Control of a Single-Star Flying Capacitor Converter Modular Multi-level Cascaded Converter (SSFCC-MMCC) STATCOM for Unbalanced Load Compensation

This paper presents a simulation study into the implementation of the single star flying capacitor converter modular multi-level cascaded converter (SSFCC-MMCC) as a STATCOM for unbalanced load compensation. The paper proposes a new concept of voltage source current control for the reference current tracking of the compensated currents. This control strategy enables the STATCOM system to compensate for both positive sequence reactive and negative sequence currents. Not only compensates for unbalanced load, but also keep the module Dc-link and flying capacitor voltages maintained at their rated values. Simulation results verify the performance of the chosen topology

Harmonics and unbalanced load compensation by a modular multilevel cascaded converter active power conditioner

This paper presents a novel control scheme for a modular multilevel cascaded converter (MMCC) functioning as an active power conditioner (APC) to control the reactive power, eliminate the current harmonics, and compensate unbalanced load current simultaneously. This combines a modified predictive current controller with the inter-cluster and intra-cluster voltage balance control for MMCC sub-module capacitors. Simulation studies of this MMCC-APC for a power network containing both an unbalanced thyristor controlled rectifier and a reactive load are performed and results verifying its performance under varying degrees of load current distortion measured by THD levels are presented

Experimental Data on Voltage and Current Harmonics

Data on Voltage and Current Harmonic

Experimental Data on Conduction and Switching Power Losses of Modular Multilevel Cascaded Converter

Experimental data of conduction and switching power losses of IGBT and diode of a modular multilevel cascaded converter. This shows the following; a. relationship between Conduction losses with respect to carrier frequencies and modulation indices for three different Pulse width Modulation technique. b. relationship between Switching losses with respect to carrier frequencies and modulation indices for three different Pulse width Modulation technique

Control of Modular Multilevel Converters Using an Overlapping MultiHexagon Space Vector Modulation Scheme

Adapting the conventional Space Vector modulation (SVM) scheme for modular multilevel cascaded converters is complicated as the number of switching vectors increases with the number of voltage levels. This paper introduces a novel SVM scheme that can be applied for the control of modular multilevel cascade converters (MMCC) with any number of levels. Instead of extending a single hexagon to the regions corresponding to the number of levels, the proposed method treats the three-phase MMCC as multiple inverters with a phase limb being a chain of basic three level H-bridge, five-level flying capacitor, or neutral point clamped inverters. Basic two or three level hexagons can be applied to determine the switch states and duty cycles separately within one tier of the converter and many such hexagons can be overlapped, with phase shift relative to each other, for the control of a complete MMCC. This approach simplifies the modulation algorithm and brings flexibility in shaping the output voltage waveforms for different applications. Simulation results confirm the good waveform performance of this scheme. An experimental 5-level MMCC, with a total of six H-bridges as the basic modules, is presented to validate the advantageous features of the method. Key words: Modular Multilevel Cascade Converters, Space Vector Modulatio

Reliability assessments of an islanded hybrid PV-diesel-battery system for atypical rural community in Nigeria

This paper presents the use of a novel approach in assessing the generation reliability of a hybrid mini-grid system(HMS) based on the optimal design result obtained from the HOMER software. A typical Nigerian rural com-munity–Lade II in Kwara State was used as a case study where the energy demand for the residential andcommercial loads was 2.5MWh/day and 171kWh/day respectively. The optimized HMS results from HOMERcomprising of a solar photovoltaic (PV) array (1.5MW), diesel generators (350kW) and battery storage (1200units) has a combined least net present cost of $4,909,206 and a levelized electricity tariff of$0.396 per kWh.Contrasting the HMS with a diesel-only system for the community, an approximate 97% reduction in all pollutantemissions was observed. Furthermore,fluctuations in diesel fuel prices, variations in average solar insolation, andvariations in the solar PV's capital/replacement costs were utilized in conducting a sensitivity analysis for theHMS. The capacity outage probability table (COPT) was utilized in validating the reliability of the simulationresults obtained from HOMER. The HMS was observed to experience a load loss of 0.769MW, 0.594MW&0.419MW when zero, one and two diesel generator(s) respectively were operational for all of the Solar PV's andBatteries being off-line. The loss of load probability (LOLP), loss of load expectation (LOLE), and total expectedload loss (ELL) obtained from the COPT were 5.76�10�8, 5.0457�10�4hr/yr and 0.025344Watt respectively.The results show the reliability of the HMS and also depicts a highly economical and feasible hybrid energysystem

Development of energy demand and carbon emission dataset for Nile University of Nigeria

The global energy crisis and ozone layer depletion as a result of carbon emissions have increased the awareness and acceptance of renewable energy sources as an alternative form of electric power, resulting in the sizing of renewable energy sources. However, in order to properly size an energy power system, the information being addressed, such as the load demand, is critical. The Load demand data of Nile University campus is obtained from one of its power stations (PS-1) for a period of eight month. The data was measured from the bus bar of the power station using smart meters on a weekly basis. To power the university campus, the diesel generators are synchronized using Genset controllers with suitable communications interfaces and a SMA hybrid controller, which continually checks the power output of the power sources as well as the working condition of all loads in the busbar. The diesel generators are synchronized using SMA hybrid controllers and combined with the other source of the energy at a common bus bar and used to power the university campus. Additionally, carbon emission data were obtained from the PV solar system reading