Electromagnetic field calculation of stator slot and operation simulation for salient pole synchronous machine

Salient pole synchronous machine is a kind of motive power machine with simple structure, rapid response and diversified control, which has been widely applied in constant-speed industrial drive system. Analysis of operation feature and electromagnetic field of salient pole synchronous machine has become an important research topic. In this study, a 500kW salient pole synchronous machine was adopted as the research object, and the characteristic curve of such motor during excitation process and loading process was calculated using equivalent circuit method and field circuit coupling method. The calculation results were validated through comparing the simulation waveforms of electromagnetic torque, rotor speed and excitation current. Then, the magnetic field distribution and magnetic flux density distribution of feature parts under steady-state load were calculated. Simulation results showed that the steady-state speed and torque after excitation remained unchanged so did the steady-state excitation current and speed after loading. The rotor kept constant speed after loading, with steady-state power angle of 47°. The flux density amplitude of stator teeth was higher than that of intertooth part; normal flux density amplitude was significantly larger than tangential flux density amplitude. The maximum and minimum flux density amplitude were associated with stator slot number. 7th-harmonic exerted great influence on the main flux density of magnetic field, which provides reference for fault diagnosis and operating characteristic analysis of various motors.