CN112924757B - Online rapid detection system and detection method for impedance spectrum of series power supply system - Google Patents
Online rapid detection system and detection method for impedance spectrum of series power supply system Download PDFInfo
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- 238000001514 detection method Methods 0.000 title claims abstract description 87
- 238000001453 impedance spectrum Methods 0.000 title claims abstract description 40
- 238000006243 chemical reaction Methods 0.000 claims abstract description 9
- 238000005070 sampling Methods 0.000 claims description 46
- 238000004364 calculation method Methods 0.000 claims description 20
- 230000006870 function Effects 0.000 claims description 17
- 230000004044 response Effects 0.000 claims description 11
- 230000008859 change Effects 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 7
- 230000000737 periodic effect Effects 0.000 claims description 7
- 238000012360 testing method Methods 0.000 claims description 7
- 238000012544 monitoring process Methods 0.000 claims description 5
- 238000012545 processing Methods 0.000 claims description 5
- 230000008569 process Effects 0.000 claims description 4
- 235000014676 Phragmites communis Nutrition 0.000 claims description 3
- 230000002457 bidirectional effect Effects 0.000 claims description 3
- 238000000354 decomposition reaction Methods 0.000 claims description 3
- 230000005284 excitation Effects 0.000 abstract description 12
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 6
- 239000000446 fuel Substances 0.000 description 6
- 229910001416 lithium ion Inorganic materials 0.000 description 6
- 238000010248 power generation Methods 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 239000000178 monomer Substances 0.000 description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
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- 231100000572 poisoning Toxicity 0.000 description 1
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/08—Measuring resistance by measuring both voltage and current
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/25—Arrangements for measuring currents or voltages or for indicating presence or sign thereof using digital measurement techniques
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- 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
- G01R31/40—Testing power supplies
Abstract
An on-line rapid detection system and detection method for impedance spectrum of a series power supply system comprises a basic detection unit, a microcontroller and a detected unit; the tested unit is connected with the basic detection units in parallel, and M basic detection units are connected in series to form a series power supply system, wherein M is more than or equal to 1; the basic detection unit is connected with the microcontroller; an analog-to-digital conversion end ADC of the microcontroller receives a current signal and a voltage signal of the basic detection unit; the IO end of the microcontroller sends a bypass signal to the basic detection unit; according to the invention, the current or voltage signal excitation of the tested unit is realized in a mode of bypassing the working current of the tested unit, and the rest parts of the serial power supply system can work normally, so that the system can detect the tested unit on line in real time; unlike available special equipment, the present invention has no limitation of the number of channels, and has high detection efficiency and less detection time.
Description
Technical Field
The invention belongs to the technical field of power supply system impedance spectrum online detection, and particularly relates to a series power supply system impedance spectrum online rapid detection system and a detection method.
Background
With the increasing pressure of the traditional energy, traffic and other industries on the environment year by year, the demands of the nation and the society on new energy power, new energy traffic and the like are becoming stronger. The advent of various policies has also facilitated the rapid development of new energy industries.
In the new energy power and transportation industry, a large number of clean energy power sources are employed to provide power supply. For example, in a photovoltaic power generation system, a photovoltaic module is used as a power generation source; in an electric automobile, a lithium ion battery is used as an automobile power supply; the hydrogen fuel cell engine as the final clean energy source also adopts a fuel cell as a power source of the vehicle; various electrochemical cells, supercapacitors or other power electronic power supplies are used as basic power supplies in a large amount in the energy storage products matched with new energy sources.
Because the single voltage or the current of the power supplies is low, the power supplies are often required to be used in series-parallel connection, so that a series power supply system is formed. Meanwhile, due to the inconsistency of the single power supply, the failure of a serial system is easy to be caused, for example, the lithium ion battery is easy to age in the use process due to the inconsistency of the single power supply, and if the battery cannot be identified in time, the efficiency of the system is easy to be reduced; even in severe cases, system failures or even system damage can occur. Individual cell output characteristics in a hydrogen fuel cell stack are inconsistent, or catalyst poisoning, etc., can easily cause degradation of stack system performance, or even system failure, when used in series. The photovoltaic string causes a decrease in string power generation due to the shadow of individual components therein, potential induced decay, and the like. How to detect the essential characteristics of each power source in a series power source system, such as the electrochemical characteristics of lithium batteries, fuel cells, the internal equivalent characteristics of photovoltaic modules, etc., is therefore a prerequisite for avoiding such problems.
