Essay: Smart-phone controlled remote devices and slider based mutual coupling control between two or among multiple coil interaction

Smart-phone controlled remote devices and slider based mutual coupling control between two or among multiple coil interaction with possible parameter tuner.
We envision this device as essential experimental element for electrical engineers, young physicists and system integrators
This project innovates on existing wireless power transfer technology by building smart-phone controlled remote devices and slider based mutual coupling control between two or among multiple coil interaction with possible parameter tuner. We envision this device as essential experimental element for electrical engineers, young physicists and system integrators. We believe that our innovation will facilitate learn even from remote places without actually going to the physical lab and will be a leap forward in remote instrumentation of engineering and educational equipments. Its commercial offshoots can be design as a mother power base system which can wireless charge all other devices present in certain locality. Future extensions include a multi-coil interaction environment with the optional power-on or power-off mode and related closed loop measurement system. We believe that this kind experimentation is first of its kind and needs to be explored.
INTRODUCTION
Wireless tranmission is the transmission of the electrical energy from a power source to an eletrical load without man-made conductors over a distance where in distances involved may be small or long. Wireless operations permits services, such as long-range communications, that are unfeasible using wires. Wireless power transmission is the transmittance of electrical energy from a power source to an electrical load without interconnecting wires. Wireless transmission is useful in cases where interconnecting wires are inconvenient, hazardous, or impossible. The problem of wireless power transmission differs from that of wireless telecommunications, such as radio. In the latter, the proportion of energy received critical only if it is too low for the signal to be distinguished from the background noise. With wireless power, efficiency is the more significant parameter. A large part of the energy sent out by the generating plant must arrive at the receiver to make the system economical. The most common form of wireless power transmission is carried out using direct induction followed by resonant magnetic induction. Other methods under consideration include electromagnetic radiation in the form of microwaves or laser beam technology. Wireless communication is considered to be a branch of telecommunications. It encompasses various types of fixed, mobile, and portable two-way radios, cellular telephones, personal digital assistance (PDAs), and wireless networking. Wireless operations permits services, such as long-range communications, that are impossible and impractical in conventional methods.
1.1 Conventional Power System
One of the major issue in power system is that the loss occurring during the transmission and allocation of electrical power. As the demand drastically increases day by day, the power generation increases and the power loss is also increased. The percentage of loss of power during transmission and distribution is approximated as 26%. The main reason for power loss during transmission and distribution is the resistance of wires used for grid. The efficiency of power transmission can be improved to certain level by using high strength composite over head conductors and underground cables that use high temperature super conductor. But, the transmission is still inefficient. According to the World Resources Institute(WRI), India’s electricity grid has the highest transmission and distribution losses in the world i.e. around 27%.Numbers published by various Indian government agencies put that number at 30%, 40% and greater than 40%. This is attributed to technical losses (grid’s inefficiencies) and theft. It is indeed alarming to know the level of losses in Indian electricity and transmission business. These losses not only eat the revenues of the companies but also hinder the financing of future projects, which require huge capital, because of increased risk. However, it would be worth knowing the categorization of technical and commercial losses that add up to the total losses. The theft comes in the latter category. Majority of theft is happening because the line is open to theft. The pole and the wires are bare and the voltage is at lower level than transmission and thus useful to run the 240 V equipment only. The theft always occurs at 400V and 240V level and not on transmission levels. Not much of energy auditing is done in most of the state utilities. Long low tension (LT) line are being pulled to reach villages under much publicized government schemes. Low tension lines are many times over the High tension lines causing more technical I2R losses. Transformer are running at less than optimal efficiency when in fact they should have the efficiency rate close to 99% since they do not have any moving part . It’s a vicious circle. Theft is done when people are not willing to pay the high price of electricity.
There are different concepts used in the field of wireless transfer technology. The one more thing is that the percentage of energy transfer is main criteria to transfer between places of very large distances. These are discussed in the sections following.
1.2 Transformer coupling
Energy transfer between two coil through magnetic fields but in this method, distance between two coils should be too close.
