A ripple communication based adjacent battery energy equalization system

Abstract

This invention provides an adjacent battery energy balancing system based on ripple communication, comprising multiple energy balancing units. Each unit includes a signal sampling and conditioning module, a demodulation module, and a control module. Two adjacent units communicate using the voltage or current ripple of a shared battery. This system eliminates the need for additional communication cables, achieving low-latency and high-reliability communication between balancing systems. The communication data can be used for lithium battery state monitoring, control, and protection, and communication control is decoupled from power control. Furthermore, this system supports various data modulation methods, including FSK, PSK, DPSK, and FH-DPSK modulation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of intelligent battery management, and particularly relates to an adjacent battery energy equalization system based on ripple communication. BACKGROUND

[0002] Modern life cannot be separated from electricity, and traditional fossil energy power generation has problems such as environmental pollution and non-sustainability, so using renewable energy to replace fossil energy for power generation is the development goal of the power industry. Lithium batteries have become a key link for energy storage in the new energy industry due to their high energy density. For safety reasons, the capacity of a single lithium battery is not large, and single lithium batteries are generally connected in series and parallel to supply power externally. Lithium batteries are affected by production factors such as process, material, and electrolyte density during production, and are affected by external factors such as temperature, humidity, and vibration during use, and gradually become inconsistent. The inconsistency of lithium batteries gradually increases with the use of the battery, thereby reducing the reliability, battery performance, and service life of the lithium battery. In order to solve the problem of poor consistency of lithium batteries, a battery equalization system needs to be added to fully utilize the performance of single batteries and improve the service life of the battery. In addition, in order to realize the functions of detection, protection, and control, communication needs to be carried out inside the battery management system, which will increase the communication cable and require additional communication circuit, thereby increasing the complexity of the system.

[0003] According to the topology structure of the battery equalization system, it can be divided into centralized equalization system and distributed equalization system. The centralized equalization system uses the energy of the entire battery string to equalize each single battery, and the equalization speed is fast, but each time only a single battery can be equalized, and with the increase of the number of batteries, the complexity of the cable increases, making the scalability of this topology poor. The distributed equalization system can parallelly equalize the battery capacity, and has good scalability.

[0004] The communication of the existing battery equalization system relies on a special communication line. With the increase in the number of batteries, the communication cable also increases. On the one hand, the communication cable occupies space and increases the complexity of the system, and on the other hand, with the aging of the cable, safety problems may occur. Therefore, if the ripple generated during the operation of the battery equalization system is used for communication, the communication cable can be removed, the complexity of the system can be reduced, and the safety and reliability of the system can be improved. SUMMARY

[0005] In view of the above, the application provides an adjacent battery energy equalization system based on ripple communication, which does not require additional communication cables and can realize low-latency and high-reliable communication between equalization systems.

[0006] An adjacent battery energy balancing system based on ripple communication includes multiple energy balancing units for energy balancing control of battery strings. Each battery string consists of multiple batteries connected in series, and any pair of adjacent batteries is controlled by its corresponding energy balancing unit. If battery C... i The preamp is battery C i-1 The subsequent stage is battery C. i+1 Adjacent battery C i-1 and C i Controlled by energy balancing unit A, adjacent battery C i and C i+1 Controlled by energy balancing unit B, energy balancing units A and B are adjacent to each other, C i If energy balancing units A and B share a common controlled battery, then energy balancing units A and B utilize the common controlled battery C. i The voltage or current ripple is used for communication, where i is the battery serial number.

[0007] Furthermore, the energy equalization unit includes a signal sampling and conditioning module, a demodulation module, and a control module, wherein:

[0008] The signal sampling and conditioning module is used to collect the voltage and current of two adjacent batteries controlled by the energy equalization unit, and output the DC component of the voltage or current after filtering to the control module for power control, and output the AC ripple component of the voltage or current after filtering to the demodulation module for data demodulation and reception.

[0009] The demodulation module demodulates the AC ripple component through circuitry or algorithms to achieve the reception of communication data.

