LOW-VOLTAGE RIDE-THROUGH CONTROL STRATEGY OF PV SYSTEM BASED ON ACTIVE AND REACTIVE POWER CONTROL

摘要

This paper presents a novel control strategy of the two-stage three-phase photovoltaic (PV) system based on the active and reactive power control to improve the low-voltage ride-through (LVRT) capability. With the help of the new strategy, the PV array can generate the appropriate active power according to the depth of the grid voltage dip to restrain the over-voltage and over-current. Simultaneously, the proposed strategy can ensure the reactive power support to help the voltage recovery. Besides, a feed forward compensation is used to smooth the DC-link voltage fluctuations during the grid fault. The effectiveness of the proposed control strategy is verified through various simulation scenarios when different grid voltage drop depths occur. The proposed control strategy can not only enhance the LVRT capability of the PV system, but also provide the reactive power support.