Design of an efficient small wind-energy conversion system with an adaptive sensorless MPPT strategy

This paper presents an original method for the sensorless Maximum Power Point Tracking (MPPT) of a small power wind turbine using a permanent magnet synchronous generator (PMSG) to supply a DC load. This method does neither require to measure the wind speed nor to know the turbine parameters. After a presentation of the energy conversion chain (wind turbine and PMSG), we first derive an analysis of its energy efficiency. This analysis shows that the highest power at the output of the turbine and the highest power supplied to the load are not obtained at the same rotor speed. This clearly shows the interest to maximize the power supplied to the load rather than to track the maximum power at the output of the turbine deduced from its theoretical power coefficient Cp, and the interest to use an active three-phase rectifier combined with a field oriented control of the PMSG. We then describe the proposed MPPT process and the speed estimator used to design a sensorless MPPT. Simulation results demonstrate the feasibility of the proposed approach.