INTRODUCTION• Wireless power transfer can make electronic devices like cell phones, household robots, mp3 players, laptop computers and other portable electronics wire-free.• Resonant inductive coupling which is one of the various power transmission techniques is demonstrated here.
ABSTRACT• Many researchers have developed several techniques for moving electricity over long distances without wires.• Witricity is based upon coupled resonant objects.• Two objects having same resonating frequency and in magnetic resonance tend to exchange energy, while dissipating relatively little energy to the extraneous off-resonant objects.
RESONANT INDUCTIVE COUPLING• Inductive charging uses an electromagnetic field to transfer energy between two objects.• Greater distances can be achieved by using resonant inductive coupling.• Resonant inductive coupling or electrodynamic induction is the near field wireless transmission between two coils that are tuned to resonate at the same frequency.
RESONANT INDUCTIVE COUPLING• The capacitor and inductor forms the resonator. Charge oscillates between inductor (as magnetic field) and capacitor (as electric field.)• This type of oscillation is called resonance if the reactances of the inductor and capacitor are equal.
RESONANT INDUCTIVE COUPLING• Resonant transfer works by making a coil ring with an oscillating current.• This generates an oscillating magnetic field.• Because the coil is highly resonant any energy placed in the coil dies away relatively slowly over very many cycles.• But if a second coil is brought near it, the coil can pick up most of the energy before it is lost, even if it is some distance away.
BLOCK DIAGRAM• Oscillator used is an astable multivibrator using 555timer which switches IRFP250 to produce oscillations in the primary coil.• Secondary coil kept at a distance resonates at the same frequency and power transfer takes place.• Signal received in the secondary is rectified and regulated.
PRIMARY CIRCUIT• Oscillator is an astable multivibrator using 555 timer a rectangular-wave generating circuit.• A pot connected between the 6 and 7 terminals of the timer is adjusted to tune the primary and secondary coils at the same resonating frequency.• The astable multivibrator causes an IRFP250 transistor to undergo switching to produce oscillations of required strength.• A primary coil made of 8 turns of a magnetic wire is connected to IRFP250
APPLICATIONS• Provides charging stations for handheld devices like phones ex:powermat, removes the need for multiple power sockets• Can operate appliances like tv• Electric car manufacturers consider it for charging electric cars, currently using wires for this purpose is not entirely practical
ADVANTAGES• Non-radiative energy transfer is safe for people and animals.• Wastage of power is less.• Highly resonant strong coupling provides high efficiency over distance.• Does not interfere with radio waves.
CONCLUSION• Wireless power transfer is quickly becoming a viable reality.• This technology offers an extremely efficient alternative to previous attempts at providing wireless power.• Future improvements in wireless technology offer world changing implications.