提出了一种适用于光伏发电系统或大容量UPS系统的高性能逆变器并联的控制方案。该控制技术利用FPGA产生各并联逆变器SPWM调制波的频率和相位,并确保输出电压同步。把单相交流电压、电流构造成三相交流电压、电流,根据瞬时无功理论计算方法变换成2个直流分量,再用同步d-q变换得到有功电流和无功电流,利用DSP使2台逆变器并联的瞬时有功、无功功率相等,从而实现2台逆变器输出电流的均流。实验结果表明,该控制方法能达到功率均分,逆变电源之间的环流很小。
A control scheme of two parallel high-performance inverters is proposed,suitable for photovoltaic generation system and large scale UPS system.FPGA is used to produce the SPWM frequency and phase for each inverter and ensures the synchronization of output voltages.The single-phase voltage and current are reconstructed to three-phase voltage and current,which are then transformed into two direct components by instantaneous reactive power theory.The active current and reactive current are obtained by synchronous d-q transformation.The instantaneous reactive power and instantaneous active power of two inverters are calculated and kept equal by DSP to achieve the current-sharing between two inverters.Experimental results show that the control scheme achieves power-sharing and small circumfluence.