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The intermittent character of the photovoltaic generator, power electronic converters and load dynamic are the main factors leading operation instability in islanded microgrids. The necessity of the immediate control within the micro-source is very important since it impacts the interaction between micro-sources in the microgrid. This control level must be characterized by a fast and accurate response...
Outstanding efficiencies can be achieved by the utilization of the latest technology of low voltage, SMD-packaged Si- or GaN-based semiconductors. These devices allow a heatsink- and fan-less converter design, thus lightweight and high power density converters are typically derived. This paper investigates the advantages of using these relatively low cost SMD-packaged devices in medium power industrial...
This paper discusses a single-phase inverter with a buck-boost converter for single-phase applications such as photovoltaic (PV) systems. The inverter consists of a buck-boost converter and an H-bridge unfolder circuit. The inverter requires only 1 controllable switch to obtain 100 Hz pulsating DC-link voltage. However, a conventional PV inverter requires two-stage power conversion. Thus, the power...
Renewable Energy Sources, especially solar energy, are important in mitigating environmental problems. Following, a step-by-step modeling of a photovoltaic (PV) system that can be connected to the grid through converters is achieved. The proposed mathematical model is implemented in MATLAB/ Simulink. A maximum power point tracking (MPPT) algorithm finds the maximum power for the operation of the PV...
Vietnam has declared its first official support mechanisms for the development of solar power projects by the Decision 11/2017/QD-TTg, officially signed by the Prime Minister of Vietnam in April 2017. The Decision creates a legal framework for solar energy market and promotes solar electricity development in Vietnam. Since 2016, Energy Department of the University of Science and Technology of Hanoi...
Power volatility of grid-tied photovoltaic (PV) sources can be responsible for various power quality issues in utility grids with high renewable sources penetration. Problems such as voltage flickering or frequency deviations can become more severe for isolated grids or islanded microgrids. Various solutions have been proposed to address these issues, mainly based on smoothing the PV output power...
Photovoltaic systems, whether they are domestic, commercial or industrial often incorporate some forms of system protection. However, elaborate real-time fault detection is not defined for most such systems. To address this shortfall, a comprehensive photovoltaic installation system fault detection and control strategy is presented in this paper. The designed system is made up of fault detection in...
Power system frequency quality has become topical due to the installation of variable renewable generation. The present paper contributes to the topic by investigating the sizing of a photovoltaic energy storage (PV-ES) system for frequency maintenance. The core content of the paper is threefold. Firstly, an algorithm is proposed to optimize storage capacity required to provide virtual kinetic energy...
Solar energy has the characteristics of intermittent and unstable, and it results in the negative impact on power quality of the utility grid while the penetration rate of the grid-connected photovoltaic generation system is increased. The energy storage system (ESS) can alleviate the negative impact on power quality of the utility grid so as to increase the penetration rate of the grid-connected...
This paper describe and present the study on online tap change (OLTC) operation in distribution network in the case of utilizing reactive power capability of PV inverter. The conventional voltage control scheme and the effect of solar PV variation on the voltage profile in distribution network are discussed. Solar resources in the state of Qatar for different seasons and weather condition are presented...
The modulation technique is an effective measure to suppress the leakage current in three-phase three-level transformer-less photovoltaic systems. This paper further analyzes the intrinsic relationship between the common mode voltage and the zero-sequence voltage of three-phase three-leg three-level inverters, with a novel SVPWM method proposed. The presented algorithm makes the zero-sequence voltage...
In order to simplify the configuration of photovoltaic (PV) grid-connection system, this paper proposes to adopt a buck-boost dc-dc converter, and then develops a single-phase inverter via the connection with an H-bridge unfolding circuit with line-commutated. Depending on the conditions of dc input-voltage and ac output-voltage, the proposed circuit can work functionally as either a step-down or...
This treatise deals with Transistor Clamped Five Level Inverter using Non-Inverting Double Reference Single Carrier PWM (NIDRSC PWM) Technique. Conventional or two level inverter have drawbacks like: i) Requirement of fast switching devices, ii) Very high dv/dt, iii) High Electromagnetic Interferences (EMI), iv) Bulky filters, v) Faster heating of switches, and vi) Not suitable for high voltage applications...
This paper evaluated the impact of smart inverter Volt-VAR function on voltage reduction energy saving and power quality in electric power distribution systems. A methodology to implement the voltage reduction optimization was developed by controlling the substation LTC and capacitor banks, and having smart inverters participate through their autonomous Volt-VAR control. In addition, a power quality...
The boost inverter is an attractive solution for photovoltaic (PV) microinverters since it is a single stage architecture. Indeed, in comparison, most of the microinverters topologies consist of two-stage structures, a DC-DC converter for voltage elevation and an inverter for grid connection, resulting in a lower efficiency. The boost inverter consists of two DC-DC boost converters connected in differential...
This paper offers a microgrid (MG) system equipped with a classical proportional-integral (PI) control operating in two conditions, i.e., grid-connected and islanding modes. The proposed microgrid mainly consists of hybrid photovoltaic/wind sources, a synchronous generator, a battery storage and a load. The microgrid is able to provide a power factor correction close to unity in the grid-connected...
Nowadays multilevel inverters are a very attractive solution for medium-voltage high-power conversion applications; they convert DC power to AC power at required output voltage and frequency level. In the design of multilevel inverters, different topologies have been evolved. These topologies include diode clamped multilevel 1 inverter, flying capacitor multilevel inverter and cascaded H bridge multilevel...
Nowadays, transformerless photovoltaic (PV) inverter systems are becoming to be used widely to achieve high efficiency, and the research level of PV systems is widespread continuously. However, main problems of PV inverter systems are the leakage currents, electromagnetic emissions, and losses in system. This paper introduces the buck-boost-based three-switch three-state Z-source inverter for using...
Grid connected photovoltaic inverters play an important role to achieve an effective and efficient system with reduced total cost of the system. The photovoltaic inverters convert the dc source and delivered into the ac system. The main aim of this paper is to analyse the performance of HERIC inverter for photovoltaic applications for different Pulse-Width Modulation (PWM) techniques. The two different...
In this work, the phase shifted carrier pulse width modulation (PSC PWM) technique is applied as the most favorable modulation scheme for a photovoltaic (PV) fed cascaded multilevel-micro-grid connected inverter (CM-MGCI), with consideration of the total harmonic distortion (THD) of the output voltage. In addition to this, a modified PSC PWM method named as variable amplitude PSC-PWM (VA-PSC-PWM)...
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