Research On Control Topology Of A Fourphase Wound-field Doubly Salient Motor

With the prominent advantages of simple structure, high reliability, controllable excitation and flexible control, the Wound-Field Doubly Salient Motor(WFDSM) enjoyssignificant value for research and application.This thesis mainly researches on the drive system of a four-phase WFDSM and analyzes the working principles of WFDSM under a traditional control topology as well as a new control topology using multiplexing excitation in details.First of all, this thesis derives the mathematical models of WFDSM and the working principles are introduced The optimal conduction regions for producing the maximal average torque are obtained on the basis of the finite element simulations of single-phase conduction. Operating modes of both the standard angle control strategy and the advanced angle control strategy under the traditional topology are analyzed. Appropriate advanced angle may help to higher phase current amplitude in the conduct regions, then the output power of WFDSM is raised. The magnetic-thermal coupling simulations are conducted, where the influences of winding resistance and copper loss caused by temperature rising are taken into consideration. The simulation shows that the main loss of WFDSM is copper loss since windings are the major heat loads. And the poor heat dissipation condition of windings loads to its higher temperature.Secondly, a new topology using multiplexing excitation is put forword in this thesis. The field windings in this topology act not only as the sources of exciting fields but also as the inductance of the Buck converter. The typical current-fed mode, typical voltage-fed mode and normal mode are simulated and analyzed with the new topology. The results show that WFDSM works in current-fed mode for a long region under low-speed light-load conditions while works in current-fed mode for a short region under high-speed heavy-load conditions.Finally, the control system of WFDSM based on LabVIEW/FPGA is designed in order to realize fuctions including position signals processing, rotational speed calculations, inverter control, closed-loop control and circuit protections. The mechanical characteristics of WFDSMare obtained through the experiments, and the closed-loop control of WFDSM is accomplished. In the experiments, the WFDSM with the multiplexing excitation topology exhibits good operating performances.