Detection Method, Device, Equipment and Medium for Internal Resistance of Hydrogen Stack in Hydrogen Fuel Cell Vehicle

Abstract

The present application discloses a method for detecting the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle, including: constructing a DC / DC converter by using a multi-phase interleaved parallel single-phase boost converter; generating disturbance harmonics by using a multi-frequency sine superposition technique and a known sine wave; constructing a low-pass filter module according to the known sine wave to filter out the high-order harmonics of each phase boost converter to obtain a target direct current; constructing a band-pass filter according to the known sine wave to separate and restore the disturbance harmonics, and performing feedback control on the restored harmonic components to obtain a target alternating current; generating a PWM wave by using the above-mentioned alternating and direct currents, so that the DC / DC converter uses the PWM wave to convert the output current of the hydrogen stack and supply power to the hydrogen fuel cell vehicle; determining the internal resistance of the hydrogen stack in real time according to the sampled feedback input voltage and current of the DC / DC converter. In this way, the on-line monitoring of the internal resistance of the hydrogen stack is realized, and at the same time, the detection design cost of the internal resistance of the hydrogen stack can also be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy, and particularly relates to a method, device, equipment and medium for detecting the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle. Background Art

[0002] Hydrogen fuel cell vehicles have been widely used in real life because of their functional characteristics of "zero emissions, long endurance and strong power". Please refer to Figure 1 , Figure 1 which is the main electrical structure diagram of a hydrogen fuel electric vehicle. Among them, the hydrogen stack (fully called: hydrogen fuel cell stack) is used as the power supply of the entire power system. The DC / DC converter will convert the voltage output by the hydrogen stack into a stable voltage to supply power to devices such as the motor controller and high-voltage accessories in the hydrogen fuel cell vehicle, or to charge the power battery in the hydrogen fuel cell vehicle.

[0003] Since the health state of the hydrogen stack directly determines the operating performance of the hydrogen fuel cell vehicle, in order to ensure the safety, stability and efficiency of the hydrogen fuel system during the vehicle operation, it is necessary to monitor and diagnose the health state of the hydrogen stack. In the prior art, the health state of the hydrogen stack is usually detected by detecting the internal resistance of the hydrogen stack. However, the common existing methods for detecting the internal resistance of the hydrogen stack are all to perform off-line detection on the hydrogen stack by adding additional detection equipment or circuits in the hydrogen fuel cell vehicle. This detection method not only has limited application scenarios, but also has high manufacturing costs. At present, there is no relatively effective solution to this technical problem. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method, device, equipment and medium for detecting the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle, so as to realize on-line monitoring of the internal resistance of the hydrogen stack and reduce the design cost required for detecting the internal resistance of the hydrogen stack. The specific scheme is as follows:

[0005] A method for detecting the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle includes:

[0006] Constructing a DC / DC converter by using a multi-phase interleaved parallel single-phase boost converter; wherein, the input end of the DC / DC converter is connected to the output end of the hydrogen stack in the target hydrogen fuel cell vehicle;

[0007] Based on the multi-frequency sine superposition technology, generating a target disturbance harmonic by using a known target sine wave and a multi-phase interleaved parallel single-phase boost converter, and superimposing the target disturbance harmonic on the output current of the hydrogen stack;

[0008] Constructing a low-pass filter module according to the target sine wave, and using the low-pass filter module to filter out the high-order harmonics in each phase boost converter to obtain a target direct current;

[0009] Construct a band - pass filter module according to the target sine wave, use the band - pass filter module to separate and restore the target disturbance harmonics, obtain the restored harmonic components, and perform feedback control on the harmonic components to obtain a target alternating current with both frequency and amplitude maintained within a preset range;

[0010] Generate a target PWM wave using the target direct current and the target alternating current, so that the DC / DC converter uses the target PWM wave to convert the output current of the hydrogen stack and supply power to the target hydrogen fuel cell vehicle;

[0011] Determine the target internal resistance of the hydrogen stack in real - time according to the sampled feedback input voltage and the sampled feedback input current of the DC / DC converter.

[0012] Preferably, the process of constructing a DC / DC converter using a multi - phase interleaved parallel single - phase boost converter includes:

[0013] Construct the DC / DC converter using a 4 - phase interleaved parallel single - phase boost converter.

[0014] Preferably, the process of constructing a low - pass filter module according to the target sine wave and using the low - pass filter module to filter out high - order harmonics in each phase boost converter to obtain the target direct current includes:

[0015] Construct 4 low - pass filters according to the target sine wave;

[0016] Based on the PID control principle, use 4 low - pass filters to filter out high - order harmonics in each phase boost converter to obtain the target direct current; where the ripple of the total input current of the DC / DC converter is 0.25 times the current ripple in the single - phase boost converter.

