Calculation of iron losses in inverter-fed induction motorbased on field-circuit coupled method
WANG Hai-rong，WU Jian-hua
（College of Electrical Engineering，Zhejiang University，Hangzhou 310027，China）
Abstract：Compared to the sinusoidal excitation，iron losses in inverter-fed induction motors are calculated more complex due to manyharmonic components in the inverter. In order to calculate iron losses in inverter-fed induction motors accurately，an computation ironlosses model was established based on 2-D circuit-field coupled time-stepping finite element method. Taking a 1.5 kW motor as anexample，iron losses in the motor were calculated at the no-load condition. The specific distribution of iron losses in the induction motor
under sinusoidal and inverter excitation were also studied and compared respectively. Based on the above analysis，the influences of thecontrol strategy for the inverter on iron losses were also investigated. Finally，iron losses in the prototype motor were measured by the noloadtest. The results indicate that the calculated value can make a good agreement with the measured，and iron losses at the rotor sidewhich is normally neglected in the sinusoidal supply can't be neglected. The iron losses in the tooth area are due to high harmonics. The
achievement can provide some technical support for developing optimized design of core structure to reduce iron losses and temperaturerisestudy in motors.
Key words：iron losses；inverter-fed induction motor；finite element method（FEM）；field-circuit