Thermal analysis and efficiency of an induction motor driven by a fault-tolerant multilevel inverter using FEM

Abstract

Purpose

The purpose of this paper is to present a comparative study of the thermal behavior and efficiency of an induction motor fed by a fault-tolerant Three-Level Neutral Point Clamped (3LNPC) inverter, under normal conditions as well as after a post-fault reconfiguration, following an open-circuit fault in the inverter. For this purpose, a Matlab/Simulink model and three-phase induction motor models using a finite element method (FEM) software were developed. Besides, some experimental tests were conducted for different values of the induction motor load torque and speed reference to validate the models.

Design/methodology/approach

To assess the thermal behavior and efficiency of the motor, electromagnetic and thermal models using a FEM software were developed. The coupling with the inverter drive is accomplished through a developed model in Matlab/Simulink which also includes the control system. The simulation tests were performed for a healthy and faulty inverter at different operating points of the three-phase induction motor. To validate the FEM models some experimental tests were performed.

Findings

When the inverter operates in reconfigured mode the motor losses are higher and consequently temperature is higher and the motor efficiency is lower. The developed models are an alternative to a more detailed study of the motor when fed by a 3LNPC inverter and consequent optimization of the control system.

Originality/value

With the developed tools, a better understanding of the motor behavior and performance is gained, allowing to forecast scenarios and optimize fault-tolerant control strategies for the drive.

Citation

Baptista, B.R.O., Mendes, A.M.S. and Cruz, S.M.A. (2015), "Thermal analysis and efficiency of an induction motor driven by a fault-tolerant multilevel inverter using FEM", COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, Vol. 34 No. 2, pp. 573-589. https://doi.org/10.1108/COMPEL-08-2014-0222