CN115085549A - Impedance measuring device based on interleaved boost circuit and measuring method thereof - Google Patents

Impedance measuring device based on interleaved boost circuit and measuring method thereof Download PDF

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CN115085549A
CN115085549A CN202210715189.7A CN202210715189A CN115085549A CN 115085549 A CN115085549 A CN 115085549A CN 202210715189 A CN202210715189 A CN 202210715189A CN 115085549 A CN115085549 A CN 115085549A
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inductor
fuel cell
boost
circuit
switch tube
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刘芙蓉
卢忠昌
谢长君
杨扬
朱文超
石英
杜帮华
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Wuhan University of Technology WUT
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/378—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC] specially adapted for the type of battery or accumulator
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/389—Measuring internal impedance, internal conductance or related variables
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/14—Arrangements for reducing ripples from dc input or output

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  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Fuel Cell (AREA)

Abstract

The invention relates to the technical field of fuel cells, and discloses an impedance measuring device based on a staggered parallel boost circuit, which is characterized in that: the device comprises an interleaved boost main circuit, a boost disturbance circuit, a PI controller, a driving circuit, a signal acquisition module and an impedance calculation module, wherein the PI controller compares a load signal fed back and a given reference signal, and calculates an obtained error value to obtain a duty ratio which is used as the duty ratio of a PWM (pulse width modulation) module in the PI controller. The invention also discloses a measuring method of the impedance measuring device based on the staggered parallel boost circuit. The impedance measuring device and the impedance measuring method based on the staggered parallel boost circuit realize the measurement of the impedance of the fuel cell without an external excitation source while realizing the boost of the fuel cell of the electric automobile through the staggered parallel boost circuit.

Description

Impedance measuring device based on interleaved boost circuit and measuring method thereof
Technical Field
The invention relates to the technical field of fuel cells, in particular to an impedance measuring device and an impedance measuring method based on a staggered parallel boost circuit.
Background
When the fuel cell malfunctions, its internal impedance changes, and the performance of the entire fuel cell is degraded. Therefore, it is necessary to accurately diagnose the state of the fuel cell. By measuring the impedance of the fuel cell on line and based on the coupling relation between the impedance of the fuel cell and the internal state parameters, the internal state of the fuel cell can be estimated on line, the working state can be adjusted in time, the faults of over-dry of a fuel cell membrane or electrode flooding and the like can be effectively avoided, and the service life of the fuel cell is prolonged.
At present, the internal resistance measuring methods of fuel cells adopted at home and abroad mainly comprise a current-cut method and an alternating current impedance spectroscopy method. The ac impedance spectroscopy requires designing an independent excitation source to generate an ac perturbation signal to be applied to both ends of the fuel cell, and the design of the excitation source is usually complicated and too slow.
Disclosure of Invention
The invention aims to provide an impedance measuring device based on a staggered parallel boost circuit and a measuring method thereof aiming at the defects of the technology, and the impedance measuring device realizes the measurement of the impedance of the fuel cell without an additional excitation source while realizing the boost of the fuel cell of the electric automobile by the staggered parallel boost circuit.
In order to achieve the above object, an impedance measuring apparatus based on an interleaved boost circuit according to the present invention includes:
staggered boost main circuit: the input end is connected with the fuel cell, the output end is connected with the load, and the output voltage of the fuel cell is boosted and converted;
boost disturbance circuit: the alternating boost main circuit is connected in parallel to generate a disturbance signal to disturb the output voltage and current of the fuel cell;
a PI controller: the input end is connected with the load, the output end is connected with a driving circuit, and the output PWM signal controls the boost disturbance circuit to generate a disturbance signal of an orthogonal pseudo-random binary sequence;
a drive circuit: performing power amplification on the PWM signal output by the PI controller, driving a switching tube of the boost disturbance circuit to work, and protecting the switching tube of the boost disturbance circuit;
the signal acquisition module: the input end of the impedance calculation module is connected with the fuel cell, and the output end of the impedance calculation module is connected with the impedance calculation module and used for acquiring the output voltage and the output current of the fuel cell;
an impedance calculation module: receiving output voltage and output current signals of the fuel cell acquired by the signal acquisition module, and calculating by adopting fast m-sequence transformation and fast Hadamard transformation to obtain the impedance of the fuel cell;
and the PI controller compares the fed back load signal with a given reference signal, and calculates the obtained error value to obtain a duty ratio which is used as the duty ratio of a PWM module in the PI controller.
