基于无线充电系统的多模块扩展均压技术研究与设计

Modular Extensible Voltage Equalization Based on Wireless Charging System

该文提出一种基于无线充电系统的多模块可扩展充电均压系统,该系统利用无线充电系统自身高频特性取代传统均压电路所需高频电源。同时,基于其物理隔离特性提高无线充电系统应对复杂场景的可行性,解决传统均压系统体积大,难以用于对体积要求高的无线充电场景这一问题。该文分析非理想状态下各电池串充电电压不均导致的电池寿命削减和充电灵活性较差问题,并提出一种在非理想状态下系统可靠充电的方法,通过设定期望的阈值电压可靠关断充电系统,实现灵活充电。该无线充电均压系统可实现电池充电过程中的电压均衡、延长电池寿命,同时减小系统的体积占用,无线充电均压系统对于偏移状态也具有一定适应性,可广泛应用于机器人、无人机等多种无线充电场景,为无线充电均压系统的设计和应用提供了有效的解决方案。

Wireless power transfer technology with the characteristic of physical isolation solves the power supply problem in situations where wires are inconvenient,making power delivery more flexible.It is commonly used in complex unmanned scenarios,such as drones,autonomous vehicles,and remote control devices.These scenarios have high requirements for the reliability of energy storage systems.The inconsistent initial voltages or charging currents caused by inherent parameter errors in the charging module of the energy storage system result in uneven charging voltages among multiple battery cells,leading to excessive current stress on battery devices.Excessive current stress disrupts system stability and even causes system failure.As a result,the battery’s operational lifespan is reduced,and the system’s safety is compromised.Traditional voltage-balanced modules have the disadvantages of complex structure,large volume,and high cost.This paper proposes a modular and scalable voltage multipliers constant system based on wireless power transfer technology.The voltage multiplier significantly decreases the number of diodes and capacitors in the system,reducing the construction cost.In the design of the wireless power transfer module,the transmitting coil side adopts the LCL-S compensation topology with constant voltage output characteristics,and the receiving coil side adopts the S-type topology to reduce the additional inductance and capacitance elements of the receiving unit.The voltage multiplier takes the two ends of the input from the receiving module in the wireless charging part.Taking a single receiving module and a voltage multiplier module as an example,the current flows in opposite directions during the positive and negative half-waves of the output voltage of the receiving coil,which complements the conducting diodes.The input is equilibrated by transition capacitors and diodes and distributed to each supercapacitor.This paper establishes an experimental model scaled down in equal proportions.The effectiveness of ideal and non-ideal charging constant voltage is verified through the system’s charging curve,and a flexible constant voltage process is achieved using fewer components without additional control elements.By replacing the AC inputs of the three voltage multipliers with wireless power transfer modules,additional devices are reduced.The physical isolation characteristic of wireless power transfer technology is utilized to solve the inconvenience of wired charging,improving the reliability of the energy storage system and expanding the application scenarios for battery charging.The system’s overall charging efficiency reaches 76.87%when the total voltage of the three supercapacitors is 48 V.Each energy storage unit ultimately converges to the target voltage value set under non-ideal charging positions.Setting of a threshold voltage solves the problem of inconsistent charging speeds of voltage multiplier constant voltage modules under non-ideal charging positions,enabling the system to charge more reliably.This system can be expanded to various charging scenarios,such as robots and drones.