Study on Overmodulation Control Strategy of Cascaded H-bridge Photovoltaic Grid-connected Inverter
Aiming at the problem that THCS can not cope with the serious imbalance of input power between modules,which leads to the overmodulation unit regulation greater than 1.155,an overmodulation control strategy for grid-connected PV inverters is proposed based on THCS.The simulation results show that under the same illu-mination condition,the THD value of grid-connected current is 10.6%because the output power of PV module is different greatly when THCS control is used,which exceeds the linear modulation range(1.155).However,the overmodulation control strategy can avoid overmodulation even if the H-bridge unit modulation system is greater than 1.155,and the THD value of grid-connected current is 2.03%,and the current quality improvement effect is significant.