一种双直流输入多电平双Buck逆变器

摘要

A dual-DC-input multi-level dual-Buck inverter (DI-ML-DBI) is proposed in this paper. A direct power flow path between the low voltage DC input source and the AC output of the inverter is built by introducing two dual-DC-input three-level switching cells into a traditional dual-buck inverter. Therefore, partial input power from the low voltage source can be directly fed to the AC output through the inverter without being processed by the front-end Boost converter of the inverter. Hence, the power rating and power losses of the front-end Boost converter are reduced significantly. Meanwhile, five voltage-levels are generated by the DI-ML-DBI with the help of the two DC input sources, which lead to the reduction of switch voltage stresses and switching losses. In addition, the proposed DI-ML-DBI retains the advantages of no shoot-through and no body-diode reverse-recovery problems. The operation principles and characteristics of the proposed DI-ML-DBI are analyzed in detail, and an adaptive-carrier-based modulation strategy is presented for wide DC input voltage range application. The experimental results verify the proposed DI-ML-DBI and its control strategy.%提出一种包含两个直流输入端口的多电平双Buck逆变器.通过在传统双Buck逆变器中引入双直流输入三电平开关单元,构建低压直流输入源与逆变器交流输出侧的直接功率通路,使得低压直流输入源的部分功率无需经过逆变器前级升压电路处理,有效减小了逆变器前级升压电路的功率应力和损耗.同时,逆变器利用两个直流输入在交流电压周期内实现五电平输出,有效减小了逆变器自身开关管的电压应力和开关损耗.此外,逆变器保留了传统双 Buck 逆变器无桥臂直通、无体二极管反向恢复问题的优点.详细分析逆变器的工作原理和特性,并给出一种适应宽直流电压范围的载波自适应调制策略.实验结果证明了所提出双直流输入多电平双 Buck 逆变器及其控制策略的正确性和有效性.