Research Of Iron Losses In Induction Motor Fed By Inverter

As is well known, induction motor plays an important role in modern industry, and is a kind of electric equipments which have the most power consumption. Therefore, it is important to improve the efficiency of induction motor not only from the viewpoint of energy saving, but also from the broad perspective of environmental. In the motors, iron losses account for a larger proportion of the total losses. In particular, with the power electronics technology development, more and more motors are supplied by power inverter. And the output harmonic component of the inverter will not only generate additional losses in the stator core, but also in the rotor core. Taking into account the cooling condition of the rotor is bad, this will have an effect on working life of the motor. Therefore, it is necessary for the iron losses of the induction motor fed by inverter to analyze further, in order to improve the working performance.Based on the magnetization mechanism of the ferromagnetic material, the work deeply analyzes the generated reason and calculated methods of the losses in ferromagnetic material, including hysteresis losses, eddy losses and anomalous losses. The iron loss model of the motor under non-sinusoidal supply is also deduced. Furthermore, the generation mechanics of time and space harmonics in the inverter-fed induction motor is analyzed in details. The influences of both types of harmonics on the iron losses of induction motor are described. Next, the finite element model of induction motor is established by using Maxwell 2D transient module, and the inverter control circuit is also designed by its own circuit design editor. Consequently, a complete field-circuit coupled simulation model of inverter control system is presented. At the same time, Rmxprt software is adopted to analyze the magnetic circuit of the motor, in order to use the calculated results of the required electrical parameters as finite element analysis of input data. Through transient finite element analysis to the simulation model, the effect of inverter parameters, such as amplitude modulation ratio and switching frequency, on eddy current losses in induction are studied. In addition, because it is difficult to measure the rotor iron losses, there is no appropriate experimental vertification method for the calculation method. An experimental verification method which can verify the calculation method is presented, so as to improve the accuracy of the electrical design and to provide guidance of the engineering.