational amplifier AD629, and the control end of the mechanical relay EB2-5NU is connected to the output end of the relay drive circuit. The relay drive circuit determines the enable state of the single-channel analog multiplexer CD74HC4067 and the drive IO output state of the main control unit MCU through an internally set logic gate, thereby controlling the execution of the self-test calibration task, thereby ensuring that no fuel cell voltage is connected to the input end of the signal conditioning circuit during the self-test calibration process.

[0030] Preferably, the main chip of the main control unit MCU adopts the NXP MC9S08 single-chip microcomputer, which is used to perform logic control on each integrated chip, and interact with the 16-bit ADC inspection voltage sampling data of the external fuel cell system test bench or electrolyzer test bench, and exchange information with the external CAN network through the CAN communication unit.

[0031] Preferably, the CAN communication unit specifically includes a digital isolator ADUM5201 and a CAN bus transceiver TCAN1042, a first end of the digital isolator ADUM5201 is connected to the NXP MC9S08 single-chip microcomputer, the other end of the digital isolator ADUM5201 is connected to the CAN bus transceiver TCAN1042, the other end of the CAN bus transceiver TCAN1042 is connected to the EMI filtering circuit, the EMI filtering circuit is connected to an external CAN bus network, and the digital isolator ADUM5201 is used to provide an isolated 5V power rail and provide isolated power supply requirements for the CAN bus transceiver.

[0032] The detection device with high-precision and high common-mode single-cell voltage of the utility model is adopted, and the limitation of the common-mode voltage of high-power multi-chip fuel cell stacks and electrolyzers during cascading is solved through the input floating ground solution. At the same time, the solid-state relay input isolation solution is adopted to solve the leakage current problem caused by the excessive internal resistance of the optocoupler, and greatly reduce the influence of the input front-end leakage current on the signal conditioning end. In this technical solution, multi-channel sampling only requires one operational amplifier to condition the signal, and can meet the requirements of positive and negative voltage sampling of fuel cell stacks and electrolyzers, and can achieve a sampling error of ±1mV and an accuracy of ±0.02%rdg and a resolution requirement of 0.1mV. By adopting an external TI company's 16-bit 600ksps sampling rate SAR analog-to-digital converter, the sampling rate can be increased while meeting the accuracy and resolution, and the current voltage value state of the object being measured can be better restored. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the overall structure of the detection device with high precision and high common mode monomer voltage of the utility model.

[0034] Figure 2 This is a schematic diagram of the structure of the power supply unit of the utility model.

[0035] Figure 3 This is a schematic diagram of the detection unit structure of the utility model.

[0036] Figure 4 This is a schematic diagram of the analog front-end principle structure of the signal conditioning circuit of the utility model.

[0037] Figure 5 It is a schematic diagram of the structure of the self-checking and calibration unit of the utility model.

[0038] Figure 6 This is a schematic diagram of the structure of the main control unit MCU of the utility model.

[0039] Figure 7This is a schematic diagram of the structure of the CAN communication unit of the utility model.

[0040] Figure 8 This is a schematic diagram of the channel selection principle of the utility model.

[0041] Fig. 9 This is a schematic diagram of the input isolation principle of the utility model.

[0042] Fig.10 This is a schematic diagram of the signal conditioning and filtering principle of the utility model. DETAILED DESCRIPTION

[0043] In order to more clearly describe the technical content of the present invention, further description is given below in conjunction with specific embodiments.

[0044] Before describing in detail the embodiments according to the present invention, it should be noted that, hereinafter, the terms "comprises", "comprising" or any other variations are intended to cover non-exclusive inclusion, whereby a process, method, article or apparatus comprising a series of elements includes not only these elements, but also other elements not explicitly listed or inherent to such process, method, article or apparatus.