The detection of the essential characteristics of the power supply at present requires the use of special equipment for off-line detection. The special equipment mainly detects the response of the special equipment to the micro disturbance by injecting the micro disturbance with different frequencies into the single power supply, and samples the response to the micro disturbance to realize detection, so that the precision of a sampling system is often required to be very high. Since the frequency range tends to be wide, the cost of generating a wide frequency range microscale signal device is enormous and the number of channels that can be detected is limited, requiring a significant amount of time. Meanwhile, the problems of the power supply monomer cannot be found in real time due to the fact that the power supply monomer cannot be detected on line, and huge detection omission risks exist. Due to the need of offline detection, the series power supply system cannot work normally, and thus lost benefits are caused, especially, the series power supply system is not allowed in the fields of new energy automobiles and the like, or repeated resource investment is needed to ensure uninterrupted power supply of the series power supply system, and the cost of the series power supply system is increased by times.
Disclosure of Invention
The invention aims to provide an on-line rapid detection system and a detection method for impedance spectra of a series power supply system, so as to solve the problems.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
an on-line rapid detection system for impedance spectrum of a series power supply system comprises a basic detection unit, a microcontroller and a detected unit; the tested unit is connected with the basic detection units in parallel, and M basic detection units are connected in series to form a series power supply system, wherein M is more than or equal to 1; the basic detection unit is connected with the microcontroller; an analog-to-digital conversion end ADC of the microcontroller receives a current signal and a voltage signal of the basic detection unit; and the IO end of the microcontroller sends a bypass signal to the basic detection unit.
Furthermore, the tested unit is a system formed by connecting N equivalent power supplies in series, wherein N is more than or equal to 1.
Further, the equivalent power supply is a parallel equivalent power supply of a single power supply or a plurality of power supplies.
Further, the basic detection unit comprises a multipath real-time voltage sampling module, a real-time current sampling module and a bypass device; the bypass device is connected in parallel between the positive and negative poles of the multipath real-time voltage sampling module and the real-time current sampling module; the multipath voltage sampling module at least comprises N paths of real-time voltage sampling input channels, wherein 1 path of real-time voltage sampling input channels are connected to 1 equivalent power supply, real-time acquisition processing is carried out on the terminal voltage of the equivalent power supply, and real-time voltage signals of the measured equivalent power supply are output; each equivalent power supply in the tested unit is respectively connected with at least one path of voltage sampling channel in the multipath real-time voltage sampling module in the basic detection unit; the real-time current sampling module is in series connection with the unit to be tested, and can detect the real-time current value flowing through the unit to be tested; the real-time current sampling module comprises a current sensor for collecting real-time current flowing through the equivalent power supplies connected in series.
Further, the bypass device comprises a first bypass device, a second bypass device, a third bypass device or a fourth bypass device; the first bypass device comprises a controllable switch K1 and a diode D, wherein the anode of the diode D is connected with the V-end, the cathode of the diode D is connected with the Vout end, a bypass signal is connected with the control end of the K1, and the K1 is arranged between the port V+ and the cathode of the diode D; the second bypass device comprises controllable switches K2 and K3, a bypass signal is connected with the control end of the K2, the bypass signal is connected with the control end of the K3 after reverse, the K2 is arranged between the Vout end and the V+ end, and the K3 is arranged between the Vout end and the V-end; the third bypass device comprises a controllable switch K4, a bypass signal is connected with the control end of the switch K4, and the switch K4 is arranged between the Vout end and the V+ end; the fourth bypass device comprises a single-pole double-throw switch K5, a bypass signal is connected with the control end of the K5, the movable end of the single-pole double-throw switch K5 is connected with the Vout end, and the two fixed ends are respectively connected with the V+ end and the V-end.
