A Wind-Hydro Power System Using a Back-to-Back PWM Converter and Parallel Operated Induction Generators

In this paper, an isolated three-phase wind-hydro power system (WHPS) using squirrel cage induction generators, a hydraulic turbine (HT) with governor, an AC/DC/AC electronic converter, compensating capacitors and variable speed wind turbines (WTs) is considered. The stator terminals of the wind turbine generators are connected to the WT generators-side converter of the system. The speeds of the fixed pitch WTs are controlled according to the torque reference-based MPPT algorithm. The rotor flux magnitudes of the wind turbine generators are controlled to regulate the overload capability. The HT power is regulated by the wicket gate according to the deficit of active power in the system. Electrical frequency in the autonomous grid (AG) is controlled by the dc-link chopper feeding a dump load. The objectives of the autonomous grid-side converter in the WHPS are to keep constant the AG voltage magnitude and the dc bus voltage. Simulation of the system under varying wind speed and constant load has been performed and discussed.