[0010] The control module is connected to two adjacent batteries controlled by the energy balancing unit. It calculates the remaining power of the battery based on the DC component of the battery voltage or current, and then controls the energy transfer between the two adjacent batteries based on the remaining power information of the two batteries and the data information received by the demodulation module. It also modulates the data to be transmitted onto the voltage ripple or current ripple of the corresponding battery.

[0011] Furthermore, the control module is a bidirectional DC / DC converter, and its topology can adopt Buck-Boost or bidirectional flyback circuit, etc.

[0012] Furthermore, the demodulation module can be implemented using discrete circuits, or it can be implemented using (or partially using) MCU, FPGA, CPLD or application-specific integrated circuits.

[0013] Furthermore, the control module employs power information fusion regulation technology to modulate the data to be transmitted onto the voltage ripple or current ripple of the corresponding battery to send the data to the adjacent energy equalization unit. The specific implementation of the power information fusion regulation technology is as follows: by changing the duty cycle of the switching device drive signal in the control module, the energy transfer between two adjacent batteries is controlled, and at the same time, by changing the frequency or phase of the switching device drive signal, the data to be transmitted is modulated onto the voltage ripple or current ripple of the corresponding battery to send the data to the adjacent energy equalization unit.

[0014] Furthermore, the control module employs power information fusion modulation technology to modulate data in ways including FSK (Frequency-Shift Keying), PSK (Phase-Shift Keying), DPSK (Differential Phase-Shift Keying), or FH-DPSK (Frequency Hopping Differential Phase-Shift Keying).

[0015] This invention provides an adjacent battery energy equalization system based on ripple communication. It utilizes power information fusion and control technology to modulate data, achieving ripple communication functionality and eliminating the need for dedicated communication cables. Furthermore, it supports various data modulation methods, including FSK, PSK, DPSK, and FH-DPSK. Compared to existing technologies, this invention offers the following advantages:

[0016] 1. This invention can achieve low-latency and high-reliability communication between equalization systems, and the communication data can be used for lithium battery status monitoring, control and protection.

[0017] 2. This invention does not require additional communication cables.

[0018] 3. This invention can decouple power control from communication control, avoiding the influence of communication control on power control. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the adjacent battery energy balancing system (three batteries and two units) of the present invention.

[0020] Figure 2 This is a schematic diagram of the control module structure based on Buck-Boost topology.

[0021] Figure 3 This is a block diagram illustrating the modulation process principle of the system of the present invention.

[0022] Figure 4 This is a schematic diagram illustrating the principle of quaternary FSK modulation.

[0023] Figure 5This is a schematic diagram illustrating the principle of quaternary PSK modulation.

[0024] Figure 6 This is a schematic diagram illustrating the principle of 4-ary DPSK modulation.

[0025] Figure 7 This is a schematic diagram illustrating the principle of quaternary FH-DPSK modulation.

[0026] Figure 8 This is a schematic diagram of the experimental waveform modulation of the system in an embodiment of the present invention. Detailed Implementation

[0027] To describe the present invention in more detail, the technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] This invention relates to an adjacent battery energy balancing system based on ripple communication, comprising multiple energy balancing units for energy balancing control of battery strings. Each battery string consists of multiple batteries connected in series. Any pair of adjacent batteries in a battery string is controlled by its corresponding energy balancing unit. In a pair of adjacent batteries, the battery closer to the positive busbar of the battery string is defined as the front-stage battery, and the battery closer to the negative busbar is defined as the rear-stage battery. If battery C... i The preamp is battery C i-1 The subsequent stage is battery C. i+1 Adjacent battery C i-1 and C i Controlled by energy balancing unit A, adjacent battery C i and C i+1 Controlled by energy balancing unit B, energy balancing units A and B are adjacent to each other, C i If energy balancing units A and B share a common controlled battery, then energy balancing units A and B utilize the common controlled battery C. i Communication is achieved through voltage or current ripple.

