一种新的逆变器并网控制策略的研究

Research on a Novel Grid-connected Control Strategy of Inverter

提出了一种新的逆变器并网控制策略。可独立与并网双模式运行的逆变器在并网模式下,由于输出滤波电容的影响,在轻载时进网电流ηTHD高,输出功率因数低。该逆变器在传统控制策略的基础上,加入输出滤波电容电流补偿器,消除输出滤波电容电流对电网的影响,从而可以实现独立与并网2模式之间的无缝切换;全负载范围内或电网电压谐波含量大时,可实现高的输出功率因数和低的进网电流ηTHD。该文阐述了该控制策略的工作原理和参数设计原则,并以一台500W基于DSP控制的双降压式半桥逆变器进行了实验验证。

A novel grid-connected control strategy is proposed. In grid-tied mode, because of the effect of the output filter capacitor, the grid-connected inverter has high THD of the grid current and low power factor at light load. An output filter capacitor current compensating adjuster is added on the traditional controlled grid-connected inverter to eliminate the bad effect of the output filter capacitor current on the grid. With this control method, seamless transfer can be achieved between stand-alone and grid-tied mode. THD of the grid current is small and power factor is high at full range of loads or even in abnormal grid voltage. The principle of the control method and the design principle of the parameters are analyzed. Finally, a 500W dual buck half-bridge inverter operating on two modes is established based on DSP control. The experimental results verify the theoretical analysis.