Design of a continuously and linearly controlled VSI-based STATCOM for load current balancing purposes

Abstract

In this paper, load current balancing are reviewed in both three-wire and 4-wire systems taking into account linearity, harmonics injection, and control schemes. A linearized static compensator (STATCOM) based on H-bridge voltage source inverter (VSI). The proposed STATCOM is controlled in closed loop mode via equipping it with a new current controller. The DC capacitor voltage of the STATCOM is kept constant without using external energy injection or storage devices via shunting the DC capacitor with a suitable series filter. The simulation results of the current responses of the 220V, 50Hz STATCOM reveal continuous and linear performance during responding to reactive current demands from 123A inductive current to 227A capacitive current. The transition time required for the proposed STATCOM during treatment of a sudden change in reactive current demand from maximum inductive current to maximum capacitive current is less than 40ms. The steady state portions of the STATCOM current responses show pure sinusoids, thus the proposed STATCOM can be promoted as harmonic free static Var compensator. The closed loop continuous mode control and the considerable linearity of the proposed STATCOM promot it as a bipolar susceptance (capacitive and inductive) in applications of load current balancing systems in both three and four wire power systems.

Enactment of HBMMC five-level inverter based D-STATCOM using robust controllers

“…From Figure 1, the non-linear load current including source/grid current and MMC current is written as (2).…”

Balancing of four wire loads using linearized H-bridge static synchronous compensators

“…The first compensator is built using three similar susceptances connected in delta-form, whereas the second one is built of three identical susceptances connected in star-form. All susceptances are assumed to be linearly controlled in capacitive and inductive modes [6], [24]. The first compensator is designed to balance active components of the phase currents, while the second one is dealt with cancelling the reactive current components.…”

“…The signal vMOD is compared with a triangular voltage vTRI to produce the triggering signal VZ1 of the IGBT Z1, whereas -vMOD is compared with vTRI to produce the triggering signal VZ3 of Z3. The voltage vi shown in Figures 2 and 3 can be given by (19) [24].…”

“…Load balancing systems are usually built of compensating susceptances to accomplish two main functions, which are reactive current compensation and balancing of active currents [9], [15], [26]. The Int J Reconfigurable & Embedded Syst ISSN: 2089-4864  Balancing of four wire loads using linearized H-bridge static synchronous … (Abdulkareem Mokif Obais) 463 compensating susceptances are required to be linearly controlled in both capacitive and inductive modes in order to accomplish reliable load current compensation [6], [24]. Distribution STATCOMs are widely used to apply load compensation for 4-wire systems [2], [7], [25].…”

Attenuation of voltage sags effects and dynamic performance improvement of a multi-motor system

“…Many solutions have been considered and proposed, many of which involve modifications to the traditional topology of multi-motor systems and/or incur significant costs. Mechanical or electrical auxiliary energy storage units [6], [7], unified power quality controller (UPQC) [8], [9], the application of converters with inductive elements, such as autotransformers, static power compensators (STATCOM) [10], static voltage regulator (SVR), dynamic voltage restorer (DVR) [11], [12] and energy storage devices including superconducting magnetic energy storage (SMES) [13]. These solutions, however, are still general in nature and have not been applied in multi-motor configurations.…”