1.3 Resonant induction coupling (Evenescent wave coupling)
Electro magnetic wave in a high angular waveguide is called as evenescent waves which carry no energy, when if a proper resonant waveguide is brought near the transmitter then a tunnel is formed to the power drawing waveguide which can be converted in DC using rectifier circuits. A prototype model is achieved with 5 meters of ranges with this method.
1.4 Radio and microwave energy transfer
With this method a long range is possible. In this method microwave is sent to the long distances and can be received through rectenna which extract microwave energy back to electrical energy. But the problem with this method is that the diameter of antenna should be order of kilometer.
1.5 Laser beam transfer
In this method, laser is beamed to the photo voltaic cells which extract the electrical energy. This very difficult to implement and manage.
1.6 Electrical conduction method
In this method, during transfer energy through wires or conductors, when the voltage reaches the breakdown voltage, the surrounding medium start conducts, in this way the energy can be transferred through air medium.Though there are several methods available, in practical cases there is no device for transmitting power wirelessly with high energy capacity. But at low power transfer there are so many devices available in the market.
HISTORY OF WIRELESS POWER TRANSMISSION
Nikola Tesla he is who invented radio and is referred to as ‘Father of Wireless’. Nikola Tesla is the one who first conceived the idea Wireless Power Transmission and demonstrated ‘the transmission of electrical energy without wires” that depends upon electrical conductivity as early as 1891. In 1893, Tesla demonstrated the illumination of vacuum bulbs without using wires for power transmission at the World Columbian Exposition in Chicago. The world’s first fuel free airplane powered by microwave energy from ground was reported in 1987 at Canada. This system is called SHARP (Stationary High ‘ Altitude Relay Platform) .A physics research group, led by Prof. Marin Soljacic, at the Massachusetts Institute of technology (MIT) demonstrated wireless powering of a 60W light bulb with 40% efficiency at a 2m (7ft) distance using two 60cm-diameter coils in 2007.In 2008, Intel reproduced the MIT group’s experiment by wirelessly powering a light bulb with 75% efficiency at a shorter distance.MIT team experimentally demonstrates wireless power transfer, potentially useful for powering laptops, cell phones without any cords. Imagine a future in which wireless power transfer is feasible: cell phones, household robots, mp3 players, laptop computers and other portable electronics capable of charging themselves without ever being plugged in, freeing us from that final, ubiquitous power wire. Some of these devices might not even need their bulky batteries to operate.
2.1 WIRELESS ELECTRICITY TECHNOLOGY Wireless Electricity technology is transferring electric energy or power over distance without wires is quite simple. Understanding how it works is a bit more involved, but it doesn’t require an engineering degree. We’ll start with the basics of electricity and magnetism, and work our way up to the Wireless Electricity technology.
2.1.1 Electricity
The flow of electrons (current) through a conductor (like a wire), or charges through the atmosphere (like lightning). A convenient way for energy to get from one place to another.
2.1.2 Magnetism
A fundamental force of nature, which causes certain types of materials to attract or repel each other. Permanent magnets, like the ones on your refrigerator and the earth’s magnetic field, are examples of objects having constant magnetic fields. Oscillating magnetic fields vary with time, and can be generated by alternating current (AC) flowing on a wire. The strength, direction, and extent of magnetic fields are often represented and visualized by drawings of the magnetic field lines. As electric current, I, flows in a wire, it gives rise to a magnetic field, B, which wraps around the wire. When the current reverses direction, the magnetic field also reverses its direction. The blue lines represent the magnetic field that is created when current flows through a coil. When the current reverses direction, the magnetic field also reverses its direction.
2.1.3 Electromagnetism
A term for the interdependence of time -varying electric and magnetic fields. For example, it turns out that an oscillating magnetic field produces an electric field and an oscillating electric field produces a magnetic field.
