Duty-cycle control is a widely used control method of resonant converters. In this article, the existing model of duty-cycle controlled resonant converters is found to have discrepancy compared with the simulation and experimental results. The reason behind is investigated, showing the phase change in the output voltage of the inverter bridge caused by the duty-cycle perturbation was ignored in the existing model. The phase change law is highly dependent on the duty-cycle scheme used, which is further determined by the forms of the carriers and the switching sequences of the resonant converters. With this consideration, improved models of both full-bridge and half-bridge resonant converters with different duty-cycle control schemes are rederived. It is revealed that different duty-cycle control schemes lead to different phase curves of the duty-cycle-to-output-voltage transfer functions, therefore care should be taken when selecting the appropriate duty-cycle control scheme. In the end, a series-series compensated wireless power transfer system is built to verify the validity of the proposed models.

中文翻译：

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考虑不同占空比控制方案的谐振转换器小信号模型


占空比控制是谐振变换器广泛使用的控制方法。在本文中，发现占空比控制谐振转换器的现有模型与仿真和实验结果相比存在差异。对其背后的原因进行了调查，结果表明现有模型忽略了占空比扰动引起的逆变桥输出电压的相位变化。相变定律高度依赖于所使用的占空比方案，而占空比方案进一步由载波的形式和谐振转换器的开关序列决定。考虑到这一点，重新推导了具有不同占空比控制方案的全桥和半桥谐振变换器的改进模型。结果表明，不同的占空比控制方案会导致占空比到输出电压传递函数的相位曲线不同，因此在选择合适的占空比控制方案时应小心。最后，建立了串联补偿无线电力传输系统来验证所提出模型的有效性。