Harmonic Brushless Field Excitation Methods for Electrical Machines

The objective of this research project, entitled “Harmonic Brushless Field Excitation Methods for Electrical Machines” (HARMFIX), is the design and development of new rotor field excitation methods to achieve brushless operation in wound field electrical machines.

Electric motors and generators are key components in the ongoing energy transition and electrification efforts, and they will play an integral role in people’s lives in a future low-carbon society. Statistical data and estimates show that electric motors consume over 45% of the world’s electricity, and the number of motors is expected to double by 2040. Therefore, it will be difficult to achieve the EU policy targets and the UN Sustainable Development Goals (SDGs) without significant improvements in electric machines (motors and generators) to create a more sustainable, greener world.

This research project will provide an opportunity to reduce the reliance of electric machines on rare-earth materials, of which the EU has limited resources, and eliminate the need for brushes in their rotor field excitation, while improving the reliability and cost-efficiency of electromechanical energy conversion systems. Through this project, new armature winding configurations will be developed to generate not only the fundamental magnetomotive force (MMF) but also a suitable harmonic MMF component in the airgap of the electric machines, all while powered by a single, standard current-controlled voltage source inverter (VSI). The rotor of these machines will be modified to accommodate both harmonic and field windings. The harmonic MMF component will be used to induce a harmonic current in the rotor's harmonic winding, which will be rectified to excite the rotor field winding, thus enabling brushless operation and torque generation.