Simplified algorithm for assessment equivalent circuit parameters of induction motors

Abstract

Induction or asynchronous AC motors are widely used in the electromechanical industries. However, the selection of an appropriate motor for specific drive applications represents a non-trivial task. The most effective and universally accepted method is to use equivalent T-circuit for this purpose. Parameter determination of equivalent circuit should be done relatively fast and accurately. This article describes a novel and simplified method for the estimation of equivalent circuit parameters, which is exclusively based on the manufacturer's datasheet. The proposed method is based on the synergetic interaction between the numerical and analytical dimensionless approach using the Thevenin theorem. Initially, rated motor parameters and unknown variables of the equivalent circuit are combined into dimensionless expressions using the Thevenin approach. This method is simple, original, and useful to prevent instability in the numerical solution. Importantly, the high convergence of a solution and relatively fast calculation of parameters reveals the significant novelty of the proposed method. This method provides accurate and sustainable results for a wide range of low voltage asynchronous motors with different rotational velocities, torque, and power range from a few to hundreds of kilowatts. The proposed method is validated by the application of three types of asynchronous AC motors.