SimPowerSystems Library Research Articles

AC Networks With Microgrids: Passivity-Based Controllers in Single Phase Electric Network

—This paper is an investigation of the possible integration of distributed energy resources (DERs) in single-phase alternating current networks, using voltage-controlled converters, based on passivity-based control theory. In closed-loop operation, Hamiltonian representations facilitate the development of passive controllers that guarantee stability. The trajectory tracking problem can be solved as a regulation problem by transforming the non-autonomous dynamical model into an incremental model. In this work, the primary contribution is the ability to control active and reactive power flows between DERs and the grid according to the availability of primary energy resources and converter capacity. Simulated results indicate that all passive controllers achieve the control objective, maintaining asymptotic stability and achieving the same dynamic performance as integral proportional controllers. SimPowerSystems library is used to develop all simulations under the MATLAB/Simulink environment. The paper presents a novel approach to integrating distributed energy resources into single-phase alternating current networks, utilizing voltage-controlled converters and leveraging passivity-based control theory.

Utilization of superconducting magnetic energy storage and doubly fed induction generator for enhancing stability of interconnected power system

SummaryAs the share of wind power keeps on increasing, the interaction between synchronous and wind generators pose a challenging issue on power system stability. In order to investigate the impact of wind penetration on stability of power system, appropriate modeling of wind energy conversion systems (WECSs) is necessary. Moreover, it is needed to comprehensively study the impact of wind penetration on power system oscillations. This paper presents a didactic approach for integrating a doubly fed induction generator (DFIG)‐based wind farm from SimPower Systems library to a five‐area 68‐bus power system modeled in Simulink. Inter‐area oscillations with and without wind power penetration are investigated for their characteristics. Renewable energy sources are connected to the grid via power electronics converters at the cost of a reduction in inertia. The concept of virtual synchronous generator (VSG) produces virtual inertia by exchanging active power with the power system. The impact of superconducting magnetic energy storage (SMES) and DFIG on enhancing damping performance of inter‐area is investigated. The increase in damping ratios of inter‐area oscillatory modes verifies the enhancement in small signal stability by connecting SMES and DFIG to the power system. The usage of SMES operating in VSG mode to improve the dynamic stability with highly erratic wind profile is also investigated. The developed MATLAB/SIMULINK‐based DFIG model is simple to use and can be expanded to build efficient controllers. The fidelity of the DFIG model and VSG technology is verified in real time by Opal‐RT (OP4510).

Average model of wind energy system dedicated to optimal design of the global system

This paper presents an average model based on justified simplifications dedicated to the design and optimization of wind energy systems. Indeed, the classic models of wind energy systems are complex and their use is not efficient for the optimal design of the components of the power chain given the complexity, the significant time of resolution and the strong correlation of the physical parameters of these models. For these reasons, a model based on the theory of average values with reduced simulation time of a wind turbine structure is developed. This model is validated against the classic model of the wind chain using the SimPowerSystem library of power component models integrated under the Matlab-Simulink simulation environment.

Повышение эффективности электроэнергетической системы земснаряда

Most river dredgers are equipped with several electric positioning drives, a soil pump electric drive and a hydraulic washing pump. The listed electric drives are the main consumers of electricity from the dredger diesel generators. It is necessary to change the structure of the ship electric power network in order to reduce fuel consumption by diesel generators. The energy characteristics of the dredger electric drive system with a different configuration of the converter equipment are determined. Simulation models of the dredger DC and AC power systems have been developed. The models were built using MATLAB Simulink software and SimPowerSystem library. Application of simulation models made it possible to assess the efficiency of using a DC bus in the power system of the dredger. The circuits of the dredger electric power system, electric drives of cross-dredging winches are illustrated. The operation modes of electric drives of cross-dredging winches are analyzed. The necessity of analyzing the operation of electric drives and of developing the control signals for the braking resistors of the frequency converter in the power control system is revealed. The parameters of the presented electric drives and their values are considered. The expressions for calculating the total power of the system nodes are given, taking into account the characteristics of the operating modes of the dredger electric drives based on an alternating current network. Using the developed version of the power system contributes to saving capital costs and specific fuel consumption. Modernization of the power system helps reduce the power of diesel generators, increase the efficiency of the system and reduce the power of the ventilation system of compartments with winch frequency converters, due to regenerative braking by the electric drives.

