A Combined Feed forward-Feedback Strategy for Rotor Eccentricity Control in Switched Reluctance Motor Drive

Abstract

Rotor eccentricity in electrical machines can occur due to number of reasons like unbalance in rotor assembly, aging/loose bearings, windage etc. The eccentricity of rotor leads to Unbalanced Magnetic Pull (UMP) leading to permanent damage of rotor and stator of the machine. Due to its small air-gap, Switched Reluctance Motor (SRM) is very sensitive to even a slight variation in the assembly of rotor. This paper discusses the development of a suitable method to reduce the UMP by controlling the rotor eccentricity in SRM. Finite Element Method (FEM) is used to determine the UMP is due to variation in rotor eccentricity. The values of UMP show that the radial force acting of the rotor under loaded condition are dangerously high. Active Magnetic Bearing (AMB) with suitable control system will help the entire system mitigate the UMP. A Rotor-AMB system is analyzed and suitable controllers are designed for control the rotor eccentricity under rated load condition. For this a feed forward controller is introduced in addition to the feedback PID controller, for the effective mitigation of Unbalanced Magnetic force.