Wireless Energy Transmission using Magnetic Resonance

Project Title

Wireless Energy Transmission using Magnetic Resonance

Project Area of Specialization Artificial IntelligenceProject Summary

The project proposes the broadest way to transmit the power wirelessly in the surroundings which enable to connect different devices. The aim is to provide a solution for tangled up wires system and get devices to charge remotely. The project focuses on power transmission and ways to achieve the highest efficiency; the distance and the amount of power delivered will be discussed.  The transmitter used for our purpose is the Tesla coil which is a multipurpose device, but our goal is to achieve wireless transmission. The transmitting tower can be supposed to be a radio tower connected in the center of the city and receivers being different lights and charging devices. The tower can connect multiple devices and power them at a certain distance depending on designing and cost parameters. Wireless energy transfer has a number of application for the likes of electric vehicles, nanotechnology, medical appliances, etc. The magnetic field is achieved using inductive coupling between coils of wire or electric fields using capacitive coupling between electrodes. The most common type of transmission is carried using induction phenomenon followed by magnetic resonance. The fluxes induced in the inductor can be captured using another inductive coil that could produce an induced flux between the coils from the receiver which is coupled to the primary coil. The key technique used i.e. magnetic resonance uses a Tesla coil to produce high voltage, high frequency, and low ac current in order to produce high-density flux. The Tesla coil is the main component in this magnetic resonance technique and needs special consideration for designing how the magnetic induction is coupled to perform wireless energy transfer.  The main advantage of the wireless energy system would be completely eliminating the wiring system for electrical appliances between power sources.

Project Objectives

The implementation of this project shall meet the objectives of transmitting power, under controlled factors, into a certain range of area wirelessly. This will enable new research gates to find ways to improve the efficiency of transmitted power, obliterate or minimize the losses resulted in the proposed process, and improve the range of delivered power. Resembling the tesla tower the goal is to connect multiple electronic devices into a certain area, and improving the efficiency if multiple devices are connected. The very reason for opting this project is its significance from charging the mobile phones to charging electric cars. The other and very important reason for this project's importance is its technology being used by space agencies to transmit power. Japan Aerospace Exploration Agency (JAXA) transmitted 1.8 Kilo-Watts with pinpoint accuracy to a receiving antenna 55 meters away using the phenomenon of wireless power transmission. Likewise, Massachusetts Institute of Technology (MIT) lit up 50W bulb through a distance of 2 meters using the same phenomenon. These recent developments have resulted in a number of applications for wireless energy transmission. The other techniques to deliver power wirelessly i.e. capacitive coupling, microwave, laser beam shall also be compared with the proposed project of magnetic resonance.

Project Implementation Method

The project uses the resonance technique to transmit energy. The occurrence of resonance of an LC circuit takes place due to the collapsing of the field on an inductor and electric field in the windings that charge the capacitor. The discharging capacitor provides an electric current that develops a magnetic field in the inductor and this process is repeated continuously. The resonance often occurs when the inductive and capacitive reactance of the circuit becomes equal. Resonance is used for regulation and filtering because it occurs at a particular frequency for specific values of inductance and capacitance. Parallel resonance shall be used to make the inductor provide for the capacitor by maintaining the similar resonant current in the circuit. To attain resonance, the inductive reactance and capacitive reactance ought to be of equal magnitude. The resonant frequency is given by

Fr= 1/  where L is the inductance and C is the capacitance.

Resonant energy transfer is the short distance wireless transmission of energy between two coils which will reach the highly resonant level when the same frequency is applied.

A typical magnetic resonant coupling system consists of two electromagnetic subsystems with the same natural resonant frequency which thus enables the power transfer. Such a system can usually be represented by a standard RLC circuit consisting of a resistor, inductor, and capacitor. Resonant energy transfer is the short distance wireless transmission of energy between two coils which will reach the highly resonant level when the same frequency is applied.