Preferably, the staggered boost main circuit comprises a first boost circuit, a second boost circuit and a first capacitor connected in parallel, the first boost circuit comprises a first inductor, a first switch tube and a first diode, the second boost circuit comprises a second inductor, a second switch tube and a second diode, the anode of the first inductor is connected with the anode of the fuel cell, the cathode of the first inductor is connected with the anode of the first diode, the anode of the second inductor is connected with the anode of the fuel cell, the cathode of the second inductor is connected with the anode of the second diode, the collector of the first switch tube is connected with the cathode of the first inductor, the emitter of the first switch tube is connected with the cathode of the fuel cell, the collector of the second switch tube is connected with the cathode of the second inductor, the emitter of the second switch tube is connected with the cathode of the fuel cell, the first capacitor is connected in parallel with the output terminal of the staggered boost main circuit, the boost disturbance circuit comprises a third inductor, a third switching tube, a third diode and a second capacitor, wherein the anode of the third inductor is connected with the anode of the fuel cell, the cathode of the third inductor is connected with the anode of the third diode, the collector of the third switching tube is connected with the cathode of the third inductor, the emitter of the third switching tube is connected with the cathode of the fuel cell, and the second capacitor is connected with the first capacitor in parallel.
Preferably, gate electrodes of the first switching tube and the second switching tube receive the disturbance signal, the phase positions are controlled to be 180 degrees in a staggered mode, the duty ratios of the first switching tube and the second switching tube receiving the disturbance signal are the same, and the first diode and the second diode play a role in freewheeling when the first switching tube and the second switching tube are turned off.
Preferably, the alternating boost main circuit is divided into a current continuous mode and a current discontinuous mode according to whether the inductive current is continuous or not.
Preferably, the signal acquisition module comprises a voltage sampling circuit and a current sampling circuit.
A measurement method of the impedance measurement device based on the interleaved parallel boost circuit comprises the steps that a PI controller outputs a PWM signal to control the boost disturbance circuit to generate a disturbance signal of an orthogonal pseudo-random binary sequence, the PI controller compares the output current of an interleaved boost main circuit with the actual output current of a fuel cell, the difference value of the output current of the interleaved boost main circuit and the actual output current of the fuel cell is input into the PI controller to output a duty ratio, the output current of the fuel cell is further controlled, meanwhile, the PI controller introduces the disturbance signal into the fuel cell through the boost disturbance circuit, the output voltage and the output current of the fuel cell are collected through a signal collection module, and then the internal resistance of the fuel cell is calculated through fast m sequence conversion and fast Hadamard conversion.
Preferably, the operation of the staggered boost main circuit comprises the following four stages:
1) when the first switch tube and the second switch tube in the first boost circuit and the second boost circuit are both conducted, the first inductor and the second inductor in the first boost circuit and the second boost circuit store electric energy through the output of the fuel cell, the current flowing through the first inductor and the second inductor is gradually increased, and the following formula is satisfied:
Figure BDA0003708546900000031
in the formula, V 1 Is the voltage of the first inductor, V 2 The voltage of the second inductor, the inductance values of the first inductor and the second inductor are both L,
Figure BDA0003708546900000032
is the current of the first inductor and is,
Figure BDA0003708546900000033
is the current of the first inductor;
2) the second switch tube is closed, the first switch tube is continuously conducted, the first inductor continuously stores electric energy through the output of the fuel cell, the second inductor supplies power to a load through the second diode and the output voltage of the fuel cell, and the current flowing through the second inductor is gradually reduced to meet the following formula:
Figure BDA0003708546900000041
3) the first switch tube and the second switch tube are both conducted, a first inductor and a second inductor in the first boost circuit and the second boost circuit store electric energy through the output of the fuel cell, and the current flowing through the first inductor and the second inductor is gradually increased;
4) the first switch tube is closed, the second switch tube is continuously conducted, at the moment, the second inductor continuously stores electric energy through the output of the fuel cell, the first inductor supplies power to a load through the first diode and the output voltage of the fuel cell, at the moment, the current flowing through the first inductor is gradually reduced, and the electric energy storage device is obtained according to a volt-second balance principle:
Figure BDA0003708546900000042
wherein T is as definedThe conducting time of the second switch tube is shorter,
Figure BDA0003708546900000043
representing the ripple current of the first and second inductors, A V Representing the voltage gain and D the duty cycle.
