Simulation Research On AC Synchronous Motor Vector Control System

This paper focused on the studies of mathematical model of salient pole synchronous machine and its vector control system. Theory analysis, model construction, software simulation and other methods were adopted to the investigation of the mathematical simulation model of synchronous machine based on normalized per-unit of Xad and simulation platform of vector control system. Based on all of this, the speed identification method was studied.In view of the problems existed in the simulation models of synchronous machine in generally used simulation software in the field of Power Electronics and AC Drives, and the need for simulation platform of vector control system, simulation models were built in Matlab/Simulink. Using parameters of 40kW synchronous machine of the laboratory, the platform was verified through simulation in several industrial conditions.The mathematical models of synchronous machine in various coordinate systems were detailed analyzed in this paper. Several simulation models of synchronous machine were established according to the dqO coordinate state equations based on normalized per-unit of Xad. Combined with Park and Clark transforms, using the per-unit parameters above, the established simulation models were proved to be valid and identical. The simulation results show that the simulation models were able to represent the characteristics of actual motors.Vector control method of AC synchronous machine was classical and practical. The structure of AC synchronous machine vector control system was introduced in this paper. The basic units in the system were derived and established in Matlab/Simulink. Using these basic unit models, the vector control simulation platform was built, simulation results proved the validity and feasibility of this simulation platform. This platform laid the foundation for further studies.In order to identify the speed of synchronous machines in some special occasions that can not install speed sensors, speed sensorless vector control method was proposed in recent years. In accordance with the specific studies, the speed observer based on dq coordinate induced electromotive force was discussed and analyzed, and the speed sensorless vector control system were established based on this speed observer and the simulation platform set up before. Simulation in various industrial conditions and actual synchronous experiment proved that this speed observer can better identify the actual speed and have both good static and dynamic performance.