一种应用于光伏系统的单级升压式无变压器型逆变器

A single stage step up transformerless inverter for photovoltaic system

文章提出了一种应用于光伏发电的新型升压式无变压器逆变器拓扑结构。该拓扑结构使用双载波同相层叠调制技术,可实现电压的高增益,仅使用较低占空比即可将低压直流侧电压并网。该拓扑输入负极与电网中性点共地,可将分布的杂散电容短路,完成无共模电流运行。同时,所提拓扑结构通过多单元整合实现了能量的单级传递,仅含6个功率开关管。文章详细分析了所提拓扑各功率元件的设计及主要工作模式。最后,通过一台120 W的试验样机,验证了所提拓扑的正确性和控制策略的有效性。

A novel boost transformerless inverter topology for photovoltaic power generation is proposed. In short, the topology uses dual carrier in-phase cascade modulation technology, which can achieve high voltage gain, so the low-voltage DC side voltage can be connected to the grid only with low duty cycle. The input negative pole of the topology is grounded together with the neutral point of the power grid, so as to short circuit the stray capacitance distributed in the circuit and complete the operation without common mode current. At the same time, the proposed topology achieves single-stage energy transfer through multi cell integration. Finally, a 120 W prototype is built to verify the correctness of the proposed topology and the effectiveness of the control strategy.