Single-neuron Quasi-PID Control Method for Switching Power Amplifiers in Protective Relay Test Devices

Abstract

KEYWORD: switching power amplifiers; quasi-PID control method; single neuron; adaptive control method; protective relay test devices ABSTRACT: Protective relay test devices (PRTDs) are indispensable tools for testing protective relays and other security and automatic equipment. To promote test qualities, it is required that modern PRTDs be able to adapt to different loads, time-variant system parameters, random disturbances and fault waveforms containing various frequency components and nonperiodic components so as to ensure the accuracies of output waveforms, and this is directly determined by the performance of power amplifiers (PAs) adopted by PRTDs. Linear PAs (LPAs) are generally the preference choices, considering the difficulties in controlling the tracking accuracies of switching PAs (SPAs). Except that, however, SPAs have many advantages over LPAs. This paper presents an effective control method, named single-neuron quasi-PID control method, to improve the tracking accuracies of SPAs to make their applications in modern PRTDs feasible. Experiments show that the mean square error of this control method is less than 0.15%, meaning that the accuracy requirement of modern PRTDs is satisfactorily fulfilled. And the computational complexity of this control method is small and so it is very suitable for realization on lowperformance microprocessors.