A.K. Saha

Modelling, simulation and performance analysis of a PV array in an embedded environment

Photovoltaic (PV) generation involves the direct conversion of sunlight into electrical energy. In recent years it has proved to be a cost-effective method for generating electricity with minimum environmental impact. Due to the environmental and economic benefits PV generation is now being deployed worldwide as an embedded renewable energy source and extensive research is being performed in order to study and assess the effectiveness of PV arrays in Distributed Generation (DG) systems either as a potential energy source or as energy reserve in combination with other types of distributed energy resources. This paper presents the modeling and MATLAB simulation of a stand-alone polycrystalline PV Array system and investigates load following performance efficiency under various loading and weather conditions as well as suitability with regard to enhancing power supply reliability to critical loads. The modeling of the PV array that has been performed in this research using MATLAB Simulink is based on the calculation of parameters for the Thevenins equivalent circuit of each cell of the array. The standard double exponential polycrystalline cell model has been adopted for this research with solar irradiance E and ambient temperature T as the input and Thevenins voltage Vthar and Thevenins resistance Rthar as the output.

Efficiency Optimization of Induction Motor Using a Fuzzy Logic Based Optimum Flux Search Controller

Induction motors are, without any doubt, the most used in industry. Motor drive efficiency optimization is important for two reasons: economic saving and reduction of environmental pollution. In this paper, advantages of using fuzzy logic in steady-state efficiency optimization for induction motor drives are described. Experimental results of a fuzzy logic based optimum flux search controller are presented. There are so many speed control techniques available, like scalar control, vector control, sensor less control etc. Due to coupling effect, the scalar control has inferior performance and vector control is a method of speed control in which both magnitude and phase angle of current can be controlled. In vector control, the presence of speed sensor at shaft decreases the reliability and ruggedness. For transient states, a new original idea is introduced: a fuzzy logic based controller, actuating as a supervisor, is proposed to work with reduced flux levels during transients to optimize efficiency also in dynamic mode. Two different rule tables are designed, for torque transitions and for reference speed changes. With this controller, efficiency can be improved in transients, and also search controller convergence speed is increased. In my work efficiency optimization of induction motor using fuzzy logic controller was carried out using Matlab.

Application of wavelets in power system load forecasting

Forecasting of electric load demand on power system using wavelet transform is presented in this work. It utilizes the periodicities of past load demand data. Load demand data is presented as an image of size of 7times24 for a week, from which the image of a year is obtained by stacking 52 weeks. Medium range forecasting has been performed using wavelet with autoregressive modeling and smoothing techniques. Various types of wavelets bases are applied to extract the data features to be used as priori knowledge for prediction instead of the actual utility data as may be in the case of majority of forecast models and used to forecast the demand. Inversion of the forecast coefficients leads to the actual forecast. As it is simple and efficient, can effectively be utilized by the power sector utilities for forecasting of electrical load demand occurring on them

Study of microturbine models in islanded and grid-connected mode

This paper presents modeling and simulation of microturbine (MT) models to analyze its load following performance as distributed energy resource (DER) with general as well as critical priority loads. Two different models of MT were considered for performance analysis. The first model consists of speed governor, acceleration control, and temperature control blocks while the other is GAST model of MT. The system comprises of a synchronous generator and a MT coupled to it. Simulations are carried out in islanded and grid-connected mode of the system to observe its behavior when supplying customerpsilas variable loads. The load following characteristics is observed and validated for this MT-synchronous generator model in Matlab-Simulink environment with power system block sets. This is applicable with combined heat power (CHP) generators both with general fuel as well as bio-fuels. The use of bio-fuels is very much promising for generating green power preventing green house gas emissions for fighting against global warming. But it may take some time to be in the market place for its commercial use.

Software simulation of PEM fuel cell system for dynamic performance analysis

Fuel cell power generation technology is gaining importance on its own way as it has many advantages like less environmental pollution, high efficiency, cleanliness and safe operation with the present global scenario of electricity generation, distribution and meeting the consumer demand. Several research works have been done in this area of power generation. In this paper, a dynamic model of a Proton Exchange Membrane (PEM) fuel cell (FC) has been developed and the dynamic behavior are studied. PEMFC has been chosen due its low operating temperature and little start-up time that are suitable for stationary applications like residential and transportation uses. This model is used to simulate dynamic behavior of FC system that can be further used for distributed energy resources (DER) integration study and their simulation. The model uses a proportional-integral controller to control the fuel flow to the reformer of the fuel cell system. The dynamic behavior of the fuel cell system with a step load change is studied and the outputs are found to be promising. Therefore, this model can be used for other dynamic behavior study and DER integration study.

A Simulink Based Microgrid Modelling & Operational Analysis Using Distributed Generators

This paper describes dynamic modeling of a microgrid operating in grid-connected mode. The model is applied to a distributed utility grid that uses three gas turbine based distributed generators (D.G.), generating power at distribution voltage level (415 volts) and these are connected to a MV grid through a transformer. These DGs are dynamic devices & hence affect the dynamic behavior of the distribution grid. The transient simulation in this paper is done using MATLAB SIMULINK. Analysis of the transient behavior of DGs in simulated environment is important for control of generators during faults, generator trip, surges and switching conditions

Dynamic model of PEM fuel cell with fuzzy logic controller

With the present global scenario of electricity generation, distribution and meeting the consumer demand, fuel cell power generation technology is gaining importance on its own way as it has many advantages like less environmental pollution, high efficiency, cleanliness and safe operation. Several research works have been done in this area of power generation. In this paper, a dynamic model of a proton exchange membrane (PEM) fuel cell (FC) has been developed and the dynamic behaviors are studied. PEMFC has been chosen due its low operating temperature and little start-up time that is suitable for stationary applications like residential and transportation uses. This model uses fuzzy logic controller to replace conventional proportional-integral (PI) controller. Fuzzy logic control is used to the fuel flow to the reformer of the fuel cell system. The dynamic behavior of the fuel cell system with both the types of controllers i.e. FLC and PI are studied and compared. It is observed that the FLC functions as well as a PI controller and enhances the performance of the FC system. The dynamic behavior of the system is found to be more improved as compared with the PI controller system.

Process Improvement Initiatives in a Newly Reformed Distribution Company

After the formation of a distribution company (DISCOM), it takes a lot of initiatives to become a preferred provider of reliable and competitive power to people it serves and a favored company to work for. This work covers the initiatives taken by a DISCOM in different areas like O&M process improvement, commercial process improvement, and customer care process improvement to enhance all the related performances. Key challenges involving the initiatives are to deliver quality and cost effective electricity, ensure excellence in customer care, create a work environment that encourages teamwork & innovation. With the implementation of the initiatives, dramatic improvements in the performances in all the areas were observed which enabled the company to orient the core business operations with information systems and world-class practices for sustainable reforms