Online measurement system, method and equipment for energy storage impedance spectroscopy of super capacitor based on equalization system, and medium

Abstract

The invention discloses a super-capacitor energy storage impedance spectroscopy online measurement system, method and device based on an equalization system and a medium, and relates to the field of power system energy storage, and the system comprises a super-capacitor energy storage cluster which is formed by connecting N super-capacitor energy storage modules and an electric box in series; the super-capacitor energy storage module is composed of a super-capacitor energy storage module, a BMS system and an equalization system. The super-capacitor energy storage modules in the N super-capacitor energy storage modules in the super-capacitor energy storage cluster are connected in series; the BMS systems in the N super-capacitor energy storage modules in the super-capacitor energy storage cluster are connected in series in a daisy chain mode in an SPI bus mode and are finally connected with the FPGA system in the electric box. Compared with an off-line impedance spectroscopy measurement system, the on-line measurement system provided by the invention can obtain data in real time in the production process, timely discover problems in the production process, and avoid loss caused by the fact that the problems are found only when the product is produced in the off-line measurement process.

Description

Technical Field

[0001] The present invention relates to the field of power system energy storage, and in particular to an online measurement system, method, equipment and medium for supercapacitor energy storage impedance spectrum based on a balancing system. Background Art

[0002] Electrochemical impedance spectroscopy is a research method that studies the processes occurring in electrochemical systems by measuring electrical quantities. It is divided into offline measurement methods and online measurement methods. Offline impedance spectroscopy measurement technology requires continuous AC signal frequency sweeping, and the measurement process is time-consuming. It is also unable to achieve real-time impedance identification of the battery under working conditions, and is unable to meet the demand for real-time monitoring of the battery status during operation. Therefore, online measurement methods of electrochemical impedance spectroscopy have become the current research direction. Currently, an online measurement scheme for electrochemical impedance spectroscopy has been proposed in the industry, but due to its high cost, it cannot be implemented in practical applications. Aiming at the characteristics of supercapacitor energy storage systems, the present invention proposes an online impedance spectrum measurement method based on its equalization system, which has low cost and better effect in practical applications. Summary of the invention

[0003] In view of the above-mentioned problems, the present invention is proposed.

[0004] Therefore, the problem to be solved by the present invention is that the offline impedance spectrum measurement technology requires continuous AC signal frequency sweeping, the measurement process is time-consuming, and it is impossible to realize the real-time impedance identification of the battery in the working state. The existing online measurement solution, however, cannot be implemented in practical applications due to its high cost.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: an online measurement system for supercapacitor energy storage impedance spectrum based on a balancing system, comprising: a supercapacitor energy storage cluster is composed of N supercapacitor energy storage modules and an electric box connected in series; the supercapacitor energy storage module is composed of a supercapacitor energy storage module, a BMS system and a balancing system; each supercapacitor energy storage module in the N supercapacitor energy storage modules in the supercapacitor energy storage cluster is connected in series; each BMS system in the N supercapacitor energy storage modules in the supercapacitor energy storage cluster is connected in series in the form of a daisy chain using an SPI bus, and finally connected to the FPG in the electric box. A system is connected; a positive DC bus and a negative DC bus are provided in the balancing system, the positive electrode of the balancing capacitor is connected to the positive DC bus through a MOSFET marked as b, and the negative electrode is directly connected to the negative DC bus; a calibration resistor R0 is provided in the balancing system, the positive electrode of the calibration resistor is connected to the positive DC bus through a MOSFET marked as c, and the negative electrode is directly connected to the negative DC bus; the gates of the MOSFETs marked as b and c are connected to the chip controller of the BMS system; the positive and negative electrodes of the multi-sine wave generator in the balancing system are connected to the positive DC bus and the negative DC bus respectively through resistors R1 and resistor R2.

[0006] As a preferred solution of the online measurement system of supercapacitor energy storage impedance spectrum based on the balancing system described in the present invention, the chip in the BMS system is connected to both ends of each supercapacitor monomer in the supercapacitor energy storage module through the GPIO interface to obtain the voltage signal of the supercapacitor monomer.

