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Design of a continuously and linearly controlled VSI-based STATCOM for load current balancing purposes Faris Asaad Abdulmunem; Abdulkareem Mokif Obais
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 12, No 1: March 2021
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijpeds.v12.i1.pp183-198

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.
Design and implementation of an efficient WPT system Abdulkareem Mokif Obais; Ali Faeq Ruzij
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 11, No 2: June 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1001.963 KB) | DOI: 10.11591/ijpeds.v11.i2.pp711-725

Abstract

Wireless power transfer (WPT) is a technique introduced to transfer power wirelessly. Generally, WPT systems are characterized by low efficiency and low output power. Since WPT process depends mainly on mutual coupling between transmitting and receiving coils in addition to load requirements, it is focused in this work toward enhancing the mutual coupling and conditioning the receiving circuit so as to optimally satisfy the load demand. The mutual coupling between transmitting and receiving nodes is enhanced via inserting three resonating circuits along with energy transmission path and conditioning the receiving circuit such that it accomplishes delivering maximum power to the load node. In this work, an adaptive efficient WPT system is introduced. This system is carried out on PSpice and validated experimentally. Both simulative and experimental WPT systems have accomplished significant enhancement in efficiency. The proposed WPT system has three resonators and three parallel connected identical receiving coils located at 6.61m from the power transmitter. The efficiency enhancement approaches thousands of times the efficiency of a conventional WPT system having similar power transmitter located at the same distance from the receiving circuit, which has a single coil identical to those in the proposed efficient WPT system.
Load current balancing for 4-wire systems using harmonic treated TCR based SVCs Abdulkareem Mokif Obais; Ali Abdulkareem Mukheef
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 13, No 3: September 2022
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijpeds.v13.i3.pp1922-1950

Abstract

In this paper, a harmonic-treated thyristor-controlled reactor TCR is presented as a linearized harmonic-free compensating susceptance controllable in inductive and capacitive modes. The harmonic-treated TCR is a traditional TCR conditioned in such a manner that it can respond continuously and linearly to capacitive and inductive reactive current demands without noticeable harmonic association or active power contribution. The conditioned configuration is produced by equipping the TCR with self-harmonic suppressing and filtering circuitries, which guarantee harmonic cancellation with minimal no load operating losses. The harmonic treated TCR avoids the need to high power harmonic filters required to treat the harmonics of the traditional TCR. The devised susceptances are used to build a load current balancing system for grounded loads in a 380-V, 50Hz power distribution system. Both the compensating susceptances and the load current balancing system were designed and tested on PSpice. The simulation results have demonstrated the linearity, control continuity, and harmonic cancellation of the proposed harmonic-treated TCR as a fast response compensating susceptance reliable for load current balancing purposes. The proposed load current balancing system revealed superior treatment to various unbalance conditions, thus it is deservedly promoted to have the feasibility of supporting grids having fast varying loads.
Energy saving through load balancing of 3-wire loads Abdulkareem Mokif Obais; Ali Abdulkareem Mukheef
International Journal of Electrical and Computer Engineering (IJECE) Vol 13, No 4: August 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijece.v13i4.pp3857-3875

Abstract

In this paper, static var compensators (SVCs) and many load compensation techniques are reviewed. A continuously and linearly controlled compensating susceptance is devised from a switched capacitor bank and a switched reactor bank. The switched capacitor bank is built of four binary weighted thyristor switched capacitors, while the switched reactor bank is built of three binary weighted thyristor switched reactors. Although few switched capacitors and reactor are used, their binary weighted values beside their control scheme make them respond as a continuously and linearly controlled reactive device in capacitive and inductive modes of operation. A load balancing system is constructed of three identical devised compensating susceptances connected in delta-form. It is designed for balancing an 11 kV 50 Hz distribution station. The proposed system is designed and tested on PSpice which is a computer program equivalent in performance to real hardware design. The simulation results of the proposed system have showed significant treatment of severe imbalance conditions.
Design of a linearized 4-H-bridge STATCOM for load balancing purposes Abdulkareem Mokif Obais; Ali Abdulkareem Mukheef
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 14, No 4: December 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijpeds.v14.i4.pp2080-2093

Abstract

In this paper, a 4-H-bridge STATCOM (4-HB STATCOM) is introduced. Four H-bridges are cascaded to build the proposed STATCOM. Cascading the H-bridges makes it possible to operate the devised STATCOM on high voltage levels with less voltage harmonic association. The proposed STATCOM is equipped with an adaptive current controller and a voltage balancing technique for its DC capacitor voltages. The adopted controlling strategy makes the STATCOM respond continuously and linearly to current demand in both inductive and capacitive operational modes without noticeable association of harmonics. The DC capacitor of each H-bridge is shunted by a second harmonic filter to stabilize its voltage. The proposed STATCOM does not require initial charging of its DC capacitors because it is provided with a utilized technique for charging them rapidly by disabling the STATCOM carrier for a certain period sufficient to build up the required level of DC voltages. In this work, the proposed STATCOM is designed to operate on 11 kV AC voltage as a continuously and linearly controlled compensating susceptance. It can deservingly be employed in load balancing systems for achieving big amount of energy savings in power generation and big reduction in transmission losses.
Balancing of four wire loads using linearized H-bridge static synchronous compensators Abdulkareem Mokif Obais; Ali Abdulkareem Mukheef
International Journal of Reconfigurable and Embedded Systems (IJRES) Vol 12, No 3: November 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijres.v12.i3.pp462-477

Abstract

In this paper, a load balancing system is designed to balance the secondary phase currents of 11 kV/380 V, 50 Hz, 100 kVA power transformer in a three phase 4-wire, distribution network. The load balancing system is built of six identical modified static synchronous compensators (M-STATCOMs). Each M-STATCOM is constructed of a voltage source converter-based H-bridge controlled in capacitive and inductive modes as a linear compensating susceptance. The M-STATCOM current is controlled by varying its angle such that it exchanges pure reactive current with the utility grid. Three identical M-STATCOMs are connected in delta-form to balance the active phase currents of the power transformer, whereas the other three identical M-STATCOMs are connected in star-form to compensate for reactive currents. The M-STATCOMs in the delta-connected compensator are driven by 380 V line-to-line voltages, whilst, those connected in star-form are driven by 220 V phase voltages. The results of the 220 V and 380 V M-STATCOMs have exhibited linear and continuous control in capacitive and inductive regions of operation without steady-state harmonics. The proposed load balancing system has offered high flexibility during treating moderate and severe load unbalance conditions. It can involve any load unbalance within the power transformer current rating and even unbalance cases beyond the power transformer current rating.