Research On Online Inertia Identification And Controller Of AC Servo System

With the development of permanent magnet synchronous motor, middle-sized PMSM is used in electric vehicle technology, the portion of small type PMSM and microtype PMSM in servo system is increasing. The standard for the dynamic characteristic of AC servo is much higher. AC servo system is sensitive to the interference signal, the variation of system inertia will impact the performance of the system.This thesis proposes a method using model reference adaptive identification, which changes the adaptive gain nonlinearly. In the MRAI identification of inertia, when the system is interferenced by the load torque, the result is badly influenced and the error is significant. Specific to the problem, the thesis proposes a improvement of tuning the adaptive gain of MRAI and inhance the anti-interference of identification system.In order to reduce the influence of covariance matrix in extended kalman filter identification, the thesis proposes a method to adaptive tuning covariance matrix. The original covariance matrix is set to an invariant value, this improvement tuning the value in according to the previous stable value.When inertia changes frequently, this algorithm improves the identified speed and capabilty.Based on the result of indentification, the thesis analyzes a simple algrithm of tuning speed controller. Once the inertia changed, set the PI of speed controller propotionally to the identification value. That can keep the system characterisitic. The automatic disturbance rejection contoller(ADRC) is being used widely, it can also be used in ac servo system. The thesis applys ADRC in speed controller, analyzes and contrasts the effects with traditonal PID in situation of the inertia and load torque is diturbed.A model-based auto optimal ADRC is designed to work under the situation when the load torque is periodic variation. Compensating the reasult of identification into ESO of ADRC, alleviate the burden of ESO and improve the speed of observer, make the characteristic of ADRC controller better.