High-performance current regulation and efficient PWM implementation for low-inductance servo motors

This paper reports on a standard microcontroller implementation of a pulsewidth modulator and near-deadbeat current regulator for high switching frequency. The application is in high-performance positioning systems. The control strategy relies on a simplified machine model without incurring performance degradations. Changes between different modulation strategies are programmed depending on the modulation index. The values of switching time durations are obtained exclusively by decision making, thus minimizing computational load. Features like over-modulation (OVM), dynamic OVM, anti-windup, and reduction of switching frequency at thermal overload are included.