[0045] See also Figure 1 As shown, the detection device with high precision and high common mode monomer voltage, wherein the device comprises: a power supply unit, a detection unit, a self-test calibration unit, a main control unit MCU and a CAN communication unit, wherein,

[0046] The power supply unit is used to input 9V to 32V DC power from the outside, and performs power filtering, reverse connection protection, overvoltage protection, overcurrent protection, undervoltage protection and overtemperature protection on the input current through the dual power isolation module integrated inside the device, and at the same time provides ±15V power rails for the fuel cell single-chip voltage patrol meter CVM;

[0047] The detection unit is connected to the power supply unit and is used to inspect and sample voltage values ​​of the fuel cell stack and the electrolyzer monomer in a floating manner;

[0048] The self-checking and calibration unit is connected to the detection unit, and is used to control the execution of the self-checking and calibration task by judging the enabling state of the multiplexer in the inspection switching channel inside the detection unit and the driving IO output state of the main control unit MCU;

[0049] The main control unit MCU is connected to the detection unit and the self-test calibration unit, and is used to perform logic control and data interaction processing on each integrated chip;

[0050] The CAN communication unit is connected to the power supply unit, the detection unit and the main control unit MCU. The device performs CAN communication processing through an external CAN bus network, thereby realizing detection processing for a fuel cell system test bench or an electrolyzer test bench.

[0051] As a preferred embodiment of the present utility model, the power supply unit specifically includes:

[0052] An external DC power supply is used to provide a 9 to 32V DC power supply to the fuel cell single-chip voltage monitor CVM;

[0053] The CVM internal power supply integrates a dual power isolation module URA2415S-6WR3 and corresponding peripheral circuits, one end of the peripheral circuit is connected to the external DC power supply, and the other end is connected to the dual power isolation module URA2415S-6WR3, and the peripheral circuit includes an EMI filter circuit and a reverse connection protection circuit; the dual power isolation module URA2415S-6WR3 and the peripheral circuit are used to provide ±15V power rails.

[0054] The power supply unit is implemented as follows Figure 2 As shown, the external power input is compatible with 9V to 32V DC power supply voltage input. Through the integrated dual power isolation module URA2415S-6WR3 and peripheral circuits, input power filtering, reverse connection protection, overvoltage protection, overcurrent protection, undervoltage protection, overtemperature protection and other functions are realized, and ±15V power rails are provided. The ±12V power rails are provided by TI's LDO chips TPS7A4901 and TPS7A3001 to meet the positive and negative 12V dual-rail power supply requirements of the operational amplifier in the analog front-end signal conditioning circuit. The 5.5V power rail is provided by TI's BUCK conversion chip LMR14010 to meet the power supply requirements of the high-precision voltage reference source ADR4550 and the LDO chip TPS74650. The 5V power rail is provided by the LDO chip TPS74650 to meet the power supply requirements of the high-precision voltage reference source ADR4525, the main control chip, the digital circuit chip and the digital isolator. The isolated 5V power rail is provided by the digital isolator ADUM5201 to meet the isolated power supply requirements of the CAN bus transceiver.

[0055] As a preferred embodiment of the utility model, the detection unit includes several solid-state relays AQW210, two 16:1 single-channel analog multiplexers CD74HC4067, a signal conditioning circuit, a first high-precision voltage reference source ADR4550, a second high-precision voltage reference source ADR4525 and an analog-to-digital converter SAR ADC chip ADS8353, wherein:

[0056] The first input terminal of the first solid-state relay AQW210 is connected to the even-numbered cells of the fuel cell, and the second input terminal is connected to the non-inverting input terminal +IN terminal of the differential operational amplifier AD629 in the signal conditioning circuit; the first input terminal of another adjacent solid-state relay AQW210 is connected to the odd-numbered cells of the fuel cell, and the second input terminal is connected to the inverting input terminal -IN terminal of the differential operational amplifier AD629 in the signal conditioning circuit; and a plurality of adjacent solid-state relays AQW210 are grouped in pairs, and both input terminals are connected to the differential operational amplifier AD629 in the above manner;

[0057] The control end of each of the solid-state relays AQW210 is alternately connected to the input end of two 16:1 single-channel analog multiplexers, and the output end and control end of the two 16:1 single-channel analog multiplexers are connected to the GPIO port of the main control unit MCU, and the main control unit MCU controls the polling of the corresponding channel switching;

[0058] Through the polling switching between the solid-state relay AQW210 and the main control unit MCU, the detection unit inputs the measured voltage to the analog front end of the signal conditioning circuit. The analog front end further processes the measured voltage through the differential operational amplifier AD629 and the first high-precision voltage reference source ADR4550, and outputs the measured voltage to the input end of the analog-to-digital converter SAR ADC chip ADS8353 through a filtering buffer.

