Grid integration of large capacity solar PV plant using multipulse VSC with robust PLL based control

This paper deals with the grid integration of a large capacity double stage solar photovoltaic (PV) power generating system using two-level 18-pulse double bridge VSC (voltage source converter) with robust synchronizing PLL based control. The maximum power is tracked from solar PV array using incremental conductance maximum power point tracking (MPPT) technique and is transferred to a three phase ac grid. Multipulse VSC consists of six 6-pulse two-level VSC operated at 50 Hz switching frequency and each VSC is commonly connected with phase shift transformers which cancel most of the harmonics between the converter modules and makes the ac waveform nearly sinusoidal without using high frequency switching control. Simulated results are presented for the proposed system configuration to demonstrate its performance under varying conditions.