Preferably, the generation of the disturbance signal comprises the steps of:
A) forming a set of pseudo-random binary sequences as a first set of sequences;
B) performing modulo-2 addition operation on the 01010101 … sequence and the first group of sequences to generate a second group of sequences;
C) performing modulo-2 addition on the sequence 001100110011 … and the first set of sequences to generate a third set of sequences;
D) performing a modulo-2 addition of the sequence 0000111100001111 … with the first set of sequences to generate a fourth set of sequences … …;
according to the signal generation principle, a partial time domain waveform diagram of an orthogonal pseudo-random binary sequence is obtained and generated at the rate of 10kHz, the length of the signal is 63 bits, and harmonic waves with the same frequency do not exist in two groups of orthogonal sequences.
Preferably, when a system response signal is solved, in order to reduce an operation load, a fast Hadamard transform is introduced to realize a fast M-sequence transform, a Hadamard matrix is an n-order square matrix, n is a multiple of 1,2,4,8, …,2M, matrix elements are all ± 1, and M matrix and the Hadamard matrix have equivalence, and the fast Hadamard transform can be used to accelerate the computation speed by equivalently converting M matrix into the Hadamard matrix:
Figure BDA0003708546900000051
the procedure for estimating the impedance spectrum using the fast m-sequence transform algorithm is as follows: first, an excitation signal U of a time domain OPRBS is obtained s(t) Then obtaining a fuel cell system impact response signal I by means of two sets of transposed matrixes and fast Hadamard transformation r(t) Finally, the Fourier transform of the above formula is carried out on the impulse response signal to obtain the transfer function of the system, namely, the fast impedance spectrum is realizedAnd (6) detecting.
Compared with the prior art, the invention has the following advantages:
1. the on-line measurement of the impedance of the fuel cell is completed while the voltage boosting of the vehicle-mounted fuel cell is realized through the staggered parallel boost circuit;
2. the input current ripple can be reduced, the voltage gain ratio can be improved, the efficiency can be improved, the structure is compact, and the current stress of each power switch can be reduced;
3. an external excitation source is not needed, the device is small in size and easy to measure, and the internal resistance measuring time is shortened.
Drawings
FIG. 1 is a schematic structural diagram of an impedance measuring apparatus based on an interleaved boost circuit according to the present invention;
FIG. 2 is a schematic diagram of an interleaved boost circuit according to the present invention;
FIG. 3 is a time domain waveform diagram of an OPRBS disturbance signal according to an embodiment of the present invention;
FIG. 4 is a time domain waveform diagram of an OPRBS disturbance signal according to an embodiment of the present invention;
FIG. 5 is a schematic structural diagram of a control method according to an embodiment of the present invention;
fig. 6 is a flow chart of the OPRBS signal processing in the embodiment of the invention.
The components in the figures are numbered as follows:
the fuel cell system comprises a staggered boost main circuit 1, a fuel cell 2, a load 3, a boost disturbance circuit 4, a PI controller 5, a driving circuit 6, a signal acquisition module 7, an impedance calculation module 8, a first inductor L1, a first switch tube Q1, a first diode D1, a first capacitor C1, a second inductor L2, a second switch tube Q2, a second diode D2, a third inductor L3, a third switch tube Q3, a third diode D3 and a second capacitor C2.