[0059] like Figure 3 As shown, the detection unit adopts group polling detection, with several series-connected fuel cells as a group, and collects the voltage values ​​of all series-connected batteries in a group of fuel cells. The detection unit includes several Panasonic solid-state relays AQW210, two 16:1 single-channel analog multiplexers CD74HC4067, signal conditioning circuits, two ADI high-precision reference voltage source chips ADR4525 and ADR4550, and TI's 16-bit successive approximation analog-to-digital converter SAR ADC chip ADS8353.

[0060] For the sampling voltage value of the fuel cell stack and the electrolyzer monomer in the floating ground mode, one end of the input end of the solid-state relay AQW210 is connected to the even-numbered nodes of the fuel cell, and the other end of the input end of the solid-state relay AQW210 is connected to the non-inverting input end "+IN" of the differential operational amplifier AD629 of the analog front-end ADI in the signal conditioning circuit. One end of the adjacent solid-state relay input end is connected to the adjacent odd-numbered nodes of the fuel cell, and the other end of the solid-state relay input end is connected to the inverting input end "-IN" of the analog front-end differential operational amplifier in the signal conditioning circuit. The two input ends of the solid-state relay are connected to the even-numbered nodes, odd-numbered nodes of the fuel cell end and the input ends "+IN" and "-IN" of the analog front-end differential operational amplifier in the signal conditioning circuit in the above manner, and the control end of the solid-state relay is alternately connected to the input ends of two 16:1 single-channel analog multiplexers in turn, and the output ends and control end of the two 16:1 single-channel analog multiplexers are connected to the GPIO port of the main control unit MCU, and the main control unit MCU controls the polling of channel switching. The measured voltage is input to the analog front end of the signal conditioning circuit through polling switching of solid-state relays and analog switches. The analog front end uses ADI's high common-mode differential operational amplifier AD629 and high-precision reference voltage source chip ADR4550 to realize the pre-processing of the measured voltage data, and is output to the input end of the back-end 16-bit analog-to-digital converter through a filter buffer composed of TI's precision rail-to-rail amplifier AD8628 and RC.

[0061] Among them, Figure 3 As shown in the figure, the signal conditioning analog front end consists of three parts: channel selection, differential amplifier and filter circuit, and reference voltage circuit. When detecting voltage, the corresponding battery of the solid-state relay is selected through the analog switch, and the common mode voltage is eliminated through the differential amplifier. At the same time, the reference voltage source provides a DC bias voltage, and the output is processed by the voltage divider filter circuit, and the voltage value of the single battery is obtained through external ADC sampling.

[0062] As a preferred embodiment of the utility model, the CVM internal power supply further includes: a BUCK conversion chip LMR14010, a first LDO chip TPS7A4901, a second LDO chip TPS7A3001, and a third LDO chip TPS74650, wherein:

[0063] The BUCK conversion chip LMR14010 and the first LDO chip TPS7A4901 are both connected to the +15V power rail of the dual power isolation module URA2415S-6WR3, and the second LDO chip TPS7A3001 is connected to the -15V power rail of the dual power isolation module URA2415S-6WR3;

[0064] The first LDO chip TPS7A4901 and the second LDO chip TPS7A3001 are used to provide positive and negative 12V dual-rail power supply requirements for the differential operational amplifier AD629;

[0065] The BUCK conversion chip LMR14010 is used to provide a 5.5V power rail and to supply power to the first high-precision voltage reference source ADR4550 and the third LDO chip TPS74650;

[0066] The first high-precision voltage reference source ADR4550 is used to provide a 5V reference power supply for the differential operational amplifier AD629;

[0067] The third LDO chip TPS74650 is used to provide a 5V power rail and provide power supply requirements for the main control chip, the digital circuit chip, the analog-to-digital converter ADC ADS8353, the second high-precision voltage reference source ADR4525 and the CAN communication unit.

