Research On The Performance Of Permanent-Magnet Synchronous Motor Servo System Based On DSP

With the development of modern control theory, power electronics and computer sciences, the permanent magnet synchronous motor (PMSM) ac servo system has been widely applied in many fields because of its high precision and high reliability. However, for the influence of parameter variety and load disturbance, high precision and high reliability servo controller must be designed, to obtain advanced adaptability and anti-disturbance.The operation principle of vector control is given. Disadvantages and advantages of current control strategies are analyzed, also analyzes their apply range. The model of motor and the theory of field oriented control based on vector control are given. The frequency-domain model is established.For servo system based on vector control, the control of torque means the control of current. The engineering design method of current regulator and parameters has been given. The thesis also analyzes factors that influence the performance of current loop. Aimed at the zero drift and back EMF, the method which can reduce the influence has been given. The experimental and simulation results indicate that the over modulation can improve the performance of current loop.Fast and accurate speed response is needed in high performance servo system. The engineering design method of speed regulator and parameters has been given. The influence of load disturbance can be compensated by load torque observer, and the dynamic performance of speed control can be improved by it. The low speed problems have been analyzed, and the method to reduce the error of low speed feedback has been given.The position of the rotor must be known accurately in servo system. For position feedback error caused by error installation of incremental encoder, two zero adjustment methods have been given, the position feedback error can be reduced by these two methods. The thesis also gives the method of getting the initial position of rotor.The structure is the base of high performance servo system. The digital servo controller based on DSP has been designed in this thesis, including protecting and monitoring circuits. And the analog current loop and the digital speed loop are introduced. The experimental results indicate the feasibility of proposed optimizing methods.