Comparative Evaluation and Fault Tolerance Analysis of Dual Stator Induction Motors under Unbalanced Load Conditions: Simulation and Experimental Study

Abstract

In the pursuit of energy-efficient and fault-resilient electric drive systems, multiphase machines such as dual stator induction motors (DSIMs) have emerged as promising alternatives to conventional three-phase designs. This study presents a comprehensive simulation and experimental evaluation of a six-phase DSIM, designed by integrating two spatially displaced three-phase windings within a 24-slot, 5.5kW stator core. The machine was mathematically modelled using dq - axis transformation, and its dynamic behavior was simulated in MATLAB/Simulink, with supplementary loss and thermal analysis carried out in Motor-CAD. The system was tested under both balanced and unbalanced loading conditions, including single-phase disconnection and voltage asymmetry, to assess its fault tolerance and operational robustness. An experimental prototype was validated using test bench equipped with real-time measurement tools for torque, current, and speed. The results demonstrated that the DSIM exhibits superior fault tolerance, maintaining operation with minimal degradation under asymmetric conditions. Compared to its three-phase counterpart, the DSIM achieved improved torque stability, reduced harmonic distortion, and enhanced synchronization characteristics. Loss analysis revealed a reduction in both stator and rotor copper losses, with overall machine efficiency increasing from 84.0% in the conventional design to 88.4% in the DSIM configuration. Additionally, the DSIM displayed faster settling times and better phase current stability during transients. These findings confirm the DSIM’s suitability for high-reliability applications, energy-sensitive environments, and academic laboratories. The study not only bridges the gap between theoretical modelling and practical implementation but also supports the deployment of DSIMs in real-world systems requiring high resilience and energy performance. For high-power industries, electric vehicle traction, renewable energy systems, and critical infrastructure, these efficiency gains directly translate into lower operational costs, enhanced system resilience, and a smaller carbon footprint. It also leads to energy savings, operational reliability, reduced lifecycle costs, and sustainability benefits. In the pursuit of energy-efficient and fault-resilient electric drive systems, multiphase machines such as dual stator induction motors (DSIMs) have emerged as promising alternatives to conventional three-phase designs. This study presents a comprehensive simulation and experimental evaluation of a six-phase DSIM, designed by integrating two spatially displaced three-phase windings within a 24-slot, 5.5kW stator core. The machine was mathematically modelled using  transformation, and its dynamic behavior was simulated in MATLAB/Simulink, with supplementary loss and thermal analysis carried out in Motor-CAD. The system was tested under both balanced and unbalanced loading conditions, including single-phase disconnection and voltage asymmetry, to assess its fault tolerance and operational robustness. An experimental prototype was validated using test bench equipped with real-time measurement tools for torque, current, and speed. The results demonstrated that the DSIM exhibits superior fault tolerance, maintaining operation with minimal degradation under asymmetric conditions. Compared to its three-phase counterpart, the DSIM achieved improved torque stability, reduced harmonic distortion, and enhanced synchronization characteristics. Loss analysis revealed a reduction in both stator and rotor copper losses, with overall machine efficiency increasing from 84.0% in the conventional design to 88.4% in the DSIM configuration. Additionally, the DSIM displayed faster settling times and better phase current stability during transients. These findings confirm the DSIM’s suitability for high-reliability applications, energy-sensitive environments, and academic laboratories. The study not only bridges the gap between theoretical modelling and practical implementation but also supports the deployment of DSIMs in real-world systems requiring high resilience and energy performance. For high-power industries, electric vehicle traction, renewable energy systems, and critical infrastructure, these efficiency gains directly translate into lower operational costs, enhanced system resilience, and a smaller carbon footprint. It also leads to energy savings, operational reliability, reduced lifecycle costs, and sustainability benefits.