Design, Simulation and Performance of a Four Phases Linear Variable Reluctance Motor

Abstract

The linear variable reluctance motor (LVRM) is a motor used in linear applications converting electromagnetic energy into linear movement and thrust. This paper aims at the analytical design of the machine and its validation through the finite element method. The design of a unilateral LVRM model of longitudinal flux type with passive translation movement is developed through the output power equation of the variable reluctance machine (VRM). The finite element analysis (FEA) is applied in order to check the values of inductance, the normal forces and propulsion. The FEA is also necessary to observe the undulation factor (ripple force), highly present in LVRM's, which produces vibration and acoustic noise. The analysis of the relationship between polar arcs and polar pitches plays an important role in the development of LVRM’s output force in the reduction of motor weight and volume. The LVRM model is developed from desired parameters, the maximum length of the stator, maximum speed and mass of the translator; through the design of a variable reluctance rotary motor (VRRM). The VRRM specifications are then converted into its linear equivalent. Keywords – finite elements; FEMM; ripple factor, ripple force; linear machines; variable reluctance motors.