Humans have invented thousands of machines and appliances that utilize energy to make the daily works easier, for instance to heat our house, to get ourselves from place to place. Some of this machines use electricity, while others, like automobiles use the energy stored in gasoline. Much of the energy supply comes from coal, oil, natural gas, or radioactive element. In fact, all these natural resource deposits took millions of years to form. They are considered non-renewable which means once they are removed from the ground, they are not immediately replaced within the human timescale.
This current issue is frequently discussed at the level of whole world in order to look for a solution. Nowadays, we will ultimately need to search for renewable or virtually inexhaustible energy for the human development to continue. Renewable energy is defined as the energy generated by the natural resources such as wind, sun light, water which are quickly replace itself and is usually in never ending supply. The exploration of renewable energy is the only approach to reduce our dependence on fossil fuels. Among those renewable energy resources, wind energy is the only resource that will be concerned in this paper. Wind energy was first harvested centuries ago, when early windmills were used to power millstones, pumps, and forges. More recently, the wind is harnessed by using a special collector, called wind turbine to produce a clean, safe source of electricity.
This project focuses on the utilization of wind energy as a renewable source. Wind power, as an alternative to fossil fuels, is plentiful, renewable, widely distributed, clean, produces no gas emissions during operation and uses little land. Any effects on the environment are generally less problematic than those from other power sources. As of 2011, Denmark is generating more than a quarter of its electricity, and 83 countries around the world are using wind power on a commercial basis. In 2010 wind energy production was over 2.5% of total worldwide electricity usage, and growing rapidly at more than 25% per annum. The monetary cost per unit of energy produced is similar to the cost for new coal and natural gas installations. The development of wind power in India began in the 1990s, and has significantly increased in the last few years. India has the fifth largest installed wind power capacity in the world. In 2009-10 India's growth rate was highest among the other top four countries. In India wind capacity is about 6% of total installed power capacity and it continues to grow with the facilitation of new wind projects.
Various designs have been proposed in order to create a high efficient wind turbine which able to generate maximum electric power. They may either the design of shapes of the turbine blades, the axis of rotation, and other useful modification. Recently, an advance technique, Magnetic Levitation (Maglev) is incorporated into turbine system in order to fulfill the needs of those energy industries. The aim of this major qualifying project is to design and implement a magnetically levitated vertical axis wind turbine system. Our choice for this model is to showcase its efficiency in varying wind conditions as compared to the traditional horizontal axis wind turbine and contribute to its steady growing popularity for the purpose of mass utilization in the near future as a reliable source of power generation.
Unlike the traditional horizontal axis wind turbine, this design is levitated via maglev (magnetic levitation) vertically on a rotor shaft. Maglev phenomenon operates on the repulsion characteristics of permanent magnets. This technology has been predominantly utilized in the rail industry in the Far East to provide very fast and reliable transportation on maglev trains and with on-going research its popularity is increasingly attaining new heights. Using a pair of permanent magnets like neodymium magnets and substantial support magnetic levitation can easily be experienced. By placing two magnets on top of each other with like polarities facing each other, the magnetic repulsion will be strong enough to keep both magnets at a distance away from each other. The force created as a result of this repulsion can be used for suspension purposes and is strong enough to balance the weight of an object depending on the threshold of the magnets. In this project, we expect to implement this technology for the purpose of achieving vertical orientation with our rotors as well as the axial flux generator. The basic understanding of a generator is that it converts mechanical energy to electrical energy. Generators are utilized extensively in various applications and for the most part have similarities that exist between these applications. However the few differences present is what really distinguishes a system operating on an AC motor from another on the same principle of operation and likewise with DC motors.
With the axial flux generator design, its operability is based on permanent magnet alternators where the concept of magnets and magnetic fields are the dominant factors in this form of generator functioning. These generators have air gap surface perpendicular to the rotating axis and the air gap generates magnetic fluxes parallel to the axis. This maglev technology, which will be looked at in great detail, serves as an efficient replacement for ball bearings used on the conventional wind turbine and is usually implemented with permanent magnets. This levitation will be used between the rotating shaft of the turbine blades and the base of the whole wind turbine system. With the appropriate mechanisms in place, we expect to use enough wind for power generation by way of an axial flux generator built from permanent magnets and copper coils. The arrangement of the magnets will cultivate an effective magnetic field and the copper coils will facilitate voltage capture due to the changing magnetic field. This system can operate under low (as low as 1.5m/s) and high wind speed (exceeding 40m/s) condition. From the study, the generation capacity of maglev wind turbine is 20% over conventional wind turbines and decrease operational costs by 50%.This make the efficiency of the system become higher than the conventional wind turbine.