可用于分布式电源并网的双频逆变器研究

Abstract

为提高分布式电源并网的效率，减小并网电流总的谐波畸变率，降低并网逆变器的开关损耗，研究了一种新型双频并网逆变器，其中一部分工作在低频，采用电流滞环控制，快速跟踪高频单元电流，传递大部分功率；另一部分工作在高频，采用空间矢量调制，改善并网电流的动态性能，使并网电流和电网电压同频同相，并且实现了电流有功分量和无功分量的解耦控制。以双频逆变器A相工作的四种状态为例分析了系统的工作原理。Simulink仿真模型验证了双频并网逆变器能够大大降低开关损耗，使并网电流总的谐波畸变率减小，提高了并网效率。 A new type topology of dual-frequency photovoltaic grid-connected inverter is researched to improve the efficiency of distributed power grid-connected and reduce the total harmonic distortion rate of the gird-connected current and the switching losses. Part of it works in the low-frequency area to fast-track high-frequency cell current and transit most of the power by using current hysteresis control. The other part works in the high frequency area to improve the dynamic performance of the distributed power grid connected current and make grid-connected current in the same phase and frequency with grid voltage. The voltage and currents changes are analyzed in four work states of phase A. The Simulink model verifies the switching losses and the harmonic distortion rate is greatly reduced; thus grid-connected efficiency is improved.