[0007] As a preferred solution of the online measurement system of supercapacitor energy storage impedance spectrum based on the balancing system described in the present invention, the supercapacitor monomers in the supercapacitor energy storage module are marked as No. 1, No. 2, No. 3... No. m supercapacitor monomers in the connection order, and m is the total number of supercapacitor monomers; the positive electrode of each supercapacitor monomer is connected to the positive DC bus in the balancing system through a MOSFET marked as xp, and is connected to the negative DC bus in the balancing system through a MOSFET marked as xn, where x∈[1, m], representing the xth supercapacitor monomer; for supercapacitor monomers No. 1, No. 2, No. 3... No. m, the gates of the corresponding MOSFETs marked as xp and xn are connected to the chip controller of the BMS system.

[0008] To solve the above technical problems, the present invention provides the following technical solutions: an online measurement method for supercapacitor energy storage impedance spectrum based on a balancing system, comprising: when the balancing system works normally in a voltage balancing mode, the BMS system triggers the MOSFET marked as b to be turned on, and the MOSFET marked as c is turned off at the same time; when the balancing system is switched to be used for online measurement of the impedance spectrum, the BMS system turns off the MOSFET marked as b, and triggers the MOSFET marked as c to be turned on, collects the voltage across the calibration resistor R0, and calculates the current and phase angle of the multi-sine wave generator; the BMS system turns off the MOSFET marked as c, and sequentially scans the impedance spectrum of the supercapacitor monomers to calculate the real part and the imaginary part of the impedance; the real part and the imaginary part of the impedance are transmitted to the FPGA system for data analysis.

[0009] As a preferred embodiment of the online measurement method of supercapacitor energy storage impedance spectrum based on a balancing system described in the present invention, the calculation of the current and phase angle of the multi-sine wave generator includes: after triggering the MOSFET marked as c, the multi-sine wave generator simultaneously generates sinusoidal currents with frequencies of 0.1 Hz, 1 Hz, 10 Hz, 100 Hz and 1000 Hz, flowing through the calibration resistor R0, the BMS system collects the voltage across the calibration resistor, obtains the voltage U0 of the calibration resistor at each frequency point, and then calculates the current I0 and phase angle φ0 of the multi-sine wave generator, and the calculation formula of the current I0 is U0 / R0.

[0010] As a preferred solution of the method of the supercapacitor energy storage impedance spectrum online measurement system based on the balancing system described in the present invention, wherein: the calculation of the real part of the impedance and the imaginary part of the impedance includes that when the calibration is completed, the BMS system turns off the MOSFET marked as c, and starts to scan the impedance spectrum of the supercapacitor monomers in the supercapacitor energy storage module from No. 1 to No. m in the connection order; for the supercapacitor monomer numbered m, the BMS system triggers the conduction of mp and mn MOSFETs, and at the same time, the BMS system collects the voltage Um across the supercapacitor monomer numbered m, with a phase angle of φm; Through calculation, the real part of the impedance is Um / U0×R0×cos(φm-φ0), and the imaginary part of the impedance is Um / U0×R0×sin(φm-φ0).

[0011] As a preferred solution of the online measurement method of supercapacitor energy storage impedance spectrum based on the balancing system described in the present invention, the transmission of the real part of the impedance and the imaginary part of the impedance to the FPGA system for data analysis includes: the BMS system transmits the real part of the impedance and the imaginary part of the impedance at the frequency point and the current frequency point to the FPGA system in the electrical box through the SPI bus, and the FPGA system summarizes the impedance spectra of the supercapacitor monomers in the supercapacitor energy storage cluster, and uses it for data analysis to obtain the current state of the battery.

[0012] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of the above-mentioned method for online measurement of supercapacitor energy storage impedance spectrum based on a balancing system are implemented.

[0013] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the above-mentioned method for online measurement of supercapacitor energy storage impedance spectrum based on a balancing system.

[0014] The beneficial effects of the present invention are as follows: compared with the offline impedance spectrum measurement system, the online measurement system proposed by the present invention can obtain data in real time during the production process, discover problems in production in time, and avoid losses caused by discovering problems after the product has been completed in offline measurement. The online measurement system is usually equipped with automated data processing and analysis software, which can quickly and accurately process and analyze a large amount of measurement data, thereby improving work efficiency. The online measurement system can operate in an actual production environment and adapt to dynamically changing production conditions, while offline measurements are usually carried out in a relatively stable laboratory environment and may not fully reflect the actual production situation.

