Conference Agenda

In the development of ventricular assist devices (VADs), torque stability in electric motors is critical to ensuring continuous blood flow and minimizing adverse hemodynamic effects. This research describes a multi-objective geometric optimization framework for minimizing ripple torque in a brushless DC (BLDC) motor designed for a VAD with an axial drive but no central shaft. The electromagnetic model was implemented using the finite element method in COMSOL Multiphysics and coupled to MATLAB via LiveLink™, allowing for the automatic evaluation of geometric configurations. Five rotor and stator design parameters were designated as choice variables, and an optimization problem was established with three objectives: limiting torque variation, maintaining a minimal average torque of 50 mN·m, and regulating the air gap area. Optimization was performed using the NSGA-II evolutionary algorithm, running approximately 5000 model evaluations. The results showed that it is possible to reduce ripple torque from 14.8% in the original configuration to values below 5% within the Pareto feasible set, while maintaining the minimum axial torque requirement. The analysis revealed an inherent trade-off between ripple reduction and average torque magnitude. The proposed methodology proves to be an effective tool for the electromagnetic optimization of BLDC motors in biomedical applications.