Simultaneous voltage and current compensation of the 3-phase electric spring with decomposed voltage control

Abstract

A decomposed voltage control is proposed to integrate two favorable functions of the 3-ph electric spring (ES) to stabilize the mains voltage and to reduce power imbalance. As compared with its precedent counterpart, the proposed control can expand the usage of the 3-ph ES, simplify the control implementation, and enable the ES to conduct multiple tasks at one time. The decomposition of the 3-ph ES voltage into d and q components allows the 3-ph ES to conduct decoupled real and reactive current compensations. The further separation of the d component enables the 3-ph ES to simultaneously compensate the mains voltage and the real current of the critical load. The proposed method consists of three loops designed respectively for voltage regulation, real power balance, and reactive power compensation. Experimental results demonstrate that the multi-tasking of the 3-ph ES is made attainable by the proposed control, with current balancing and voltage regulation as the primary objectives and power factor correction as a favorable byproduct.