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AbstractThe evolution of high performance power electronic converters makes a feasible way to integrate the Renewable Energy System (RES) to the grid. High performance in terms of stability, good transient and steady state response, load variations is achieved in this work using Current Controlled Voltage Source Inverters (CCVSI) by deriving the control law using Lyapunov function at the expense of a time varying reference current. In this work, a single phase equivalent circuit is represented for the three phase grid connected renewable energy system, and mathematical modeling is developed to design the controller. Analysis using Lyapunov based controller is carried out to ensure the real and reactive power flow from the renewable energy system to the grid connected with the non linear load. The reference current for the controller is generated using the Symmetrical Component theory. This theory requires no transformation and desired source power factor can be achieved. To exhibit the efficacy of the Lyapunov controller, the simulation is carried out using MATLAB/Simulink environment. It is observed that the desired power factor is obtained and Total Harmonic Distortion (THD) is within the IEEE limits in the grid side. The performance of the system is validated experimentally and the results are compared with the conventional hysteresis controller for the same application.

Department of Mathematics

School of Advanced Sciences

Vellore Campus

World University root node

Department of Thermal and Energy Engineering

School of Mechanical Engineering

Fulltext

International Journal of Emerging Electric Power Systems

Power Quality Enhancement Using Lyapunov Based Voltage Source Inverter for the Grid Integrated Renewable Energy System

VIT Unitversity

IOP Conference Series: Materials Science and Engineering

Design of low Reynolds number airfoil for micro aerial vehicle

Indian Journal of Science and Technology

Experimental Investigation on Laminar Separation Bubble Over an Airfoil � a Review

Renewable energy sources (RES) are utilized to meet the power demand employing power electronic converters. This paper presents the control methodologies for the integration of renewable energy sources to the grid using Current Controlled Voltage Source Inverter (CCVSI). The inverter performs power conversion in addition to the shunt active power filter operation. The controllers shape the grid current sinusoidal making low Total Harmonic Distortion (THD) even when a non linear load is connected. The controllers are employed in three modes with zero RES power, RES power greater and lesser than load power, and the power flow is also analyzed through simulations done in MATLAB Simulink environment. Further on, it performs reactive power compensation making power factor nearer to unity in the grid side. Comparative analysis is carried out between the hysteresis and Linear Quadratic Regulator (LQR) and the results prove the supremacy of LQR. © IAEME Publication.

International Journal of Mechanical Engineering and Technology

Power flow control for the grid integrated renewable energy system

2017 Intl Conf on Advanced Control Circuits Systems (ACCS) Systems & 2017 Intl Conf on New Paradigms in Electronics & Information Technology (PEIT)

Maximum power point tracking of photovoltaic system using adaptive fuzzy controller

This paper presents an optimal control strategy using linear quadratic regulator (LQR) applied in current-controlled voltage source inverter (CCVSI) to control the real and reactive power flow between the renewable energy system (RES) and the grid. It also compensates harmonic current components drawn by the load from the grid terminal. A simplified equivalent circuit is used to develop the reduced order state space model of the three-phase grid connected renewable energy system. This makes the analysis and design of control law simpler by reducing the number of weighing variables used in LQR. The extension real–reactive power (p–q) method implemented in a–b–c frame is used to generate the reference current for controlling the real and reactive power to the grid to minimize the total harmonic distortion (THD) and to achieve unity power factor (UPF) operation at the grid side. The stated technique makes the grid current sinusoidal even under unbalanced grid voltages and the harmonic distortion factors are well within the IEEE limits. The system is simulated under changes in the real power fed from RES to the grid for both balanced and unbalanced grid conditions. The simulation results are validated by the experimental results. © 2017, Copyright © Taylor &amp; Francis Group, LLC.

