A New Experimental Method of Brushless Doubly-fed Machine Based on Differential Mode

Brushless doubly-fed motor is a new type of induction motor, which can reduce the capacity of the speed control system and has less harmonic pollution to the power grid. It has a good development prospect. Regardless of the rotor structure of the brushless doubly-fed motor used in the previous research, the natural synchronous speed is 60 f /(P
₁
+ P
₂
) and both are based on the shortcomings of the modulation operation mode. A new type of brushless operation based on the differential operation mode is proposed. The double-fed motor experimental method, that is, the natural synchronous speed is 60 f / |P
₁
- P
₂
|. The method can improve the natural synchronous speed of the brushless doubly-fed motor, expand its operation and control range, and increase the power density of the motor. The design method of the motor is given by using the wound rotor structure, and the finite element model of the brushless doubly-fed motor is analyzed in detail with a design example of a 1/4-pole generator. Finally, the test of no-load and load performance is carried out on the developed prototype. Simulation and experimental results confirm the correctness of this method.