[0068] In practical applications, the fuel cell single-chip voltage inspection instrument CVM of this technical solution uses NXP's MC9S08DZ60 single-chip microcomputer, which uses the SPI bus protocol to communicate with the external ADC chip AD8353 to achieve high-resolution, high-speed, and high-precision analog adoption. The system realizes data interaction and system cascading through the CAN bus function.

[0069] The power supply of CVM is powered by an isolated power module with ±15V output. The DCDC chip LMR14010 and LDO chip TPS74650 are used to power the digital circuit chip in the later stage. At the same time, the reference power source chips ADR4550 and ADR4525 are used to input high-precision reference voltage. LDO chips TPS7A4901 and TPS7A3001 are used to power the analog circuit chip.

[0070] As a preferred embodiment of the utility model, the output end of the signal conditioning circuit is connected to the positive polarity analog input end of the analog-to-digital converter SAR ADC chip ADS8353, and the negative polarity analog input end of the analog-to-digital converter SAR ADC chip ADS8353 is connected to the output end of the second high-precision voltage reference source ADR4525; the analog-to-digital converter SAR ADC chip ADS8353 is also provided with ADC_channel A, ADC_channel B, ADC analog-to-digital conversion module, ADC power supply module and digital SPI interface; wherein,

[0071] The ADC_channel A, ADC_channel B and ADC analog-to-digital conversion module are connected to each other and perform data exchange with the MCU through a digital SPI interface;

[0072] The signal conditioning circuit is connected to the ADC_channel A via an ADC input filter driving circuit;

[0073] The second high-precision voltage reference source ADR4525 is connected to the ADC_channel B via a reference voltage source driving circuit, and is used to detect the acquired voltage value;

[0074] The digital SPI interface communicates with the main control unit MCU via the SPI bus to perform data exchange.

[0075] In practical applications, such as Figure 4 As shown, the output end of the signal conditioning circuit is connected to the positive voltage input end of the 16-bit successive approximation analog-to-digital converter SAR ADC chip ADS8353, and the negative voltage input end of the ADS8353 is connected to the output end of the high-precision reference voltage source chip ADR4525, thereby forming an input structure of a pseudo-differential SAR. At the same time, another channel of the ADS8353 is used to detect the output voltage value of the high-precision reference voltage source chip ADR4525, and the voltage value obtained by the detection is used for software calibration to improve the sampling accuracy. The 16-bit successive approximation analog-to-digital converter SAR ADC chip ADS8353 communicates and exchanges data with the main control unit MCU through the SPI bus.

[0076] As a preferred embodiment of the utility model, the self-test calibration unit specifically includes: a mechanical relay EB2-5NU and a relay drive circuit, wherein the output end of the mechanical relay EB2-5NU is respectively connected to the in-phase input end and the inverting input end of the differential operational amplifier AD629, and the control end of the mechanical relay EB2-5NU is connected to the output end of the relay drive circuit. The relay drive circuit determines the enable state of the single-channel analog multiplexer CD74HC4067 and the drive IO output state of the main control unit MCU through the internally set logic gate, thereby controlling the execution of the self-test calibration task, thereby ensuring that no fuel cell voltage is connected to the input end of the signal conditioning circuit during the self-test calibration process.

[0077] In practical applications, such as Figure 5As shown, the self-test calibration unit includes a mechanical relay EB2-5NU and a relay drive circuit, wherein the two output ends of the mechanical relay are respectively connected to the in-phase input end and the inverting input end of the analog front-end differential operational amplifier in the signal conditioning circuit, and the control end of the mechanical relay EB2-5NU is connected to the output end of the relay drive circuit. The relay drive circuit determines the enable status of the two analog multiplexers used for the patrol switching channel and the drive IO output status of the main control unit MCU through the logic gate to control the execution of the self-test calibration task, ensuring that no fuel cell voltage is connected to the input end of the signal conditioning circuit during self-test calibration.

[0078] like Figure 6 As shown, as a preferred embodiment of the utility model, the main chip of the main control unit MCU adopts the NXP MC9S08 single-chip microcomputer, which is used to perform logic control on each integrated chip, and interact with the 16-bit ADC inspection voltage sampling data of the external fuel cell system test bench or electrolyzer test bench, and deliver information to the external CAN network through the CAN communication unit.

