A two-stage power converter for PV applications is developed in this paper. In the first stage, a multiple-input high step-up dc/dc converter is proposed. The second stage is the five-level dc/dc inverter with boosting functionality. The proposed two-stage converter harnesses the superior features of WBG devices to build a converter with high efficiency and high-power density. The high switching speed of WBG power devices allow both stages operating at high switching frequency, hence, large size film capacitors can be replaced by small size multilayer ceramic capacitors, furthermore, the high operating temperature of WBG devices will help to shrink the cooling size. In additions, a zero current-switching technique is implemented in order to reduce the switching loss and electromagnetic interferences. Prototype with 300 W is built and experimental results are presented with a peak efficiency of 98.3%.

本文开发了一种用于光伏应用的两级功率转换器。在第一阶段，提出了多输入高升压 DC/DC 转换器。第二级是具有升压功能的五电平 DC/DC 逆变器。拟议的两级转换器利用 WBG 器件的优越特性来构建具有高效率和高功率密度的转换器。WBG 功率器件的高开关速度允许两级工作在高开关频率，因此，大尺寸薄膜电容器可以被小尺寸多层陶瓷电容器代替，此外，WBG 器件的高工作温度将有助于缩小冷却尺寸。此外，还实施了零电流开关技术，以减少开关损耗和电磁干扰。