一种新型的级联逆变器电容电压平衡控制方法

摘要

级联逆变器在光伏系统中应用非常广泛，其控制的一个主要难点就是直流侧电容电压平衡问题。以5电平级联多电平逆变为研究对象，提出一种新型的电容电压平衡控制方法，并在仅有电压平衡控制和附加了MPPT控制两种条件下进行了仿真研究。研究结果表明，在稳态条件下，逆变器直流侧电容电压稳定，各桥之间电容电压基本一致，逆变器输出电流电压稳定，并且具有控制简单、可靠性高、调节速度较快等优点，具有较高的应用价值。%Cascaded inverters are now widely used in the photovoltaic systems.One of the main difficulties of controlling it is balancing the voltage of the DC capacitors.This paper puts forward a new control method for DC voltage balance based on 5-level cascaded inverter. We do simulations in the condition of the system with voltage balancing control and then added by MPPT.It is indicated in the result that the strategy is performing well during the steady state.Due to that the values of the H bridge voltage are steady and almost the same,the output of the inverter is stable.Better is that the method is simple,reliable and can quickly response,which may lead to high application value.