Wireless power transfer system needs to transfer power over wide coupling coefficient range. Traditional series-series (SS) compensation method is sensitive to the variation of coupling coefficient, which causes deep impact on the transferred power level. Traditional topology is not suitable for some applications where the coupling coefficient varies greatly. In addition, traditional SS topology exists the potential safety hazard of underloading. In this paper, a primary-side detuned SS compensation method is proposed to provide stable power transfer over wide coupling coefficient range. The power characteristic is analyzed, and the result indicates that this system maintains high misalignment tolerance and avoids the safe problem of underloading. Considering the rated power and power fluctuation, a parameter design method is put forward. Then compared with the traditional fully tuned SS system, the sensitivities of compensated capacity and the state of charge (SOC) are studied. The impact of this detuned method on the efficiency of resonant tank is developed. Finally, experimental results on a 150W prototype verify the proposed primary-side detuned SS topology, where the power transfer is maintained above 80% of its nominal power level and the efficiency of system is more than 76% when the coupling coefficient varies 200%.%无线电能传输系统的拓扑需在宽耦合系数范围内具有平稳传输功率的能力,传统的全谐振串串补偿拓扑对耦合系数较敏感,功率波动程度较大,不适合用于耦合系数变化剧烈的场合,且存在轻载安全问题.本文提出一种一次侧失谐的串串补偿拓扑,分析在一次侧失谐情况下的系统传输功率特性,结果表明该拓扑具有较强的抗偏移能力,且不存在轻载安全问题.考虑额定功率和功率波动程度两个约束条件,对补偿拓扑的相关参数进行设计,并对全谐振拓扑和失谐拓扑进行补偿电容容值及电池荷电状态(SOC)的敏感性对比,讨论一次侧失谐设计对谐振腔效率的影响.最后搭建150W的实验平台,对该抗偏移特性进行验证.实验结果表明在两倍的耦合系数变化内,系统的输出功率波动程度能保持在20%以内,且系统效率维持在76%以上.
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