Sensorless control of PM synchronous generators for micro wind turbines

Machine speed is usually required for maximum power point tracking (MPPT) control of permanent-magnet synchronous generators (PMSG). In this paper, a sensorless control method is applied to the PMSG for micro wind turbine systems. The machine speed is estimated by using a rotor flux observer and induced EMF signal, which can solve the delay problem of the estimated speed. For vector control of PMSG for micro wind turbines, a cost-effective back-to-back PWM-type converter consisting of a two-leg three phase PWM converter and a half-bridge PWM converter is used, by which generator output power can be increased both in steady state and in transient state. The validity of the proposed control algorithm has been verified by simulation results.