Harmonic Brushless Field Excitation Methods for Electrical Machines

This project is focused on the design and development of new rotor field excitation methods to achieve brushless operation for wound-field electrical machines (EMs). The proposed method will provide an opportunity to reduce the reliance of EMs on rare-earth materials of which EU is lacking its resources and eliminate the usage of brushes for their rotor field excitation while improving the reliability and cost-efficiency of the machine systems. Through this method, a new armature winding configuration will be developed to generate not only the fundamental magnetomotive force (MMF) but also a suitable harmonic MMF component in the airgap of the EMs, while powered from a single customary current-controlled voltage source inverter (VSI). The rotor of these machines will be altered to house both harmonic and field windings. The harmonic MMF component will be employed to induce a harmonic current in the harmonic winding of the rotor, which will be rectified to excite the rotor field winding to achieve brushless operation and develop torque. A new topology optimization methodology will be developed to optimize the windings and minimize copper consumption. The EMs employing HARMFIX do not require rare-earth materials, costly auxiliary electromechanical excitation systems or custom-made power electronics circuitry, or control strategies for their brushless operation. Therefore, this method is a truly viable and sustainable alternative for commercial products which are currently employing rare-earth materials, brushless exciters or brushes, and slip rings.