Investigation On The Anti-disturbance Control Of Permanent Magnetic Synchronous Motor

The permanent magnetic synchronous motor (PMSM) is widely used in modern AC driving systems owning to its advantage in small volume, light weight, low torque ripple, stable speed and simplicity in control when it is adopted by vector control. As PMSM is a multi-variables, non-linear and strong coupling system, the conventional PI controller can't perform well under the uncertain factor as the load torque disturbance and the parameter variation. Since the high performance PMSM system should guarantee no static errors and rapid response to dynamic command, anti-interference should be noticed in PMSM control under variable load situation. On the base of analyzing the mathematical model of the PMSM, the linear mathematical expression under d-q axis is adopted by combining the vector control algorithm. Then the simulation model and the experiment of the PMSM vector control system is built by adopting the rotor oriented vector control and the systemFull-order and reduced-order load torque observer are separately proposed according to the mathematical equation of the PMSM and the comparison is given according to the simulation results. The consequence indicates that the reduced-order load torque observer has the advantage of simple design, less tuning parameters, accurate estimation and good robustness to load torque disturbance.As the motor inertia is a key parameter to the observer model, research of on-line estimation to the motor inertia is done to guarantee the veracity of the load torque observer. Principles of both gradient correction method of parameters (GCMP) and recursive least square (RLS) method with forgetting factor are detailedly introduced. Then the mathematical expression of the inertia identification is calculated according to the formula of the PMSM and the simulations of both algorithms are built. The simulation demonstrates that the identification precision is higher under GCMP while the convergence time of the identification is shorter under the RLS. So GCMP is adopted in the system.Finally,200W rated hardware system is designed and developed to verify the accuracy of the motor inertia identification under the GCMP, the effectiveness of the reduced-order load torque observer and the improvement of robustness to the motor speed control with the reduced-order load torque observer.