High-performance Microcontroller-Based Transvector-Controlled Pulsewidth Modulator-Induction Motor Drive

A fully digitalised transvector control PWM-IM drive system based on the M68HC11 microcontroller is described. The controller receives a digital speed command from a host computer via RS-232 interface. The feedback control system employs a transvector control technique to achieve a high dynamic performance in the estimated frequency range from 5 to 100 Hz. The PWM modulator utilises a computational intensive, uniformly sampled sine wave technique at low frequency region while a look-up table, pattern retrieval method base on the harmonic elimination optimal technique is utilised at high frequency region. The system hardware is mostly based on the programmable counters while system software is completely written in C++.