A comprehensive analytical power loss model of an induction motor drive system with loss minimization control

This paper proposes a novel analytical loss model of an induction motor drive system and a model-based loss minimization technique (LMT). Although various models of individual motors and inverters are found in the literature, a comprehensive model of the inverter-fed drive system is lacking which impedes the optimization of the system-level efficiency. The proposed model contains a novel dynamic induction machine model including copper and core losses, and an analytical inverter model including conduction and switching losses. A parabolic curve fitting, instead of the commonly used linear curve fitting, is applied to the switch and diode conduction characteristics for low inverter currents. A loss minimization control of the system is designed based on indirect field oriented control (IFOC) to provide the optimal value of the d-axis rotor flux linkage (λ_dr*) as the control variable. Detailed mathematical derivation and simulation validation of the drive loss model are presented.