Analysis of Extreme Maximum Modulation Capability of Wound Rotor Brushless Doubly-Fed Machine

The magnetic field modulation capability is an important index to measure the performance of the brushless doubly-fed machine(BDFM), which reflects the energy conversion ability between the stator and the rotor of the motor directly. This paper takes the wound brushless doubly-fed machine as the research object, starting from the internal magnetic field of the motor, and quantitatively deduces the extreme maximum modulation capability of the motor for the first time in theory; the finite element analysis software ANSYS is used to establish a twodimensional solution model of the motor, and the theoretical analysis results are verified. The research results are helpful for the optimization of the rotor structure of the BDFM. Comparing the BDFM with two different structures of wound type and cage type, the simulation results show that the former has lower rotor magnetic field harmonic content, but the latter has better rotor extreme maximum modulation capability.