[0017] Preferably, the process of constructing a band - pass filter module according to the target sine wave, using the band - pass filter module to separate and restore the target disturbance harmonics, obtain the restored harmonic components, and perform feedback control on the harmonic components to obtain a target alternating current with both frequency and amplitude maintained within a preset range includes:

[0018] Construct 4 band - pass filters according to the target sine wave, and use the 4 band - pass filters to separate and restore the target disturbance harmonics to obtain the restored harmonic components;

[0019] Based on the PID control principle, control the frequency and amplitude of the harmonic components respectively to obtain the target alternating current with both frequency and amplitude maintained within the preset range.

[0020] Preferably, the process of separately controlling the frequency and amplitude of the harmonic components to obtain the target alternating current with both the frequency and amplitude maintained within the preset range includes:

[0021] Based on the given harmonic current, separately control the frequency and amplitude of the harmonic components to obtain the target alternating current with both the frequency and amplitude maintained within the preset range; wherein, the amplitude of the given harmonic current is less than 5% of the output current of the hydrogen stack.

[0022] Preferably, the process of determining the target internal resistance of the hydrogen stack in real time according to the sampled feedback input voltage and sampled feedback input current of the DC / DC converter includes:

[0023] Based on the internal resistance equivalent model of the hydrogen stack, determine the target internal resistance of the hydrogen stack in real time according to the sampled feedback input voltage and the sampled feedback input current of the DC / DC converter;

[0024] Wherein, the expression of the internal resistance equivalent model is:

[0025]

[0026] In the formula, Z n is the equivalent impedance of the hydrogen stack, is the sampled feedback input voltage, is the sampled feedback input current, R n is the equivalent internal resistance of the hydrogen stack, R n1 is the polarization internal resistance, L and C are respectively the equivalent inductance value and equivalent capacitance value of each phase boost converter, ω n is the disturbance angular frequency.

[0027] Correspondingly, the present invention also discloses a detection device for the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle, including:

[0028] A converter construction module, configured to construct a DC / DC converter by using a multi-phase interleaved parallel single-phase boost converter; wherein, the input end of the DC / DC converter is connected to the output end of the hydrogen stack in the target hydrogen fuel cell vehicle;

[0029] A harmonic generation module, configured to generate a target disturbance harmonic based on the multi-frequency sine superposition technology by using a known target sine wave and a multi-phase interleaved parallel single-phase boost converter, and superimpose the target disturbance harmonic on the output current of the hydrogen stack;

[0030] A DC acquisition module, configured to construct a low-pass filter module according to the target sine wave, and use the low-pass filter module to filter out the high-order harmonics in each phase boost converter to obtain the target direct current;

[0031] An AC acquisition module, configured to construct a band-pass filtering module according to the target sine wave, use the band-pass filtering module to separate and restore the target disturbance harmonics, obtain the restored harmonic components, and perform feedback control on the harmonic components to obtain target alternating current with both the frequency and amplitude maintained within a preset range;

[0032] A PWM generation module, configured to generate a target PWM wave by using the target direct current and the target alternating current, so that the DC / DC converter uses the target PWM wave to convert the output current of the hydrogen stack and supply power to the target hydrogen fuel cell vehicle;

[0033] An internal resistance measurement module, configured to determine the target internal resistance of the hydrogen stack in real time according to the sampled feedback input voltage and the sampled feedback input current of the DC / DC converter.

[0034] Correspondingly, the present invention also discloses a detection device for the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle, including:

[0035] A memory, configured to store a computer program;

[0036] A processor, configured to implement the steps of a detection method for the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle as disclosed above when executing the computer program.

[0037] Correspondingly, the present invention also discloses a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of a detection method for the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle as disclosed above are implemented.

[0038] It can be seen that in the present invention, first, a multi-phase interleaved parallel single-phase boost converter is used to construct a DC / DC converter, which can not only improve the accuracy of the output current of the hydrogen stack, but also reduce the current ripple of the DC / DC converter and improve the system performance. Then, based on the multi-frequency sine superposition technology, a known target sine wave and a multi-phase interleaved parallel single-phase boost converter are used to generate target disturbance harmonics. Obviously, through this method, not only can the generation complexity of the target disturbance harmonics be reduced, but also, since the target sine wave is known, only a corresponding band-pass filtering module needs to be designed according to the frequency of the target sine wave to separate and restore the target disturbance harmonics, thus greatly reducing the difficulty of building the hydrogen stack internal resistance detection system. At the same time, a PWM wave for controlling the DC / DC converter is generated by means of AC-DC correction, which can ensure the stability and accuracy of the output voltage of the DC / DC converter. Finally, by detecting the sampled feedback input voltage and the sampled feedback input current of the DC / DC converter in real time, the target internal resistance of the hydrogen stack can be determined, which is equivalent to realizing the on-line monitoring of the hydrogen stack internal resistance, thereby broadening the applicable scenarios of this detection method in practical applications. And, since this method does not require additional detection equipment or circuits to perform off-line detection of the hydrogen stack internal resistance, the design cost required for detecting the hydrogen stack internal resistance can be significantly reduced through this method. Correspondingly, a detection device, equipment and medium for the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle provided by the present invention also have the above beneficial effects. Description of the Drawings