Detailed Description
The invention is described in further detail below with reference to the figures and the specific embodiments.
As shown in fig. 1, an impedance measuring apparatus based on an interleaved boost circuit includes:
interleaved boost main circuit 1: the input end is connected with the fuel cell 2, the output end is connected with the load 3, the output voltage of the fuel cell 2 is boosted and converted, the staggered boost main circuit 1 can reduce the input current ripple and improve the voltage gain ratio;
boost perturbation circuit 4: the parallel connection boost main circuit 1 generates a disturbance signal to disturb the output voltage and current of the fuel cell 2, and the parallel connection boost disturbance circuit 4 enables the generation of the disturbance signal and the power conversion to be decoupled, so that the parallel connection boost main circuit is more suitable for impedance measurement of the fuel cell 1;
the PI controller 5: the input end is connected with a load, the output end is connected with a driving circuit 6, and the output PWM signal controls the boost disturbance circuit 4 to generate a disturbance signal of an orthogonal pseudo-random binary sequence;
the drive circuit 6: the PWM signal output by the PI controller 5 is subjected to power amplification to drive a switching tube of the boost disturbance circuit 4 to work, and the switching tube of the boost disturbance circuit 4 is protected;
the signal acquisition module 7: the fuel cell system comprises a voltage sampling circuit and a current sampling circuit, wherein the input end of the voltage sampling circuit is connected with a fuel cell 1, the output end of the voltage sampling circuit is connected with an impedance calculation module 8 and is used for collecting output voltage and output current of the fuel cell 1, in the embodiment, a LV-25P Hall voltage sensor is used for voltage sampling, and a CHB-50SF Hall current sensor is used for current sampling;
impedance calculation module 8: receiving the output voltage and output current signals of the fuel cell 1 acquired by the signal acquisition module 7, and calculating by adopting fast m-sequence transformation and fast Hadamard transformation to obtain the impedance of the fuel cell 1;
the PI controller 5 compares the fed back load signal with a given reference signal, and calculates the obtained error value to obtain a duty ratio as the duty ratio of a PWM module in the PI controller 5.
As shown in FIG. 2, the interleaved boost main circuit includes a first boost circuit, a second boost circuit and a first capacitor C1 connected in parallel, the first boost circuit includes a first inductor L1, a first switch tube Q1 and a first diode D1, the second boost circuit includes a second inductor L2, a second switch tube Q2 and a second diode D2, the anode of the first inductor L1 is connected with the anode of the fuel cell, the cathode of the first inductor L1 is connected with the anode of the first diode D1, the anode of the second inductor L2 is connected with the anode of the fuel cell, the cathode of the second diode D2 is connected with the anode of the second diode D8655, the collector of the first switch tube Q1 is connected with the cathode of the first inductor L1, the emitter of the first diode D1 is connected with the cathode of the fuel cell, the collector of the second switch tube Q2 is connected with the cathode of the second inductor L2, the emitter of the second inductor is connected with the cathode of the fuel cell, the first capacitor C1 is connected in parallel with the output of the interleaved boost circuit, the output of the first inductor L3 includes three disturbing circuits connected in parallel, and the output of the interleaved boost circuit, A third switch tube Q3, a third diode D3 and a second capacitor C2, wherein the anode of the third inductor L3 is connected to the anode of the fuel cell, the cathode is connected to the anode of the third diode D3, the collector of the third switch tube Q3 is connected to the cathode of the third inductor L3, the emitter is connected to the cathode of the fuel cell, and the second capacitor C2 is connected in parallel with the first capacitor C1.