МОДЕЛИРОВАНИЕ ЗАМКНУТОЙ СИСТЕМЫ ЭЛЕКТРОПРИВОДА ПОСТОЯННОГО ТОКА С ШИРОТНО-ИМПУЛЬСНЫМ ПРЕОБРАЗОВАТЕЛЕМ

This article investigates the regulation of the angular speed of an electric drive (ED) with a pulse-width converter (PWC) and a direct current motor (DC motor) of independent excitation (NV) when controlled in a closed-loop system. A proportional-integral (PI) -regulator was used as a regulator of the angular velocity. To analyze the processes in the closed-loop SHIP-DPT system, the methods of simulation are used. The principle of operation of an electric drive with control from a PWM is described. Developed and modeled EP circuits with PWM in the Matlab environment using blocks from the Simulink / SimPowerSystem library. A model block has been modeled that calculates the static and dynamic power losses of the PWP IGBT. To calculate the static and dynamic losses, the method of approximating the loss graphs was used. The obtained mathematical dependences describe quite accurately the graphs of the power losses of the IGBT transistor. It is shown that when using a PI-controller, the angular speed of the electric drive is set according to a given speed reference signal.

ИССЛЕДОВАНИЕ ЧАСТОТНО-РЕГУЛИРУЕМОГО ЭЛЕКТРОПРИВОДА С АСИНХРОННЫМ ЭЛЕКТРОДВИГАТЕЛЕМ

Relevance AC electric drive is widely used in industry, it reduces power consumption and provides high reliability. It has received its wide distribution due to its high technological characteristics and simplicity of design, which have a positive impact on the introduction into production and modernization. Modeling of the electric drive control system is carried out in order to regulate and improve technological parameters. The assembled model in the Matlab/Simulink program using the SimPowerSystem library allows you to study the efficiency of controlling the electric drive of the pump using a visual model before switching to real objects, thanks to smooth speed control in a wide range of revolutions. Aim of research In this paper, a study is made of a frequency-controlled pump electric drive. During the hours of minimum load of enterprises where this system is used, the load on the device will decrease, since the consumption will be much less. Under loads, the power consumed by the drive can be reduced by changing the motor speed. This is achieved in many ways, but the most relevant is the use of a frequency converter. The main task is computer simulation of a frequency-controlled electric pump drive and the study of simulation results. Research methods In this study, the following methods were used: the study of scientific literature, computer modeling performed in the Matlab/Simulink software package using the SimPowerSystem library. Results The authors carry out a study of a frequency-controlled electric drive of the pump, which implements a reduction in the rotation speed to reduce the power consumed by the electric drive during the hours of minimum load of enterprises. The computer model of the object under study was developed in the Matlab/Simulink software package, the scalar control of the electric drive was evaluated. As a result of the simulation, oscillograms were obtained, where the possibility of reducing power consumption by adjusting the engine speed is clearly visible.

A Nonlinear SRM Controller Design for Torque Ripple Reduction with accounting for Magnetic Saturation

In this paper, a nonlinear backstepping controller design is proposed for torque ripple minimization in switched reluctance motor (SRM) drive systems, which ensures less acoustic noise and less vibration. The proposed controller is based on a model taking into account the stator coils magnetic saturation phenomenon. For the torque ripple optimization purpose, the excitation angles are adapted according to the instantaneous SRM torque and speed values. Therefore, a lookup table is built, proposing the excitation angles optimal values for different machine operation points. The proposed control strategy validation was carried out by simulation, using MATLAB-Simulink tools. More specifically, the Simpower system library was exploited, since it offers an SRM simulator, taking into account magnetic saturation. To highlight the supremacy of the proposed controller, its performances are compared with those of conventional linear (PI) regulator. The obtained results validate the proposed controller robustness and efficiency.