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0040] Figure 1 It is the main electrical structure diagram of a hydrogen fuel electric vehicle;

[0041] Figure 2 It is the flowchart of a method for detecting the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle provided by an embodiment of the present invention;

[0042] Figure 3 It is the topological structure diagram of a 4-phase interleaved parallel DC / DC converter provided by an embodiment of the present invention;

[0043] Figure 4 It is the current ripple schematic diagram when a 4-phase interleaved parallel boost converter performs phase-shift superposition in the current continuous output mode of the hydrogen stack;

[0044] Figure 5 Schematic diagram when AC and DC are superimposed provided by an embodiment of the present invention;

[0045] Figure 6 Schematic diagram when 4Hz, 20Hz, 40Hz, and 1000Hz harmonic currents are respectively added to a 4-phase boost converter;

[0046] Figure 7 Schematic diagram of superposition after adding harmonic currents to a 4-phase boost converter;

[0047] Figure 8 Schematic diagram after separating and restoring the target disturbance harmonics;

[0048] Figure 9 Structural diagram of the control principle for detecting the internal resistance of the hydrogen stack in a target hydrogen fuel cell vehicle;

[0049] Figure 10 Equivalent schematic diagram of the hydrogen stack and the DC / DC converter in a hydrogen fuel cell vehicle;

[0050] Figure 11 Schematic diagram when a 4Hz harmonic current is added to the output current of the hydrogen stack;

[0051] Figure 12 Schematic diagram when a 20Hz harmonic current is added to the output current of the hydrogen stack;

[0052] Figure 13 Schematic diagram when a 40Hz harmonic current is added to the output current of the hydrogen stack;

[0053] Figure 14 Schematic diagram when a 1000Hz harmonic current is added to the output current of the hydrogen stack;

[0054] Figure 15 Schematic diagram of the total harmonic current obtained by superimposing harmonic currents of multiple frequencies on the output current of the hydrogen stack;

[0055] Figure 16 Spectrum schematic diagram of the calculated internal resistance of the hydrogen stack;

[0056] Figure 17 Structural diagram of a detection device for the internal resistance of the hydrogen stack in a hydrogen fuel cell vehicle provided by an embodiment of the present invention;

[0057] Figure 18 Structural diagram of a detection device for the internal resistance of the hydrogen stack in a hydrogen fuel cell vehicle provided by an embodiment of the present invention. Specific implementation manner

[0058] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0059] Please refer to Figure 2 , Figure 2 which is a flowchart of a method for detecting the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle provided by an embodiment of the present invention. The method includes:

[0060] Step S11: Construct a DC / DC converter by using a multi-phase interleaved parallel single-phase boost converter;

[0061] Among them, the input end of the DC / DC converter is connected to the output end of the hydrogen stack in the target hydrogen fuel cell vehicle;

[0062] Step S12: Based on the multi-frequency sine superposition technology, generate a target disturbance harmonic by using a known target sine wave and a multi-phase interleaved parallel single-phase boost converter, and superimpose the target disturbance harmonic on the output current of the hydrogen stack;

[0063] Step S13: Construct a low-pass filter module according to the target sine wave, and use the low-pass filter module to filter out the high-order harmonics in each phase boost converter to obtain a target direct current;

[0064] Step S14: Construct a band-pass filter module according to the target sine wave, use the band-pass filter module to separate and restore the target disturbance harmonic to obtain a restored harmonic component, and perform feedback control on the harmonic component to obtain a target alternating current with both the frequency and amplitude maintained within a preset range;

[0065] Step S15: Generate a target PWM wave by using the target direct current and the target alternating current, so that the DC / DC converter uses the target PWM wave to convert the output current of the hydrogen stack and supply power to the target hydrogen fuel cell vehicle;

[0066] Step S16: Determine the target internal resistance of the hydrogen stack in real time according to the sampled feedback input voltage and the sampled feedback input current of the DC / DC converter.

[0067] In this embodiment, a method for detecting the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle is provided. By using this method, not only can the online monitoring of the internal resistance of the hydrogen stack in the hydrogen fuel cell vehicle be realized, but also the design cost required for detecting the internal resistance of the hydrogen stack can be significantly reduced.

[0068] In this method, first, a multi-phase interleaved single-phase boost converter is used to construct a DC / DC converter (Direct Current Direct Current Converter). Among them, the input end of the DC / DC converter is connected to the output end of the hydrogen stack in the target hydrogen fuel cell vehicle. It can be understood that when using a multi-phase interleaved single-phase boost converter to construct a DC / DC converter, not only can the accuracy of the output current of the hydrogen stack be improved, but also the ripple of the output current of the DC / DC converter can be reduced.

