Current Compensation Control Strategy for Reduction Normal Force Ripple of PMLSM

Abstract

The ripple normal force of permanent magnet linear synchronous motor (PMLSM) can directly deteriorate the machining accuracy of ultra-precision CNC machine tool which use linear motor direct drive. First, the normal force of PMLSM was calculated using finite element method (FEM) .then, id current compensate lookup table was established by indexing iq current, gap and position of mover .In order to reduce the ripple of normal force and keep the thrust steady, PMLSM current compensation control system was realized by injecting the id current to counteract the normal force ripples using field oriented control (FOC) method. The effectiveness of this proposed method is verified by the simulation using Matlab according to the comparison between the compensation and no compensation cases.

Speed Control of Segmented PMLSM Based on Improved SMC and Speed Compensation Model

“…The neural network (NN) was applied to compensate the end effect of a PMLSM to minimize the fluctuation on thrust force [20][21][22], and the position error of a segmented PMLSM is accurately controlled at 0.28 mm. The current compensation model was designed to stabilize the thrust force of a PMLSM based on the position of the PM actuator [23,24]; the speed precision was enhanced by reducing the nonperiodic and uncertain components of detent force [23]. According to the state feedback of proportional-integral-derivative (PID) control, the adaptive feedforward compensation model was used to regulate the thrust force of a segmented PMLSM.…”