基于极简三电容补偿的单级式无线电池充电器

为适应锂电池的先恒流后恒压充电曲线,感应式无线电池充电器应提供其所需的输出,同时在整个充电过程中还应具备阻性输入阻抗,以降低器件应力、减少无功环流.针对4种基本补偿拓扑无法同时实现以上要求,而高阶补偿网络必须依赖更多器件实现上述需求的问题,系统地推导了具备阻性输入阻抗和恒定输出特性的基于极简三电容补偿的单级式无线电池充电器的设计自由度,分析其补偿参数与工作频率的约束条件.同时,对三电容补偿的串/串并(S/SP)和串/并串(S/PS)结构的输出特性进行分析和对比,分析补偿元件参数对输入阻抗角和输出增益的影响,以指导软开关设计.最后,搭建一台输出为48 V/2 A的单级式无线电池充电器以证明以上设计的可行性.

Single-stage Inductive Power Transferred Battery Charger Based on Minimal Three-capacitor Compensation

To adapt to the charging profile of lithium-ion battery consisting of an initial constant current (CC) and a subsequent constant voltage (CV), an inductive power transferred battery charger should provide the required output as well as resistive input impedance to reduce device stresses and reactive power during the whole charging process. In view of the fact that the four basic compensation topologies cannot meet the above requirements at the same time, and the high-order compensation network must rely on more devices to satisfy the above requirements, the design freedom of single-stage inductive power transferred battery chargers based on the minimal three-capacitor compensation is systematically derived, which has the characteristics of resistive input impedance and constant output, and the constraints of its compensation parameters and operation frequency are analyzed. Meanwhile, the output characteristics of the S/SP and S/PS structures of three-capacitor compensation are analyzed and compared, and the influence of the compensation component parameters on the input impedance angle and output gain is analyzed to guide the soft switch design. Finally, a single-stage inductive power transferred battery charger with an output of 48 V/2 A is built to verify the feasibility of the above design.