[0069] Specifically, a DC / DC converter can be constructed using a 4-phase interleaved single-phase boost converter. For details, please refer to Figure 3 , Figure 3 which is the topological structure diagram of a 4-phase interleaved DC / DC converter provided by an embodiment of the present invention. In Figure 3 , the input voltage of the DC / DC converter is U i , and the total input current is i IN , i L1 , i L2 , i L3 and i L4 are the phase currents of each phase boost converter respectively. Combining with the structure diagram shown in Figure 1 , it can be seen that the output power of the hydrogen stack can be indirectly completed by controlling the output of the DC / DC converter.

[0070] In practical applications, by controlling the sampling time point of the DSP (Digital Signal Process, digital signal processing chip) in the hydrogen fuel cell vehicle, and controlling the phase difference of the inductor currents i L1 , i L2 , i L3 and i L4 in each phase boost converter to be 90°, the ripple of the total input current of the DC / DC converter can be made 0.25 times the current ripple in the single-phase boost converter.

[0071] Based on the same design principle, Figure 3The 4-phase interleaved DC / DC converter shown is extended to a 6-phase, 8-phase or more-phase DC / DC converter. Among them, the ripple of the total input current of the DC / DC converter is 1 / n times the current ripple of the single-phase boost converter, where n is the number of interleaved single-phase boost converters in the DC / DC converter. Obviously, the DC / DC converter can convert the output voltage of the hydrogen stack into a voltage with a more stable voltage and a higher output value to supply power to electrical equipment such as the motor controller and high-voltage accessories in the hydrogen fuel cell vehicle. Moreover, the input and output states of the DC / DC converter can be directly controlled through the instructions of the fuel cell vehicle controller, so as to indirectly control the output power of the hydrogen stack.

[0072] After constructing the DC / DC converter using a multi-phase interleaved single-phase boost converter, based on the multi-frequency sine superposition technology, a known target sine wave and the multi-phase interleaved single-phase boost converter are used to generate a target disturbance harmonic, and the target disturbance harmonic is superimposed on the output current of the hydrogen stack.

[0073] Please refer to Figure 4 , Figure 4 For the hydrogen stack in the continuous current output mode, it is a schematic diagram of the current ripple when the 4-phase interleaved boost converter performs phase-shift superposition. Based on the same principle, the current ripple when the 4-phase interleaved boost converter performs phase-shift superposition in the discontinuous output mode of the single-phase current can also be obtained. Through the practical results, it can be seen that even if the input current of the single-phase boost converter is in the discontinuous state, the total input current i IN of the DC / DC converter can remain continuous within a certain range, which is very important for the hydrogen stack to ensure normal operation.

[0074] Please refer to Figure 5 , Figure 5 This is a schematic diagram of the superposition of AC and DC provided by the embodiment of the present invention. According to the current superposition principle, when an AC disturbance signal i dc is superimposed on the direct current i sin1 , the obtained i dc +i sin1 can simulate the total input current i IN of the DC / DC converter.

[0075] In this embodiment, in order to more clearly show the superposition process of the harmonic currents of each phase boost converter, four sine waves with frequencies of 4 Hz, 20 Hz, 40 Hz and 1000 Hz and equal amplitudes are used to illustrate the implementation principle of the multi-frequency harmonic superposition. Please refer to Figure 6 and Figure 7 , Figure 6Schematic diagrams when 4 Hz, 20 Hz, 40 Hz, and 1000 Hz harmonic currents are respectively added to a 4-phase boost converter. Figure 7 Schematic diagram of superposition after adding harmonic currents to a 4-phase boost converter.

[0076] When using a known target sine wave and a multi-phase interleaved parallel single-phase boost converter to generate a target disturbance harmonic, and after superimposing the target disturbance harmonic on the output current of the hydrogen stack. Then, a low-pass filter module is constructed according to the target sine wave, and the high-order harmonics in each phase boost converter are filtered out by using the low-pass filter module to obtain the target direct current. It can be conceived that through this setting method, not only can the influence of high-order harmonics in each phase boost converter on the output voltage of the DC / DC converter be eliminated, but also the current sharing of each phase boost converter is effectively guaranteed.

[0077] At the same time, since the target sine wave superimposed on the output current of the hydrogen stack is known, only a corresponding band-pass filter module needs to be designed according to the target sine wave to separate and restore the target disturbance harmonic superimposed on the output current of the hydrogen stack. Please refer to Figure 8 , Figure 8 Schematic diagram after separating and restoring the target disturbance harmonic. Obviously, through such a setting method, the cumbersome analysis process in the prior art that needs to use FFT (Fast Fourier Transform) technology to monitor the internal resistance of the hydrogen stack can be omitted, thereby greatly reducing the design difficulty in detecting the internal resistance of the hydrogen stack. When using the band-pass filter module to separate and restore the target disturbance harmonic and obtain the restored harmonic components, and at the same time performing feedback control on the restored harmonic components, a target alternating current with both frequency and amplitude maintained within a preset range can be obtained, so as to ensure the current accuracy of the target alternating current.

