ac power transfer wirelessly by hf

AC Power Transfer Wirelessly by HF

http://www.edgefxkits.com/

Introduction The main objective of this project is to transfer the AC power wirelessly from a

power source to electrical loads using a high-frequency resonating air core transformer to develop the frequency from 50Hz to 40KHz for transferring power over a distance of 3cm.Wireless power transfer can make a remarkable change in the field of electrical engineering , which eliminates the usage of conventional copper cables and current carrying wires. Based on this concept, the project is developed to transfer the power within a small range.


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Block Diagram







Hardware Requirements 8051 series Microcontroller

Relay Driver IC Relays 7 segment display Opto-isolators Crystal LED Resistors Capacitors Diodes Transformer Voltage Regulator







Software Requirements

Keil compiler

Languages: Embedded C or Assembly







HF Transformers Electric power transmission over long distances.

High-voltage direct-current HVDC power transmission systems.

Large, specially constructed power transformers are used for electric arc furnaces used in steelmaking.

Rotating transformers are designed so that one winding turns while the other remains stationary.







HF Transformers







HF Transformers A common use was the video head system as used in VHS and Beta video

tape players.

These can pass power or radio signals from a stationary mounting to a rotating mechanism, or radar antenna.







AC Power Flow


Different lines have different values for R, XL , and XC , depending on:

• Length • Conductor spacing• Conductor cross-sectional area

XC is equally distributed along the line






Resistance in AC Circuits


Resistance (R) is the property of a material that opposes current flow causing real power or watt losses due to I2R heating

Line resistance is dependent on:

Conductor material Conductor cross-sectional area Conductor length

In a purely resistive circuit, current and voltage are in phase; instantaneous power equaling the product of the two






Wireless Power Transfer


wireless power involves the transmission of energy from a transmitter to a receiver via an oscillating magnetic field.

To achieve this, Direct Current (DC) supplied by a power source, is converted into high frequency Alternating Current (AC) by specially designed electronics built into the transmitter.






Applications of Wireless Power Transfer


Reduce costs associated with maintaining direct connectors .

Greater convenience for the charging of everyday electronic devices

Safe power transfer to applications that need to remain sterile or hermetically sealed

Electronics can be fully enclosed, reducing the risk of corrosion due to elements such as oxygen and water.






Applications of Wireless Power Transfer


Robust and consistent power delivery to rotating, highly mobile industrial equipment

Delivers reliable power transfer to mission critical systems in wet, dirty and moving environments.







A rectifier is an electrical device composed of one or more diodes that converts alternating current (AC) to direct current (DC).

A diode is like a one-way valve that allows an electrical current to flow in only one direction. This process is called rectification.

A rectifier can take the shape of several different physical forms such as solid-state diodes, vacuum tube diodes, mercury arc valves, silicon-controlled rectifiers and various other silicon-based semiconductor switches.

Rectifier







Rectifiers are used in various devices, including:

• DC power supplies

• Radio signals or detectors

• A source of power instead of generating current

• As flame rectification to detect the presence of flame

• High-voltage direct current power transmission systems

Rectifier







Rectifier







Voltage Regulator A voltage regulator generates a fixed output voltage of a preset magnitude

that remains constant regardless of changes to its input voltage or load conditions.

There are two types of voltage regulators: linear and switching.

A linear regulator employs an active (BJT or MOSFET) pass device (series or shunt) controlled by a high gain differential amplifier.







Voltage Regulator It compares the output voltage with a precise reference voltage and adjusts

the pass device to maintain a constant output voltage.







Capacitors When apply a voltage to a capacitor, a electrical field is created between the

capacitor’s plates.

Energy provided by a voltage difference is stored in the electric field. The higher the voltage or bigger capacitor (higher capacitance), the stronger the electric field and more energy is stored inside the capacitor.

Capacitor does however have a limit as to the amount of energy it can store.

Energy stored in capacitor’s magnetic field can be retrieved.







Capacitors

It is clear that a capacitor stores energy in the form of a electric field created by potential difference across the capacitor plates.







The Coil An electromagnetic coil (or simply a "coil") is formed when a conductor

(usually an insulated solid copper wire) is wound around a core or form to create an inductor or electromagnet.

Primarily used for transferring energy from one electrical circuit to another by magnetic coupling

Common types of Electromagnetic coils: Tesla coil, Barker Coil, Choke coil, Maxwell coil etc.

In our set-up : Primary coil- two 9 turns in parallel – 9 cm diameter, Secondary coil- 36 turns, 9 cm diameter







Working Principle

This project can be used for charging batteries that physically are not possible to be connected electrically such as pace implanted in human body that runs on a battery.

The patient is required to be operated every year to replace the battery.

This project is designed to charge a rechargeable battery wirelessly for the purpose.

Since charging of the battery is not possible to be demonstrated, we are providing a DC fan that runs through wireless power.

http://www.edgefxkits.com/wireless-power-transfer







Working Principle

This project is built upon using an electronic circuit that converts AC 230V 50Hz to AC 12V, High frequency.

The output is fed to a tuned coil forming as primary of an air-core transformer. The secondary coil develops a voltage of HF 12volt.

Thus, the transfer of power is done from the primary (transmitter) to the secondary, which is separated with a considerable distance (say 3cm).







Working Principle

Therefore, the transfer could be seen as the primary transmission and the secondary receives the power to run the load.

Moreover, this technique can be used in number of applications: to charge a mobile phone, iPod, laptop battery, and propeller clock wirelessly.

And also this kind of charging provides a far lower risk of electrical shock as it would be galvanically isolated.







Advantages

Lower Frequency Operation – The operating frequency range is in the kilohertz range.

Low Cost - The entire system is designed with discrete components that are readily available & of affordable price.

Practical for Short Distance – The designed system is very practical for short distance as long as the coupling coefficient is optimized.







Dis Advantages

High Power Loss – Due its air core design the flux leakage is very high. This results in a high power loss and low efficiency.

Non-directionality – The current design creates uniform flux density and isn't very directional

Inefficient for longer distances- The efficiency drops exponentially with increase in distance.







Conclusion

In this PPT we have seen AC Power Transfer Wirelessly by HF, and it’s working principle, advantage and disadvantage along with applications

http://goo.gl/jlJbVz

http://goo.gl/jlJbVz





ac power transfer wirelessly by hf

Engineering