A method of torque & speed estimation for line-start IM with electrical parameter identification

This paper presents a method for estimating the torque and speed of line-start induction motor (IM). IM is being used for various purposes because that is a high trust machine for the load mechanism and can be used easily. So, IM is non-breakable. However, load mechanism sometime break. We try to check the condition of load mechanism by estimate the torque and speed of IM. We take up the motor-operated valve for load mechanism. Motor-operated valve is driven by line-start IM. Movement environment of IM is characterized by high temperature and humidity and therefore, it is difficult to position sensors near motor. In such a case, we must troubleshoot the system without using torque or speed sensors. The proposal method can estimate the torque and speed of IM by using the current and voltage near the switchboard. We use the inner and outer products between currents and voltages. Furthermore, we propose the parameter identification method of mutual inductance, leaked inductance and rotor resistance. The proposed method is validated by experimental results.