Online Estimation of Load Torque and Moment of Inertia Incorporating Extended Disturbance Observer With Trigger

In this article, based on the idea of disturbance estimation, an extended disturbance observer (EDOB), including speed, load torque, and moment of inertia, is constructed. By deeply analyzing the internal relationship between the three estimation errors in the observer, the identification of the two coupled parameters (load torque and moment of inertia) is simplified to two observation equations expressed by the speed estimation error and independent of each other. The resulting coupling error is suppressed by the designed moment of inertia trigger. The EDOB and trigger cooperate to achieve high-precision identification of load torque and moment of inertia, while also ensuring the identification accuracy of the motor's moment of inertia during steady-state operation, improving the practicality of complex industrial equipment. Finally, an experiment is carried out on a 3.1 kW surface-mounted permanent magnet synchronous motor. The experimental results show the proposed observer has excellent estimation accuracy and robustness. The moment of inertia and load torque identified by the observer are used for proportional integral parameter tuning and feedforward compensation respectively, which can enhance the anti-disturbance ability of the system to the load, reduce the tracking error and improve the system's dynamic performance.