This thesis concerns the development of a variable speed control system for a transverse-flux heteropolar linear synchronous motor and a control scheme to optimise the efficiency and minimise the interaction existing between the lift and tractive force produced by the motor. A data acquisition system was designed and built to manipulate and display data from transducers fitted to the motor on to a mini-computer. Control programs have been developed to acquire both electrical and mechanical transient conditions. A variable frequency 3 phase armature current controller and a field current controller have been developed for powering the motor. Both controllers employ power transistors as switching elements and utilise slitwidth modulation techniques. Practical aspects of designing a transistorised current controller are discussed. Strategies for controlling a synchronous motor are examined. A system for controlling the motor at a constant torque angle of 90° bas been developed to optimise the efficiency and minimise the interaction between the two forces. Experimental results suggest that the controlled motor cannot slip out of synchronism under any conditions and is self-starting. A 'software implemented* variable speed control loop is implemented on a microprocessor-based controller. Certain aspects of designing this controller are presented. Practical results show that the motor achieves a smooth drive even at low speed. Further enhancement of a constajit speed drive independent of the influence of the change in field current within a designed range is demonstrated by experimental results. Although the system is primarily designed for the linear synchronous motor, it is also applicable to other synchronous motors. A proposed position control system utilising a linear synchronous motor is also introduced.
|Date of Award||1982|