An online measurement system, method, device and medium for supercapacitor energy storage impedance spectrum based on a balancing system

Abstract

The present invention discloses an online measurement system, method, device and medium for supercapacitor energy storage impedance spectrum based on a balancing system, which relates to the field of power system energy storage, including a supercapacitor energy storage cluster consisting of N supercapacitor energy storage modules and an electrical box connected in series; the supercapacitor energy storage module consists 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 is finally connected to the FPGA system in the electrical box. 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, promptly discover problems in production, and avoid the loss caused by discovering problems after the product has been completed in offline measurement.

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, device and medium for supercapacitor energy storage impedance spectrum based on a balancing system. Background Art

[0002] Electrochemical impedance spectroscopy is a research method for studying 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 sweeping, the measurement process is time-consuming, and it is impossible to achieve real-time impedance identification of the battery in the working state, and cannot meet the demand for real-time monitoring of the battery status during operation. Therefore, the online measurement method of electrochemical impedance spectroscopy has become the current research direction. At present, the industry has proposed an online measurement scheme for electrochemical impedance spectroscopy, but due to the high cost, it cannot be implemented in practical applications. In view of the characteristics of the supercapacitor energy storage system, 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 this invention is that offline impedance spectroscopy measurement technology requires continuous AC signal frequency sweeping, which is time-consuming and cannot achieve real-time impedance identification of the battery under working conditions. Existing online measurement solutions, however, are expensive and cannot be implemented in practical applications.

[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, which includes: a supercapacitor energy storage cluster is composed of N supercapacitor energy storage modules and an electrical 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 electrical 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 R2.

[0006] As a preferred solution of the online measurement system for 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 cell in the supercapacitor energy storage module through the GPIO interface to obtain the voltage signal of the supercapacitor cell.

[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 cells in the supercapacitor energy storage module are marked as supercapacitor cells No. 1, No. 2, No. 3... No. m 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], representing 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.

[0008] To solve the above technical problems, the present invention provides the following technical solutions: an online measurement method for the impedance spectrum of supercapacitor energy storage based on a balancing system, comprising: when the balancing system is operating 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 to be turned off; when the balancing system is switched to be used for online impedance spectrum measurement, 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 supercapacitor cells to calculate the real part and the imaginary part of the impedance; and transmits the real part and the imaginary part of the impedance to the FPGA system for data analysis.

[0009] As a preferred embodiment of the online measurement method of the supercapacitor energy storage impedance spectrum based on the 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 embodiment of the method for an online measurement system for the impedance spectrum of a supercapacitor energy storage system based on a balancing system according to the present invention, the calculation of the real part of the impedance and the imaginary part of the impedance includes: when the calibration is completed, the BMS system turns off the MOSFET marked as c and begins to perform an impedance spectrum scan on the supercapacitor cells in the supercapacitor energy storage module from number 1 to number m in the order of connection; for the supercapacitor cell numbered m, the BMS system triggers the conduction of the mp and mn MOSFETs, and at the same time, the BMS system collects the voltage Um across the supercapacitor cell numbered m, with a phase angle of φm;

[0011] The real part of the impedance is calculated to be Um / U0×R0×cos(φm-φ0), and the imaginary part of the impedance is Um / U0×R0×sin(φm-φ0).

[0012] As a preferred solution of the online measurement method of the supercapacitor energy storage impedance spectrum based on the balancing system described in the present invention, the transmission of the real part and the imaginary part of the impedance to the FPGA system for data analysis includes the BMS system transmitting the frequency point and the real part and the imaginary part of the impedance at the current frequency point to the FPGA system in the electrical box through the SPI bus. The FPGA system summarizes the impedance spectra of the supercapacitor cells in the supercapacitor energy storage cluster and uses them for data analysis to obtain the current state of the battery.

[0013] A computer device includes 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.

[0014] 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.

[0015] The beneficial effects of the present invention are as follows: compared with the offline impedance spectrum measurement system, the online measurement system proposed in the present invention can obtain data in real time during the production process, promptly discover problems in production, 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 large amounts 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.

[0016] Existing online impedance spectrum measurement methods based on the battery balancing process can collect real-time voltage and current information of each single cell, as well as key data such as the switching frequency of the switching tube, during the battery balancing process. The impedance spectrum calculated using this 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 balancing control strategy, the balancing current size, and the data acquisition accuracy, and may not 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, thereby achieving the same accuracy as professional electrochemical workstation measurements under laboratory conditions. At the same time, the sine wave generator is time-shared and reused through the balancing system, thereby greatly reducing the cost of deploying an impedance spectrum online measurement system on site. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] 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.

[0019] 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

[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0021] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. 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.

[0022] Example 1, with reference to Figure 1 and Figure 2 , which is the first embodiment of the present invention, provides a supercapacitor energy storage impedance spectrum online measurement system based on a balancing system, including: Figure 1 As shown in FIG, the supercapacitor energy storage cluster is composed of N supercapacitor energy storage modules and an electrical box connected in series.

[0023] The supercapacitor energy storage module consists of a supercapacitor energy storage module, a BMS system, and a balancing system. The BMS system, or Battery Management System, is primarily used to monitor, manage, and protect the battery pack, ensuring its safe and efficient operation and extending its service life.

[0024] Each supercapacitor energy storage module in the N supercapacitor energy storage modules in the supercapacitor energy storage cluster is connected in series.

