Research On The New Type Brushless Wound-rotor Asynchronous Motor

Although cage induction motor is simple in structure, reliable in operation,but starting performance is poor. Winding asynchronous motor has better starting performance and operation performance, and the scope of application is be limited due to the complicated structure and high failure rate.In order to overcome the structurally deficient and further improve the starting performance of the winding asynchronous motor, based on the windings of electric motor, a novel type brushless wound-rotor asynchronous motor is designed with simple structure and excellent starting capability by research on the windings as a whole in this paper. Basing harmonic starting theory as a foundation, a new scheme of stator winding and rotor winding is devised by using the modern winding theory and slot-number phase graph. The winding scheme has a number of features as simple-connection, easy-embedding and capable of uninterruptible power supply switching. The stator winding has two states which one kind corresponds to states of starting and the other corresponds to states of operational. The stator winding can produce harmonics which is advantageous to starting. The Rotor winding which adopts special method of connection, can provides flow path for induced current of fundamental wave and harmonic wave. The former path has very big equivalent resistance, which can significantly reduce the starting current and improve starting torque. the resistance of other induction current flow path is very small, which can produce high efficiency of the motor. The key point for wingding design consists in research on the stator and rotor wingding as a whole. The two sets of wingding must coordinate with each other, and design the rotor winding must base on the characteristics of stator wingding.We analyzed the wingding scheme in detail by groove vector diagram and the software of analyzing harmonic. Applying by the principle of harmonic separation and superposition, the calculation methods of starting performance and circuit parameters are deduced for the novel type motor, and we also study out the electromagnetism design program, mathematical model and simulation model.Simulation and the prototype's of experiment verified the proposed novel motor's improvement of starting performance with simpler structure and the proposed winding scheme successfully resolving the contradiction between performance and structure of the traditional motor.