Research On Open-Winding Doubly Fed Induction Motor Control System

The energy crisis has always been a world wide problem. In order to solve the problem, countries in the world develop the green, low-carbon and clean energy. Besides, they also promote the technologies of energy saving to improve the efficiency of energy. During the progress, the doubly fed speed control system has gradually replaced the other speed control system and been widely applied to wind power and hydropower for its unique advantages. Multilevel technology has always been widely used in the field of high power alternating current speed control. The corresponding algorithm is more complex for producing more levels. Open winding motor can produce multilevel with simpler algorithm for its structure. At the same time, the motor with open winding structure is easy to realize power generation of multiple forms of energy. Combining with the advantages of doubly fed induction motor and open winding motor, the open-winding doubly fed induction motor system is researched in this paper.Firstly, the history and situation of the research are introduced. The traditional doubly fed induction motor exists the problems of high cost and difficult maintenance in transformer due to different voltage levels in stator side and rotor side of the motor, as well as the low voltage ride through. It is important to solve problems above. The dynamic mathematical model and structure principle of open-winding doubly fed induction motor are analyzed and the simulation model is built with Matlab/Simulink according to its mathematical model. Then, the flow of energy of open-winding doubly fed induction motor under different operating conditions are analyzed.Secondly, the relationship of power, voltage and current of open-winding doubly fed induction motor are analyzed respectively under different operating conditions, when the grid is ensured generating no reactive power and the stator flux changes with speed. Also, the relationship of power, voltage and current of open-winding doubly fed induction motor are analyzed respectively under different operating conditions, when the stator flux is kept constant under the situations of different speed. The vector control strategy of rotor side and the stator side converter are designed based on the theoretical analysis.Finally, the simulation model of open-winding doubly fed induction motor control system is built with Matlab/Simulink based on the theoretical analysis and designed control strategies. The correctness and feasibility of the speed control system are verified by simulation. Then, experimental platform of open-winding doubly fed induction motor control system is set up and the control system is digitized by DSP. The practicability of the control system is verified by experiment.