单相并网逆变器电压环控制器的设计

Design of Voltage Loop in Single Phase Grid-connected Inverter

主要针对双级单相并网逆变系统中的电压环控制器设计进行研究,根据系统即时能量平衡的基本关系对其进行了建模和设计,并对储能电容上的电压二次脉动进行了分析。为简化系统设计,电压环采用PI控制,提出一种前馈方案,削弱电容电压上的二次谐波对控制环路造成的影响,有效减小并网电流的THD。最后通过实验验证了该方案的有效性。

The design of voltage-loop controller in single phase grid-connected system was considered, and a control model was built and designed based on the basic relationship of energy balance. The double-frequency （2-f） ripples in the bus fluctuations were also analyzed. To simplify the voltage-loop design, a PI controller combined with a feed-forward scheme was proposed to weaken the influence of the double-frequency in the control loop, so as to reduce the THD of grid current. Finally, experimental results showed the validity of the proposed control scheme.