[0079] As a preferred embodiment of the utility model, the CAN communication unit specifically includes a digital isolator ADUM5201 and a CAN bus transceiver TCAN1042. The first end of the digital isolator ADUM5201 is connected to the NXPMC9S08 microcontroller, and the other end of the digital isolator ADUM5201 is connected to the CAN bus transceiver TCAN1042. The other end of the CAN bus transceiver TCAN1042 is connected to the EMI filtering circuit, and the EMI filtering circuit is connected to an external CAN bus network. The digital isolator ADUM5201 is used to provide an isolated 5V power rail and provide isolated power supply requirements for the CAN bus transceiver.

[0080] like Figure 7 As shown, the high-precision high common-mode single-cell voltage detection device of the technical solution communicates with the external CAN bus network through the output end of the CAN transceiver chip. The CAN communication unit includes a digital isolator and a CAN transceiver chip, and uses the TICAN transceiver chip TCAN1042 and the ADI digital isolator ADUM5201 to achieve isolated communication with the CAN interface of the main control unit MCU, and at the same time, the power supply isolation of the CAN transceiver chip TCAN1042 is achieved through the power supply isolation of the digital isolator.

[0081] like Figure 8As shown, the control end of each solid-state relay is alternately connected to the input end of two 16:1 single-channel analog multiplexers, and the pins 10, 11, 12, 13 and 15 of the two 16:1 single-channel analog multiplexers are connected to the GPIO port of the main control unit MCU, and the main control unit MCU controls the polling of channel switching. The measured voltage is input to the analog front end of the signal conditioning circuit through the polling switching of the solid-state relay and the analog switch, which reduces the influence of leakage current on the sampling accuracy.

[0082] like Fig. 9 As shown, the solid-state relay AQW210 pin 7 is connected to the even-numbered cells of the fuel cell, and its solid-state relay AQW210 pin 8 is connected to the pin 3 "+IN" of the differential operational amplifier AD629. The adjacent solid-state relay pin 7 is connected to the adjacent odd-numbered cells of the fuel cell, and its solid-state relay pin 8 is connected to the pin 2 "-IN" of the differential operational amplifier. The two input ends of the solid-state relay are connected to the even-numbered cells, odd-numbered cells of the fuel cell end, and the pin 3 "+IN" and pin 2 "-IN" of the analog front-end differential operational amplifier in the signal conditioning circuit in the above manner.

[0083] like Fig.10 As shown, pin 7 of the differential operational amplifier AD629 is connected to the +12V power input, and pin 4 is connected to the -12V power input. Pin 2 and pin 3 of the AD629 are connected to resistors to pin 1 and pin 5 respectively, and pin 1 and pin 5 of the AD629 are connected to a 5V reference voltage to achieve the ±5V range input function and the open circuit and disconnection state diagnosis function. Pin 6 of the AD629 is connected to two series resistors and grounded, and the middle node taps of the two resistors form a resistor divider network, which is connected to pin 3 of the AD8628 amplifier through a π-type filter circuit. Pin 4 of the AD8628 amplifier is connected to pin 1 of the AD8628 amplifier through a feedback circuit composed of RC, and pin 1 of the AD8628 amplifier is connected to the external ADC input through an RC filter.

[0084] It should be understood that each part of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution device.

[0085] A person of ordinary skill in the art may understand that all or part of the steps of the method for implementing the above-mentioned embodiment may be completed by instructing the relevant hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one of the steps of the method embodiment or a combination thereof.

[0086] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc.

[0087] In the description of this specification, the description with reference to the terms "an embodiment", "some embodiments", "example", "specific example", or "embodiment" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0088] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention.