Further, K1, K2, K3, K4 refer to devices with controllable unidirectional or bidirectional switching capability, and specifically include transistors, darlington tubes, IGBTs, MOSFETs, relays, or reed switches.
Further, when the bypass signal controls K1 to be connected with the V+ end or K2 to be connected with the V+ end, and meanwhile K3 is disconnected with the V-end or K4 is connected with the V+ end or K5 is switched to the V+ end, the bypass channel is disconnected, and current only can flow through the tested unit; when the bypass signal controls the K4 to be disconnected with the V+ end, current no longer flows through the tested unit; when the bypass signal controls the K1 to be disconnected from the V+ terminal or the V2 to be disconnected from the V+ terminal, and the K3 is connected with the V-terminal or the K5 is switched to the V-terminal, the current does not flow through the tested unit, but flows through the bypass.
Furthermore, the microcontroller is used as an execution carrier for controlling the on-line rapid detection of the impedance spectrum and calculating the impedance spectrum, can receive the signals of the ADC module or has the function of analog-to-digital conversion, is used for converting the analog signals obtained by sampling the voltage and the current into digital signals which can be used for calculation, and has the digital IO signal output capability and is used for outputting bypass signals to the bypass module in the basic detection unit.
Further, when M is greater than or equal to 2, a certain number of basic detection units can be set in a redundant state, which is called a redundant unit. When the series power supply system works normally, the redundant unit is in a bypass state. When the basic detection units with non-redundant units in the series power supply system are in a detection state, the conduction states of the corresponding number of redundant units are complementary with the conduction states of the basic detection units in the detection state, namely when the detected basic detection units are in the conduction state, the corresponding redundant units are in a bypass state, and when the detected basic detection units are in the bypass state, the corresponding redundant units are in the conduction state, so that the total external output characteristics of the series power supply system can be kept unchanged, and the influence on an external system is further reduced or even eliminated.
Further, the detection method of the series power supply system impedance spectrum online rapid detection system comprises the following steps:
step 1, monitoring working current of a series power supply system, selecting a single power supply in a tested unit to perform impedance spectrum detection when voltage response change of the single power supply in the tested unit caused by working current change is more than 5mV according to historical data or experience parameters of the power supply system, or monitoring the single power supply voltage response change in the tested unit to be more than 5mV after a microcontroller outputs a bypass signal.
Step 2, the microcontroller sends a bypass signal with a selected frequency fn, wherein the frequency fn is selected from the impedance spectrum frequency range of the unit to be tested;
and 3, after the bypass signal is sent out, the microcontroller synchronously collects real-time current and real-time voltage signals of the power supply at the frequency fs. The acquisition frequency fs is at least 10 times of the bypass signal frequency fn;
step 4, any periodic function can be expressed as the sum of direct current and infinite number formed by sine function or cosine function:
performing fast Fourier decomposition (FFT) on the voltage and current signals caused by the bypass signals to obtain sinusoidal signal quantity U (2 pi f) of the voltage and current at the frequency point corresponding to fn and the frequency multiple of the frequency point n )、I(2πf n ) The method comprises the steps of carrying out a first treatment on the surface of the For a linear system, further find the impedance at that frequency pointAnd (3) repeating the wave generation, detection and calculation processes to finish the impedance calculation of all fn frequency points and harmonic frequency points thereof, thereby obtaining the required impedance spectrum.
Further, the Goertzel algorithm is adopted in the calculation:
where g (k) is the kth current or voltage sampling result, x (k), x (k-1), and x (k-2) is the current, previous, and more previous calculation result, respectively.
Compared with the prior art, the invention has the following technical effects:
according to the invention, the current or voltage signal excitation of the tested unit is realized in a mode of bypassing the working current of the tested unit, and the rest parts of the serial power supply system can work normally, so that the system can detect the tested unit on line in real time;
unlike available special equipment, the present invention has no limitation of the number of channels and has offline operation and limited test channels, and this results in high detection efficiency and less detection time;
the invention selects part of concerned frequency points for detection, and realizes single multi-frequency signal excitation by a periodic signal instead of a sinusoidal signal excitation mode and simultaneously comprises fundamental frequency and frequency multiplication excitation signals. And a plurality of frequency point impedances can be obtained at the same time, so that the impedance spectrum calculation efficiency is improved.