It should be noted that the high self-inductance of the transformer causes the current to lag the voltage. Therefore a capacitor is needed to maintain the same phase and that lags the voltage before letting it into the transformer. This is accomplished using a power factor correction capacitor. The capacitance of an ideal run type capacitor is given by P/2?fVin2

Where f is the mains frequency (50Hz)

V is the mains voltage (230V)

Tesla coil is used as the transmitter. Its working is described in following subsections. The transmitter further consists of the following components:

AC line filter for the sole purpose of protection of the devices connected to the mains from dangerous transients generated by the Tesla coil circuit.

Terry filter serves the purpose of protecting the neon sign transformer from any hazardous condition or any overvoltage scenario. This may happen when a fault causes reverse EMF to be generated by the primary or the primary receives a spike.

Primary Capacitor which should be able to withstand very short charge/discharge time and high RMS current.

Benefits of the Project

The proposed project has wide applications both in practical and research fields. The receiving tower’s significance can be understood by drawing an analogy as a center tower installed in a town transmitting the bulk amount of power to a certain area. The other advantages of the proposed Tesla coil are:

One of the cheap ways of generating a high voltage at high frequency without complicated circuitry.

Leak detection in scientific high vacuum systems

Ignition in arc welding

Charging of electric vehicles

Its use in medical and nanotechnology appliances

Technical Details of Final Deliverable

Following is the list and description of the respective components: AC Line Filter: It serves the sole purpose of protecting the devices connected to the mains from dangerous transients generated by the Neon Sign Transformer.

Power Factor Correction Capacitor: Power factor correction capacitors absorb and release reactive power. When a PFCC is connected to an electrical system containing an inductive load, e.g., induction motor, the load will require less reactive power from the utility. It is connected to 15kV Neon Sign Transformer to correct the phase accordingly.

 Neon Sign Transformer: Neon signs use neon gas that is inert in nature. These signs are made up of tubes that are filled with this gas. This tube is supplied with a high voltage obtained from the transformers. The high voltage supplied by them increases the kinetic energy of electrons in the neon atom. The atom is ionized when the kinetic energy of electrons is high enough. Ionization develops a positive charge or a negative charge on the atom. These charged atoms create a plasma that carries the electricity from one end of the tube to another. The plasma formed in this process completes the electric circuit and causes the electrons in the atom to fall down to their regular levels from the excited state. As the electrons return to their regular energy levels, a photon is emitted. This photon illuminates the neon signs. The basic principle is that high voltage must be provided to the neon gas for illumination. This high voltage is provided by the transformers.

Terry Filter: The terry filter serves the purpose of protecting the Neon Sign Transformer from any RFI getting into the transformer and also any over-voltage situation that may occur. This is when a fault causes a reverse EMF to be generated by the primary, or the primary receives a strike from the streamer. The wire in the NST secondary coil is very thin and easily shorted by high voltage spikes generated in the primary circuit. A spark gap and a low pass filter will help protect the NST’s from voltage spikes and premature death. The filter is an RC low pass filter that consists of several capacitors wired in series to shunt high-frequency spikes to the ground and high power resistors to decouple the NST’s from the primary circuit.

Final Deliverable of the Project Hardware SystemType of Industry Energy Technologies OthersSustainable Development Goals Affordable and Clean Energy, Industry, Innovation and InfrastructureRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	31260
Neon Sign Transformer	Equipment	1	4000	4000
Motor	Equipment	1	2000	2000
Electrodes	Equipment	13	80	1040
Acrylic Sheet	Equipment	2	900	1800
Toroid	Equipment	6	200	1200
Primary Capacitor Bank	Equipment	9	1100	9900
Heat Sync Resistor	Equipment	2	1500	3000
Metal Oxide Varistor	Equipment	16	100	1600
Copper	Equipment	1	1800	1800
Copper Pipe	Equipment	1	1300	1300
Secondary Winding	Equipment	1	300	300
Acrylic Holding	Equipment	1	1500	1500
Rotator for Spark Gap	Miscellaneous	1	1000	1000
Resistors	Miscellaneous	16	15	240
Capacitors	Miscellaneous	16	15	240
Vero-Board	Miscellaneous	1	90	90
Power Factor Correction Capacitor	Equipment	1	250	250