[0029] The energy equalization unit includes a signal sampling and conditioning module, a demodulation module, and a control module, wherein:

[0030] The signal sampling and conditioning module collects battery voltage and current, outputs the filtered DC component of the voltage or current to the control module for power control, and outputs the filtered AC ripple component of the voltage or current to the demodulation module for data demodulation and reception.

[0031] The demodulation module receives communication data based on the acquired AC ripple components through demodulation circuits or demodulation algorithms.

[0032] The input and output terminals of the control module are connected to two adjacent individual battery cells. Based on the collected voltage or current, the internally stored battery power information, and the information received by the demodulation module, the control module controls the energy transfer between the adjacent batteries and modulates the data to be transmitted onto the voltage or current ripple of the battery.

[0033] The control module employs power information fusion regulation technology to modulate the data to be transmitted onto the ripple of the battery voltage or current and send the data to adjacent units. Specifically, by changing the duty cycle of the drive signal of the switching device in the control module, the energy transfer of adjacent batteries is controlled. At the same time, by changing the frequency, phase, or finely adjusting the duty cycle, the data to be transmitted is modulated onto the ripple of the battery voltage or current and sent to adjacent units.

[0034] The energy balancing system structure of the three-battery two-cell system in this embodiment is as follows: Figure 1 As shown, C1, C2, and C3 are three individual lithium batteries, and S1 and S2 are energy balancing units. The energy balancing unit includes a signal sampling and conditioning module, a demodulation module, and a control module. The two adjacent units S1 and S2 communicate using the voltage or current ripple of the common-controlled battery C2.

[0035] The control module is a bidirectional DC / DC converter, and its topology includes Buck-Boost, bidirectional flyback circuit, etc. In this embodiment, the control module adopts a Buck-Boost topology. Figure 2 As shown, the two ports of the control module CT1 are connected to two single lithium batteries, C1 and C2.

[0036] The demodulation module can be implemented with discrete circuits, or it can be implemented with MCU, FPGA, CPLD and application-specific integrated circuits.

[0037] The control module employs power information fusion and regulation technology, and the data modulation methods include digital modulation methods such as FSK, PSK, DPSK, and FH-DPSK. The modulation process in this embodiment is as follows: Figure 3 As shown, the carrier generator generates carriers of different frequencies. When no data is being transmitted, a carrier with frequency ω0 is selected by a selection switch, and the switching device drive signal is obtained by comparing it with the power reference value. When transmitting data, the method of modulating the data onto voltage or current ripple is to perform DPSK modulation on the data and carriers with frequencies ω1 and ω, and then select the modulated carrier signal by a selection switch, and obtain the switching device drive signal by comparing it with the power reference value.

[0038] Figure 4 The diagram illustrates the principle of quaternary FSK modulation, using four different frequencies f1, f2, f3, and f4 to represent data 0, 1, 2, and 3 respectively. The time to transmit one digital piece of information is T. b In the same T bThe frequency and phase of the internal drive signal remain unchanged.

[0039] Figure 5 The diagram illustrates the principle of quaternary PSK modulation, using four different phases. The numbers 0, 1, 2, and 3 represent data respectively, and the time to transmit one digital piece of information is T. b In the same T b The frequency and phase of the internal drive signal remain unchanged.

[0040] Figure 6 The diagram illustrates the principle of 4-ary DPSK modulation. The phase difference is defined as the phase difference between a selected symbol and its preceding symbol, using four different phase differences. The numbers 0, 1, 2, and 3 represent data respectively, and the time to transmit one digital piece of information is T. b In the same T b The frequency and phase of the internal drive signal remain unchanged.

[0041] Figure 7 The diagram illustrates the principle of quaternary FH-DPSK modulation. The frequency f1 for transmitting data differs from the frequency f0 when no data is transmitted. The phase difference is defined as the difference between the phase of the selected symbol and its preceding symbol, using four different phase differences. The numbers 0, 1, 2, and 3 represent data respectively, and the time to transmit one digital piece of information is T. b In the same T b The frequency and phase of the internal drive signal remain unchanged.

