光伏并网微型逆变器中功率解耦技术概述

摘要

In photovoltaic （PV） grid-connected micro-inverters, the output power contains a pulsation with twice grid frequency while the input power is constant. Usually, electrolytic capacitors of large capacitance paralleled to PV panel are employed to smooth the input voltage and balance the instantaneous input and output power mismatching （power decoupling）. Nevertheless, the life-span of the electrolytic capacitors is too short to meet the requirement of the PV panels, which become the crucial factor of the life-span and stability of micro-inverters. A review of power decoupling methods for micro-inverters in PV system was presented. These methods were categorized and introduced separately. Finally. the comparison and conclusion were t）resented.%在光伏并网微型逆变器中，输出功率舍有两倍工频的功率脉动，而光伏组件根据MPPT算法控制输出为恒定的功率，这两者的瞬时功率不平衡通常由并联在光伏组件两端的大电解电容来解决。然而电解电容寿命有限．远低于光伏纽件的寿命要求，成为影响微型逆变器寿命和稳定性的决定性因素。回顾了国内外应用于光伏并网微型逆变器中的功率解耦技术，进行分类介绍并列举了不同的电路拓扑及控制方法，最后对其进行比较并指出各种方法的优缺点。