Finite Element Analysis of a Permanent Magnet Machine with Two Contra-rotating Rotors

Abstract

Electrical machines with contra-rotating rotors find applications in direct-drive energy conversion systems and in ship propulsion systems that employ hydraulic machinery with two contra-rotating stages. In this article, the operating characteristics of permanent magnet machines with two contra-rotating rotors moving on opposite sides of a common stator core are studied via two-dimensional finite element analysis. Particular attention is devoted to the special flux distortion patterns that arise in contra-rotating machine topologies. The study suggests that the introduction of a screening iron core between the rotors provides for negligible flux distortion levels during contra-rotating synchronous operation of the two rotors.

Keywords:

• contra-rotating rotors
• finite element analysis
• permanent magnet machines