A method of tracking maximum power points in variable speed wind energy conversion systems

This paper presents a new wind speed sensorless maximum power point tracking (MPPT) controller for variable speed wind energy conversion systems (WECS). The MPPT control of the WECS, in this work, is achieved using optimum speed - power curve of the WECS after taking into account the changes in system efficiency while operating at different operating points due to the change in wind speed. The method proposed is based on the fact that the optimum output power of a WECS at a certain wind speed depends upon the total mechanical power developed by the turbine and efficiency of the WECS at the corresponding optimum speed (OS) of rotation of the turbine. Implementation of this control algorithm requires the knowledge of output power and air density as its inputs in addition to requiring the knowledge of turbine parameters. The proposed method is analyzed experimentally in a variable speed direct drive permanent magnet synchronous generator (PMSG) WECS using a wind turbine emulator.