For the power supply with a sampling system, for example, a BMS system is arranged in the power supply formed by connecting lithium ion batteries in series, and each battery of the fuel cell stack is provided with a current and voltage sampling device, the invention can further reduce the system cost by utilizing the existing device;
by means of the redundant units, the change of the external output characteristics of the serial power supply system can be greatly reduced or even eliminated, and the influence on the system is reduced to the minimum.
The excitation input is an operating current or voltage using the power supply system itself in series, without additional energy injection. The cost of the test energy and the expenditure of extra energy equipment are reduced;
different from other off-line disturbance modes, the invention adopts small signals as disturbance sources, adopts working current or voltage of a series power supply system as bypass signals, improves signal magnitude, reduces the sampling precision requirement of a sampling system, and can further reduce the cost of the sampling system;
the bypass signal frequency is limited only by the characteristics of a switching device in the bypass device, and the excitation frequency range is wider;
different from special equipment, the cost is high, and the system of the invention has low realization cost;
the invention does not need to carry out a large amount of calculation or a large amount of data storage on the data, greatly reduces the performance requirement on the microcontroller, is easy to realize and can reduce the hardware investment cost of the system;
by the bypass or circuit breaking function of the bypass device, the invention can provide additional protection function for the original series power supply system. The fault tested unit can be cut out of the system, so that other normal tested units can be ensured to work continuously.
Drawings
FIG. 1 shows a unit under test connected in parallel with a basic detection unit.
Fig. 2 is a bypass device.
FIG. 3 shows a series configuration of a plurality of basic detection units.
Detailed Description
The invention is further described below with reference to the accompanying drawings:
referring to fig. 1 to 3, the present invention provides a device for inputting signal excitation in real time on line by using the working current or voltage of the power supply itself connected in series as an excitation source, and detecting the voltage or current response of the system under the excitation. And a method for carrying out the on-line rapid detection of the impedance spectrum according to the excitation and the response corresponding to the excitation is provided. The power source refers to a device, equipment or apparatus capable of providing or absorbing electrical energy under specific conditions, including but not limited to various lithium ion batteries, lead acid batteries, fuel cells, photovoltaic modules, supercapacitors and power electronic power sources.
The invention is realized by the following technical scheme:
the object detected by the invention is defined as a unit under test. The tested unit is a system formed by connecting N equivalent power supplies in series, wherein N is more than or equal to 1. The equivalent power supply is a single power supply or a parallel equivalent power supply of a plurality of power supplies.
The unit under test is connected in parallel with the basic detection unit as shown in fig. 1. The basic detection unit comprises a plurality of paths of real-time voltage sampling and real-time current sampling and bypass devices. The multi-path voltage sampling module at least comprises N paths of real-time voltage sampling input channels, and each path of input channel can realize real-time acquisition and necessary signal processing of voltages at two ends of the measured equivalent power supply and output real-time voltage signals of the measured equivalent power supply. The two ends of each equivalent power supply in the tested unit are respectively connected with at least one voltage sampling channel in the multipath real-time voltage sampling module in the basic detection unit. The real-time current sampling module is in series connection with the unit to be tested, and can detect the real-time current value flowing through the unit to be tested. The real-time current sampling module comprises a current sensor and a necessary signal processing part, and is responsible for collecting real-time current flowing through an equivalent power supply in series, and because the currents of the series system are equal everywhere, the real-time current sampling module is placed at any position of the series branch, and one or more obtained current signals are equal.
