Identification of parameters and harmonic losses of a deep-bar induction motor

High frequency harmonics from a frequency converter causes additional losses in a deep-bar induction motor. The harmonics have their own amplitude and phase with respect to the fundamental signal, but the harmonic loss is only dependent on the amplitude of harmonics. A deep-bar induction motor can be modelled by a triple-cage circuit to take skin effect into account. The triple cage circuit having many parameters could be estimated from a small-signal model of the machine by using Differential Evolution. The correctly estimated parameters make the triple-cage circuit valid in a wide range of frequencies. However, the triple-cage circuit is very complicated which makes it difficult to model harmonic losses for motor control. A simplified circuit based on the triple cage circuit is proposed for certain frequency ranges. The identified losses implemented on the simplified circuit are verified via finite element analysis and triple-cage circuit.