[0025] 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 the SPI bus, and is ultimately connected to the FPGA system in the electrical box.

[0026] 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.

[0027] 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. Among them, the chip selected in the present invention is the E9963 chip.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] The gates of the MOSFETs marked b and c are connected to the chip controller of the BMS system.

[0032] The positive electrode and 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 resistors R1 and R2. The resistance of R1 and R2 can be 100 milliohms.

[0033] The present invention adopts the test conditions of adding an external sine wave generator under simulated laboratory conditions, thereby achieving the same accuracy as the measurement of a professional electrochemical workstation 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.

[0034] The supercapacitor cells in the supercapacitor energy storage module are marked as supercapacitor cells No. 1, No. 2, No. 3, ..., No. m in the order of connection, where m is the total number of supercapacitor cells.

[0035] 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], representing the xth supercapacitor cell.

[0036] For supercapacitor cells No. 1, No. 2, No. 3, ..., m, the gates of the corresponding MOSFETs marked as xp and xn are connected to the chip controller of the BMS system.

[0037] Example 2 is the second embodiment of the present invention, which differs 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 operates normally in voltage balancing mode, the BMS system triggers the MOSFET marked as b to turn on and simultaneously turns off the MOSFET marked as c.

[0038] When the balancing system is switched to online impedance spectrum measurement, the BMS system turns off the MOSFET marked with b and simultaneously triggers the MOSFET marked with c to turn on. The specific steps of online impedance spectrum measurement include:

[0039] Step 1: Collect the voltage across the calibration resistor R0 and calculate the current and phase angle of the multi-sine wave generator.

[0040] After the MOSFET marked as c is triggered to turn on, 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. The BMS system collects the voltage across the calibration resistor and obtains the voltage U0 of the calibration resistor at each frequency point. It then calculates the current I0 and phase angle φ0 of the multi-sine wave generator. The calculation formula for current I0 is U0 / R0.

[0041] Step 2: The BMS system turns off the MOSFET marked as c, and sequentially scans the impedance spectrum of the supercapacitor cells to calculate the real and imaginary impedance parts.

[0042] 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 cells in the supercapacitor energy storage module from No. 1 to No. m in the order of connection.

[0043] 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.

[0044] The real part of the impedance is calculated to be Um / U0×R0×cos(φm-φ0), and the imaginary part of the impedance is Um / U0×R0×sin(φm-φ0).

[0045] Step 3: Transmit the real part of the impedance and the imaginary part of the impedance to the FPGA system for data analysis.

[0046] 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 electrical box through the SPI bus. The FPGA system summarizes the impedance spectrum of the supercapacitor cells in the supercapacitor energy storage cluster and uses it for data analysis to obtain the current status of the battery.

[0047] Example 3, the third embodiment of the present invention, differs from the previous two embodiments in that, if the functions described are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product, stored in a storage medium, includes instructions for causing a computer device (such as a personal computer, server, or network device) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage media include various media capable of storing program code, such as USB flash drives, mobile hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical disks.

[0048] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0049] More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic devices), 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 disc read-only memory (CDROM). In addition, the computer-readable medium may even be 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, and then editing, interpreting, or processing in another suitable manner as necessary, and then storing it in a computer memory.

[0050] It should be understood that various components of the present invention may be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods may be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof may be used: a discrete logic circuit having logic gate circuits for implementing logic functions on data signals, an application-specific integrated circuit having suitable combinational logic gate circuits, a programmable gate array (PGA), a field-programmable gate array (FPGA), etc.

[0051] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. 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 balancing system, characterized by: include, The supercapacitor energy storage cluster consists of N supercapacitor energy storage modules and an electrical box connected in series; The supercapacitor energy storage module consists 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 format using the SPI bus, and is ultimately connected to the FPGA system in the electrical 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 the 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 balancing 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 the voltage signal of the supercapacitor cell.

3. The online measurement system for supercapacitor energy storage impedance spectrum based on a balancing system according to claim 2, characterized in that: The supercapacitor cells in the supercapacitor energy storage module are marked as supercapacitor cells No. 1, No. 2, No. 3... No. m in the order of connection, where m is the total number of supercapacitor cells; 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 cells No. 1, No. 2, No. 3, ..., 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 according to any one of claims 1 to 3, characterized in that: Including, when the balancing system is working 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 simultaneously triggers the MOSFET marked with c to turn on. The voltage across the calibration resistor R0 is collected and the current and phase angle of the multi-sine wave generator are calculated. The BMS system turns off the MOSFET marked as c and scans the impedance spectrum of the supercapacitor cells in sequence to calculate the real and imaginary impedance parts. The real and imaginary impedance parts are transmitted to the FPGA system for data analysis.

5. The method for online measurement of supercapacitor energy storage impedance spectrum based on a balancing system according to claim 4, characterized in that: 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, 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 balancing 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: 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 cells in the supercapacitor energy storage module from number 1 to number m in the order of connection; For the supercapacitor monomer numbered m, the BMS system triggers the conduction of 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; The real part of the impedance is calculated to be 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 transmitting the frequency point and the real part and the imaginary part of the impedance at the current frequency point to the FPGA system in the electrical box through the SPI bus. The FPGA system summarizes the impedance spectrum of the supercapacitor cells 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 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.

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