Bypass means in the basic detection unit as shown in fig. 2. The device can control the switching device to realize one-way or two-way on and off functions according to the input bypass signal, thereby controlling the current to flow and not flow through the tested unit. On the basis, a bypass function can be added, so that the control current can continue to flow through other paths when the control current does not flow through the tested unit. The bypass device may be implemented using four ways including, but not limited to, the one shown in fig. 2, where D is a diode, K5 is a single pole double throw switch, and K1, K2, K3, K4 are devices with controllable unidirectional or bidirectional switching capability, and implementations may be implemented using devices including, but not limited to, a triode, darlington, IGBT, MOSFET, relay, reed switch, and combinations thereof. When the bypass signal controls K1 to be connected with the V+ end or K2 to be connected with the V+ end, and meanwhile K3 is disconnected with the V-end or K4 is connected with the V+ end or K5 is switched to the V+ end, the bypass channel is disconnected, and current only can flow through the tested unit; when the bypass signal controls the K4 to be disconnected with the V+ end, current no longer flows through the tested unit; when the bypass signal controls the K1 to be disconnected from the V+ terminal or the V2 to be disconnected from the V+ terminal, and the K3 is connected with the V-terminal or the K5 is switched to the V-terminal, the current does not flow through the tested unit, but flows through the bypass.
M (M is larger than or equal to 1) basic detection units are connected in series and can be used as a power supply system to supply power to a load, a power supply or other power electronic devices or absorb energy from other power supplies or power electronic devices. The invention adopts a microcontroller as an execution carrier for controlling the on-line rapid detection of the impedance spectrum and calculating the impedance spectrum, the microcontroller can receive the signals of an analog-to-digital conversion module (ADC) or has the function of analog-to-digital conversion, and is used for converting the analog signals obtained by sampling voltage and current into digital signals which can be used for calculation, and meanwhile, the controller has the digital IO signal output capability and is used for outputting bypass signals to a bypass module in a basic detection unit. The microcontroller can be independently arranged, and can also adopt the existing control devices in the original power supply system. The real-time voltage sampling signal and the real-time current sampling signal output by the power supply system are subjected to analog-to-digital conversion and then enter the microcontroller, and the microcontroller can output a bypass signal to the basic detection unit. The connection relation between the micro control and the basic detection unit connected in series is shown in fig. 3.
The impedance spectrum detection method based on the impedance spectrum online detection device comprises the following steps:
step 1, monitoring working current of a series power supply system, and selecting the working current to be large enough according to historical data or experience parameters of the power supply system, namely, detecting impedance spectrum when voltage response change of a single power supply in a tested unit caused by the working current change is more than 5 mV. Or after the microcontroller outputs the bypass signal, the single power supply voltage response change in the tested unit is monitored to be more than 5 mV.
Step 2, the microcontroller sends a bypass signal with a selected frequency fn, wherein the frequency fn is selected by engineering personnel in the frequency range of the impedance spectrum of the tested unit. Taking lithium ion battery impedance spectrum test as an example, the impedance spectrum frequency range of interest of the lithium ion battery is within [0.1Hz,1kHz ], and the frequencies can be selected as follows:
and 3, after the bypass signal is sent out, the microcontroller synchronously collects real-time current and real-time voltage signals of the power supply at the frequency fs. The acquisition frequency fs is at least 10 times of the bypass signal frequency fn.
Step 4, any periodic function can be expressed as the sum of direct current and infinite number formed by sine function or cosine function:
therefore, the sinusoidal signal quantity U (2 pi f) of the voltage and the current at the corresponding fn frequency point and the frequency of the voltage and the current at the frequency of the fn frequency point can be obtained by performing fast Fourier decomposition (FFT) on the voltage and the current signals caused by the bypass signals n )、I(2πf n ). For a linear system, the impedance at the frequency point can be further obtainedBy repeating the wave generation, detection and calculation processes, the impedance calculation of all fn frequency points and harmonic frequency points thereof can be completed, so that the required impedance spectrum is obtained.
Furthermore, since the amplitude of the fundamental frequency signal is the largest and the amplitude of the higher harmonic frequency is gradually reduced, in order to ensure the sampling precision, impedance spectrum is formed by only selecting the impedance of fundamental frequency and harmonic frequency points with the amplitude of the voltage signal being more than 5 mV.