DESFĂȘURAREA VIRTUALĂ A LUCRĂRILOR DE LABORATOR DE MAȘINI ELECTRICE ÎN MEDIUL DE CALCUL MATLAB -SIMULINK

"The paper presents the author's experience in supporting laboratory applications in the Electrical Machines course during the pandemic caused by the SARS-CoV-2 virus, when teaching hours were conducted online, like activities specific to the distance learning. The experiments in the laboratory works are simulated in the MATLAB-Simulink computing environment by using and adapting the existing transformer and electrical machine models in the SimPowerSystem library. The design of numerical applications was made so that the implementation of electrical diagrams is performed by students, given that they have no experience in numerical modeling of electrical machines. Several methods for obtaining the results from numerical experiments are presented, which allow to ensure a balance between the number of data specific to each experiment and the calculation effort required, so that the experiments can be performed in the time allotted to a laboratory work. Paper purpose: Description of practical teaching aspects related to the simulation classical tests of the electrical machines in MATLAB- Simulink, in order to virtualize the laboratory works and to adapt them to on-line distance learning. Elements of originality: 1. Developing models for adjustable circuit elements and instrumentation required for simulation testing of electrical machines in steady-state regime. 2. Development of the more accurate DC electric machines model that considers the magnetic circuit hysteresis. 3. Analysis of the methods of using the simulation schemes for obtaining in a reasonable time the data that allow the representation of the operating characteristics."

Assessment of the Efficiency of Wind Energy Use in Russia

The constant increase in the requirements for the generation of electricity forces the search for new means of generating energy. It is not the first year that technologies for the development of alternative energy sources have been considered and introduced in the largest countries of the world. Wind power occupies a special place in this direction. In Russia, this industry is still not sufficiently developed to provide a significant share of energy consumption, but the industrial potential with the proper level of technological support can radically correct this situation. This article discusses the perspectives for using wind power plants in Russia. A mathematical model of a wind power plant was built in this study, taking into account the parameters of a WH6.4-5000W type wind generator and consisting of a virtual synchronous generator, which is an element of the SimPowerSystem library, and blocks from the Simulink application of the Matlab software package that simulates the effect of wind and the movement of the mechanical part of the wind generator. An assessment of the economic efficiency of the use of wind turbines in Russia was carried out using the constructed model.

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

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.

Model of a Photovoltaic Module for the MatLab/Simulink SimPowerSystems Library

The relevance of research is caused by the increase of the number of photovoltaic power plants in the Republic of Belarus and, accordingly, the need to solve problems of diagnostics of photovoltaic modules. A new Simulink model of a photovoltaic module focused on using the standard SimPowerSystems library of power supply system elements (a part of the MatLab/Simulink) is proposed. The model allows altering solar irradiation values for each solar cell of the module. The use of the model also makes it possible to obtain calculated values of voltages and currents at the photovoltic module output. In addition, the model provides the simulation of individual solar cells shading in the module. The developed Simulink model operates on the base of a well-known exponential dependence describing the volt-ampere characteristic of a photovoltaic module, and also takes into account the real circuit of the module with bypass diodes. The series resistance of the photovoltaic module is calculated by the subtraction between its experimental and theoretical volt-ampere characteristics for conditions that are close to normal. The Simulink model of the SF-P672300 module contains 72 nonlinear elements implemented on the basis of controlled current sources and connected in series. The model solved the problems of the algorithm stability for calculating algebraic cycles by introducing constraint the current and the voltage parameters. Experimental studies for the fully illuminated and partially shaded SF-P672300 module have demonstrated that the maximum relative error of the developed Simulink model does not exceed 15 %. Experimental and theoretical current-voltage characteristics of the SF-P672300 module under full illumination and partial shading are presented. The presented Simulink model may be used both at the design stage and at the operation stage of photovoltaic power plants in order to simulate and analyze the factors that affect the operation of them.

