Tilak Thakur

Power quality improvement of solar photovoltaic transformer-less grid-connected system with maximum power point tracking control

This paper presents a transformer-less single-stage grid-connected solar photovoltaic (PV) system with active reactive power control. In the absence of active input power, grid-tied voltage source converter (VSC) is operated in the reactive power generation mode, which powers control circuitry and maintains regulated DC voltage. Control scheme has been implemented so that the grid-connected converter continuously serves local load. A data-based maximum power point tracking (MPPT) has been implemented at maximum power which performs power quality control by reducing total harmonic distortion (THD) in grid-injected current under varying environmental conditions. Standards (IEEE-519/1547) stipulates that current with THD greater than 5% cannot be injected into the grid by any distributed generation (DG) source. MPPT tracks actual variable DC link voltage while deriving maximum power from PV array and maintains DC link voltage constant by changing the converter modulation index. Simulation results with the PV model and MPPT technique validations demonstrate effectiveness of the proposed system.

Power quality assessment of a solar photovoltaic two-stage grid connected system: Using fuzzy and proportional integral controlled dynamic voltage restorer approach

Dynamic voltage restorer (DVR) is used to protect sensitive loads in voltage disturbances of distribution generation (DG) system. In this paper, a variable step size incremental resistance based incremental conductance maximum power point tracking (MPPT) technique is implemented for solar photovoltaic (PV) grid connected system. A power quality study which includes perturb & observe (P&O) MPPT comparison is carried out during fault on grid side. At the same time, proportional integral and artificial intelligence-based fuzzy-logic controlled DVR is operated which injects voltage during the faulted grid side. Simulation results during fault show fuzzy logic based DVR scheme demonstrates simultaneous exchange of active reactive power, less total harmonic distortion in voltage source converter (VSC) current and grid current, less fluctuation of DC bus voltage to VSC, less DC current injection, and fast tracking of optimum operating point at unity power factor. This paper aims at simulating and validations of ...

Grid connected photovoltaic system with data-based MPPT and fuzzy controlled DVR

This paper presents the impact of a fuzzy logic controlled dynamic voltage restorer on a transformer-less single-stage grid-connected solar photovoltaic system controlled by a data based maximum power point tracking technique. The solar photovoltaic system uses a data based maximum power point technique to derive maximum power from solar photovoltaic array and maintains constant DC voltage by changing modulation index of voltage source converter. A dynamic voltage restorer with pulse width modulated control is introduced to mitigate unbalanced sag in grid voltage and current during fault conditions. Fuzzy logic control (FLC) has been implemented to maintain voltage at grid side for normal as well as for faulted conditions. Simulation results show that distortion in active and reactive power exchange among solar photovoltaic converter, load and grid is reduced during fault conditions. A reduction in total harmonic distortion for all temperature conditions, low and high solar radiation is observed in grid voltage and current. Apart from these, it has been observed that distortion in DC link voltage while deriving maximum power from photovoltaic array is considerably reduced by introducing fuzzy logic controlled dynamic voltage restorer in proposed system.

Data based MPPT technique for photovoltaic system

This paper presents a control scheme which controls the active and reactive power flow from the photovoltaic system to grid connected load. PV system can be connected to the grid using two stage or single stage method. In this paper we use single stage method to reduce the cost and losses of the system. As we are injecting reactive power to grid when there is no solar irradiation. To inject reactive power, system extracts active power from the grid when there is no solar irradiation. Therefore the converter has to work continuously with grid. This forces to use single stage system. Control scheme is implemented in such a manner that it provides maximum active power from the PV module and reactive power as per the requirement of the load or grid. Photovoltaic module simulation is done using the basic equation. Photovoltaic module is taken as a voltage source supplying maximum power using the data based MPPT technique. Data is generated from the photovoltaic power-voltage characteristics. According to the data control scheme changes the PV modules voltage and with this method MPPT can be achieve. To study the effect of solar irradiation variation on the output power flow from photovoltaic system to grid. Reactive power is independent of the solar irradiation. Passive filter is used to reduce the harmonic produced by two level inverter.