2.1.4 Magnetic Induction
A loop or coil of conductive material like copper, carrying an alternating current (AC), is a very efficient structure for generating or capturing a magnetic field. If a conductive loop is connected to an AC power source, it will generate an oscillating magnetic field in the vicinity of the loop. A second conducting loop, brought close enough to the first, may “capture” some portion of that oscillating magnetic field, which in turn, generates or induces an electric current in the second coil. The current generated in the second coil may be used to power devices. This type of electrical power transfer from one loop or coil to another is well known and referred to as magnetic induction. Some common examples of devices based on magnetic induction are electric transformers and electric generators.
2.1.5 Energy/Power Coupling
Energy coupling occurs when an energy source has a means of transferring energy to another object. One simple example is a locomotive pulling a train car the mechanical coupling between the two enables the locomotive to pull the train, and overcome the forces of friction and inertia that keep the train still and, the train moves. Magnetic coupling occurs when the magnetic fields of one object [5]. An electric transformer is a device that uses magnetic induction to transfer energy from its primary winding to its secondary winding, without the windings being connected to each other. It is used to “transform” AC current at one voltage to AC current at a different voltage.Interacts with a second object and induces an electric current in or on that object. In this way, electric energy can be transferred from a power source to a powered device. In contrast to the example of mechanical coupling given for the train, magnetic coupling does not require any physical contact between the object generating the energy and the object receiving or capturing that energy.
2.1.6 Resonance
Resonance is a property that exists in many different physical systems. It can be thought of as the natural frequency at which energy can most efficiently be added to an oscillating system. A playground swing is an example of an oscillating system involving potential energy and kinetic energy. The child swings back and forth at a rate that is determined by the length of the swing. The child can make the swing go higher if she properly coordinates her arm and leg action with the motion of the swing. The swing is oscillating at its resonant frequency and the simple movements of the child efficiently transfer energy to the system. The resonant frequency depends on the size, shape and thickness of the material.
2.1.7 Resonant Magnetic Coupling
Magnetic coupling occurs when two objects exchange energy through their varying or oscillating magnetic fields. Resonant coupling occurs when the natural frequencies of the two objects are approximately the same. Two idealized resonant magnetic coils, shown in yellow. The blue and red color bands illustrate their magnetic fields. The coupling of their respective magnetic fields is indicated by the connection of the colorbands.
2.2 WORKING OF WIRELESS TECHNOLOGY
The concept of wireless electricity works on the principle of using coupled resonant objects for the transfer of electricity to objects without the use of any wires. This concept of WiTricity was made possible using resonance where an object vibrates with the application of a certain frequency of energy. So two objects having similar resonance tend to exchange energy without causing any effects on the surrounding objects.
STEP 1
A circuit attached to the wall socket converts the standard 60-hertz current to 10 megahertz and feeds it to the transmitting coil. The oscillating current inside the transmitting coil causes the coil to emit a 10 -megahertz magnetic field.
STEP 2
The receiving coil [C] has the exact same dimensions as the sending coil and thus resonates at the same frequency and, in a process called magnetic induction, picks up the energy of the first coil’s magnetic field.
STEP 3
The energy of the oscillating magnetic field induces an electrical current in the receiving coil, lighting the bulb. Wireless Electricity technology is a non-radioactive mode of energy transfer, relying instead on the magnetic near field. Magnetic fields interact very weakly with biological organisms people and animals and are scientifically regarded to be safe. WiTricity products are being designed to comply with applicable safety standards and regulations. Hence witricity is technology safe.witricity can transfer power depends on the source and receivers. if it is relatively close to one another, and can exceed 95%.Efficiency is primarily determined by the distance between the power source and capture device, however,the shape may impact the efficiency. it can transfer the power through walls also.Wireless Electricity technology is based on sharply resonant strong coupling, and is able to transfer power efficiently.
BASIC DESIGN AND IMPLEMENTATION OF WIRELESS POWER SYSTEM
Fig3.1 Wireless power system
Fig 3.2 Flow and components of Wireless power System
The key for the present world is to save energy and related recourses in the organizations and as well as at home. Energy costs account for a huge portion of most companies operating expenses, so monitoring, controlling and conserving a building’s lighting, heating and cooling, and other energy-hungry systems can lead to substantial savings. Several energy management vendors report that customers have shrunk their power bills by at least 30 percent. Saving energy also means lowering your carbon footprint, which could help reduce carbon taxes and promote a green image, another plus for business.
