Design to reduce the cost and to improve the mechanical durability of IPMSM for the traction motor of military truck

Abstract

The interior permanent-magnet synchronous motor (IPMSM) is often used as the traction motor of hybrid electric vehicles (HEVs) and electric vehicles (EVs) due to its high power density and wide speed range. This paper introduces the 120kW class IPMSM for the traction motor of military truck. This system as SHEV (series hybrid electric vehicle) needs a traction motor which generates high torque. To reduce the cost, the design approach which the reluctance torque would be maximized by varying the dq-axis inductance is introduced. If the model designed by design approach satisfies the desired torque, the magnetic torque can be reduced as much as reluctance torque increases, and consequently the amount of permanent magnets can be reduced. The reduction gear and high speed operation of motor are needed for the miniaturization of motor. Thus, a fairly large centrifugal force is generated due to the high speed operation of motor. This force causes the mechanical interference between the rotor and the stator, and the design approach which adds the iron bridge is explained to solve the interference. The initial model and improved model which reduce the cost and improve the mechanical durability are compared by FEA, and the models are produced. Finally, the FEM results were verified through an experiment.