Optimisation of Imbalance Cost for Wind Power Marketibility using Hydrogen Storage

Large scale trading of wind power in the electricity markets is constrained by the large imbalance costs associated with the wind power. The present short-term power markets are designed for trading conventional generation. For wind generation to participate in the short-term energy markets, lengthy wind power production forecasts are required. Since the wind power forecasts are never perfect, they lead to forecast errors in wind power prediction. The predicted wind power is bid in the power market in the 24 hours day ahead power market and that power is called contracted power. Due to the errors in the forecasting techniques, the wind power producers are penalized for the deviations from the contracted power, which lead to commercial risk to wind farm owners while advance contracting, known as imbalance cost. This paper addresses the problem of high imbalance costs and studies the optimal market structure for effective trading of wind power. The solution to the problem has been obtained with the use of grid connected wind hydrogen system. The paper presents the operation strategy for the minimization of imbalance costs by the use of hydrogen storage. Simulations are carried on a hypothetical system with the help of Matlab and their results are presented.

Design and Real Time Simulation of Artificial Intelligent Based MPP Tracker for Photo-Voltaic System

This paper presents an Artificial Intelligent based Maximum Power Point Tracking (MPPT) of a photo-voltaic system implementation using dSPACE 1104. The paper also proposes a novel Adaptive Neuro-Fuzzy Inference System (ANFIS) / Constant Voltage Tracker (CVT) for a photovoltaic (PV) powered multilevel inverter which requires a fixed constant dc voltage at its input. The MPPT algorithms viz. perturb and observe, incremental conductance, neural network, ANFIS and ANFIS/CVT have been designed and implemented on laboratory prototype. The modeling of various MPPT algorithms have been done on MATLAB/SIMULINK platform. Real time simulations have been carried out using dSPACE R&D controller board and CONTROLDESK software. The performance comparisons of various MPPT techniques applied to stand-alone PV system with resistive load have been presented for varying solar radiation conditions. The authors hope that the comparative analysis presented in this work will be helpful for further research.© 2014 ASME

Utilization of Solar Power through PEM Fuel cells

The fuel cells used in the newly designed hydrogen storage system to store solar energy has the power quality of low voltage as well as high current due to the electrochemical reaction and moreover it is also being investigated as an alternate power source for various applications like transportation and emergency power supplies. The paper presents the configuration and operation of fuel cell system along with the circuit model for a PEM fuel cell that can be used to design and analyze fuel-cell power system. Cost analysis of the storage system has been done which includes the major capital and operating expenses in storing hydrogen.

Economic viability of PEM fuel cells for harnessing solar energy

This study presents a newly designed system (hydrogen storage system) to store solar energy in order to supply a highly reliable utility power. As the fuel cells used in this system has the power quality of low voltage as well as high current due to the electrochemical reaction and moreover it is also being investigated as an alternate power source for various applications like transportation and emergency power supplies. The paper presents the configuration and operation of fuel cell system along with the circuit model for a proton exchange membrane (PEM) fuel cell that can be used to design and analyze fuel-cell power system. Cost analysis of the storage system has been done which includes the major capital and operating expenses in storing hydrogen.

Deciding switching angles and voltage levels for a multilevel inverter using grey relational approach

Inverter is an integral part of any renewable energy conversion system. For a multilevel inverter, attempt is to obtain an output voltage which is near sinusoidal in shape. The switching angles and the voltage levels are decided in such a way so as to maximize the fundamental component with minimum THD. In this paper, it is shown how a simple method like Grey Analysis method can be used to decide the switching angles and voltage levels of a multilevel inverter so as to get an output with maximum fundamental component and reduced total harmonic distortion (THD). For a seven level inverter, six output waveforms are assumed and then the best suitable one from amongst these six waveforms is found out using this method. It is the magnitude of fundamental component and presence of harmonics, especially the lower order harmonics, which affects the output of any inverter. Thus a Multivariable Grey Relational Function is generated by quantifying the effects of multiple factors, i.e. magnitude of fundamental component and also the weighted (WTHD) effect of its harmonics, into a single index. The result thus obtained was authenticated using simulations in Matlab Simulink platform.

Design and modeling of hybrid MPPT MJSC photovoltaic and wind based microgrid using multilevel inverter

Renewable energy sources has found wide acceptance all over the world for its clean and abundant energy availability. For the growing power demand, generating systems of alternative power sources have become much more important than any other sources and also for the purpose to reduce the fossil fuel usage. Due to increase in the power demand a constant load is required. The paper presents a Hybrid PV/Wind design and model, where MPPT based Multi-junction solar cell (MJSC) photovoltaic and wind energy sources are grid integrated using a converter topology to improve power quality delivered to grid in terms of harmonics, by total harmonic distortion minimization. The design of the multi-level inverter is modified from the conventional configuration in order to reduce switches. On the availability of the renewable energy sources, the two sources, simultaneously supply load. The entire system is simulated and tested using MATLAB/Simulink.