LCL型感应式能量传输系统的时域特性分析

Time-domain Analysis of LCL Compensated Inductive Power Transfer Systems

LCL型补偿的感应式能量传输拓扑由于其输出特性对负载变化不敏感的优点,在耦合系数波动小而负载范围较宽的无线能量传输场合应用较广。但由于系统中主要波形的高次谐波成分的存在,导致按常规基波近似法分析的误差较大,影响了参数设计的可靠性。为此该文考虑高次谐波的影响,针对变换器的时域特性进行研究。对高次谐波作用下的谐振腔进行简化,建立不同阶次谐波的统一阻抗解析表达式。在此基础上求解谐振腔稳态时域波形。结合稳态时域分析,可以详细指导谐振腔参数设计,保证移相控制下全负载段的零电压开通条件以及较高的功率因数。最后,设计一台300 W的LCL型变换器样机,谐振腔稳态时域波形与分结果吻合良好,验证了所提出的时域分析方法的正确性。

The LCL compensated inductive power transfer system has been widely used in applications where the load range is wide due to its insensitivity of output characteristics to loads variation. However, being affected by harmonics, the conventional fundamental harmonic approximation analysis produces relatively large errors which make the design unreliable. The time-domain analysis of the converter was studied considering the effect of the high order harmonics. The simplification of the resonant tank helped establish the unified expression of the high order impedance. The instantons state variables of the resonant tank were then quantified to solve the steady state waveform. The steady state analysis can instruct the parameter design to guarantee zero voltage switching（ZVS） conditions and high power factors within the full load range. Finally, a 300 W converter was built. The experimental results showed good agreement with that of the calculations, thus verified the accuracy of the proposed method.