Abstract
In response to the problem of incomplete calculation methods for inductance parameters of wound brushless doubly fed motors, this paper starts with the internal magnetic field of the motor and the spatial distribution of the magnetic electromotive force of a single coil, derives the amplitude of the fundamental magnetic electromotive force of the brushless doubly fed motor, and then obtains the inductance calculation formula of the stator winding. This paper first introduces a multi span wound rotor structure, and then analyzes and calculates the main inductance of the stator winding. The calculation formula for the stator leakage inductance of a brushless doubly fed motor is mainly derived, including stator end leakage inductance, stator slot leakage inductance, and stator harmonic leakage inductance. Finally, based on the calculation of the main inductance and leakage inductance parameters of a multi span wound rotor brushless doubly fed motor with a capacity of 700kVA and an efficiency of 96%, the accuracy of the method was verified by comparing it with the results calculated by the analytical method. The results show that the analytical method and finite element method derived in this paper have relative errors within 5% when calculating the main inductance, end leakage inductance, slot leakage inductance, and harmonic leakage inductance, and have good consistency. In addition, it was found that slot leakage inductance accounts for 70.41% and 61.54% of the main components of both power winding and control winding leakage inductance, respectively.