scholarly journals Control Methods for Single-phase Voltage Supply with VSCs to Feed Nonlinear Loads in Rural Areas

2020 ◽  
Vol 1 (1) ◽  
pp. 33-47
Author(s):  
Walter Julián Gil Gonzalez ◽  
Sara Yulieth Bocanegra ◽  
Federico M. Serra ◽  
Maximiliano Bueno-López ◽  
Guillermo Luciano Magaldi
Keyword(s):  
Rural Areas ◽  
Single Phase ◽  
Hamiltonian Structure ◽  
Tracking Error ◽  
Open Loop ◽  
Voltage Source ◽  
Sinusoidal Voltage ◽  
Nonlinear Loads ◽  
Linear Load ◽  
Voltage Generation

This paper addresses the problem of sinusoidal voltage generation in linear loads using a voltage source inverter (VSI). The port-Hamiltonian structure in open-loop is used to design a passivity-based controller with proportional-integral gains (PI-PBC) in order to develop the control strategy. The main advantage of using passivity-based controllers corresponds to the possibility of guaranteeing asymptotic stability by transforming the trajectory tracking problem into a regulation control one. In addition to the PI-PBC, a linear load estimator is employed based on an integral formulation to determine the value of the equivalent conductance in the load, which reduces the number of current sensors. Numerical validations demonstrate that the sinusoidal voltage provided by the VSI to the load has a tracking error lower than $1~\%$, with harmonic distortions lower than $2.6~\%$, both for voltage and currents in the load. All the simulations were conducted in MATLAB/Simulink using the SimPowerSystems library version 2017a.

scholarly journals HIL-Assessed Fast and Accurate Single-Phase Power Calculation Algorithm for Voltage Source Inverters Supplying to High Total Demand Distortion Nonlinear Loads

Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1643
Author(s):  
Jorge El Mariachet ◽  
Yajuan Guan ◽  
Jose Matas ◽  
Helena Martín ◽  
Mingshen Li ◽  
...  
Keyword(s):  
Steady State ◽  
Single Phase ◽  
Reactive Power ◽  
Dynamic Performance ◽  
Active Power ◽  
Voltage Source ◽  
Power Calculation ◽  
Calculation Algorithm ◽  
Nonlinear Loads ◽  
Voltage Source Inverters

The dynamic performance of the local control of single-phase voltage source inverters (VSIs) can be degraded when supplying to nonlinear loads (NLLs) in microgrids. When this control is based on the droop principles, a proper calculation of the active and reactive averaged powers (P–Q) is essential for a proficient dynamic response against abrupt NLL changes. In this work, a VSI supplying to an NLL was studied, focusing the attention on the P–Q calculation stage. This stage first generated the direct and in-quadrature signals from the measured load current through a second-order generalized integrator (SOGI). Then, the instantaneous power quantities were obtained by multiplying each filtered current by the output voltage, and filtered later by utilizing a SOGI to acquire the averaged P–Q parameters. The proposed algorithm was compared with previous proposals, while keeping the active power steady-state ripple constant, which resulted in a faster calculation of the averaged active power. In this case, the steady-state averaged reactive power presented less ripple than the best proposal to which it was compared. When reducing the velocity of the proposed algorithm for the active power, it also showed a reduction in its steady-state ripple. Simulations, hardware-in-the-loop, and experimental tests were carried out to verify the effectiveness of the proposal.

scholarly journals HARMONIC DOMAIN MODEL OF AN OPEN-LOOP CONTROLLED PWM CONVERTER

2018 ◽  
Vol 8 (2) ◽  
pp. 25-29 ◽  
Author(s):  
Malte John ◽  
Axel Mertens
Keyword(s):  
Single Phase ◽  
Steady State Solution ◽  
Equation System ◽  
Open Loop ◽  
Domain Model ◽  
Voltage Source ◽  
Switching Function ◽  
Loop Control ◽  
Voltage Source Inverters ◽  
Harmonic Interaction

An harmonic domain model is developed for open-loop controlled voltage source inverters, which provides the steady-state solution for integer multiples of the fundamental frequency. The convolution of the switching function spectrum with the converter currents and voltages is used to describe the coupling of the AC side and the DC side. The modeling is based on a single phase leg and is extended to a single-phase and a three-phase voltage source inverter, which results in a non-linear algebraic equation system. For open-loop control the switching function is independent of the converter currents and voltages and the model is simplified to a linear equation system. This straightforward and fast model is verified by time domain simulations and experimental results. The modeling can be adapted to systems of coupled converters, which is presented for a back-to-back converter system showing the harmonic interaction of the connected subsystems.

Part 2: Reactive Compensation of the Linear Load in Three-Phase Four-Wire Systems Supplied with Asymmetrical Sinusoidal Voltage Following Currents’ Physical Components Theory

2020 ◽  
Vol 11 (4(42)2020) ◽  
pp. 52-64
Author(s):  
Zbigniew SOLJAN ◽  
Keyword(s):  
Single Phase ◽  
Supply Voltage ◽  
Industrial Plant ◽  
Sinusoidal Voltage ◽  
Home Office ◽  
Reactive Compensation ◽  
Load Imbalance ◽  
Power Equation ◽  
Linear Load ◽  
Three Phase

Four-wire systems are the most common ones in everyday life. Electrical installations within the home, office, or industrial plant are mostly four-wire installations. Receivers connected to such a system are mainly single-phase loads, which from the power connection are an unbalanced three-phase load. Apart from, the load imbalance, the supply voltage also has some asymmetry. Voltage asymmetry, load imbalance, the design of reactance compensators are issues that were not simultaneously included in the power equation in fourwire systems. This article presents the mathematical fundamentals of the construction of reactance compensators operating in voltage asymmetry.