ПЕРСПЕКТИВЫ ДЕЦЕНТРАЛИЗОВАННЫХ СИСТЕМ ЭЛЕКТРОСНАБЖЕНИЯ ПОСТОЯННОГО ТОКА С РАСПРЕДЕЛЁННОЙ СОЛНЕЧНОЙ ГЕНЕРАЦИЕЙ

Актуальность исследования обусловлена необходимостью расширения вариантов автономных систем электроснабжения, в частности, фотоэлектрических, в рамках постановления правительства, связанного с ратификацией Россией Парижского соглашения по климату от 23.09.19. Системы электроснабжения постоянного тока с участием возобновляемых энергоисточников для децентрализованных потребителей могут стать предпочтительной альтернативой переменному токуприусловиисоответствия большинству обязательств Парижского соглашения по климату, а также требованиямповышения энергетической безопасности. Цель: повышение качества электрической энергии в распределительных сетях 0,4 кВ, декарбонизация окружающей среды от углеводородных энергоносителей, повышение энергетической безопасности автономной системы электроснабжения путём увеличения вкладав энергетический баланс возобновляемого энергоресурса, а также снижение стоимости вырабатываемойэлектрической энергии путём перехода с переменного на постоянный ток. Методы. Ввиду сложности натурного исследования электроэнергетических систем с генерацией различной физической природы в качестве инструментов исследования были определенны: математическоемоделирование споследующей компьютерной реализацией в программныхкомплексах высокого уровня.Наиболее полно условиям моделирования отвечает MatLab, в частности, его приложение блочного моделированияSimulink и библиотека блоков SimPowerSystems. Результаты. Разработан программный инструмент, позволяющий осуществлять имитационное моделирование режимов работы фото-дизельных систем электроснабжения, включая генерацию с учётом текущего электропотребления и инсоляции с целью определения рациональных технико-экономических параметров гибридных генерирующих систем; выявлены критерии целесообразности и эффективности построения фото-дизельных электрических систем на постоянном токе для электроснабжения удаленных потребителей.

Анализ энергетических показателей импульсных преобразователей

The aim of this study was to analyse the energy indices of pulse semiconductor converters, including efficiency as an important characteristic of their operation. This aim was achieved through the use of the simulation modelling methods in the MATLAB 7.5 Simulink environment. In particular, blocks from the SimPowerSystem library were used. The authors developed the models of semiconductor converters with pulse-width modulation having a single power switch on the IGBT type transistor, coupled with a semiconductor converter with pulse-frequency modulation having four power switches on the permanently-open SCR type thyristors. The operation accuracy of the models was confirmed in a series of experimental studies carried out on the laboratory mock-ups of pulse converters implemented in the power electronics laboratory of the Department of Electric Drive and Electrical Transport. This article presents the developed models of semiconductor converters with pulse-width and pulse-frequency modulation. The dynamic and static characteristics of pulse semiconductor converters are determined. An analysis of the obtained static characteristics of pulse converter diagrams showed that the stiffness of output characteristics of the converter with pulse-frequency modulation is higher than that of a converter with pulse-width modulation. The calculation results of the efficiency of pulse semiconductor converters conducted on the basis of the analysis of static output characteristics presume that the efficiency of the semiconductor converter with pulse-frequency modulation is more than one percent higher than the efficiency of a semiconductor converter with pulse-width modulation. The developed models of converters with pulse-width and pulse-frequency modulation can be used for studies of DC electric drive angular velocity controls.

Design and Research of a Model of a Pair Active Aircraft Control Sidesticks Operation in MATLAB

Development of an aircraft active sidestick control is an actual direction in modern flight control systems which allows to increase safety, to improve cabin ergonomics and to reduce the mass and weight of control levers. The article devoted to simulation modeling of a pair active sidesticks based on electromechanical actuators coupled by a frameless kinematic scheme, providing identical dynamic characteristics for the pitch and roll channels. MATLAB, Simulink, Simscape, with SimMechanics and SimPowerSystems libraries was used to create the mathematical model. Parameters such as moments of inertia was count based on the 3D model of the active sidestick. The complex model includes two active sidesticks units, three blocks as the input source ("Autopilot", blocks of the 1st and 2nd pilots), a block that compute a loading characteristic for the manual control mode and a block with logic for switching from automatic to manual mode. The model of each active sidestick unit consists of three main blocks: a regulator, an electric motor with a control system, and a block of mechanics. The regulator block includes a PID regulator and a PWM modulator. The electric motor unit includes a power source, a three-phase bridge inverter, a model of a brushless three-phase electric motor from the SimPowerSystems library and a power switch control unit. The mechanics block includes a planetary gearbox, hinge mechanism, handle, moments of inertia, a position sensor, a torsion rod equal to tension springs which are used in device, a nonlinear speed damper and a torque source unit, depending on the force applied by the pilot. Developed model makes it possible to get static and dynamic characteristics of the actuators, to check control algorithms to simulate operating modes in automatic and manual control, including piloting by both pilots at the same time and the interruption in automatic control mode. Including in model a " hold position block" allowed to simulate situation when in manual control mode the 1st pilot tries to hold the handle in a position that he considers correct, despite the intervention of the 2nd pilot. The simulation results showed that developed device meets specified requirements for the aircraft active sidesticks.

