28-06-2013, 03:25 PM
satellite power station and microwave power transmission
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ABSTRACT
The objective of the present study is to drive or charge a ZigBee device by intermittent microwave power transmission, which is compatible with the wireless sensor network.We found out that intermittent microwave power transmission drove the rectifier circuit with high efficiency at the average consumed power of the ZigBee devices. Also we confirmed that the ZigBee device could communicate correctly in high power density with intermittent microwave irradiation; whereas it could not communicate robustly in slight power density with continuous microwave irradiation. We finally demonstrated that the ZigBee device worked and communicated correctly without a battery by intermittent microwave power transmission.
Introduction:-
• The demand for energy worldwide has increasing by 100% or almost doubled in every decade.
• The world’s main source of power is still generated by fossil fuels which is limited (85% of the total power globally).
• Harmful effects of hydrocarbon-based power sources to environment.
• Regional political and religious conflicts can disrupt world-wide distribution of fossil fuel.
• Requirement of clean energy sources.
• Building a power station in space to transmit electricity to Earth by way of radio waves-the solar power satellites.
• Advances in phased array antennas and rectennas have provided the building blocks for a realizable WPT system.
• The exponential increase in population has led to the global crisis such as global warming, environmental pollution and change and rapid decrease of fossil reservoirs
SERT sandwich concept NASA:-
In 1999, NASA's space solar power Exploratory Research and Technology program (SERT) was initiated for the following purposes:
Perform design studies of selected flight demonstration concepts.
Evaluate studies of the general feasibility, design, and requirements.
Create conceptual designs of subsystems that make use of advanced SSP technologies to benefit future space or terrestrial applications.
Formulate a preliminary plan of action for the U.S. (working with international partners) to undertake an aggressive technology initiative.
Basic concept:-
• Solar Power Satellites providing a better way of power generation
• Transmission of power to earth via microwaves.
• Collection of power by specially developed antennas (rectennas).
• No need for costly storage devices for when the sun is not in view only a few days at spring and equinox would the satellite be in shadow.
The Sun Tower:-
The Sun Tower is a super tall gravity stabilized structure that uses inflatable circular solar concentrators, multi-junction solar cells and magnetron segments to transmit the suns energy down to earth. In laymen terms, it is similar in design to a sunflower, with the flower facing the Earth and sending the energy down the stem using microwaves. The predicted cost – before any energy has been produced – of one Sun Tower is estimated at $12 billion. Though the Sun Tower is an interesting concept, it soon became clear that the approach could only deliver power to a given ground station for a few minutes a day.
Conclusions:-
• In order for SPS to become a reality several things have to happen:
– Government support.
– Cheaper launch prices.
– Involvement of the private sector.
• More reliable than ground based solar power.