Study And Design Of Servo Controller For Permanent Magnet Synchronous Machine

Traditional direct current motors were adopted widely in servo-control fields fortheir outstanding mechanical characteristics and simply control ways. But due to theircommutators and brushes, the reliability and the applicability of direct current motorsare depressed. As a new type, for the commutators and brushes are removed, PermanentMagnet Synchronous Machines(PMSM) have a simpler structure and smaller size thanthat of direct current motors, and no power loss in rotors when running. So, they cantake the place of direct current motors, and can be widely used in many servo-controlfields.Researches for control strategies of PMSM are important to adopt them inservo-control systems. The rotor field oriented vector control strategy is generallyadopted in many alternating current servo-control systems. The fundamental principleof the strategy is controlling the magnet current and torque current in stator windingsseparately by using coordinate transforming. So, as well as direct current motors,alternating current motors have a good performance. In this paper, a improved controlmethod for PMSM servo-control system which adopt coupling terms are set up based onthe theory of the rotor field oriented vector control strategy and the characteristics ofPMSM. By adopting the improved control method, high precision servo-controlling forPMSM is achieved at different rotor speeds by precise controlling the currents andvoltages of PMSM. Based on the control theories, a design scheme for Digital SignalProcessor (DSP) based PMSM servo controller has been presented. Then the hardwareand software designs were complete. By using this controller, rotor positionservo-control, speed servo-control and torque control for PMSM have been achieved.The experimental results verified that the studies on PMSM and the control strategy arecorrect, the theory can be easily put into practice, and the control effects are fine.The studies in this paper offer some elements and practical methods for adoptingPMSM in servo-control systems.