高效率五电平双降压式全桥并网逆变器

为提高并网逆变器的变换效率,提出一种新颖的五电平双降压式全桥并网逆变器,它由三电平双降压式全桥拓扑、输入分压电容和钳位支路组合得到。其滤波电感和开关器件的电压阶梯仅为输入电压的一半,故磁性元件体积小、质量轻,且每个开关周期仅有一个开关管高频动作,降低了开关损耗。分析了该拓扑的工作原理和调制策略,并分别搭建五电平和三电平双降压式全桥并网逆变器实验样机进行效率比较。实验结果表明,所提五电平拓扑的欧洲效率较三电平拓扑高出0.5%。由三电平双降压式半桥拓扑与两电平桥臂组合,提出另外2种五电平双降压式全桥并网逆变器拓扑。最后对提出的3种拓扑的损耗和成本进行了详细的分析和对比。

Grid Connected Five-level Dual-Buck Full-bridge Inverter With High Efficiency

In order to improve the efficiency of the grid-tied inverter,a novel five-level dual Buck full bridge inverter,which s derived from a three-level dual Buck full bridge inverter by adding two input split capacitors and a clamping circuit,was proposed.In the proposed inverter,the step voltages both on the filter inductor and across the switches are only half of the input voltage,resulting in a smaller size of the inductor.Furthermore,only one of these switches is operating at high switching frequency in any switching cycle,thus reducing switching losses.The operation principle and modulation strategy of the proposed inverter were analyzed.In order to make comparison,the proposed inverter prototype and a three-level inverter prototype were built respectively.Efficiency measurement show that the proposed inverter gains 0.5% higher Europe efficiency than the three-level inverter.Another two five-level dual Buck full bridge inverters were derived by combining a three-level dual Buck half bridge inverter and a two-level half bridge topology.These three proposed inverters were analyzed and compared in details in terms of power losses and cost.