Dynamic Performance of Three-Level Back-to-Back VSC-HVDC System Using Space Vector Modulation under Faults Conditions

Abstract

This paper presents a comprehensive model of the Back-to-Back HVDC system based on the three-level Neutral-Point Diode Clamped (NPC) converter. The ac-side controllers are achieved in a synchronous rotating reference frame (d-q) controls direct and quadrature currents to obtain independent control of real and reactive powers. This is achieved by means of PI controllers. The voltage-balancing control of two split DC capacitors of the three-level Back-to-Back HVDC system is achieved using three-level space vector modulation (SVM) with balancing strategy based on the effective use of the redundant switching states of the inverter voltage vectors.
The reported study results demonstrate a satisfactory response of the VSC-HVDC station operating based on the proposed SVM strategy, under various conditions of studied different normal and fault cases.