Synchronous servo-drive: a compact solution of control problems by means of a single-chip microcomputer

The completely digital control of high dynamic synchronous servo-drives with rare-earth permanent-magnet (PM) disk rotor is considered. The aim was to bring the hardware of the control unit into a very small and compact form. The realized unit consists of two modules: a 16-b single-chip microcomputer including measurement value detection, set value output, and communication interfaces; and a MOSFET voltage source inverter controlled by pulsewidth modulation techniques. Due to the structure of the digital system, several control strategies were realized and compared: a mathematical model of the PM synchronous motor was derived, methods of voltage space phasor generation were found, and digital control algorithms without the support of any analog feedback circuits were implemented. A position feedback controller was realized. Results of the digital simulation and of the practical plant are given