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 commercial appliances. The power converter used is a low-cost thyristor-based load-commutated inverter (LCI). Although LCIs have been used to supply 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 a BPM motor driven by an 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 has been implemented on an INTEL 80C196KD microcontroller board. Simulation and experimental results to support the use of an LCI to drive a BPM motor are included in the paper.