Digital Temperature Observer for Rolling Mill Motors

Digital automation and monitoring tools for industrial equipment are developed in the IIoT paradigm through the introduction of digital twins and digital shadows. The reliability of rolling mill electric drives can be improved with the continuous control of the thermal state of stand motors. In practice, despite the critical importance of these motors, not all of them are fitted with temperature sensors. The review of publications showed that the indirect measurement (recovery) of temperature with observers acting as digital shadows is the most efficient method. Currently, there is a large number of observers designed for monitoring the thermal state of various electric motors, including the synchronous motors of rolling mills. The authors aim at developing and testing an industrial observer that can calculate motor temperature based on arrays of currents or electromagnetic moments registered during rolling. They propose a solution for the reserve cold rolling mill stand motor. To accomplish this purpose, they have produced a methodology for the online indirect assessment of temperature based on the results of its recovery for a specific moment. The authors review a model for the calculation of equivalent loads and temperature implemented in Matlab Simulink. The proposed model has been tested for adequacy. To achieve this, the authors compared the calculated motor temperature obtained with the developed observer and the actual temperature registered by the sensors installed in the motor. Thus, the authors conclude that the developed observer can be used in the electric drives of rolling mill stands.