Brushless permanent magnet (BPM) motor drive system using load commutated inverter

The goal of this work is to develop a brushless permanent magnet (BPM) motor drive system with low total system cost, high reliability, and adequate performance for high volume production and application to residential and commercial appliances. The converter used is a low cost thyristor based load commutated inverter (LCI). Although, LCIs have been used to supply the sinusoidally excited permanent magnet motors, their application to BPM motors is a key contribution of this work. A detailed digital computer model capable of predicting the steady state as well as the transient performance of the BPM motor driven by a LCI has been developed. The utility side phase controlled rectifier as well as the motor side inverter including the DC link inductor are modeled. A load commutated inverter, specifically designed to supply the BPM motor has been fabricated in the laboratory. The developed control strategy which has been implemented on an INTEL 80C196KD microcontroller board is also presented. Simulation and experimental results to support the use of a LCI to drive a BPM motor is included in the paper