The rotor copper and iron loss analysis of inverter-fed induction motor considering rotor slip frequency

Abstract

Due to the harmonics produced by inverter supply, the distribution characteristics of rotor copper and iron losses become more complicated in the inverter-fed induction motor (IFIM). To study the distribution characteristics of rotor copper and iron losses of the IFIM, we propose a new method to identify the harmonics of current density in the rotor bar and flux density in the rotor core using one supply cycle's data from the finite element model. The harmonic components in slip frequency are computed by the space-time symmetrical characteristics of the induction motor (IM). And based on a mathematical approach, the higher order frequency harmonics are calculated using data from one supply cycle. Then, we have calculated and analyzed the rotor copper and iron losses of a 5.5 kW IFIM. The experimental validation is performed using the 5.5 kW IFIM under different load conditions. And the calculated and the method motor losses of the 5.5 kW IFIM agree well.