Induction Machine with Integrated Magnetic Gear

Abstract

There have been many recent advancements in magnetic gears and pseudo-direct drive permanent magnet machines with integrated magnetic gears. Despite these advances, there several applications where induction machine drives are preferable. This proposed work investigates the feasibility of a pseudo-direct drive induction machine, with an integrated magnetic gear. It presents some of the difficulties in the design process as compared to the design process for permanent magnet machines. The performance of a pseudo-direct drive induction machine, with an integrated magnetic gear, is investigated. A prototype design at a small scale is developed, and simulation results demonstrate the potential for high torque density with good loading characteristics. This research work presents a design process to integrate a magnetic gear with an induction machine. The resulting integrated machine has the potential to offer a high torque density with asynchronous speed characteristics. Such characteristics may be desirable for applications that require a sensorless operation or may be subject to severe backlash or jamming. An investigation into magnetic gear modulating ring design geometry and the performance of a magnetic gear integrated into an induction machine are presented. Modulating ring construction is one of the difficult aspects of magnetic gear design, and a compromise between magnetic performance, losses in conductive supporting parts, and manufacturability is often required. Six possible designs for modulating rings are presented, and their magnetic performances are compared with an ideal but unrealistic case of independent modulating parts. Results are presented for the case with a magnetic gear integrated with an induction machine but may be generally applicable to all radial flux magnetic gear configurations. The assembly of the prototype machine and its experimental performance are presented. Complications during the experimental work and modulating ring failure are discussed. Finally, recommendations for design improvement and future work are suggested.