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Research on Speed Stability of Permanent Magnet Synchronous Servo System

The paper concerns with the speed stability of permanent magnet synchronous servo system. Used in numerical control machines, the servo system is required to output steady rotor speed. Based on vector control theory, a servo system is designed with PID module as the regulators of the speed and current loops. The effect of important factors including speed regulator, current regulator, the speed and current feedback are analyzed. Then the methods to enhance the rotor speed stability are discussed, including optimizing the regulators and filtering the current signals. The feedback speed gotten from positional sensor whose precision is decided by the sensor adapts to this servo system. The result of both simulation and screw thread process experiments on NC lathe validated their effectiveness.