Further, since the fast fourier transform requires real-time processing of large amounts of data, or storing large amounts of data for subsequent computation, extremely high demands are placed on the computing power and storage power of the microcontrol. And a large amount of data in the final calculation result is not satisfied with the signal amplitude requirement and is discarded, so that the microcontroller performance and the memory resource are wasted greatly. The Goertzel algorithm is therefore used in the calculation:
where g (k) is the kth current or voltage sampling result, x (k), x (k-1), and x (k-2) is the current, previous, and more previous calculation result, respectively. The algorithm can greatly reduce the calculated amount of the microcontroller, does not need to store data, and calculates the frequency point value in real time.
Furthermore, a Goertzel algorithm is adopted, limited secondary frequency is selected according to the response amplitude to calculate the voltage and current signals, and fundamental frequency, frequency multiplication and third harmonic are generally selected to calculate, so that the impedance spectrum calculation requirement is met, and the calculated amount is further reduced.
Claims (8)
1. The on-line rapid detection system for the impedance spectrum of the series power supply system is characterized by comprising a basic detection unit, a microcontroller and a detected unit; the tested unit is connected with the basic detection units in parallel, and M basic detection units are connected in series to form a series power supply system, wherein M is more than or equal to 1; the basic detection unit is connected with the microcontroller; an analog-to-digital conversion end ADC of the microcontroller receives a current signal and a voltage signal of the basic detection unit; the IO end of the microcontroller sends a bypass signal to the basic detection unit;
the basic detection unit comprises a multipath real-time voltage sampling module, a real-time current sampling module and a bypass device; the bypass device is connected in parallel between the positive and negative poles of the multipath real-time voltage sampling module and the real-time current sampling module; the multipath voltage sampling module at least comprises N paths of real-time voltage sampling input channels, wherein 1 path of real-time voltage sampling input channels are connected to 1 equivalent power supply, real-time acquisition processing is carried out on terminal voltages of the equivalent power supplies, and real-time voltage signals of the equivalent power supplies are output; each equivalent power supply in the tested unit is respectively connected with at least one path of voltage sampling channel in the multipath real-time voltage sampling module in the basic detection unit; the real-time current sampling module is in series connection with the unit to be tested, and can detect the real-time current value flowing through the unit to be tested; the real-time current sampling module comprises a current sensor and is used for collecting real-time current flowing through the equivalent power supplies connected in series;
the bypass device comprises a first bypass device, a second bypass device, a third bypass device or a fourth bypass device; the first bypass device comprises a controllable switch K1 and a diode D, wherein the anode of the diode D is connected with the V-end, the cathode of the diode D is connected with the Vout end, a bypass signal is connected with the control end of the K1, and the K1 is arranged between the port V+ and the cathode of the diode D; the second bypass device comprises controllable switches K2 and K3, a bypass signal is connected with the control end of the K2, the bypass signal is connected with the control end of the K3 after reverse, the K2 is arranged between the Vout end and the V+ end, and the K3 is arranged between the Vout end and the V-end; the third bypass device comprises a controllable switch K4, a bypass signal is connected with the control end of the switch K4, and the switch K4 is arranged between the Vout end and the V+ end; the fourth bypass device comprises a single-pole double-throw switch K5, a bypass signal is connected with the control end of the K5, the movable end of the single-pole double-throw switch K5 is connected with the Vout end, and the two fixed ends are respectively connected with the V+ end and the V-end.
2. The system for on-line rapid detection of impedance spectra of a series power supply system according to claim 1, wherein the unit to be detected is a system formed by connecting N equivalent power supplies in series, wherein N is greater than or equal to 1.
3. The system for on-line rapid detection of impedance spectra of a serial power supply system of claim 1, wherein the equivalent power supply is a parallel equivalent power supply of a single power supply or a plurality of power supplies.
4. The system of claim 1, wherein K1, K2, K3, and K4 are devices with controllable unidirectional or bidirectional switching capability, and specifically include transistors, darlington transistors, IGBTs, MOSFETs, relays, or reed switches.
