DEVELOPMENT OF A PWM INVERTER FED 1M DRIVE WITH HARMONIC ELIMINATION

Abstract

The technique of Selective Harmonic Elimination ( SHE ) is an established method of generating PWM signals which allows the PWM waveforms to be obtained for a given fundamental voltage and for a set of any chosen harmonics eliminated. This technique hOweVer suffers from the limitation that it requires pre-calculation of optimal angles which may then be implemented in a microprocessor based system by storing them in the form of bulky look-up tables. Recently harmonic elimination PWM strategy has been developed using modified 'Regular SampLine techniques. These PWM strategies can be impleMented using microprocessor software algorithm, without going to usual off-line mainframe harmonic elimination numerical computations. This new PWM technique can be implemented for complete voltage/frequency range of the drive and Quasi Square Wave operation is also possible.