PV Power System With Multi-Mode Operation and Low-Voltage Ride-Through Capability
A multi-mode operation for the three-phase photovoltaic (PV) power system with low-voltage ride-through (LVRT) capability is proposed. With the proposed multi-mode control strategy, the active power from the PV arrays can be continuously extracted by the interleaved boost converter during LVRT, whereas the maximum power point tracking operation can be quickly achieved after the grid fault clearance. In addition, the multi-channel boost converter with interleaved operation can increase power conversion efficiency while decreasing the input current ripple. On the other hand, the current amplitude limitation control of the three-phase inverter can provide maximum reactive power under rated current amplitude during the voltage sag period and output the demanded reactive/rated current ratio to meet different LVRT codes. A three-phase 5-kVA prototype PV converter is built and tested to verify the performance of the proposed multi-mode operation strategy and the LVRT capability.