Analysis, design and control aspects of linear machines using co-simulation

Abstract: This research work describes the permanent magnet linear machines, their characteristics, control and applications. It aims to develop a linear machine model in finite element based software, Flux2D. The Finte Element Method (FEM) model consists of 8 poles and 9 slots where periodicity of poles is used to simulate inifinite travel length. The no-load and nominal load conditions are also simulated to validate the performance of the model. At no-load, the cogging force is simulated and is found to be 1.1N. The machine produces sinusoidal back EMF of 264V. For nominal load, machine is simulated with three-phase current source of 2A. Under nominal load conditions, nominal thrust of 784.8N with 1.08% ripple is achieved. The average force of attraction between the mover and stator is 4307N. The report also describes the current research trends and market of linear machine’s applications. Linear machines are 3.8 billion US$ industry in which robotic applications have a major share. The controller model is implemented in simulation software Portunus. Literature review of different control strategies for motion control of permanent mangnet linear synchronous machines is included. However, vector control is chosen for simulation purposes. The controller model is validated using the analytical model of rotary machine in Portunus. The controller is then integrated with machine model developed in Flux2D and co-simulation is performed. A simulation of 100ms takes up to 24 hours and 30 GB of disk space. Better computing abilities may help improving the simulation speed in future.