| The objective of this work was to investigate induction motor control techniques that maintain maximum thrust per ampere in the presence of varying secondary resistance due to variation in reaction rail temperature, geometry and material. This study has relevance to linear induction motor (LIM) propulsion systems for transit vehicles.; Field oriented control has been widely investigated for the control of the rotary induction machine in high performance applications, but no attempt to implement it on a linear induction machine has yet been reported. The slip-frequency stator-current control method was investigated and was used for comparison with the field oriented control method.; Instead of maintaining the flux constant, as is typically done in variable speed electrical drives with flux regulation, an expression is derived for a demand flux as a function of the demand torque. The flux is then adjusted for the load condition in a way that forces the induction machine to operate at maximum torque per ampere. Simulation studies are performed to evaluate the system steady state and dynamic response to various perturbations. (Abstract shortened by UMI.)... |
