Vertical axis wind turbines: minimising generator losses by torque control

Vertical Axis Wind Turbines (VAWTs) tend to produce mechanical torque which varies significantly with rotor azimuth angle. The cost of the electrical generator is related to the peak generator torque which in turn depends on the choice of torque/speed control strategy. This choice of control strategy also affects the copper and iron losses of the generator; these can be modelled using harmonic analysis. The paper demonstrates how an optimal control strategy (from a generator loss point of view) can be achieved without significant extra cost.