Torque and rotational speed estimation with parameter identification of Line-start Induction Motor for Motor Operated Valve

This paper presents a torque and rotational speed estimation method for line-start induction motor operated valves. Routine inspections are carried out to those valves, because motor operated valves are used in the serious plant such as power plant. and securing reliability is an extreme important matter for these systems. Movement environments in these plants are high temperature and humidity, so it is difficult to put sensors near motors. In such a case, we must find the trouble of the system without torque sensor or speed sensor. The proposal method can estimate the torque and rotational speed of induction motor by using time-series data of voltages and currents at the switchboard. Furthermore, we propose the parameter identification method of mutual inductance by comparing the inner and outer products between voltages and currents. First, a torque and rotational speed of induction motor are estimated. Next, a mutual inductance parameter is got. Last, the proposed estimation method is verified by results of experiment.