High speed brushless DC PMSM: optimal design and control contributions

Abstract

The present thesis investigates the optimal design with embedded FEM of a 6/4 brushless DC motor fed with trapezoidal currents for refrigerator compressors. Validation of the optimal topologies is done through FEM and cogging torque reduction techniques are employed in order to minimize as possible torque pulsations. A dynamic model is built taking into account phase commutation phenomenon and using back EMF waveforms from FEM to be more realistic. Sensorless control based on active power combined with I-f method for low speeds is developed and verified through simulations and experiments with satisfying results. A new PAM converter is introduced in the DC link to reduce the size and cost of the inverter and simulated with satisfying results.