14-06-2013, 11:58 AM
DYNAMIC MODELING AND SIMULATION OF HYBRID POWER SYSTEMS BASED ON RENEWABLE ENERGY
DYNAMIC MODELING.pptx (Size: 1.32 MB / Downloads: 31)
ABSTRACT
Detailed dynamic model and simulation of a solar cell, wind turbine and fuel cell hybrid power system is developed.
FC(FUEL CELL) system with an UC(ULTRA CAPACITOR) bank can be integrated to ensure that the system performs under all conditions.
Excess wind and solar energies when available are converted to hydrogen using electrolysis for later use in the fuel cell.
PEMFC(PROTON EXCHANGE MEMBRANE FUEL CELL) units has created many new opportunities to design hybrid energy systems for remote applications with energy storage in hydrogen form.
The output fluctuations of the wind turbine varying with wind speed and the solar cell varying with both environmental temperature and sun radiation are reduced using a fuel cell.
Therefore, this system can tolerate the rapid changes in load and environmental conditions, and suppress the effects of these fluctuations on the equipment side voltage.
INTRODUCTION
The solar energy, wind power, hydraulic power and tide energy are natural resources of the interest to generate electrical sources.
Extensive and generalized usage of renewable energy is very popular to reduce the pollutions we have cause on earth.
The recent commercial availability of small PEMFC units has created many new opportunities to design hybrid energy systems for remote applications with energy storage in hydrogen form .
By using an electrolyzer, hydrogen conversion allows both storage and transportation of large amounts of power at much higher energy densities.
Furthermore, coupling a wind turbine, a solar cell, fuel cells and electrolyzers is efficacious to improve environment pollution because of by using natural energy.
SOLAR CELL
A solar cell (also called a photovoltaic cell) is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect.
When exposed to light, can generate and support an electric current without being attached to any external voltage source.
A number of solar cells electrically connected to each other and mounted in a single support structure or frame is called a ‘photovoltaic module’.
The current produced is directly dependent on the intensity of light reaching the module.
Several modules can be wired together to form an array.
They can be connected in both series and parallel electrical arrangements to produce any required voltage and current combination.
DESIGN OF HORIZONTAL AXIS ROTOR WIND TURBINE
The horizontal-axis wind turbine is designed so that the blades rotate in front of the tower with respect to the wind direction.
The axis of rotation are parallel to the wind direction. These are generally referred to as upwind rotors.
Another type of horizontal axis wind turbine is called downwind rotors which has blades rotating in back of the tower.
Upwind rotors are used in large-scale power generation .
Horizontal-axis wind turbine refers to the upwind rotor arrangement.
PARTS OF WIND TURBINE
Tower – Most expensive element,major components such as rotor brake,gear box,coontroller,generator are mounted on the tower.
Rotor– Primary part which extracts energy from the wind. Constitutes blade and hub assembly
Hubs - Blades are fixed to a hubs which is a central solid part of the turbine
Generator – Converts the turning of a wind turbine’s blades into electricity.
Yaw control– It is the control for orienting the axis of wind turbine in the direction of wind.
FUEL CELL EFFICIENCY
The efficiency of a fuel cell is dependent on the amount of power drawn from it.
Drawing more power means drawing more current, which increases the losses in the fuel cell.
Most losses manifest themselves as a voltage drop in the cell, so the efficiency of a cell is almost proportional to its voltage.
A typical cell running at 0.7 V has an efficiency of about 50%, meaning that 50% of the energy content of the hydrogen is converted into electrical energy; the remaining 50% will be converted into heat.
CONCLUSION
Novel renewable energy based hybrid power system is proposed.
The available power is highly dependent on wind speed, radiation and ambient temperature.
To overcome this deficiency of the solar cell and wind system, we integrated them with the FC/UC system using a novel topology.
The output fluctuations of the wind turbine varying with wind speed and the solar cell varying with both environmental temperature and sun radiation are reduced using a fuel cell.
Therefore this system can tolerate the rapid changes in load and environmental conditions and suppress the effects of these fluctuations.
The proposed system can be used for off-grid power generation in non inter connected areas or remote isolated communities.