Design and performance analysis of novel coaxial magnetic gear using subdomain method

Abstract

This paper has introduced an innovative coaxial magnetic gear (CMG) design that has addressed limitations in volume, weight, magnetic losses, and corrosion in conventional CMGs by strategically segmenting permanent magnets and incorporating electrical steel sheet supports within a comb-shaped outer yoke. An inverted T-shaped pole piece has been introduced to enhance the magnetic field. To analyze the CMG, it has been divided into five subdomains, and an analytical method employing Laplace and Poisson equations, along with boundary and continuity conditions, has been used to derive the magnetic field and torque equations. The proposed model has been validated against finite element analyses using the Maxwell stress tensor, which has demonstrated excellent agreement. Furthermore, the design has been verified by comparing it with an equivalent existing CMG model in a small-scale wind turbine application. The results have shown a 3.2% increase in magnetic flux density and a 2.06% increase in magnetic torque. These improvements have highlighted the potential for the proposed CMG design to advance the application of electrical machines in modern engineering solutions.