Gates of the first switch tube Q1 and the second switch tube Q2 receive disturbance signals, phases are controlled to be staggered by 180 degrees, so that current ripples are greatly reduced, the current ripples can be controlled to be 0 in a specific situation, duty ratios of the disturbance signals received by the first switch tube Q1 and the second switch tube Q2 are the same, the first diode D1 and the second diode D2 play a role of follow current when the first switch tube Q1 and the second switch tube Q2 are turned off, and the staggered boost main circuit is divided into a current continuous mode and a current discontinuous mode according to whether the inductive current is continuous or not. The staggered boost main circuit is used for power conversion between the fuel cell and the load, low direct-current voltage input and high direct-current voltage output are completed, the power utilization rate is high, the output direct-current amplitude is small, and the power supply quality is high.
The boost disturbance circuit 4 performs on-line AC impedance measurement of the fuel cell 2 through the disturbance signal, so that the generation of the fluctuation signal and the power conversion are decoupled, and the method is more suitable for the application of the fuel cell 2.
In this embodiment, the PI controller 5 is used for outputting a PWM signal to control the boost disturbing circuit 4 to generate an OPRBS (orthogonal pseudo random binary sequence) disturbing signal, the control part of the PI controller 5 comprises 2 closed loops, as shown in fig. 5, the loop 1 compares the output current I of the interleaved boost main circuit 1 through the PI controller 5 ref Output current I substantially corresponding to the output current of the fuel cell 2 O The difference between the two is inputted to a PI controller 5 to output a duty ratioThe duty ratio of a PWM module in the DSP is used for further controlling the output current of the fuel cell 2, meanwhile, the ring 2 is used for controlling disturbance signals, the PI controller 5 introduces the disturbance signals into the fuel cell 2 through a boost disturbance circuit 4, the output voltage and the output current of the fuel cell 2 are collected through a signal collection module 7, and then the internal resistance of the fuel cell 2 is calculated through fast m-sequence conversion and fast Hadamard conversion.
Specifically, the operation of the staggered boost main circuit 1 includes the following four stages:
1) when the first switch tube Q1 and the second switch tube Q2 in the first boost circuit and the second boost circuit are both turned on, the first inductor L1 and the second inductor L2 in the first boost circuit and the second boost circuit store electric energy through the output of the fuel cell, and the current flowing through the first inductor L1 and the second inductor L2 gradually increases, and the following formula is satisfied:
Figure BDA0003708546900000081
in the formula, V 1 Is the voltage, V, of the first inductor L1 2 The inductance values of the first inductor L1 and the second inductor L2 are both L, which is the voltage of the second inductor L2,
Figure BDA0003708546900000082
is the current of the first inductor L1,
Figure BDA0003708546900000083
is the current of the first inductor L2;
2) the second switch tube Q2 is turned off, the first switch tube Q1 continues to conduct, the first inductor L1 continues to store electric energy through the output of the fuel cell 2, the second inductor L2 supplies power to the load through the second diode D2 and the output voltage of the fuel cell 2, and at this time, the current flowing through the second inductor L2 gradually decreases, and the following formula is satisfied:
Figure BDA0003708546900000091
3) the first switch tube Q1 and the second switch tube Q2 are both turned on, the first inductor L1 and the second inductor L2 in the first boost circuit and the second boost circuit store electric energy through the output of the fuel cell 2, and the current flowing through the first inductor L1 and the second inductor L2 is gradually increased;
4) the first switch Q1 is turned off, the second switch Q2 is turned on continuously, at this time, the second inductor L2 continues to store electric energy through the output of the fuel cell 2, the first inductor L1 supplies power to the load through the first diode D1 and the output voltage of the fuel cell 2, at this time, the current flowing through the first inductor L1 becomes gradually smaller, and the voltage-second balance principle is obtained:
Figure BDA0003708546900000092
wherein T is the conduction time of the second switch tube Q2,
Figure BDA0003708546900000093
represents the ripple current of the first inductor L1 and the second inductor L1, A V Representing the voltage gain and D the duty cycle.
