Advantages and disadvantages of brushless doubly-fed generator

Brushless doubly-fed machine (BDFM), the stator winding is composed of two groups of three-phase symmetrical windings, one for power winding and the other for control winding. It has the advantages of asynchronous motor and synchronous motor, with adjustable speed and power factor and small inverter capacity. Brushless doubly-fed motor removes the brush on the rotor side, which improves the mechanical stability and reduces the maintenance cost.

Disadvantages: In the doubly-fed wind turbine, in order to match the rotation speed of the wind turbine with that of the generator, a gearbox must be used to connect the wind turbine and the generator, which increases the total cost of the generator; However, the gearbox is noisy and has a high failure rate, which requires regular maintenance and increases mechanical loss; The structure and control of the bidirectional frequency converter used in the unit are complicated; There is also mechanical wear between the brush and the slip ring.