一种基于O-Z源的光伏并网逆变器

O-Z Source Based Photovoltaic Grid-connected Inverter

传统Z源逆变器(ZSI)存在体积大,电容电压应力高以及升压能力不突出等问题。通过使用高频变压器改进传统ZSI拓扑,提出了一种基于O-Z源的具有升降压能力的新型逆变器(O-ZSI)。其利用状态空间平均法,对新型逆变器的电路拓扑、稳态原理和动态模型进行了详细的分析,得到了该拓扑的升压比公式和传递函数;此外,比较了几种常见的Z源逆变器与所提O-ZSI之间的特性参数,结果表明O-ZSI具有更高的升压能力、更低的电容电压应力,且能够有效抑制启动冲击电流。并在此基础上建立了基于O-ZSI的单级三相光伏并网系统的试验样机,实验结果验证了O-ZSI的可行性和有效性。

Traditional Z-source inverters(ZSI) have problems such as large size, high capacitor voltage stress,and limited boost capability. An O-Z-source inverter(O-ZSI) with buck-boost capability is proposed by using a high-frequency transformer to improve the traditional ZSI topology. The state-space averaging method is used to analyze the circuit topology, steady-state principle and dynamic-state model of the new inverter. The boost ratio formula and transfer function are obtained. In addition, the characteristic parameters are compared between several common ZSI and the proposed O-ZSI. The results show that the O-ZSI has higher boost capability,lower capacitor voltage stress, and can suppress the starting inrush current effectively. Furthermore, a prototype of a single-stage three-phase photovoltaic grid-connected system based on the O-ZSI is established, and the experimental results verify the feasibility and effectiveness of the O-ZSI.