Study on control system of low speed PM generator direct driven by wind turbine

The rotor of a typical wind turbine rotates at a speed of 20-100 rpm. In conventional wind power plants the generator is coupled with the turbine via a gearbox so that it can rotate at a speed of 1000 r/min or higher. However, the gearbox brings weight, generates noise, needs regular maintenance and increases losses. There is currently a great deal of interest in directly driven generators. In a directly driven, low-speed wind generator no gears are needed and these disadvantages can be avoided. This paper introduces the control system of a permanent magnet (PM) generator direct driven by a variable speed wind turbine with rated power in the region of 10-50 kW. The wind generator can be either grid connected or stand alone as a distributed power supply. The system design, control strategy and implementation method based on the PIC single-chip-computer for a practical 20 kW PM generator direct driven by wind turbine are introduced in detail. The dynamic performance simulation results under optimal power control during the wind speed variation are presented.