Connected PV System Research Articles

Improve power quality and stability of grid - Connected PV system by using series filter

As the world increasingly focuses on renewable energy sources, grid-connected PV systems will continue to play a critical role in meeting our energy needs. This integration has brought many benefits, but has also created various problems related to power quality and stability at the connection points. Various techniques are used to improve the power quality, such as passive filters, tuned passive harmonic filters, and active filters. This paper presents the use of a series active filter on the DC side of grid-connected PV systems to improve their power quality, stability, and dynamic performance. The proposed filter consists of an inductor, two capacitors, and four transistor-diode pairs, the operation of which is controlled by a sinusoidal pulse width modulation (SPWM) scheme. The MATLAB/Simulink is used to build and validate a comprehensive mathematical model of the studied system. The transfer function of the system is identified and its transient response is studied under various test input signals. A Bode plot is also generated to assess the impact of the integration of this component on the stability of the system. The results showed that incorporating the filter resulted in a significant reduction in the total harmonic distortion factor (Thd%) for both the voltage and current waves at the inverter output. Moreover, it improved the transient response characteristics of the system by significantly reducing the maximum overshoot value of the system response with respect to the test input signals. The results indicate that the stability of the system is improved after the filter addition, as evidenced by the increased gain margin and phase margin in the system Bode plot.

Solar Energy Potentials of Some Selected Locations in Northeastern Nigeria

Sunlight is the primary source of clean and cheap energy but its intensity varies from one location to another depending on the latitude, altitude, atmospheric absorption and scattering by air molecules, dust particle and water vapour among others. The aim of this work is to determine the solar energy potentials of Gombe ( latitude 10° 16' 59.9988'' N and longitude of 11° 10' 0.0012'' E), Jalingo (latitude 8° 53' 34.2672'' N and Longitude 11° 22' 37.74'' E), Damaturu (Latitude 11° 44' 49.1856'' N and Longitude 11° 57' 58.2912'' E) and Bauchi (latitude 10° 18' 50.9724'' N and longitude 9° 50' 46.6152'' E) in northeastern Nigeria, the process involves obtaining the solar irradiation data for these four locations from a renewable energy simulation package ( photovoltaic geographical information system, PVGIS) for a period of 10 years, a daily, monthly and annual solar irradiation was obtained for each of these locations. A peak monthly values was obtained in the month of January for Gombe, Jalingo and Bauchi while the month of March has the peak value for Damaturu, an average daily solar irradiation of 5.8977kWh/m2/day, 5.9026 kWh/m2/day, 6.0337 kWh/m2/day and 5.9821kWh/m2/day and an annual values of 2154.44kWh/m2/yr, 2056.17 kWh/m2/yr, 2202.30kWh/m2/yr and 2150.60kWh/m2/yr for Gombe, Jalingo, Damaturu and Bauchi respectively. These locations have very similar atmospheric conditions and hence a closer range of solar energy potentials compared to places like Lagos, Onitsha and Sapele in Delta state with (4.42kWh/m2/day), (4.43kWh/m2/day, and 5.31 kWh/m2/day respectively. Damaturu has the highest solar irradiance among the four locations studied. Grid- connected PV system and thermal system (concentration thermal technology) can be built to support electricity generation and hot water production respectively for residential and industrial use. The utilization of Solar oven, cookers and coolers technology should be encourage by government and non-governmental organization, this will help stop global warning and desert encouragement and hence conserve other natural resources( such as forest) for other use ( furniture construction).

Performance Analysis of Three-Phase Inverter Using Different Techniques for the Grid- Connected Pv System

The model of a three-phase voltage source inverter is examined based on space vector theory. SVPWM offers an improved outcome with the inverter as compared to the conservative SPWM technique for the inverter. There is a 15.5% upsurge in the line voltage of the inverter. SVPWM better exploits the available DC-link power with the SVPWM inverter. It has been revealed that the SVPWM method utilizes DC bus voltage extra competently and produces a smaller amount of harmonic distortion and easier digital realization in a three-phase voltage-source inverter. For converter‘s gating signals generation, the space-vector pulse width modulation (SVPWM) strategy lessens the switching losses by restricting the switching to two-thirds of the pulse duty cycle. A hypothetical study regarding the use of the SVPWM the three-level voltage inverter and simulation results are offered to prove the usefulness of the SVPWM in the involvement in the switching power losses lessening, output voltages with fewer harmonics. Nevertheless, despite all the above-cited benefits that SVPWM enjoys over SPWM, the SVPWM technique used in three-level inverters is more difficult on account of a large number of inverter switching states. The attained simulation outcomes were satisfactory. As prospects, future experimental works will authenticate the simulation results. A software simulation model is developed in Matlab/Simulink.

Voltage Profile Improvement of Solar PV Grid – Connected Inverter with Micro Grid Operation using PI Controller

Microgrids (MGs) are initiating the large number of opportunities for the future of distribution units. Distributed generation resources (DERs) such as solar, wind, combined heat and power, energy storage, etc are tie up with the microgrid or distribution grid (DG) which can be used for improving the power quality. Distributed generation and microgrid are the most challenges to the power system network. This includes the stability, reliability, increasing power demand and power quality issues in power system. The objective of this paper is to improve the voltage profile of grid – connected PV systems. In the distribution system, PV source is the challenging one which is directly disturbs the power quality issues. Here MPPT algorithm is used to achieve the maximum amount of power in grid – connected PV systems. This paper presents the grid connected inverter with a PI controller is proposed. At the connection of point of common coupling real and reactive power by abc to dqo transformation could be compensated under the unbalanced load condition. The proposed control method is used to improve the voltage profile in the PV systems, dc voltage regulation across the grid side inverter control and to reduce the distortions under the sudden load changes. The effectiveness of the proposed system is replicated through the MATLAB/SIMULINK using Simpower system library.

A Unified Seamless Transfer Control Scheme for Grid-Connected and Islanding Modes of Operation of Grid- Connected PV System

Objectives: This paper proposes a concept of micro-grid under smart distribution environment conditions with distributed generation resources like solar, wind etc. Methods/ Statistical Analysis: In present scenario, the importance of distribution sources is very high for maintaining the system reliability and also for providing backup generation under islanding condition and also as well as in grid-connected conditions. Findings: In this paper, a new control concept has been proposed for the seamless transfer who is based on Phase-Locked Loop (PLL) control for islanding and grid connected modes. In this paper the phase locked loop is used to maintain phase synchronization between grid and load voltages under grid and islanding conditions. And also, this paper proposes a current and voltage controller for stability analysis. The proposed method interfaces the PV system to the grid effectively. This proposed system is implemented and verified by using Matlab/Simulink. Applications/ Improvement: The proposed architecture is greatly beneficial for practical implementation of standalone and Islanded hybrid systems.