Advanced Materials Research Vol. 768

Abstract: This paper presents the comparative dynamic analysis of full bridge and half bridge three port dc-dc converter topology interfacing the renewable energy sources along with the energy storage devices. The three port converter comprises the active bridge circuit and the three winding transformer. It uses single power conversion stage with high frequency link to control power flow between the batteries, load and the renewable energy sources. The power flow between the ports is controlled by phase shifting the square wave outputs of the active bridges in combination with pulse width modulation (PWM) technique. The analysis reveals that the battery discharges when the source is not sufficient to supply the load and it was charged when the source alone is capable of supplying the load. Hence there is a bidirectional power flow in the storage port when there is a transition in the source.

Abstract: This paper presents the comparison between various numerical methods namely Euler's Method, Midpoint Method, 2nd order Runge Kutta Method and 4th order Runge Kutta Method with the analytical method to solve a power electronic system in both single phase and three phase configuration using decoupled methodology. The values of source current, load current and DC link voltage are obtained for each method using Matlab software and compared with each other. Also, the error in each numerical method with respect to analytical method is calculated and tabulated. These power electronic models could be an excellent research platform for testing the renewable energy systems without going for full scale or scaled down models.

Abstract: Wind energy has drawn worldwide attention because of its simple structure, high efficiency and stable operation. Recently, variable speed constant frequency (VSCF) direct-drive wind power generation system using permanent magnet synchronous generator (PMSG) has gained popularity. This paper focuses on the simulation of PMSG fed diode clamped MultiLevel Inverter (MLI) for wind applications. A three-level MLI with phase disposition PWM technique has been proposed. Simulation studies on the proposed scheme have been carried out in MATLAB and spectral quality of the output has been investigated.

Abstract: Maximum power point tracking techniques are used in photovoltaic systems to make best use of the photovoltaic array output power. Maximum power point depends on the temperature and irradiance conditions. Perturb and observe method is considered here. This method is widely used because of its low-cost and ease of implementation. The simulation of photovoltaic array modeling & Perturb & Observe method have been carried out in this paper.

Abstract: In recent years, many researches are being carried out on the integration of solar thermal systems with solar photovoltaic modules in many countries for heat generation along with electricity generation. The electrical energy generated by the solar PV modules is utilized for the operation of fan. The hybrid solar photovoltaic - Thermal (PV/T) technology provides an opportunity to enhance the electrical and thermal performances. This paper deals with analysis of various parameters which affect the electrical and thermal performances of different types of hybrid solar photovoltaic - Thermal (PV/T) air heating systems. These systems deliver more useful energy per unit area of the heater than that of individual solar PV and solar thermal systems and can be used for preheating the air for many applications such as drying of agricultural products, space heating and industrial process heating. The performance comparisons among the various models reveal that the model III in which the air flows above and below the absorber plate is most suitable for converting the solar energy into high quality electrical energy and low quality heat energy.

Abstract: Wind turbines blades of propeller type are made according to various blade profiles such as NACA, LS, and LM. There are many factors for selecting a profile. One significant factor is the chord length, which depend on various values throughout the blade. In this work a NACA 4412 profile was created using DESIGN FOIL software to obtain the coordinates of a wind turbine blade in PRO/E. Aerodynamic analysis was done on the created design. Maximum lift to drag ratio was calculated by varying angle of attack of the blade. To find a suitable composite for wind turbine blade, Modal and Static analysis were performed on the modified design using Carbon fiber, E-Glass, S-Glass and Kevlar fiber composites in ANSYS APDL 12.0 software.

Abstract: The generation of electricity from solar energy has gained worldwide acceptance and serves as a critical objective for the future due to its abundance and eco-friendly nature. However, the output power extracted from solar PV module varies based on the variation in environmental conditions such as irradiance, temperature, shadow etc. Therefore, Maximum Power Point Tracking (MPPT) algorithms are implemented for the proper utilization of the available photovoltaic energy. This paper proposes an algorithm using Particle Swarm Optimization technique which involves a simple and effective method to calculate the required duty cycle. The key feature of this method is its ability to track the maximum power accurately with almost zero steady state oscillations which in turn improves the performance of the tracking system. The effectiveness of this algorithm has been evaluated under uniform change in environmental conditions in MATLAB/SIMULINK. Moreover, superiority of the proposed method is verified by comparing its results with the conventional algorithms such as Hill Climbing and Incremental Conductance in terms of tracking speed and steady state oscillations.

Abstract: The total power demand in our country is increasing every year because of the increasing population. Conventional energy sources are limited by the constraints such as emission of CO2, increasing price of oil etc. To increase the power generation we need to go for non conventional energy sources among which wind energy is available in abundance. This paper discusses the possibility of using wind energy for the stand alone large scale applications eliminating the constraints on the grid connection. This is the pre feasibility study of wind power generation by analyzing the daily wind patterns in the coastal areas. This forms a good base for analyzing the feasibility of standalone wind system to large scale applications. HOMER software is used as an optimization tool. From the results Chennai has better energy density and Tutukurin has higher capacity factor. The study makes it feasible to next step in analyzing the feasibility of implementing a standalone desalination unit in coastal regions of Tamilnadu.

Abstract: Heating of water for domestic purpose is simple and effective way of utilizing solar energy. Though the initial cost of solar water heating system is high, the maintenance cost and zero green energy cost. To overcome the problem of high initial cost, this paper suggests utilizing alternative material with very good absorbing efficiency material instead of copper. The stainless steel tube coated with epoxy-polyether and aluminium with copper oxide coating are used as a header and riser tube material instead of copper which is in practice now-a-days. This paper introduces a new heating system which has flat plate collector of effective performance at low cost even though stainless steel and aluminium has low thermal conductivity. Experiments have been conducted by using copper, stainless steel and aluminium tubes as header and riser tubes. The result shows that copper, aluminium and stainless bestow the same performance. Also the cost of stainless tube with epoxy-polyether and aluminium with copper oxide are less than that of copper tube.