In addition, the generation of the disturbance signal comprises the following steps:
A) forming a set of pseudo-random binary sequences as a first set of sequences;
B) performing modulo-2 addition operation on the 01010101 … sequence and the first group of sequences to generate a second group of sequences;
C) performing modulo-2 addition on the sequence 001100110011 … and the first set of sequences to generate a third set of sequences;
D) performing a modulo-2 addition of the sequence 0000111100001111 … with the first set of sequences to generate a fourth set of sequences … …;
according to the signal generation principle, a partial time domain waveform diagram of an orthogonal pseudo-random binary sequence is obtained and generated at the rate of 10kHz, the length of the signal is 63 bits, and harmonic waves with the same frequency do not exist in two groups of orthogonal sequences. In addition to the above features, the orthogonal pseudo-random binary sequence can suppress the nonlinear effect of the system, so that the sequence is well suited for the impedance detection of the fuel cell 2.
The boost disturbing circuit 4 is used for generating a disturbing signal, an orthogonal pseudo random binary sequence disturbing signal (OPRBS signal) is used, the orthogonal pseudo random binary sequence is composed of a group of orthogonal sequences, the signal not only meets the condition that each channel signal is irrelevant, but also overcomes the defect of overlong test time caused by time shift intervals, the OPRBS signal contains a plurality of frequency information, and the characteristic enables the OPRBS signal to realize the impedance test work of a plurality of target frequency points by applying an exciting signal once.
As shown in FIG. 6, the OPRBS signal is generated by using an OPRBS signal generator and converted into an analog voltage U by a D/A converter s(t) The excitation signal is applied to the fuel cell through a boost disturbance circuit, then a transimpedance amplifier is selected to convert the current response into a voltage signal, the voltage signal is converted into a digital signal through an A/D converter, the signal processing is carried out by an upper computer, and the impedance value is calculated.
When the disturbance signal is an OPRBS signal, a response signal of a linear system is solved by using a fast m-sequence transformation algorithm, and a transfer function of the system can be further obtained by performing fast Fourier transformation on the response signal, namely, the fast impedance spectrum test is realized.
When a system response signal is solved, in order to reduce operation load, fast Hadamard transform is introduced to realize fast M sequence transform, a Hadamard matrix is an n-order square matrix, n is a multiple of 1,2,4,8, … and 2M, matrix elements are +/-1, the M matrix and the Hadamard matrix have equivalence, and the M matrix is equivalently transformed into the Hadamard matrix, namely the fast Hadamard transform is used for accelerating the calculation speed:
Figure BDA0003708546900000101
the procedure for estimating the impedance spectrum using the fast m-sequence transform algorithm is as follows: first, an excitation signal U of a time domain OPRBS is obtained s(t) Then obtaining a fuel cell system impact response signal I by means of two sets of transposed matrixes and fast Hadamard transformation r(t) Finally, the Fourier transform of the above formula is carried out on the impact response signal to obtain the transfer function of the system, namely the realization of the methodAnd (4) fast impedance spectrum detection.
The invention relates to an impedance measuring device and an impedance measuring method based on a staggered parallel boost circuit, which can complete the on-line measurement of the impedance of a fuel cell while realizing the voltage boosting of a vehicle-mounted fuel cell through the staggered parallel boost circuit; the input current ripple can be reduced, the voltage gain ratio can be improved, the efficiency can be improved, the structure is compact, and the current stress of each power switch can be reduced; an external excitation source is not needed, the device is small in size and easy to measure, and the internal resistance measuring time is shortened.

Claims (9)

1. An impedance measurement device based on interleaving parallel boost circuit is characterized in that: the method comprises the following steps:
staggered boost main circuit: the input end is connected with the fuel cell, the output end is connected with the load, and the output voltage of the fuel cell is boosted and converted;
boost disturbance circuit: the alternating boost main circuit is connected in parallel to generate a disturbance signal to disturb the output voltage and current of the fuel cell;
a PI controller: the input end is connected with the load, the output end is connected with a driving circuit, and the output PWM signal controls the boost disturbance circuit to generate a disturbance signal of an orthogonal pseudo-random binary sequence;
a drive circuit: performing power amplification on the PWM signal output by the PI controller, driving a switching tube of the boost disturbance circuit to work, and protecting the switching tube of the boost disturbance circuit;
the signal acquisition module: the input end of the impedance calculation module is connected with the fuel cell, and the output end of the impedance calculation module is connected with the impedance calculation module and used for acquiring the output voltage and the output current of the fuel cell;
an impedance calculation module: receiving output voltage and output current signals of the fuel cell acquired by the signal acquisition module, and calculating by adopting fast m-sequence transformation and fast Hadamard transformation to obtain the impedance of the fuel cell;
and the PI controller compares the fed back load signal with a given reference signal, and calculates the obtained error value to obtain a duty ratio which is used as the duty ratio of a PWM module in the PI controller.