Bluetooth operated SLIDER using Mobile android App.
Here is a circuit to control slider using Bluetooth Module HC-05 & 89c2051 Microcontroller with your Android Smartphone device.
Circuit diagram of Wireless Android Based Remote Control to control slider
AT89C2051
8-bit Microcontroller with 2K Bytes Flash
Features:
‘ Compatible with MCS-51’ Products
‘ 2K Bytes of Reprogrammable Flash Memory
‘ Endurance: 1,000 Write/Erase Cycles
‘ 2.7V to 6V Operating Range
‘ Fully Static Operation: 0 Hz to 24 MHz
‘ Two-level Program Memory Lock
‘ 128 x 8-bit Internal RAM
‘ 15 Programmable I/O Lines
‘ Two 16-bit Timer/Counters
‘ Six Interrupt Sources
‘ Programmable Serial UART Channel
‘ Direct LED Drive Outputs
‘ On-chip Analog Comparator
‘ Low-power Idle and Power-down Modes
Description:
The AT89C2051 is a low-voltage, high-performance CMOS 8-bit microcomputer with 2K bytes of Flash programmable and erasable read only memory (PEROM). The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard MCS-51 instruction set. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C2051 is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applications.
The AT89C2051 provides the following standard features: 2K bytes of Flash, 128 bytes of RAM, 15 I/O lines, two 16-bit timer/counters, a five vector two-level interrupt architecture, a full duplex serial port, a precision analog comparator, on-chip oscillator and clock circuitry. In addition, the AT89C2051 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system to continue functioning. The power-down mode saves the RAM contents but freezes the oscillator disabling all other chip functions until the next hardware reset.
MERITS
1. Various methods of transmitting power wirelessly have been known for centuries. Perhaps the best known example is electromagnetic radiation, such as radio waves. While such radiation is excellent for wireless transmission of information, it is not feasible to use it for power transmission. Since radiation spreads in all directions, a vast majority of power would end up being wasted into free space.
2. Wireless Power Transmission system would completely eliminates the existing high-tension power transmission line cables, towers and sub stations between the generating station and consumers and facilitates the interconnection of electrical generation plants on a global scale.
3. It has more freedom of choice of both receiver and transmitters. Even mobile transmitters and receivers can be chosen for the WPT system.
4.The power could be transmitted to the places where the wired transmission is not possible. Loss of transmission is negligible level in the Wireless Power Transmission; therefore, the efficiency of this method is very much higher than the wired transmission.
5. Power is available at the rectenna as long as the WPT is operating. The power failure due to short circuit and fault on cables would never exist in the transmission and power theft would be not possible at all. 6. More user supported – cable device have limited slots whereas wireless does not. Less cost for cabling infrastructure and device
APPLICATIONS OF WPT
1. Generating power by placing satellites with giant solar arrays in Geosynchronous Earth Orbit and transmitting the power as microwaves to the earth known as Solar Power Satellites (SPS) is the largest application of WPT.
2. Moving targets such as fuel free airplanes, fuel free electric vehicles, moving robots and fuel free rockets. The other applications of WPT are Ubiquitous Power Source (or) Wireless Power Source, Wireless sensors and RF Power Adaptive Rectifying Circuits (PARC).
3. Mobility – user device can be moved easily within the wireless range.
4. Neat and easy Installation – since no cable running here and there, just start up the wireless device and you’re ready to rumble .
DEMERITS
1.Capital Cost for practical implementation of WPT to be very high.
2.The other disadvantage of the concept is interference of microwave with present communication systems.
3.Common belief fear the effect of microwave radiation.
4.But the studies in this domain repeatedly proves that the microwave radiation level would be never higher than the dose received while opening the microwave oven door, meaning it is slightly higher than the emissions created by cellular telephones