Parameter Estimation and Self-Commissioning of High Power Induction Motor Drive: Importance with a Case Study

In this paper, a simple approach to estimate the parameters of induction motor drive is presented along with the importance of parameter estimation and self-commissioning of an induction motor drive. In the proposed method, parameters such as stator resistance, stator transient inductance and rotor time constant are estimated and used for designing and tuning of PI controllers for a vector controlled induction motor drive, which is the prerequisite for self-commissioning of drive. The parameters estimated through this method takes care of variation in resistance and inductance based on site condition, compared to design parameters of the machine. The proposed parameter estimation method is validated on 875 kW induction motor and found in-line with the design values of the machine and the field conditions. The proposed method focuses on high power machines in standstill condition because of limitations in conducting NO load and blocked rotor tests to obtain the machine parameters. However, the same method is also validated on 5 HP induction machine and found in-line with the test parameters. The paper also presents a case study of forced draft fan application for a boiler in a refinery plant, where one of the drive is commissioned with the design values of the machine instead of self-commissioning procedure resulting in malfunctioning of drive operation for particular speed range, which lead to repeated failure of motor fan coupling, sheering of coupling bolts and damage in drive end bearings.