2. The interleaved boost circuit based impedance measurement device of claim 1, wherein: the staggered boost main circuit comprises a first boost circuit, a second boost circuit and a first capacitor which are connected in parallel, the first boost circuit comprises a first inductor, a first switch tube and a first diode, the second boost circuit comprises a second inductor, a second switch tube and a second diode, the anode of the first inductor is connected with the anode of the fuel cell, the cathode of the first inductor is connected with the anode of the first diode, the anode of the second inductor is connected with the anode of the fuel cell, the cathode of the second inductor is connected with the anode of the second diode, the collector of the first switch tube is connected with the cathode of the first inductor, the emitter of the first switch tube is connected with the cathode of the fuel cell, the collector of the second switch tube is connected with the cathode of the second inductor, the emitter of the second switch tube is connected with the cathode of the fuel cell, the first capacitor is connected in parallel with the output end of the staggered boost main circuit, the boost disturbance circuit comprises a third inductor, a third switching tube, a third diode and a second capacitor, wherein the anode of the third inductor is connected with the anode of the fuel cell, the cathode of the third inductor is connected with the anode of the third diode, the collector of the third switching tube is connected with the cathode of the third inductor, the emitter of the third switching tube is connected with the cathode of the fuel cell, and the second capacitor is connected with the first capacitor in parallel.
3. The interleaved boost circuit based impedance measurement device of claim 2, wherein: the gate poles of the first switch tube and the second switch tube receive disturbance signals, the phases are controlled to be 180 degrees in a staggered mode, the duty ratios of the disturbance signals received by the first switch tube and the second switch tube are the same, and the first diode and the second diode play a role in follow current when the first switch tube and the second switch tube are turned off.
4. The interleaved boost circuit based impedance measurement device of claim 1, wherein: and the alternating boost main circuit is divided into a current continuous mode and a current discontinuous mode according to whether the inductive current is continuous or not.
5. The interleaved boost circuit based impedance measurement device of claim 1, wherein: the signal acquisition module comprises a voltage sampling circuit and a current sampling circuit.
6. A method for measuring the impedance measuring device based on the interleaved boost circuit according to claim 1, wherein: the PI controller outputs a PWM signal to control the boost disturbance circuit to generate a disturbance signal of an orthogonal pseudo-random binary sequence, compares the output current of the staggered boost main circuit with the actual output current of the fuel cell, inputs the difference value of the output current of the staggered boost main circuit and the actual output current of the fuel cell into the PI controller to output a duty ratio, further controls the output current of the fuel cell, simultaneously introduces the disturbance signal into the fuel cell through the boost disturbance circuit, acquires the output voltage and the output current of the fuel cell through the signal acquisition module, and then calculates the internal resistance of the fuel cell by using fast m sequence conversion and fast Hadamard conversion.