[0078] Finally, the target PWM wave is generated by using the target direct current and the target alternating current, so that the DC / DC converter can use the target PWM wave to convert the output current of the hydrogen stack and supply power to the target hydrogen fuel cell vehicle. At this time, by using the measurement chip on the DC / DC converter to detect the sampled feedback input voltage and the sampled feedback input current of the DC / DC converter in real time, the target internal resistance of the hydrogen stack in the target hydrogen fuel cell vehicle can be determined according to the sampled feedback input voltage and the sampled feedback input current of the DC / DC converter.

[0079] Compared with the prior art, since this method can realize the on-line detection of the internal resistance of the hydrogen stack, and there is no need to additionally add detection equipment or circuits in the target hydrogen fuel cell vehicle to detect the hydrogen stack, the design cost required for detecting the internal resistance of the hydrogen stack can be significantly reduced through this method.

[0080] It can be seen that in this embodiment, first, a multi-phase interleaved parallel single-phase boost converter is used to construct a DC / DC converter. This can not only improve the accuracy of the output current of the hydrogen stack, but also reduce the current ripple of the DC / DC converter and improve the system performance. Then, based on the multi-frequency sine superposition technology, the known target sine wave and the multi-phase interleaved parallel single-phase boost converter are used to generate the target disturbance harmonics. Obviously, through this method, not only can the generation complexity of the target disturbance harmonics be reduced, but also, since the target sine wave is known, only a corresponding band-pass filter module needs to be designed according to the frequency of the target sine wave to separate and restore the target disturbance harmonics, thus greatly reducing the difficulty of building the hydrogen stack internal resistance detection system. At the same time, the PWM wave used to control the DC / DC converter is generated by means of AC-DC correction, so as to ensure the stability and accuracy of the output voltage of the DC / DC converter. Finally, the target internal resistance of the hydrogen stack can be determined by real-time detecting the sampled feedback input voltage and the sampled feedback input current of the DC / DC converter, which is equivalent to realizing the on-line monitoring of the hydrogen stack internal resistance, and thus the applicable scenarios of this detection method in practical applications can be broadened. Moreover, since this method does not require additional detection equipment or circuits to perform off-line detection on the internal resistance of the hydrogen stack, the design cost required for detecting the internal resistance of the hydrogen stack can be significantly reduced by this method.

[0081] Based on the above embodiment, this embodiment further explains and optimizes the technical solution. As a preferred implementation manner, the above step: constructing a low-pass filter module according to the target sine wave and using the low-pass filter module to filter out the high-order harmonics in each phase boost converter to obtain the target direct current includes:

[0082] Construct 4 low-pass filters according to the target sine wave;

[0083] Based on the PID control principle, and using the 4 low-pass filters to filter out the high-order harmonics in each phase boost converter to obtain the target direct current; wherein, the ripple of the total input current of the DC / DC converter is 0.25 times the current ripple in the single-phase boost converter.

[0084] Please refer to Figure 9 , Figure 9 , which is the control principle structure diagram when detecting the internal resistance of the hydrogen stack in the target hydrogen fuel cell vehicle. In this embodiment, in order to filter out the harmonic current in the 4-phase interleaved parallel boost converter, 4 low-pass filters are constructed according to the known target sine wave, and based on the PID (Proportion Integral Differential) principle, these 4 low-pass filters are used to filter out the high-order harmonics in each phase boost converter to obtain the target direct current.

[0085] Among them, the transfer function of the low-pass filter is as follows:

[0086]

[0087] In the formula, ω n is the center frequency, is the damping ratio.

[0088] It should be noted that in Figure 9 , C_PID is the closed-loop controller for the hydrogen stack current output when the target hydrogen fuel cell vehicle is operating normally. I dc_ref is the given current for controlling the output of the hydrogen stack, and PID feedback control is performed with the input currents of each phase boost converter. This can not only ensure the stability of the output voltage of the DC / DC converter, but also effectively equalize the currents of each phase boost converter.

[0089] As a preferred implementation manner, the above steps: constructing a band-pass filter module according to the target sine wave, using the band-pass filter module to separate and restore the target disturbance harmonics to obtain the restored harmonic components, and performing feedback control on the harmonic components to obtain the target alternating current with both the frequency and amplitude maintained within the preset ranges, include:

[0090] Construct 4 band-pass filters according to the target sine wave, and use the 4 band-pass filters to separate and restore the target disturbance harmonics to obtain the restored harmonic components;

[0091] Based on the PID control principle, control the frequency and amplitude of the harmonic components respectively to obtain the target alternating current with both the frequency and amplitude maintained within the preset ranges.

