A novel topological family of multi-level inverters with flyback high frequency link is proposed in this study. The inverters can transfer high DC voltage into regulated sinusoidal voltage with low total harmonic distortion (THD). The circuit configuration consists of high DC input voltage, DC-link capacitors, novel multi-level conversion unit, high frequency flyback transformer, cyclo-converter, output filter capacitor and AC load. This topological family includes diode-clamp type full-wave mode, hybrid-clamp half-bridge mode, multi-end mode and improved multi-end mode. To achieve reliable multi-level inversion and overcome DC-link capacitor voltages unbalance, multi-carrier modulation and DC-link capacitor voltage balancing strategy are presented. In addition, steady principle and AC small-signal model are analysed. Simulation and experimental results are given to prove that the novel flyback high frequency isolated multi-level inverters have the following advantages such as the high frequency electrical isolation, the bi-directional power flow, the two-stage power conversion (DC-high frequency AC (HFAC) - low frequency AC (LFAC)), the lower voltage stress of power switches and the low THD of output voltage.

中文翻译：

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具有反激式高频链路的新型多电平逆变器

这项研究提出了一种新颖的具有反激式高频链路的多电平逆变器拓扑家族。逆变器可以将高直流电压转换为具有低总谐波失真（THD）的稳定正弦电压。电路配置包括高直流输入电压，直流链路电容器，新颖的多电平转换单元，高频反激变压器，循环转换器，输出滤波电容器和交流负载。该拓扑系列包括二极管钳位型全波模式，混合钳位半桥模式，多端模式和改进的多端模式。为了实现可靠的多电平逆变并克服直流母线电容器电压不平衡，提出了多载波调制和直流母线电容器电压平衡策略。另外，分析了稳态原理和交流小信号模型。