Design And Analysis Of Inverter-driven Induction Motor

Following with the development of power electronics technology, the inverter-driven induction motor is widely used in all kinds of industry field. The utility of variable frequency and adjustable speed systems brings a new research area of power electronics and motor drive subject, which is the design and analysis of inverter-driven induction motor. This paper begins with the design of inverter-driven induction motor. Firstly, compare the design method of inverter-driven induction motor with that of conventional induction motor. And point out the limitations of design method of conventional induction motor which is used in the design of inverter-driven induction motor. In the design of inverter-driven induction motor, the designs of rotor's slot number, slot type and insulation are different from those of conventional one. The design of inverter-driven induction motor has many advantages. The generation mechanics of time and space harmonics in the inverter-driven induction motor is analyzed in details. The influences of both types of harmonics to the operation of induction motor are described, especially the harm to the insulation structure of induction motor. Based on the characteristics of time and space harmonics in the inverter-driven induction motor, several effective strategies for restraining the harmonics are presented from the aspects of motor design and control. The total harmonics distortions of input line voltage of inverter-driven induction motor are compared between the simulation results and experiment results. Because the variable frequency and adjustable speed systems are commonly used in the situations which need frequent starting-up and speed adjustment, the inverter-driven induction motor is required to work under different power points. The parameters, such as efficiency, power factor, loses and so on, are different under different power points. With the supply of inverter, the harmonics of input voltage and current affect the operating performance of induction motor, for the curves of input voltage and current are different from those of normal supply. According to above reasons, the simulation and research of inverter-driven induction motor are carried through under different power points and supplies. And the simulation results are compared with those of experiment. Compared with the conventional induction motor, the work conditions of medium-voltage high-capacity induction motor fed by inverter change. Therefore, some special measures should be adopted in the design, such as widening the airgap, using the technology of vacuum pressure impregnation, and so on. Based on the harmonics analysis of inverter-driven induction motor, a 6000V 1250kW induction motor is designed in this paper, which could be used in the variable frequency and adjustable speed systems.