ANALYSIS AND PERFORMANCE ENHANCEMENT OF GRID CONNECTED HYBRID SYSTEM FOR EFFECTIVE POWER TRANSFER

Abstract

A new topology and effective power transfer scheme with minimum number of converters is proposed for a
grid connected wind/photovoltaic (PV) system. Distributed generation sources considered are permanent magnet
synchronous generator (PMSG)-based wind energy conversion system and PV array system. Two voltage source
converters with a common DC-link serve as wind side converter (WSC) and grid side converter (GSC), respectively. The
Perturb and Observe technique extracts the maximum power from PV and the DC-link voltage is set to the maximum
power point (MPP) voltage of the PV array. The output DC voltage of WSC is regulated to an MPP PV voltage using an
outer proportional–integral voltage control loop. The maximum power from the PMSG and stator voltages is utilized to
generate the reference currents for WSC to make stator currents to follow stator voltages. With unity power factor
control, the overall VA of the WSC would contribute to the active power transfer and thereby reduce the kVA rating of
the WSC in the proposed configuration. GSC tracks the maximum power from wind and PV array, and serves as a shunt
active power filter to compensate for the current unbalance due to the connection of non-linear loads at the grid. The
THD value of the system is being compared by using hysteresis and fuzzy logic controller