[0042] In this embodiment, the signal sampling and conditioning module of the energy equalization unit consists of an operational amplifier and passive devices. The control module adopts a Buck-Boost topology and generates control signals using an STM32G431. The demodulation module also uses an STM32G431 to implement its internal structure.

[0043] When two energy equalization units use FH-DPSK modulation for ripple communication, the data transmission system switches the ripple signal from 400kHz to 333.33kHz. By changing the phase of the 333.33kHz voltage ripple signal, data is transmitted to the other system through the phase difference of the ripple signal. To avoid the impact of sudden changes in symbol phase on circuit operation, a continuous transition ripple period is added between the two symbols to achieve the change in symbol phase. The experimental waveform is shown below. Figure 8As shown in the figure, ripple 1 is the battery voltage or current ripple signal without adding a phase-continuous transition ripple period, and ripple 2 is the actual battery voltage or current ripple signal, which changes the last two ripple periods in the symbol to a phase-continuous transition ripple period. Ripple 1 and ripple 2 achieve the same ripple communication effect. The driving signal is the driving signal of the switch in the control module. The data receiving system demodulates the ripple signal after passing it through the signal sampling and conditioning module to complete the data reception.

[0044] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. Those skilled in the art can readily make various modifications to the above embodiments and apply the general principles described herein to other embodiments without creative effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made to the present invention by those skilled in the art based on the disclosure thereof should be within the scope of protection of the present invention.

Claims

1. An adjacent battery energy balancing system based on ripple communication, characterized in that: It includes multiple energy balancing units for energy balancing control of the battery string, which consists of multiple batteries connected in series. Each pair of adjacent batteries is controlled by its corresponding energy balancing unit. If battery C... i The preamp is battery C i-1 The subsequent stage is battery C. i+1 Adjacent battery C i-1 and C i Controlled by energy balancing unit A, adjacent battery C i and C i+1 Controlled by energy balancing unit B, energy balancing units A and B are adjacent to each other, C i If energy balancing units A and B share a common controlled battery, then energy balancing units A and B utilize the common controlled battery C. i Communication is based on voltage or current ripple, where i is the battery serial number; The energy equalization unit includes a signal sampling and conditioning module, a demodulation module, and a control module, wherein: The signal sampling and conditioning module is used to collect the voltage and current of two adjacent batteries controlled by the energy equalization unit, and output the DC component of the voltage or current after filtering to the control module for power control, and output the AC ripple component of the voltage or current after filtering to the demodulation module for data demodulation and reception. The demodulation module demodulates the AC ripple component through circuitry or algorithms to achieve the reception of communication data. The control module is connected to two adjacent batteries controlled by the energy balancing unit. It calculates the remaining power of the battery based on the DC component of the battery voltage or current, and then controls the energy transfer between the two adjacent batteries based on the remaining power information of the two batteries and the data information received by the demodulation module, and modulates the data to be sent onto the voltage ripple or current ripple of the corresponding battery. The control module employs power information fusion regulation technology to modulate the data to be transmitted onto the voltage ripple or current ripple of the corresponding battery to send the data to the adjacent energy equalization unit. The specific implementation of the power information fusion regulation technology is as follows: by changing the duty cycle of the switching device drive signal in the control module, the energy transfer between two adjacent batteries is controlled, and at the same time, by changing the frequency or phase of the switching device drive signal, the data to be transmitted is modulated onto the voltage ripple or current ripple of the corresponding battery to send the data to the adjacent energy equalization unit.

2. The adjacent battery energy balancing system according to claim 1, characterized in that: The control module is a bidirectional DC / DC converter, and its topology adopts Buck-Boost or bidirectional flyback circuit.

3. The adjacent battery energy balancing system according to claim 1, characterized in that: The demodulation module uses discrete circuits to implement its internal structure, or uses MCU, FPGA, CPLD or application-specific integrated circuits to implement its internal structure.

4. The adjacent battery energy balancing system according to claim 1, characterized in that: The control module uses power information fusion modulation technology to modulate the data in ways including FSK, PSK, DPSK, or FH-DPSK.

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