Mathematical Modeling and Experimental Validation of a Fault-Tolerant Dual Stator LHEFSM for Rail Transit Applications

Due to the properties of high thrust density, power density, and efficiency, Linear Hybrid Excited Flux Switching Machines (LHFSM) are centric for many researchers, especially in rail transit applications. A segmented mover dual stator LHFSM (SMDS-LHFSM) with concentrated armature and field windings is proposed in this paper. The concentrated windings help in reducing the overall copper losses. Flux gaps are added between the mover segments, making the machine a fault-tolerant. A small quantity of permanent magnets is used to reduce the overall cost of the machine. The suitable coil combination and open-circuit flux linkage are derived by magnetic circuit modeling and validated by FEM to reduce time and drive storage. Genetic algorithm (GA) is used to globally optimize the varying parameters of the proposed design and improve the initial performance. After GA, the thrust and thrust ripples are improved by 35.92% and 13.16%, respectively. A mathematical model is developed to verify the fault-tolerant capability and thrust of the proposed machine. Key electromagnetic performance parameters are investigated in depth. The proposed design has 17.6% higher thrust than the conventional machine. Finally, a prototype is fabricated to validate the theoretical analysis. The proposed SMDS-LHFSM has achieved fault-tolerant capability by achieving the mutual inductance value close to zero, flux regulation of 61.16% that is important in variable speed applications and a good temperature distribution after putting it for 2 hours under test.