Torque/power rating design of an IPM machine for maximum profit-to-cost ratio in wind power generation

This paper presents some comparisons of different design choices in micro wind power systems design. An economic analysis is carried out on the basis of generator, power converter and mechanical system costs. An Interior Permanent Magnet (IPM) motor is considered since it can be driven in the flux weakening region, exploiting higher turbine rotation speeds. Several cases are considered, by imposing some constraints both on the maximum input torque of the generator and on the maximum design power of power converter, also combining both limitations together. In fact, the paper shows that economic advantages are obtained introducing such limitations, both in terms of return on investment and on money profit during a period of 20 years. The optimal power and torque limitations are found on the basis of the maximum profit over payback time.