Engineering of Light Electric Commercial Vehicle

The paper describes the process and results of the development of the light commercial electric vehicle. In order to ensure maximum energy efficiency of the developed vehicle the key parameters of the original electric motor. The article also presents the results of power electronic thermal calculation. For the mathematical model of the vehicle, the driving cycle parameters of the electric platform were determined in accordance with UNECE Regulations No 83, 84. The driving cycle was characterized by four successive urban and suburban cycles. The mathematical model also takes into account the time phases of the cycle, which include idling, vehicle idling, acceleration, constant speed movement, deceleration, etc. The model of the electric part of the vehicle was developed using MatLab-Simulink (SimPowerSystems library) in addition to the mechanical part of the electric car. The electric part included the asynchronous electric motor, the motor control system and the inverter. This model at the output allows to obtain such characteristics of the electric motor as currents, flows and voltages of the stator and rotor in a fixed and rotating coordinate systems, electromagnetic moment, angular speed of rotation of the motor shaft. The developed model allowed to calculate and evaluate the performance parameters of the electric vehicle. Technical solutions of the electric vehicle design were verified by conducting strength calculations. In conclusion, the results of field tests of a commercial electric vehicle are presented.

ПУТИ ПОВЫШЕНИЯ ЭФФЕКТИВНОСТИ УСТАНОВОК ЭЛЕКТРОЦЕНТРОБЕЖНЫХ НАСОСОВ ДОБЫЧИ НЕФТИ

Актуальность работы обусловлена необходимостью верификации данных узла «погружной электродвигатель – внутрискважинный компенсатор», полученных на имитационной модели с результатами стендовых испытаний. Внутрискважинная компенсация реактивной мощности является относительно новой технологией повышения энергетической эффективности нефтедобывающих объектов по сравнению с существующими способами. Ввиду технических особенностей размещения внутрискважинных компенсаторов реактивной мощности в эксплуатационной колонне нефтедобывающей скважины, в некоторых случаях, экономически не целесообразно исследование установки электроцентробежного насоса с внутрискважинным компенсатором, с целью определения оптимальных параметров работы установки на реальном объекте. Поэтому разработка адекватной имитационной модели узла «погружной электродвигатель – внутрискважинный компенсатор» является важной задачей, позволяющей при минимальных материальных затратах решить проблемы построения, функционирования и модернизации установок электроцентробежных насосов. Цель: исследование внутрискважинного компенсатора реактивной мощности в программной среде Matlab Simulink и экспериментальные исследования погружного асинхронного электродвигателя с внутрискважинным компенсатором на лабораторном стенде. Объект: погружной асинхронный электродвигатель с внутрискважинным компенсатором реактивной мощности. Методы. При разработке имитационной модели погружного асинхронного электродвигателя использованы готовые блоки библиотеки SimPowerSystem программного комплекса MATLAB Simulink. Для проверки адекватности имитационной модели изготовлен погружной асинхронный электродвигатель и опытный образец внутрискважинного компенсатора реактивной мощности. Стендовые испытания проведены на заводе ООО «Алмаз», имеющем лицензированные лаборатории и аттестованных специалистов. Результаты. Разработана имитационная модель узла нагрузки «ПЭД-ВКРМ» для моделирования электромеханических процессов узла. Разработан опытный образец внутрискважинного компенсатора реактивной мощности. По результатам стендовых испытаний получены рабочие характеристики погружного асинхронного электродвигателя с внутрискважинным компенсатором. Проведена верификация данных, полученных на имитационной модели, с результатами эксперимента. Расхождения между расчетными и экспериментальными данными составили менее 10 %. Таким образом, разработанная имитационная модель узла нагрузки «ПЭД-ВКРМ» адекватно отображает электромеханические процессы узла. Определены перспективы проведения опытно-промышленных испытаний погружного асинхронного электродвигателя с внутрискважинным компенсатором реактивной мощности.

Control por Modos Deslizantes de la Relación de Exceso de Oxígeno en una PEMFC Interconectada a un Motor de CD mediante un Convertidor Boost

In this work, a proton exchange membrane fuel cell (PEMFC) is used to electric energy supply to a permanent magnet DC motor in a sustainable way and the inlet air flow in the cathode is manipulated to ensure the PEM fuel cells efficient operation. A boost-type DC/DC converter is connected to the PEMFC, it is used with a PI linear control loop to regulate the speed of the DC motor under some possible load disturbances. In addition, a nonlinear sliding mode control (SMC) is designed for regulated the excess oxygen ratio considering constant the temperature and humidity of membrane, to achieve the PEM full cell operate in the ohmic region of the polarization curve, to avoid the oxygen starvation at the cathode and to prevent damage to fuel cell components. The results are validated using the internal models of the PEMFC and the power electronics from SimPowerSystems library of Matlab/Simulink.