[0092] In this embodiment, in order to ensure the accuracy of the harmonic current, PID control also needs to be performed on the harmonic components obtained after separating and restoring the target disturbance harmonics. During the process of performing feedback control on the harmonic components, first, 4 band-pass filters are constructed according to the target sine wave, and the 4 band-pass filters are used to separate and restore the target disturbance harmonics to obtain the restored harmonic components; then, based on the PID control principle, the frequency and amplitude of the harmonic components are controlled respectively, and the target alternating current with both the frequency and amplitude maintained within the preset ranges can be obtained.

[0093] Among them, the transfer function of the band-pass filter is as follows:

[0094]

[0095] In the formula, is the damping ratio, ω n is the center frequency.

[0096] Specifically, in this embodiment, the frequency and amplitude of the harmonic components are controlled based on the given harmonic current to obtain an AC target current with both the frequency and amplitude maintained within a preset range; wherein, the amplitude of the given harmonic current is less than 5% of the output current of the hydrogen stack.

[0097] Please refer to the control process in Figure 9 , in Figure 9 , A_PID is the amplitude controller of the harmonic current output by each phase boost converter, F_PID is the frequency controller of the harmonic current output by each phase boost converter, I 0 is the given harmonic current, and the total input current i IN of the DC / DC converter obtains the corresponding frequency harmonics through a band-pass filter, and then through the detection results of the amplitude and frequency and I 0 * [sin(ω 0 t)+sin(ω 1 t)+sin(ω 2 t)+sin(ω 3 t)] for closed-loop feedback control, which can ensure the accuracy of the harmonic current. Among them, ω 0 , ω 1 , ω 2 and ω 3 are the given angular frequencies of the harmonics. Specifically, in this embodiment, ω 0 , ω 1 , ω 2 and ω 3 are 4Hz, 20Hz, 40Hz, and 1000Hz respectively. Finally, based on the AC target current and the DC target current, the target PWM wave can be obtained. At this time, the DC / DC converter can use the target PWM wave to convert the output current of the hydrogen stack and supply power to the target hydrogen fuel cell vehicle.

[0098] Based on the above embodiment, this embodiment further explains and optimizes the technical solution. As a preferred implementation, the above step: the process of determining the target internal resistance of the hydrogen stack in real time according to the sampled feedback input voltage and the sampled feedback input current of the DC / DC converter includes:

[0099] Based on the internal resistance equivalent model of the hydrogen stack, the target internal resistance of the hydrogen stack is determined in real time according to the sampled feedback input voltage and the sampled feedback input current of the DC / DC converter;

[0100] Among them, the expression of the internal resistance equivalent model is:

[0101]

[0102] In the formula, Z n is the equivalent impedance of the hydrogen stack, is the sampled feedback input voltage, is for sampling the feedback input current, and R n is the equivalent internal resistance of the hydrogen stack, and R n1 is the polarization internal resistance. L and C are the equivalent inductance value and equivalent capacitance value of each phase boost converter respectively, and ω n is the disturbance angular frequency.

[0103] It can be understood that by deforming the detection topology structure of the internal resistance of the hydrogen stack shown in Figure 9 , the equivalent schematic diagram for calculating the internal resistance of the hydrogen stack can be obtained. For details, please refer to Figure 10 , Figure 10 , which is the equivalent schematic diagram of the hydrogen stack and the DC / DC converter in the hydrogen fuel cell vehicle.

[0104] According to Figure 10 , it can be known that the AC disturbance signals i and i IN on the output bus U of the hydrogen stack and are the voltage across the internal resistance of the hydrogen stack and the current signal flowing through the internal resistance in the equivalent model of the hydrogen stack. Therefore, the target internal resistance of the hydrogen stack can be determined through the internal resistance equivalent model of the hydrogen stack.

[0105] Obviously, through the technical solution provided in this embodiment, the accuracy and reliability of the calculation result of the internal resistance of the hydrogen stack can be guaranteed.

[0106] Based on the technical content disclosed in the above embodiment, this embodiment uses specific experimental results to elaborate in detail on the technical effects that can be achieved by the previously disclosed method for detecting the internal resistance of the hydrogen stack in a hydrogen fuel cell vehicle. Specifically, in practical applications, corresponding designs are carried out on the DC / DC control software, multi-frequency superposition of harmonic currents is performed on the direct current output by the hydrogen stack of the target hydrogen fuel cell vehicle, and the Figure 9 shown control loop is used to detect the internal resistance of the hydrogen stack in the target hydrogen fuel cell vehicle.

