一种低输入电流纹波的单级式三相并网逆变器

A Single-Stage Three-Phase Grid-Connected Inverter with Low Input Current Ripple

针对单级式单相并网逆变器输入电流存在低频纹波的问题,提出一种单级式三相并网逆变器拓扑及双调制策略。变压器一次侧电路三相共用,引进有源钳位电路,在简化电路的基础上减小了损耗;一次、二次侧双调制,一次侧采用恒功率控制输入电流的方法,降低了输入电流低频纹波,二次侧调制逆变输出,且三相逆变系统输出功率之和接近恒定值,无功率脉动问题。详细介绍该逆变器工作原理、双调制驱动逻辑及并网控制策略。最后研制一台480W的样机进行实验,验证了该拓扑的可行性。

The single-stage single-phase grid-connected inverter has the defect of low-frequency ripple in input current. To overcome this defect, a novel single-stage three-phase grid-connected inverter topology and the strategy of double modulation are proposed in this paper. The three-phase output circuits share primary circuit and the active-clamp circuit is applied in this inverter, which can simplify the circuit and improve system efficiency. The input current low-frequency ripple can be reduced by using the strategy of constant power to control input current in the primary side. The strategy of inverter modulation is adopted in secondary side, and the output power of the three-phase inverter system is close to a constant value without power pulsation problem. The inverter principles, driver logic of double modulation and grid-connected algorithm are also analyzed. Finally, a 480 W prototype is developed and tested, and the experimental results verify the feasibility of the micro-inverter.