[0089] The detection device with high-precision and high common-mode single-cell voltage of the utility model is adopted, and the limitation of the common-mode voltage of high-power multi-chip fuel cell stacks and electrolyzers during cascading is solved through the input floating ground solution. At the same time, the solid-state relay input isolation solution is adopted to solve the leakage current problem caused by the excessive internal resistance of the optocoupler, and greatly reduce the influence of the input front-end leakage current on the signal conditioning end. In this technical solution, multi-channel sampling only requires one operational amplifier to condition the signal, and can meet the requirements of positive and negative voltage sampling of fuel cell stacks and electrolyzers, and can achieve a sampling error of ±1mV and an accuracy of ±0.02%rdg and a resolution requirement of 0.1mV. By adopting an external TI company's 16-bit 600ksps sampling rate SAR analog-to-digital converter, the sampling rate can be increased while meeting the accuracy and resolution, and the current voltage value state of the object being measured can be better restored.

[0090] In this specification, the utility model has been described with reference to its specific embodiments. However, it is obvious that various modifications and changes can be made without departing from the spirit and scope of the utility model. Therefore, the description and drawings should be regarded as illustrative rather than restrictive.

Claims

1. A detection device with high precision and high common mode monomer voltage, characterized in that: The device comprises: a power supply unit, a detection unit, a self-test calibration unit, a main control unit MCU and a CAN communication unit, wherein: The power supply unit is used to input 9V to 32V DC power from the outside, and performs power filtering, reverse connection protection, overvoltage protection, overcurrent protection, undervoltage protection and overtemperature protection on the input current through the dual power isolation module integrated inside the device, and at the same time provides ±15V power rails for the fuel cell single-chip voltage patrol meter CVM; The detection unit is connected to the power supply unit and is used to inspect and sample voltage values ​​of the fuel cell stack and the electrolyzer monomer in a floating manner; The self-checking and calibration unit is connected to the detection unit, and is used to control the execution of the self-checking and calibration task by judging the enabling state of the multiplexer in the inspection switching channel inside the detection unit and the driving IO output state of the main control unit MCU; The main control unit MCU is connected to the detection unit and the self-test calibration unit, and uses the NXP MC9S08 single-chip microcomputer to perform logic control on each integrated chip, interact with the 16-bit ADC inspection voltage sampling data of the external fuel cell system test bench or electrolyzer test bench, and deliver information to the external CAN network through the CAN communication unit; The CAN communication unit is connected to the power supply unit, the detection unit and the main control unit MCU. The device performs CAN communication processing through an external CAN bus network, thereby realizing detection processing for a fuel cell system test bench or an electrolyzer test bench.

2. The detection device with high precision and high common mode monomer voltage according to claim 1, characterized in that: The power supply unit specifically includes: An external DC power supply is used to provide a 9V to 32V DC power supply to the fuel cell single-chip voltage monitor CVM; The CVM internal power supply integrates a dual power isolation module URA2415S-6WR3 and corresponding peripheral circuits, one end of the peripheral circuit is connected to the external DC power supply, and the other end is connected to the dual power isolation module URA2415S-6WR3, and the peripheral circuit includes an EMI filter circuit and a reverse connection protection circuit; the dual power isolation module URA2415S-6WR3 and the peripheral circuit are used to provide ±15V power rails.

3. The detection device with high precision and high common mode monomer voltage according to claim 2, characterized in that: The detection unit includes several solid-state relays AQW210, two 16:1 single-channel analog multiplexers CD74HC4067, a signal conditioning circuit, a first high-precision voltage reference source ADR4550, a second high-precision voltage reference source ADR4525 and an analog-to-digital converter SAR ADC chip ADS8353, wherein: The first input terminal of the first solid-state relay AQW210 is connected to the even-numbered cells of the fuel cell, and the second input terminal is connected to the non-inverting input terminal +IN terminal of the differential operational amplifier AD629 in the signal conditioning circuit; the first input terminal of another adjacent solid-state relay AQW210 is connected to the odd-numbered cells of the fuel cell, and the second input terminal is connected to the inverting input terminal -IN terminal of the differential operational amplifier AD629 in the signal conditioning circuit; and a plurality of adjacent solid-state relays AQW210 are grouped in pairs, and both input terminals are connected to the differential operational amplifier AD629 in the above manner; The control end of each of the solid-state relays AQW210 is alternately connected to the input end of two 16:1 single-channel analog multiplexers, and the output end and control end of the two 16:1 single-channel analog multiplexers are connected to the GPIO port of the main control unit MCU, and the main control unit MCU controls the polling of the corresponding channel switching; Through the polling switching between the solid-state relay AQW210 and the main control unit MCU, the detection unit inputs the measured voltage to the analog front end of the signal conditioning circuit. The analog front end further processes the measured voltage through the differential operational amplifier AD629 and the first high-precision voltage reference source ADR4550, and outputs the measured voltage to the input end of the analog-to-digital converter SAR ADC chip ADS8353 through a filtering buffer.