[0015] The existing online impedance spectrum measurement method based on the battery equalization process can collect the voltage and current information of each single cell, as well as key data such as the switching frequency of the switch tube in real time during the battery equalization process. The impedance spectrum calculated using these data can more accurately reflect the impedance characteristics of the battery under actual operating conditions. Although online measurement can be achieved, the measurement accuracy may be affected by factors such as the battery pack equalization control strategy, the equalization current size, and the data acquisition accuracy, and may not be able to achieve the accuracy of professional electrochemical workstation measurements under laboratory conditions. The present invention still simulates the test conditions of using an external sine wave generator under laboratory conditions, so that it can achieve the same accuracy as the professional electrochemical workstation measurements under laboratory conditions. At the same time, the time-sharing multiplexing of the sine wave generator is realized through the equalization system, thereby greatly reducing the cost of deploying the impedance spectrum online measurement system on site. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0017] Figure 1 This is a structural diagram of a supercapacitor energy storage cluster of an online measurement system for supercapacitor energy storage impedance spectrum based on a balancing system in Example 1.

[0018] Figure 2 This is a structural diagram of a supercapacitor energy storage module of an online measurement system for supercapacitor energy storage impedance spectrum based on a balancing system in Example 1. DETAILED DESCRIPTION

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0020] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0021] Example 1, reference Figure 1 and Figure 2 , which is the first embodiment of the present invention, and which provides an online measurement system for supercapacitor energy storage impedance spectrum based on a balancing system, including: Figure 1 As shown, the supercapacitor energy storage cluster is composed of N supercapacitor energy storage modules and an electric box connected in series.

[0022] The supercapacitor energy storage module is composed of a supercapacitor energy storage module, a BMS system and a balancing system. Among them, the BMS system is a Battery Management System, which is mainly used to monitor, manage and protect the battery pack to ensure its safe and efficient operation and extend its service life.

[0023] Each supercapacitor energy storage module in the N supercapacitor energy storage modules in the supercapacitor energy storage cluster is connected in series.

[0024] Each BMS system in the N supercapacitor energy storage modules in the supercapacitor energy storage cluster is connected in series in a daisy chain form using an SPI bus, and is ultimately connected to the FPGA system in the electrical box.

[0025] To further explain, FPGA system refers to Field-Programmable Gate Array. FPGA is a programmable logic chip that can be configured by the user after manufacturing to achieve specific logic functions. It has the advantages of high flexibility, short development cycle and high parallel computing efficiency.

[0026] The chip in the BMS system is connected to both ends of each supercapacitor cell in the supercapacitor energy storage module through a GPIO interface to obtain the voltage signal of the supercapacitor cell, wherein the chip selected in the present invention is the E9963 chip.

[0027] The balancing system is provided with a positive DC bus and a negative DC bus. The positive electrode of the balancing capacitor is connected to the positive DC bus through a MOSFET marked as b, and the negative electrode is directly connected to the negative DC bus. Figure 2 shown.

[0028] Among them, MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), that is, metal oxide semiconductor field effect transistor, is a widely used semiconductor device that adopts voltage control and has the advantages of high input impedance, low power consumption, fast switching speed and good thermal stability.

[0029] A calibration resistor R0 is set in the balancing system, the positive electrode of the calibration resistor is connected to the positive DC bus through a MOSFET marked as c, and the negative electrode is directly connected to the negative DC bus.

[0030] The gates of the MOSFETs marked b and c are connected to the chip controller of the BMS system.

[0031] The positive electrode and the negative electrode of the multi-sine wave generator in the balancing system are connected to the positive DC bus and the negative DC bus respectively through the resistor R1 and the resistor R2. The resistors R1 and R2 can be selected to have a resistance value of 100 milliohms.

[0032] The present invention adopts the test condition of adding an external sine wave generator under simulated laboratory conditions, so as to achieve the same accuracy as that of professional electrochemical workstation measurements under laboratory conditions. At the same time, the time-sharing multiplexing of the sine wave generator is realized through the balancing system, thereby greatly reducing the cost of on-site deployment of the impedance spectrum online measurement system.

[0033] The supercapacitor cells in the supercapacitor energy storage module are marked as No. 1, No. 2, No. 3, ... No. m supercapacitor cells in the order of connection, where m is the total number of supercapacitor cells.

