Magnetic Characteristics Investigation of an Axial-Axial Flux Compound-Structure PMSM Used for HEVs

Abstract

An axial-axial flux compound-structure permanent-magnet synchronous machine (CS-PMSM) system used for hybrid electric vehicles (HEVs) enables the internal combustion engine (ICE) to operate at optimum efficiency region independent of road conditions, thus decreasing the fuel consumption and emissions remarkably. The axial-axial flux CS-PMSM is a high-degree integration of two axial-flux PMSMs. The magnetic coupling problem of the CS-PMSM is investigated based on magnetic circuit and finite-element method (FEM). The influences of the magnet rotor structures on the magnetic coupling are evaluated. Halbach structure is used for the magnet rotor, which makes the design of CS-PMSM more flexible. Further, a prototype machine of the axial-axial flux CS-PMSM was designed and manufactured. The experimental results show that the magnetic coupling problem can be solved perfectly due to special structural design, which verifies the theoretical analysis.