4. The detection device with high precision and high common mode monomer voltage according to claim 3, characterized in that: The CVM internal power supply also includes: a BUCK conversion chip LMR14010, a first LDO chip TPS7A4901, a second LDO chip TPS7A3001, and a third LDO chip TPS74650, wherein: The BUCK conversion chip LMR14010 and the first LDO chip TPS7A4901 are both connected to the +15V power rail of the dual power isolation module URA2415S-6WR3, and the second LDO chip TPS7A3001 is connected to the -15V power rail of the dual power isolation module URA2415S-6WR3; The first LDO chip TPS7A4901 and the second LDO chip TPS7A3001 are used to provide positive and negative 12V dual-rail power supply requirements for the differential operational amplifier AD629; The BUCK conversion chip LMR14010 is used to provide a 5.5V power rail and to supply power to the first high-precision voltage reference source ADR4550 and the third LDO chip TPS74650; The first high-precision voltage reference source ADR4550 is used to provide a 5V reference power supply for the differential operational amplifier AD629; The third LDO chip TPS74650 is used to provide a 5V power rail and provide power supply requirements for the main control chip, the digital circuit chip, the analog-to-digital converter ADC ADS8353, the second high-precision voltage reference source ADR4525 and the CAN communication unit.

5. The detection device with high precision and high common mode monomer voltage according to claim 4, characterized in that: The output end of the signal conditioning circuit is connected to the positive polarity analog input end of the analog-to-digital converter SAR ADC chip ADS8353, and the negative polarity analog input end of the analog-to-digital converter SAR ADC chip ADS8353 is connected to the output end of the second high-precision voltage reference source ADR4525; the analog-to-digital converter SAR ADC chip ADS8353 is also provided with ADC_channel A, ADC_channel B, ADC analog-to-digital conversion module, ADC power supply module and digital SPI interface; wherein, The ADC_channel A, ADC_channel B and ADC analog-to-digital conversion module are connected to each other, and the digital SPI interface exchanges data with the main control unit MCU through the SPI bus; The signal conditioning circuit is connected to the ADC_channel A via an ADC input filter driving circuit; The second high-precision voltage reference source ADR4525 is connected to the ADC_channel B via a reference voltage source driving circuit, and is used to detect the acquired voltage value; The digital SPI interface communicates with the main control unit MCU via the SPI bus to perform data exchange.

6. The detection device with high precision and high common mode single voltage according to claim 5, characterized in that: The self-test calibration unit specifically includes: a mechanical relay EB2-5NU and a relay drive circuit, wherein the output end of the mechanical relay EB2-5NU is respectively connected to the in-phase input end and the inverting input end of the differential operational amplifier AD629, and the control end of the mechanical relay EB2-5NU is connected to the output end of the relay drive circuit. The relay drive circuit determines the enable state of the single-channel analog multiplexer CD74HC4067 and the drive IO output state of the main control unit MCU through the internally set logic gate, thereby controlling the execution of the self-test calibration task, thereby ensuring that no fuel cell voltage is connected to the input end of the signal conditioning circuit during the self-test calibration process.

7. The detection device with high precision and high common mode monomer voltage according to claim 6, characterized in that: The CAN communication unit specifically includes a digital isolator ADUM5201 and a CAN bus transceiver TCAN1042. The first end of the digital isolator ADUM5201 is connected to the NXP MC9S08 single-chip microcomputer, and the other end of the digital isolator ADUM5201 is connected to the CAN bus transceiver TCAN1042. The other end of the CAN bus transceiver TCAN1042 is connected to the EMI filtering circuit, and the EMI filtering circuit is connected to an external CAN bus network. The digital isolator ADUM5201 is used to provide an isolated 5V power rail and provide isolated power supply requirements for the CAN bus transceiver.

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