[0034] The positive electrode of each supercapacitor cell is connected to the positive DC bus in the balancing system through a MOSFET marked as xp, and is connected to the negative DC bus in the balancing system through a MOSFET marked as xn, where x∈[1,m], indicating the xth supercapacitor cell.

[0035] For supercapacitor cells No. 1, No. 2, No. 3, ..., No. m, the gates of the corresponding MOSFETs marked as xp and xn are connected to the chip controller of the BMS system.

[0036] Embodiment 2 is the second embodiment of the present invention, which is different from the first embodiment in that: an online measurement method for supercapacitor energy storage impedance spectrum based on a balancing system includes: when the balancing system works normally in a voltage balancing mode, the BMS system triggers the MOSFET marked as b to be turned on, and at the same time turns off the MOSFET marked as c.

[0037] When the balancing system is switched to the online impedance spectrum measurement, the BMS system turns off the MOSFET marked with b and triggers the MOSFET marked with c to turn on. The specific steps of the online impedance spectrum measurement include: Step 1: Collect the voltage across the calibration resistor R0 and calculate the current and phase angle of the multi-sine wave generator.

[0038] After triggering the MOSFET marked as c, the multi-sine wave generator simultaneously generates sinusoidal currents with frequencies of 0.1Hz, 1Hz, 10Hz, 100Hz and 1000Hz, which flow through the calibration resistor R0. The BMS system collects the voltage across the calibration resistor and obtains the voltage U0 of the calibration resistor at each frequency point, and then calculates the current I0 and phase angle φ0 of the multi-sine wave generator. The calculation formula for current I0 is U0 / R0.

[0039] Step 2: The BMS system turns off the MOSFET marked as c, and sequentially scans the impedance spectrum of the supercapacitor monomers to calculate the real impedance and the imaginary impedance.

[0040] When the calibration is completed, the BMS system turns off the MOSFET marked as c and starts to perform impedance spectrum scanning on the supercapacitor monomers in the supercapacitor energy storage module from No. 1 to No. m in the order of connection.

[0041] For the supercapacitor monomer numbered m, the BMS system triggers to turn on the mp and mn MOSFETs. At the same time, the BMS system collects the voltage Um across the supercapacitor monomer numbered m, with a phase angle of φm.

[0042] Through calculation, the real part of the impedance is Um / U0×R0×cos(φm-φ0), and the imaginary part of the impedance is Um / U0×R0×sin(φm-φ0).

[0043] Step 3: Transmit the real part of the impedance and the imaginary part of the impedance to the FPGA system for data analysis.

[0044] The BMS system transmits the frequency point and the real and imaginary impedance parts at the current frequency point to the FPGA system in the power box through the SPI bus. The FPGA system summarizes the impedance spectra of the supercapacitor cells in the supercapacitor energy storage cluster and uses the data for analysis to obtain the current state of the battery.

[0045] Embodiment 3 is the third embodiment of the present invention, which is different from the first two embodiments in that: if the function is implemented in the form of a software function unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0046] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0047] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0048] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0049] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. An online measurement system for supercapacitor energy storage impedance spectrum based on a balanced system, characterized in that: include, The supercapacitor energy storage cluster is composed of N supercapacitor energy storage modules and an electric box connected in series; The supercapacitor energy storage module is composed of a supercapacitor energy storage module, a BMS system and a balancing system; Each supercapacitor energy storage module in the N supercapacitor energy storage modules in the supercapacitor energy storage cluster is connected in series; Each BMS system in the N supercapacitor energy storage modules in the supercapacitor energy storage cluster is connected in series in a daisy chain form using an SPI bus, and is ultimately connected to the FPGA system in the electric box; The balancing system is provided with a positive DC bus and a negative DC bus, the positive electrode of the balancing capacitor is connected to the positive DC bus through a MOSFET marked as b, and the negative electrode is directly connected to the negative DC bus; A calibration resistor R0 is set in the balancing system, the positive electrode of the calibration resistor is connected to the positive DC bus through a MOSFET marked as c, and the negative electrode is directly connected to the negative DC bus; The gates of the MOSFETs marked b and c are connected to the chip controller of the BMS system; The positive electrode and the negative electrode of the multi-sine wave generator in the balancing system are connected to the positive DC bus and the negative DC bus through the resistor R1 and the resistor R2 respectively.