MATHEMATICAL MODELING OF ANALOG CONTROLLED VOLTAGE SOURCE CONVERTERS FOR IMPROVED DYNAMIC RESPONSE

1998 ◽  
Vol 08 (04) ◽  
pp. 483-496 ◽  
Author(s):  
M. N. GITAU ◽  
I. R. SMITH ◽  
J. G. KETTLEBOROUGH
Keyword(s):  
Single Phase ◽  
Pulse Width Modulation ◽  
Voltage Source ◽  
Current Loop ◽  
Voltage Source Converter ◽  
Switching Frequency ◽  
Voltage Source Converters ◽  
Phase Voltage ◽  
Nonlinear Loads ◽  
Three Phase

Increases in the occurrence of nonlinear loads have resulted in the need to reduce or minimize the levels of harmonic currents being injected into the power supply. As a consequence, active current waveshaping and pulse-width modulation have now replaced conventional phase-controlled and diode bridge rectifiers in many applications. In this paper, mathematical models are developed for the power circuits of analog controlled single-phase and three-phase voltage source converters, and then used to analyse the performance of current- and voltage-control loops for the converters. Analytical expressions are derived for the gains and time constants of the current and voltage controllers, and it is shown that the bandwidth of the current-loop is a function of the switching frequency, and that of the voltage-loop is a function of the DC-busbar capacitance and the voltage filter cut-off frequency. To illustrate the application of the models, simulation results are presented from investigations into the control of a 5 kW single-phase voltage-source converter and a 100 kW three-phase boost converter.

Battery Losses In a MMC for BEVS Application

2018 ◽  
Vol 12 (1) ◽  
pp. 98-109 ◽  
Author(s):  
Adolfo Dannier ◽  
Gianluca Brando ◽  
Ivan Spina ◽  
Diego Iannuzzi
Keyword(s):  
Mathematical Model ◽  
System Architecture ◽  
Electrochemical Cell ◽  
Voltage Source ◽  
Modular Multilevel Converter ◽  
Voltage Reference ◽  
Sinusoidal Voltage ◽  
Current Waveform ◽  
Voltage Source Inverter ◽  
Multilevel Converter

Objective:This paper analyses the Modular Multilevel Converter (MMC) topology, where each individual Sub Module (SM), in half bridge configuration, is directly fed by an elementary electrochemical cell.Methods:The aim is to investigate how the reference voltages influence the cells currents waveforms, determining how the active powers and the losses are distributed among the cells. Considering a 2-level Voltage Source Inverter (VSI) topology working in the same conditions, the ratio between the MMC total cells losses and VSI total cells losses is calculated. After showing the system architecture and mathematical model, the cells current waveform investigation is presented and detailed both for triangular and sinusoidal voltage reference waveform.Results:Finally, the results are critically discussed with particular focus on the comparison between the MMC and the VSI topologies.

scholarly journals SPEAR (Solar Pyrolysis Energy Access Reactor): Theoretical Design and Evaluation of a Small-Scale Low-Cost Pyrolysis Unit for Implementation in Rural Communities

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2189
Author(s):  
Cesare Caputo ◽  
Ondřej Mašek
Keyword(s):  
Waste Management ◽  
Rural Areas ◽  
Net Present Value ◽  
Agricultural Waste ◽  
Tracking Error ◽  
Sub Saharan Africa ◽  
Small Scale ◽  
Energy Access ◽  
Efficient System ◽  
Pyrolysis Unit

Energy access and waste management are two of the most pressing developmental and environmental issues on a global level to help mitigate the accelerating impacts of climate change. They are particularly relevant in Sub–Saharan Africa where electrification rates are significantly below global averages and rural areas are lacking a formal waste management sector. This paper explores the potential of integrating solar energy into a biomass pyrolysis unit as a potentially synergetic solution to both issues. The full design of a slow pyrolysis batch reactor targeted at biochar production, following a strict cost minimization approach, is presented in light of the relevant considerations. SPEAR is powered using a Cassegrain optics parabolic dish system, integrated into the reactor via a manual tracking system and optically optimized with a Monte-Carlo ray tracing methodology. The design approach employed has led to the development an overall cost efficient system, with the potential to achieve optical efficiencies up 72% under a 1.5° tracking error. The outputs of the system are biochar and electricity, to be used for soil amendment and energy access purposes, respectively. There is potential to pyrolyze a number of agricultural waste streams for the region, producing at least 5 kg of biochar per unit per day depending on the feedstock employed. Financial assessment of SPEAR yields a positive Net Present Value (NPV) in nearly all scenarios evaluated and a reasonable competitiveness with small scale solar for electrification objectives. Finally, SPEAR presents important positive social and environmental externalities and should be feasibly implementable in the region in the near term.

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