A discrete derivative control technique for DC link voltage in shunt compensator

Abstract

This paper presents a discrete derivative control technique for dc-link voltage in shunt compensator. It is desired to maintain the dc-link voltage at reference level value for current compensation using Distribution Static Compensator (DSTATCOM) to improve the power quality of distribution systems. The proposed control strategy improves the dynamic performance of DC control loop by taking the values of the error of the reference and feedback quantity with its discrete derivative value. Multiplied these values with the proportional factors in such a way that they maintained these values at the same scale level. The errors with their absolute values are taken in account to keep the calculation amount close to that of PI (Proportional Integral) controller. The performance was studied by MATLAB software simulation using Power System toolbox, result shows reduction in the occurrence of transient occurred on DC-Link voltage at the initial stage, also it reaches the reference level so fast. The control technique has been implemented with the Anti-Hebbian control algorithm developed for the extraction of fundamental reference source currents required for power devices switching. The control technique has been verified for power factor correction to improve the power quality of a three phase distribution system using DSTATCOM. MATLAB Simulink platform is used to study the performance of the proposed control technique under dynamic conditions of nonlinear load.