Electric Power Components and Systems

Power Quality Enhancement Using Linear Quadratic Regulator Based Current-controlled Voltage Source Inverter for the Grid Integrated Renewable Energy System

Due to the development of global economy, the energy demand rises exponentially. Hence, the electrical sector needs to fill the gap between the supply demand through conventional and non conventional energy sources. Most of the conventional energy sources pollute the environment causing global warming. Hence, the usage of non conventional energy sources like solar, wind energy increases rapidly. But the power extraction from these sources should be operated in optimum operating point. This paper presents the extraction of maximum power using fuzzy logic from solar Photo Voltaic (PV) cells. The PV cells exhibit non-linear characteristics and its optimum power point depends on solar irradiation and temperature. Fuzzy logic is a problem solving control methodology used to solve problems with non-linearities and uncertain information. The fuzzy logic algorithm is simulated for different atmospheric conditions and also verified experimentally. © IAEME Publication.

Maximum power point tracking of boost converter on a PV system using fuzzy logic

The solarized steam injection gas turbine (STIG) cycle uses both the fuel and solar heat simultaneously for power generation. The annual thermodynamic performances of the cycle for sites in India with local climatic conditions such as ambient temperature, relative humidity and availability of direct normal irradiance (DNI) to the solar concentrators under two modes of constant and variable power are presented in this paper. The results reveal that the solar to electricity efficiency of solar hybrid STIG plant with a simple parabolic trough collector (PTC) is similar to existing solar thermal technologies, and also higher solar share is obtained. The study also reveals that the annual CO2 emission is similar to combined cycle plants and lower than gas turbine technologies. The incremental CO2 avoidance is also computed due to solar participation. The annual values of exergetic solar fraction and exergetic efficiency at Indore are higher than Jaipur. Results of an improved economic assessment show that the levelized tariff (LT) of solar hybrid STIG plant is 0.2-0.23 $/kWh and the levelized tariff (solar only) or solar levelized tariff (SLT) of solar STIG plant ranges from 0.11 to 0.27 $/kWh for both constant and variable power scenarios. © 2015 Elsevier B.V. All rights reserved.

Applied Thermal Engineering

Annual energy and environment analysis of solarized steam injection gas turbine (STIG) cycle for Indian regions

The STIG (steam injected gas turbine) cycle offers a way for increasing the power, efficiency and NOx reduction in gas turbines by injecting steam into the combustor. The present exergetic study is to investigate the influence of compressor PR (pressure ratio), TIT (turbine inlet temperature) and SAR (steam to air ratio) on the solar hybrid STIG cycle. Exergy analysis was performed for four cases based on the parameters of real gas turbines. Annual exergetic performance is also presented for the sites Indore and Jaipur in India under constant and variable power modes. The analysis suggests that the steam injection does not affect the performance of compressor. The total exergy destruction in the cycle increases with SAR and TIT. The exergetic efficiency also increases in the range of 40%-54.2% with SAR up to 0.9. The magnitude of exergy destruction in all components in the cycle (except compressor) increases by increasing SAR. Nevertheless, largest component of exergy destruction in the combustion chamber increases with SAR and TIT about 53% at SAR 0.9. The exergetic efficiency of combustor increases from 74.5% to 81.8% with increasing SAR from 0.3 to 0.9. The exergy destruction in the turbine increases considerably with compressor pressure ratio, sparingly with SAR and independent of TIT. The exergy destruction in the SH (super heater) is less compared to the economiser in the HRSG (heat recovery steam generator). The contribution of solar energy (exergetic solar fraction) is more sensitive to TIT and SAR than PR. It is noticed that increase in turbine outlet temperature, led by PR and TIT, decreases the exergetic solar fraction, and the cycle exergetic efficiency improves as the exergetic solar fraction increases, which leads to an improved performance device. The second largest percentage of exergy destruction is in the flue gas condenser to recover water for recycling, and the heat removed from the condenser is lost to the surroundings by cooling air. The annual values of exergetic solar fraction and exergetic efficiency at Indore are higher than Jaipur in both constant and variable power modes of operation. © 2014.

