A new low-cost sensorless MPPT algorithm for small wind turbines

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 to supply a DC load. This method does neither require the knowledge of the wind speed nor the turbine parameters. After a presentation of the energy conversion chain (wind turbine, PMSM generator, rectifier and boost circuit), 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 C_p. We then describe the proposed MPPT algorithm and the speed estimator used to design a sensorless MPPT. Simulation results demonstrate the feasibility of the proposed approach.