Analysis of Variable Frequency Drive Induction Motor Current Disturbances and Motor Redesign by Intelligent Optimization Techniques

Abstract

An analytical approach is presented in this paper to minimize the influence of disruptive current spikes occurring at low frequency operation in a Variable Frequency Drive (VFD) induction motor. The recorded test data of load current at low frequency of a high power induction motor coupled with a reciprocating pump in a process industry, is analyzed by Prony Analysis (PA) and Hilbert transform (HT). Optimal values of motor design parameters that deliver sufficient mechanical power at low frequency and cause the least disruptive current spikes is arrived at, by using intelligent optimization techniques like Artificial Bee Colony (ABC), Particle Swarm Optimization (PSO), Genetic Algorithm (GA) and Simulated Annealing (SA). Using the most optimal design values obtained, Taguchi method is applied on the VFD control parameters for getting minimal current spikes. The output of the Taguchi method is compared with the experimentally set value at site. The comparison proved that with the optimal design parameters of motor obtained from the optimization methods, are effective in being able to deliver stable operation of the motor at low frequency. The optimal motor design parameters derived in this paper can be used to procure a new motor that gives stable operation at low frequency.