Dynamic Characteristics Of Theoretical Analysis And Finite Element Simulation On Low-speed Reluctance Motor

With the development of science and technology, industrial production needs the motor that can directly output low speed and high torque in many cases. For the general synchronous or asynchronous motors, increase of pole pairs reaches the required decrease of motor speed, but the size and weight of the motor is increased, the level of utilization is lower. Power index is also worse, therefore, this method applies only to certain speed range. DC(direct current) motors in general have good speed characteristics and power index, however, fluctuation of torque and speed often appears in low-speed operation. Meanwhile, the use of DC motors has been restricted because of operation environment and maintenance factors. In order to obtain low-speed and large torque, the method of deceleration using mechanical gear reducer was adopted in the past, it has many problems and defects. So development of science and technology has proposed the task of research and production of various low-speed motors.Reactive low-speed synchronous motor is a new type of magnetic resistance synchronous motor. This paper describes structure,working principle and air-gap magnetic presences wave of reactive low-speed synchronous motor, the expression of electromagnetic torque is derived. Voltage equation, flux equation and torque equation are given in the paper; the motor parameters have an effect on the torque characteristics by analyzing voltage equation of reactive low-speed synchronous motor.In the time-step finite element calculation of reactive low-speed synchronous motor.Firstly, using ANSYS software for processing of the motor gets node files and unit files; and then, parameters of the motor are calculated through the magnetic method in the case of voltage and torque given, two documents and the motor parameters are used as the input of the time-step finite element calculation; at last, this paper describes the field-circuit coupled time stepping finite element method calculation of the dynamic characteristics of the motor process. The method of the time-step finite element applied to calculate start-up process of reactive low-speed synchronous motor. Calculation shows that both oscillation and asynchronous operation may occur. Focusing on these problems, theoretical research draws that the asynchronous torque, induced from relative motion between air-gap fundamental magnetic field and stator while the speed offsets from the synchronous one, is the essential reason.Moreover,formulas of asynchronous torque is deduced.The proposals aimed to improve the motor's start-up performance are mentioned.