Permanent magnet generator is a the ordinary synchronous generator rotor change permanent magnet generator structure, commonly used permanent magnet materials ferrite (BaFeO), samarium cobalt 5 (SmCo) permanent magnet generator for general use small wind turbine. Asynchronous generator asynchronous motor is in the working state of power generation, grid power excitation power (excited) and shunt capacitance of self-excitation power (self-motivation) two cases from the incentives.

    First. The MAINS excitation power: asynchronous motor to the power line, the motor stator windings produce a rotating magnetic field rotating at synchronous speed, and then drag the original motif, so that the rotor speed is greater than the synchronous speed, the direction of the magnetic moment of the grid is certainly and the speed in the opposite direction, while the direction of the mechanical torque and speed in the same direction when the prime mover mechanical energy into electrical energy. In this case, the asynchronous motor issued by the active power to the grid transmission; while reactive power consumption of the grid for the excitation of the supply of reactive power consumed by the stator and rotor magnetic flux leakage, the asynchronous generator and grid General requirements plus reactive power compensation device, usually with a parallel capacitor compensation.

    Second. The shunt capacitor self-excitation power generation: capacitors in parallel connection is divided into two kinds of star and delta. Excitation capacitor access in the the generator itself remanence power process, the generator periodically to charge the capacitor; the same time, the capacitor is periodically discharged through the stator winding of the asynchronous motor. This capacitor winding alternately charging and discharging process, and continue to play the role of the excitation, so that the normal power generation of the generator. Excitation capacitor divided into the main excitation capacitor and auxiliary excitation capacitors, the capacitance of the main exciter is to ensure that under no load voltage capacitor, the auxiliary capacitor to prevent voltage collapse in order to ensure access to the load voltage constant. Through the above analysis, the start of the induction generator and the network is very convenient and easy automatic control, low price, reliable operation, convenient maintenance, higher operating efficiency, grid-connected wind power units are basically using asynchronous power machine, synchronous generator is commonly used to run independently.