[0107] Please refer to Figures 11 to 16 , Figure 11 , which is a schematic diagram when a 4 Hz harmonic current is added to the output current of the hydrogen stack, Figure 12 , which is a schematic diagram when a 20 Hz harmonic current is added to the output current of the hydrogen stack, Figure 13 , which is a schematic diagram when a 40 Hz harmonic current is added to the output current of the hydrogen stack, Figure 14 , which is a schematic diagram when a 1000 Hz harmonic current is added to the output current of the hydrogen stack. Figure 15 , which is a schematic diagram of the total harmonic current obtained by superposing harmonic currents of multiple frequencies on the output current of the hydrogen stack. Figure 16 , which is a frequency spectrum schematic diagram of the calculated internal resistance of the hydrogen stack.

[0108] The above experimental results show that the internal resistance of the hydrogen stack in a hydrogen fuel cell vehicle can be monitored online by the method provided in this application. Moreover, since this method does not require additional detection devices or circuits to be added to the hydrogen fuel cell vehicle to detect the internal resistance of the hydrogen stack, the design cost required for detecting the internal resistance of the hydrogen stack can be significantly reduced by this method.

[0109] Please refer to Figure 17 , Figure 17 which is a structural diagram of a detection device for the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle provided by an embodiment of the present invention. The detection device includes:

[0110] A converter construction module 21, configured to construct a DC / DC converter by using a multi-phase interleaved parallel single-phase boost converter; wherein, the input end of the DC / DC converter is connected to the output end of the hydrogen stack in the target hydrogen fuel cell vehicle;

[0111] A harmonic generation module 22, configured to generate a target disturbance harmonic based on the multi-frequency sine superposition technique by using a known target sine wave and a multi-phase interleaved parallel single-phase boost converter, and superimpose the target disturbance harmonic on the output current of the hydrogen stack;

[0112] A DC acquisition module 23, configured to construct a low-pass filter module according to the target sine wave, and use the low-pass filter module to filter out the high-order harmonics in each phase boost converter to obtain the target direct current;

[0113] An AC acquisition module 24, configured to construct a band-pass filter module according to the target sine wave, use the band-pass filter module to separate and restore the target disturbance harmonic to obtain the restored harmonic component, and perform feedback control on the harmonic component to obtain a target alternating current with both the frequency and amplitude maintained within a preset range;

[0114] A PWM generation module 25, configured to generate a target PWM wave by using the target direct current and the target alternating current, so that the DC / DC converter uses the target PWM wave to convert the output current of the hydrogen stack and supply power to the target hydrogen fuel cell vehicle;

[0115] An internal resistance measurement module 26, configured to determine the target internal resistance of the hydrogen stack in real time according to the sampled feedback input voltage and the sampled feedback input current of the DC / DC converter.

[0116] The detection device for the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle provided by an embodiment of the present invention has the beneficial effects of the detection method for the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle disclosed above.

[0117] Please refer to Figure 18 , Figure 18The figure shows the structure of a detection device for the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle provided by an embodiment of the present invention. The detection device includes:

[0118] A memory 31 for storing a computer program;

[0119] A processor 32 for implementing the steps of a method for detecting the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle as disclosed above when executing the computer program.

[0120] The detection device for the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle provided by an embodiment of the present invention has the beneficial effects of a method for detecting the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle as disclosed above.

[0121] An embodiment of the present invention also provides a computer-readable storage medium. A computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the steps of a method for detecting the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle as disclosed above are implemented.

[0122] The computer-readable storage medium provided by an embodiment of the present invention has the beneficial effects of a method for detecting the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle as disclosed above.

[0123] In this specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method part.

[0124] Finally, it should also be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0125] The above has introduced in detail a method, device, equipment and medium for detecting the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle. In this article, specific examples are used to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A method for detecting the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle, characterized in that, it includes: Construct a DC / DC converter using a multi-phase interleaved parallel single-phase boost converter; wherein, the input end of the DC / DC converter is connected to the output end of the hydrogen stack in the target hydrogen fuel cell vehicle; Based on the multi-frequency sine superposition technology, use a known target sine wave and a multi-phase interleaved parallel single-phase boost converter to generate a target disturbance harmonic, and superimpose the target disturbance harmonic on the output current of the hydrogen stack; Construct a low-pass filter module according to the target sine wave, and use the low-pass filter module to filter out the high-order harmonics in each phase boost converter to obtain a target direct current; Construct a band-pass filter module according to the target sine wave, use the band-pass filter module to separate and restore the target disturbance harmonic, obtain the restored harmonic component, and perform feedback control on the harmonic component to obtain a target alternating current with both the frequency and amplitude maintained within a preset range; Generate a target PWM wave using the target direct current and the target alternating current, so that the DC / DC converter uses the target PWM wave to convert the output current of the hydrogen stack and supply power to the target hydrogen fuel cell vehicle; Determine the target internal resistance of the hydrogen stack in real time according to the sampled feedback input voltage and the sampled feedback input current of the DC / DC converter; The process of determining the target internal resistance of the hydrogen stack in real time according to the sampled feedback input voltage and the sampled feedback input current of the DC / DC converter includes: Based on the internal resistance equivalent model of the hydrogen stack, determine the target internal resistance of the hydrogen stack in real time according to the sampled feedback input voltage and the sampled feedback input current of the DC / DC converter; wherein, the expression of the internal resistance equivalent model is: ； Wherein, is the equivalent impedance of the hydrogen stack, is the sampled feedback input voltage, is the sampled feedback input current, is the equivalent internal resistance of the hydrogen stack, is the polarization internal resistance, and are the equivalent inductance value and the equivalent capacitance value of each phase boost converter respectively, is the disturbance angular frequency.

