V-θ control of inverters used in SPM wind turbine generators

This paper examines a position sensorless modulation strategy, called V-θ control, for six-switch fully-controlled rectifiers (inverters) for surface permanent magnet (SPM) generators in small-scale wind turbines. In this strategy, the SPM generator torque is commanded by controlling the magnitude of the phase voltage and its phase shift with respect to the current waveform. Simulated results obtained using simplified and PWM inclusive simulation models were used to validate the analytical findings presented. Experimental results are shown comparing the proposed V-θ control method with both phase advance and conventional switched-mode rectifier (SMR) modulated AC/DC converters. The V-θ control was found to produce up to 22% more power at a given speed compared to phase advance modulation.