RTDS simulation for HVDC solid state transformer with photovoltaic cells when low voltage ride through base on dual control theory

摘要

Photovoltaic cells is more efficient when connecting the power grid by Discrete Current than Alternative Current. HVDC-SST is a key device by DC connection. However, Low voltage Ride Through(LVRT) often occurs in the photovoltaic fields. To solve the overcurrent problem while LVRT occurs, this paper involved a dual control strategy for each DAB unit of the HVDC-SST. There is an inverter side and a rectifier side in a DAB unit. In this paper, the inverter side of each DAB unit was under constant current hysteresis control, the rectifier side was under constant voltage PI control. And then it verified the dual control method by RTDS simulation, the results show that that the control algorithm can reduce the current when LVRT occurs, so the strategy can meet the requirement of low voltage.