2. The detection method according to claim 1, characterized in that, The process of constructing a DC / DC converter using a multi-phase interleaved parallel single-phase boost converter includes: Construct the DC / DC converter using a 4-phase interleaved parallel single-phase boost converter.

3. The detection method according to claim 2, characterized in that, The process of constructing a low-pass filter module according to the target sine wave, and using the low-pass filter module to filter out the high-order harmonics in each phase boost converter to obtain a target direct current includes: Construct 4 low-pass filters according to the target sine wave; Based on the PID control principle, and use 4 low-pass filters to filter out the high-order harmonics in each phase boost converter to obtain the target direct current; wherein, the ripple of the total input current of the DC / DC converter is 0.25 times the current ripple in the single-phase boost converter.

4. The detection method according to claim 3, characterized in that, The process of constructing a band-pass filter module according to the target sine wave, using the band-pass filter module to separate and restore the target disturbance harmonic, obtain the restored harmonic component, and perform feedback control on the harmonic component to obtain a target alternating current with both the frequency and amplitude maintained within a preset range includes: Construct four band-pass filters according to the target sine wave, and use the four band-pass filters to separate and restore the target disturbance harmonics to obtain the restored harmonic components; Based on the PID control principle, control the frequency and amplitude of the harmonic components respectively to obtain the target alternating current with both the frequency and amplitude maintained within the preset range.

5. The detection method according to claim 4, characterized in that, The process of controlling the frequency and amplitude of the harmonic components respectively to obtain the target alternating current with both the frequency and amplitude maintained within the preset range includes: Based on the given harmonic current, control the frequency and amplitude of the harmonic components respectively to obtain the target alternating current with both the frequency and amplitude maintained within the preset range; wherein, the amplitude of the given harmonic current is less than 5% of the output current of the hydrogen stack.

6. A detection device for the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle, characterized in that, comprising: A converter construction module for constructing a DC / DC converter using a multi-phase interleaved parallel single-phase boost converter; wherein, the input end of the DC / DC converter is connected to the output end of the hydrogen stack in the target hydrogen fuel cell vehicle; A harmonic generation module for generating target disturbance harmonics based on the multi-frequency sine superposition technique, using the known target sine wave and the multi-phase interleaved parallel single-phase boost converter, and superimposing the target disturbance harmonics on the output current of the hydrogen stack; A DC acquisition module for constructing a low-pass filter module according to the target sine wave, and using the low-pass filter module to filter out the high-order harmonics in each phase boost converter to obtain the target direct current; An AC acquisition module for constructing a band-pass filter module according to the target sine wave, using the band-pass filter module to separate and restore the target disturbance harmonics to obtain the restored harmonic components, and performing feedback control on the harmonic components to obtain the target alternating current with both the frequency and amplitude maintained within the preset range; A PWM generation module for generating a target PWM wave using the target direct current and the target alternating current, so that the DC / DC converter uses the target PWM wave to convert the output current of the hydrogen stack and supply power to the target hydrogen fuel cell vehicle; An internal resistance measurement module for determining the target internal resistance of the hydrogen stack in real time according to the sampled feedback input voltage and the sampled feedback input current of the DC / DC converter; The process of determining the target internal resistance of the hydrogen stack in real time according to the sampled feedback input voltage and the sampled feedback input current of the DC / DC converter includes: Based on the internal resistance equivalent model of the hydrogen stack, determine the target internal resistance of the hydrogen stack in real time according to the sampled feedback input voltage and the sampled feedback input current of the DC / DC converter; wherein, the expression of the internal resistance equivalent model is: ； In the formula, is the equivalent impedance of the hydrogen stack, is the sampled feedback input voltage, is the sampled feedback input current, is the equivalent internal resistance of the hydrogen stack, is the polarization internal resistance, and are the equivalent inductance value and equivalent capacitance value of each phase boost converter respectively, is the perturbation angular frequency.

7. A detection device for the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle, characterized in that, comprising: A memory for storing a computer program; A processor, configured to implement the steps of the method for detecting the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle according to any one of claims 1 to 5 when executing the computer program.

8. A computer-readable storage medium, characterized in that, the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for detecting the internal resistance of a hydrogen stack in a hydrogen fuel cell vehicle according to any one of claims 1 to 5 are implemented.

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