7. The method of claim 6, wherein the step of measuring comprises: the operation of the staggered boost main circuit comprises the following four stages:
1) when the first switch tube and the second switch tube in the first boost circuit and the second boost circuit are both conducted, the first inductor and the second inductor in the first boost circuit and the second boost circuit store electric energy through the output of the fuel cell, the current flowing through the first inductor and the second inductor is gradually increased, and the following formula is satisfied:
Figure FDA0003708546890000031
in the formula, V 1 Is the voltage of the first inductor, V 2 Is the voltage of the second inductor, the first inductor and the second inductorThe inductance values of (a) are all L,
Figure FDA0003708546890000032
is the current of the first inductor and is,
Figure FDA0003708546890000033
is the current of the first inductor;
2) the second switch tube is closed, the first switch tube is continuously conducted, the first inductor continuously stores electric energy through the output of the fuel cell, the second inductor supplies power to a load through the second diode and the output voltage of the fuel cell, and the current flowing through the second inductor is gradually reduced to meet the following formula:
Figure FDA0003708546890000034
3) the first switch tube and the second switch tube are both conducted, a first inductor and a second inductor in the first boost circuit and the second boost circuit store electric energy through the output of the fuel cell, and the current flowing through the first inductor and the second inductor is gradually increased;
4) the first switch tube is closed, the second switch tube is continuously conducted, at the moment, the second inductor continuously stores electric energy through the output of the fuel cell, the first inductor supplies power to a load through the first diode and the output voltage of the fuel cell, at the moment, the current flowing through the first inductor is gradually reduced, and the electric energy storage device is obtained according to a volt-second balance principle:
Figure FDA0003708546890000035
wherein T is the conduction time of the second switch tube,
Figure FDA0003708546890000041
representing the ripple current of the first and second inductors, A V Indicating electricityVoltage gain, D represents duty cycle.
8. The method of claim 6, wherein the step of measuring comprises: the generation of the disturbance signal comprises the following steps:
A) forming a set of pseudo-random binary sequences as a first set of sequences;
B) performing modulo-2 addition operation on the 01010101 … sequence and the first group of sequences to generate a second group of sequences;
C) performing modulo-2 addition on the sequence 001100110011 … and the first set of sequences to generate a third set of sequences;
D) performing a modulo-2 addition of the sequence 0000111100001111 … with the first set of sequences to generate a fourth set of sequences … …;
according to the signal generation principle, a partial time domain waveform diagram of an orthogonal pseudo-random binary sequence is obtained and generated at the rate of 10kHz, the length of the signal is 63 bits, and harmonic waves with the same frequency do not exist in two groups of orthogonal sequences.
9. The method for measuring the impedance measuring device based on the interleaved boost circuit as claimed in claim 6, wherein: when a system response signal is solved, in order to reduce the operation load, fast Hadamard transform is introduced to realize fast M sequence transform, a Hadamard matrix is an n-order square matrix, n is a multiple of 1,2,4,8, … and 2M, matrix elements are +/-1, an M matrix and the Hadamard matrix have equivalence, and the M matrix is equivalently transformed into the Hadamard matrix, namely the fast Hadamard transform is used for accelerating the calculation speed:
Figure FDA0003708546890000042
the procedure for estimating the impedance spectrum using the fast m-sequence transform algorithm is as follows: first, an excitation signal U of a time domain OPRBS is obtained s(t) Then obtaining a fuel cell system impact response signal I by means of two sets of transposed matrixes and fast Hadamard transformation r(t) And finally, Fourier of the above formula is carried out on the impact response signalAnd transforming to obtain a transfer function of the system, namely realizing rapid impedance spectrum detection.
CN202210715189.7A 2022-06-22 2022-06-22 Impedance measuring device based on interleaved boost circuit and measuring method thereof Pending CN115085549A (en)

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* Cited by examiner, † Cited by third party
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CN117478495A (en) * 2023-10-20 2024-01-30 福氏新能源技术(上海)有限公司 Automatic configuration method and circuit for CAN communication terminal resistor
CN117767749A (en) * 2023-11-17 2024-03-26 江苏道达智能科技有限公司 Non-contact power-taking high-power supply and adjusting method thereof

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117478495A (en) * 2023-10-20 2024-01-30 福氏新能源技术(上海)有限公司 Automatic configuration method and circuit for CAN communication terminal resistor
CN117478495B (en) * 2023-10-20 2024-04-16 福氏新能源技术(上海)有限公司 Automatic configuration method and circuit for CAN communication terminal resistor
CN117767749A (en) * 2023-11-17 2024-03-26 江苏道达智能科技有限公司 Non-contact power-taking high-power supply and adjusting method thereof

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