2. The online measurement system for supercapacitor energy storage impedance spectrum based on a balanced system according to claim 1, characterized in that: The chip in the BMS system is connected to both ends of each supercapacitor cell in the supercapacitor energy storage module through a GPIO interface to obtain a voltage signal of the supercapacitor cell.

3. The online measurement system for supercapacitor energy storage impedance spectrum based on a balanced system according to claim 2, characterized in that: The supercapacitor cells in the supercapacitor energy storage module are marked as No. 1, No. 2, No. 3, ... No. m supercapacitor cells in the order of connection, where m is the total number of supercapacitor cells; The positive electrode of each supercapacitor cell is connected to the positive DC bus in the balancing system through a MOSFET marked as xp, and is connected to the negative DC bus in the balancing system through a MOSFET marked as xn, where x∈[1,m], indicating the xth supercapacitor cell; For supercapacitor cells No. 1, No. 2, No. 3, ..., No. m, the gates of the corresponding MOSFETs marked as xp and xn are connected to the chip controller of the BMS system.

4. A method for online measurement of supercapacitor energy storage impedance spectrum based on a balanced system, using the online measurement system for supercapacitor energy storage impedance spectrum based on a balanced system as claimed in any one of claims 1 to 3, characterized in that: Including, when the balancing system works normally in the voltage balancing mode, the BMS system triggers to turn on the MOSFET marked with b and turns off the MOSFET marked with c; When the balancing system is switched to online impedance spectrum measurement, the BMS system turns off the MOSFET marked with b and triggers the MOSFET marked with c to turn on, collects the voltage across the calibration resistor R0, and calculates the current and phase angle of the multi-sine wave generator; The BMS system turns off the MOSFET marked as c, and scans the impedance spectrum of the supercapacitor monomers in sequence, and calculates the real and imaginary impedance parts; The real impedance and imaginary impedance transmission FPGA system is used for data analysis.

5. The method for online measurement of supercapacitor energy storage impedance spectrum based on a balanced system according to claim 4, characterized in that: The calculation of the current and phase angle of the multi-sine wave generator includes that after triggering the MOSFET marked as c, the multi-sine wave generator simultaneously generates sinusoidal currents with frequencies of 0.1 Hz, 1 Hz, 10 Hz, 100 Hz and 1000 Hz, which flow through the calibration resistor R0, and the BMS system collects the voltage across the calibration resistor to obtain the voltage U0 of the calibration resistor at each frequency point, and then calculates the current I0 and phase angle φ0 of the multi-sine wave generator. The calculation formula of the current I0 is U0 / R0.

6. The method for online measurement of supercapacitor energy storage impedance spectrum based on a balanced system according to claim 5, characterized in that: The calculation of the real part of the impedance and the imaginary part of the impedance includes that when the calibration is completed, the BMS system turns off the MOSFET marked as c, and starts to perform impedance spectrum scanning on the supercapacitor monomers in the supercapacitor energy storage module from No. 1 to No. m in the connection order; For the supercapacitor monomer numbered m, the BMS system triggers the mp and mn MOSFETs to turn on. At the same time, the BMS system collects the voltage Um across the supercapacitor monomer numbered m, with a phase angle of φm; Through calculation, the real part of the impedance is Um / U0×R0×cos(φm-φ0), and the imaginary part of the impedance is Um / U0×R0×sin(φm-φ0).

7. The method for online measurement of supercapacitor energy storage impedance spectrum based on a balancing system according to claim 6, characterized in that: The transmission of the real part and the imaginary part of the impedance to the FPGA system for data analysis includes: the BMS system transmits the real part and the imaginary part of the impedance at the frequency point and the current frequency point to the FPGA system in the power box through the SPI bus, and the FPGA system summarizes the impedance spectrum of the supercapacitor monomers in the supercapacitor energy storage cluster and uses it for data analysis to obtain the current state of the battery.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the online measurement method of supercapacitor energy storage impedance spectrum based on a balancing system according to any one of claims 4 to 7 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of an online measurement method for supercapacitor energy storage impedance spectrum based on a balancing system according to any one of claims 4 to 7 are implemented.

Images