DEVELOPMENT OF MICROPROCESSOR BASED COMMUTATORLESS CONSTANT POWER KRAMER DRIVE

Abstract

The dissertation concerns the Development of Micro - processor Based Commutatorless Constant Power Kramer Drive which consists of a wound rotor Induction motor and a con anu-tatorless motor. The slip power extracted from the stor terminals of the induction motor is rectified and converted to mechanical power by the commutatorless motor which is coupled mechanically to the induction motor shaft forming a constant power drive. The d.c. link consists of a rectifier, a chopper, and a commutated inverter. The d.c. link inverter and synchronous machine with sync, ronised firing circuit is popularly known as commutatorless motor (CLM) . The CLM is among the earliest attempts to replace the mechanical commutator of D.C.motor. Speed control in the entire sub-synchronous region is accomplished by either varying the field current of the CLM, or the duty cycle of the chopper. By reducing the - duty cycle of the chopper, the effective armature voltage of the CLM and hence the speed of the drive is reduced. The firing pulses of the thyristors of 101 and chopper are generated by the microprocessor. The firing angle of LCI is kept constant through out the operation. The system description, principle of operation and imple mentation of the system software and flowcharts are presented.