Split-Yoke Axial-Flux PM Machine with Ultra-Low Rotor Inertia for Enhanced Servo Dynamic Performance

This article introduces a novel axial-flux permanent magnet motor (AFPM) topology for servo applications. Although many papers focus on the good torque generation capability of dual rotor AFPM, the large rotor inertia is not ideal in servo drives. By increasing torque generation and reducing rotor inertia, motion control response can be improved. This article introduces a new AFPM topology with a split rotor yoke, which is simply a rolled steel plate fixed to the front cover of the machine. With this special and simple component, rotor inertia can be significantly reduced, and the manufacturing process is as simple as a regular single-rotor AFPM because there is only one winding stator. In this topology, the rotor is only composed of magnets and some structural components, thus exhibiting a very light rotor inertia. This article explains how to construct the rotor structure for a better motion performance and discusses design details. A prototype with this proposed structure was fabricated. Experimental verification includes the steady-state performance, motion response, and energy- conservation effect evaluation.