Compound-structure permanent-magnet synchronous machine used for HEVs

This paper describes a compound-structure permanent-magnet synchronous machine (CS-PMSM) system used for hybrid electric vehicles (HEVs). It enables the vehiclepsilas internal combustion engine (ICE) to run at its optimum working points regarding efficiency, almost independently of the changing load requirement at the wheels, thus improving fuel economy and reducing emissions. The key part CS-PMSM is a high integration of two electric machines. Different topologies of the CS-PMSM are put forward, and a 20 kW radial-radial flux prototype machine was designed and manufactured for the testing facilities and concept validation. Magnetic-coupling degree between the two electric machines is evaluated and the transient model of the CS-PMSM is established. Further, the magnetic characteristic is analyzed based on the calculated inductances, and the efficiency maps are presented for evaluating the prototype machine.