Research On AC And DC Multi Winding Permanent Magnet Synchronous Generator

Simultaneous AC and DC power sources are required in many isolated power systems, such as those used in naval vessels, mobile communication stations and offshore oil platforms. Those power sources are required to have the virtues such as small size, light weight, high quality and high reliability. AC and DC multi winding permanent magnet synchronous generator perfectly meets the above requirements, so it gets attention and study. This paper describes the design and study of AC and DC multi winding permanent magnet synchronous generator, which has five sets of Y connected stator windings, one set used to produce AC power, the others linked to rectifiers to produce DC power.Firstly, according to the structure parameters of the generator, the 2D simulation model of the generator was built in Ansoft, and the electromagnetic field was analyzed by finite element method, research of the following aspects was done:For different load conditions, the generator’s electromagnetic field was analyzed, and the running characteristics of the generator were studied, according to the simulation results of the motor under the rated load, the motor performance meet the design requirements. On the basis of Fourier analysis of radial air gap magnetic field, no-load winding EMF was calculated and the harmonics was analyzed. In this generator, distributed short-pitch wingdings were used to suppress harmonics and skewed slots were used to suppress the tooth harmonics. Through a variety of inspection of armature reaction under different load conditions, characteristics of DC windings’ armature reaction with rectifying device was identified and also the influence on armature reaction, by changing the relative position of AC and DC windings. According to the theoretical values, numerous winding inductances were classified, and incremental inductances were calculated by a flux method. Soft magnetic material poles were installed on the rotor to improve the load characteristics of AC windings, and the impact of changes in the length of the soft magnetic pole on the motor’s performance was analyzed. The load characteristic curves of AC windings under three different power factors was draw, finding that when under rated power factor, voltage adjustment rate of AC windings was less than 10%. The influence of the full wave rectification and half wave rectification on the output voltage of the generator was compared. The simulation results show that the output voltage waveform was better in the full wave mode than in the half wave mode.Secondly, the mathematical model in different coordinates was derived. In the dqO coordinate system, winding inductances were constants, and when ignoring mutual leakage inductances between windings belonging to different Y, d-axis windings and q-axis windings were completely decoupled, so the mathematical model of the generator became simple. And ignoring those mutual leakage inductances has little influence on the generator performance. According to the simplified mathematical model of the generator, the minimum set of parameters describing this generator was get, Matlab simulation model was established and the load performance under different conditions was analyzed.