5. The system for on-line rapid detection of impedance spectra of a serial power supply system according to claim 1, wherein when the bypass signal controls K1 to connect to the v+ terminal, or K2 to connect to the v+ terminal, and K3 to disconnect from the V-terminal, or K4 to connect to the v+ terminal, or K5 to switch to the v+ terminal, the bypass channel is disconnected, and current can only flow through the unit under test; when the bypass signal controls the K4 to be disconnected with the V+ end, current no longer flows through the tested unit; when the bypass signal controls the K1 to be disconnected with the V+ end or the V2 to be disconnected with the V+ end, and the K3 is connected with the V-end or the K5 is switched to the V-end, the current does not flow through the tested unit any more, but flows through the bypass.
6. The system for on-line rapid detection of impedance spectrum of serial power supply system according to claim 1, wherein the microcontroller is used as a carrier for performing control of on-line rapid detection of impedance spectrum and calculation of impedance spectrum, and the microcontroller can receive signals of the analog-to-digital conversion module ADC or has an analog-to-digital conversion function itself, and is used for converting analog signals obtained by sampling voltage and current into digital signals which can be used for calculation, and meanwhile, the controller has a digital IO signal output capability, and is used for outputting bypass signals to the bypass module in the basic detection unit.
7. A detection method of an online rapid detection system for impedance spectra of a serial power supply system, which is characterized by comprising the following steps based on the online rapid detection system for impedance spectra of the serial power supply system according to any one of claims 1 to 6:
step 1, monitoring working current of a series power supply system, selecting working condition operation impedance spectrum detection when voltage response change of a single power supply in a tested unit is more than 5mV due to current change of the series power supply system according to historical data or experience parameters of the power supply system, or monitoring operation impedance spectrum detection when voltage response change of the single power supply in the tested unit is more than 5mV after a microcontroller outputs a bypass signal;
step 2, the microcontroller sends out a periodic on-off bypass signal with a selected frequency fn, wherein the frequency fn is selected in the impedance spectrum frequency range of the unit to be tested;
step 3, after the bypass signal is sent out, the microcontroller collects real-time current and real-time voltage signals of the equivalent power supply at the frequency fs; the acquisition frequency fs is 10 times or more of the bypass signal frequency fn;
step 4, any periodic function f (t) can be expressed as a direct current and a frequency which are the periodic function frequency omega 0 The periodic function frequency is multiplied (nω 0 ) An infinite series of sine or cosine functions of (a):
for the periodicity of frequency fnThe voltage and current signal is subjected to fast Fourier decomposition (FFT) to obtain sine and cosine signal components U (2 pi f) of the voltage and current at the corresponding fn frequency point and the frequency times thereof n )、I(2πf n ) The method comprises the steps of carrying out a first treatment on the surface of the Further, the impedance at the frequency point is obtainedAnd (3) repeating the wave generation, detection and calculation processes to finish the impedance calculation of all fn frequency points and harmonic frequency points thereof, thereby obtaining the required impedance spectrum.
8. The detection method of the on-line rapid detection system for impedance spectra of a serial power supply system according to claim 7, wherein the calculation adopts a Goertzel algorithm in addition to the FFT algorithm:
where f (k) is the kth current or voltage sampling result, x (k), x (k-1), and x (k-2) is the current, previous, and more previous calculation result, respectively.
Priority Applications (1)
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| CN109459465A (en) * | 2018-12-12 | 2019-03-12 | 浙江大学 | A kind of fast electrochemical impedance spectrum measurement method based on current impulse injection |
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| CN111580006A (en) * | 2020-05-29 | 2020-08-25 | 中国电力科学研究院有限公司 | Online measurement method and system for dynamic impedance of battery |
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| KR20140071825A (en) * | 2012-12-04 | 2014-06-12 | (주)세네카 | The Device of Detecting the Error condition of the Solar module |
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| CN109459465A (en) * | 2018-12-12 | 2019-03-12 | 浙江大学 | A kind of fast electrochemical impedance spectrum measurement method based on current impulse injection |
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