Enhanced Indirect Field-Oriented Control of Single-Phase Induction Motor Drive Using H∞ Current Controller

In this paper, the enhanced indirect rotor field-oriented control (IRFOC) of single-phase induction motor (SPIM) drive is proposed. Its optimal stator currents are ensured by the multi-input and multi-output H∞ stator current controller, which is designed through solving the weighted mixed sensitivity criterion by the improved loop-shaping two-Riccati formulae. Moreover, the SPIM’s rotor speed is also ensured by the PID controller, which is designed from solving the mean square error criterion using the genetic algorithm. The SPIM’s actual behavior is modeled by the unstructured uncertainty model where significant variations in its stator and rotor resistors are taken into accounts. Therefore, an optimal trade-off between nominal performance and robust stability should be attained by the proposed IRFOC strategy while respecting some requirements such as a good tracking dynamic of the reference stator trajectories, as well as the reference rotor speed, a good decoupling behavior of the measured stator currents, a good rejection dynamic of plant uncertainties and a good suppression dynamic of prospective sensor noises. The modeling and control framework of the SPIM drive are simulated in MATLAB®/Simulink using Simpower systems library, in which the enhanced IRFOC performances are compared with those given by the standard IRFOC based upon the hysteresis current controller.

Model of a Photovoltaic Cell for the MatLab/Simulink SimPowerSystems Library

A new Simulink model of a photovoltaic cell has been proposed. The model is focused on the use of a standard SimPowerSystems library with power engineering elements from the MatLab/Simulink software package. The model allows altering the values of solar irradiance, photovoltaic cell temperature and load resistance. The results of the model application are the calculated values of voltages and currents at the photovoltaic cell output. The Simulink model that has been developed implements the known dependence of the photovoltaic cell volt-ampere characteristic by using both standard MatLab/Simulink blocks and special electric SimPowerSystems library blocks. The model is characterized by the fact that the series and parallel resistance of the photovoltaic cell are made in the form of resistors from the SimPowerSystems library. The main calculation algorithm is implemented programmatically by using the “C” programming language. To increase the algorithm stability to algebraic cycles the restrictions parameters are introduced. A new technique of calculating the photovoltaic cell model parameters based on experimental data has been proposed. The technique includes the preparation of a system of equations with experimental values of the photovoltaic cell voltages and currents. Experimental tests have been carried out for the photovoltaic module OSP XTP 250 under different solar irradiance values. The tests showed that the relative error of the Simulink model that has been developed does not exceed 12 %. The Simulink model makes it possible to build photovoltaic modules and then to build schemes of photovoltaic power plants as a part of power supply systems. Due to the latter it is possible to simulate the electricity consumers’ work, weather conditions, and the presence of shadows or pollution on the surface of photovoltaic modules. Also, one can carry out a simulation of increasing failures in power plant photovoltaic modules, e.g. simulating of modules efficiency reducing because of their degradation, or simulating of modules series resistance increasing because of the photovoltaic cell internal contacts deterioration. The Simulink model that has been developed can be used both at the design stage and at the stage of photoelectric power plants operation.

Current Balancing in Electric Power Networks Using an Electronic Inactive-Power Regulator

A device for balancing currents in three-phase power supply networks has been examined that contains a three-phase semiconductor converter, output matching chokes, and capacitor batteries on the side of the dc converter. The feedback of the controller system is organized by the magnitude of choke current. The algorithm for determining reference signals is implemented by means of separate calculation of currents of the direct, reverse, and zero sequences using the Park–Gorev transformation equations. Pulse-width modulation of the converter voltage is used to modulate the calculated signals. To study the operation of a power compensator, unbalance and control algorithms, a computer model has been developed in the MATLAB/Simulink program using the SimPowerSystems library. The results of experiments with a physical prototype of a regulator with a power of 3 kVA performing compensation of unbalanced currents are presented. Diagrams are given in the case of current balancing in a three-phase network with and without a neutral wire when one phase is broken. Diagrams are also presented in the case of combining the functions of reactive power balancing and compensation.