Energy

Exergy analysis and annual exergetic performance evaluation of solar hybrid STIG (steam injected gas turbine) cycle for Indian conditions

Steam injection for power augmentation is one of the significant modifications of gas turbines that has been commercialized for natural gas-fired applications. The primary objective of this work is to demonstrate that the installation of a solar hybrid steam injected gas turbine plant (STIG) for power generation could have a lower installed cost and lower solar levelized tariff compared to the solar-only thermal power plant while producing a comparable energy output. An economic evaluation is presented for the locations Indore and Jaipur in India under constant, variable power and mixed power scenarios. The levelized tariff (LT) of solar hybrid STIG plant ranges 0.24-0.26 $/kWh, and the levelized tariff (solar only) or solar levelized tariff (SLT) of solar STIG plant ranges from 0.29 to 0.4 $/kWh in constant power (CP) and variable power (VP) scenarios. In case of mixed power (MP) scenario, the range of LT varies from 0.16 to 0.21 $/kWh for CP and VP modes basis. In this analysis, size of the solar STIG plant varies from 48 MW to 212 MW based on the steam to air ratio. The IRR and payback period varies between 12%-17% and 6.3-8 years for both CP and VP scenarios at Jaipur and Indore. Sensitivity analysis reports that the performance of the power plants depends, to a large degree, on boundary conditions such as fuel and equipment costs. © 2014 Elsevier Ltd. All rights reserved.

An economic analysis of solar hybrid steam injected gas turbine (STIG) plant for Indian conditions

The solar hybrid Steam Injection Gas turbine (STIG) cycle uses both recuperated heat and solar heat in order to generate steam at a low temperature and pressure, and inject it into the cycle in order to augment the power output. An annual performance analysis of the Solar STIG cycle is presented for sites in Israel and India, with moderate and high annual direct insolation. The cycle operation was simulated in two modes: constant power output and variable power output following the variation of solar input. The solar contribution to the electricity production of the hybrid cycle and the solar to electricity efficiency were calculated, where the conventional reference system was either a conventional STIG or a conventional recuperated Brayton cycle. Results show annual solar fraction of up to 31% in constant power mode and up to 33% in variable power mode. The annual solar to electricity efficiency was in the range of 22-26% when the reference efficiency was based on the recuperated Brayton cycle, and 12-16% when the reference efficiency was based on an optimal conventional STIG cycle. These values are similar to or higher than the annual efficiency of current solar thermal power technologies, even though the hybrid STIG cycle uses low-grade solar heat at only 200. °C. © 2014 Elsevier Ltd.

Solar Energy

Annual performance of the solar hybrid STIG cycle

Solar thermal energy is now being widely utilized to meet the world's energy demand due to its huge potential. Power generation from solar is varying and high cost of solar thermal energy systems that makes sense only in regions with high solar insolation. In order to overcome these practical issues, low cost solar hybrid steam injection gas turbine (STIG) cycle is adapted. Both gas turbine exhaust stream and solar heat are used for steam generation, and then it is injected into the combustor. The steam injection reduces NOX and CO2 emission in addition to increased power output and plant efficiency compared to the simple cycle. It offers a path for high conversion efficiency without the requirement of operating at high temperature and high pressure in the solar components. The objective of the proposed work is to investigate a conversion method for solar radiation that offers potentially high conversion efficiency and for increased competitiveness against fossil fuels. The annual performance of the cycle for sites in India with local climatic conditions such as ambient temperature, relative humidity and availability of direct normal irradiance to the solar concentrators under two modes of constant and variable power is presented in this paper. The results reveal that the solar to electricity efficiency of solar hybrid STIG plant with a simple Parabolic Trough Collector (PTC) is similar to existing solar thermal technologies and higher solar share is obtained. The study also reveals that the annual CO2 emission is similar to combined cycle plants and lower than gas turbine technologies. © 2014 The Authors. Published by Elsevier Ltd.