Modeling and Simulation of Grid Connected Permanent Magnet Generator (PMG)-based Small Wind Energy Conversion Systems

A small scale wind energy conversion system has tremendous diversity of use and operating conditions, and consequently is evolving rapidly along with the large scale wind energy conversion system for generation of electricity in either stand-alone or grid connected applications. In recent years, the grid connected small wind turbine industry is primarily dominated by the Permanent Magnet Generator (PMG) machines. The power conditioning systems for grid connection of the PMG-based system requires a rectifier, boost converter and a grid-tie inverter. Such system should be based on an appropriate control strategy to control the aerodynamic power during high wind speed, maximum power production, and maximum power flow to the grid at all operating conditions. This paper presents mathematical modeling and control strategy for the grid connected PMG-based small wind turbine systems. Furling control and expected dynamics are adopted with the wind turbine for aerodynamic power control, while the optimum speed of the PMG is followed to ensure maximum power production. A novel controller is derived from the optimum speed information that promise maximum power flow to the grid by controlling the boost converter output voltage and current through the duty cycle. It is found that the proposed modeling and control strategy is feasible and results are verified through simulation.