WIRELESS CHARGING Presented by: K.MAHESH (08T81A1236)

ABSTRACT  Today we are surrounded by electronic gadgets and many of them run on electricity from battery as source.  Battery makes these electronic gadgets mobile which makes it easy to carry around anywhere we want.  Now imagine a way through which we can recharge the battery without the wire-recharger.  This technology uses a wireless charger which converts the RF/Microwave frequency waves into DC signal and this energy can be stored in the battery.

INTRODUCTION  We are using electricity for more than a century now and all these years electricity is transmitted through wire cables to commercial and home units.  Wireless energy transmission or wireless power transmission (WPT) is different from wireless information transmission.  In short wireless power transmission is defined as the process through which energy/electricity can be transferred to the conductor without any physical means of contact.

TECHNIQUES OF WIRELESS CHARGING/ELECTRICITY TRANSMISSION  Inductive Charging  Evanescent Wave Coupling  Capacitive Induction  Far Field Electricity Transmission

INDUCTIVE CHARGING  Induction is the production of electricity across a conductor situated in a changing magnetic field moving or a conductor moving through a changing magnetic field.  The transfer of energy takes place by electromagnetic coupling through a process known as mutual induction.  This process works only in short distances and can be used to run electric gadgets.  When a conductor is subjected through a changing magnetic field a current is induced in the conductor and this current can be stored or used.

  These chargers are now commercially available and this can be used to charge any device which uses a battery. Like cell phones, lap tops etc.

EVANESCENT WAVE COUPLING  This concept works on the principle that if both the coils of the gadget and the transmitter to resonate at the same frequency then electricity can be induced in them.  One good point to be noted is that this process can be carried out even if distance between the conductor coil and the transmitter coil is high and even multiple devices can be powered through this process till they share the same frequency.  The efficiency is highest when both the couples are tight and with increase in distance the magnetic energy is lost between the coils and efficiency reduces

 The efficiency is highest when both the couples are tight and with increase in distance the magnetic energy is lost between the coils and efficiency reduces.  This technology is not commercially available yet but the future is bright as lots of research is going on.

CAPACITIVE INDUCTION  Capacitive Induction or Capacitive coupling is an electric field created through differential capacities between two electrodes using high frequency AC current.  The alternative current produces a changing electric field which induces a current in the electrodes. This effect is knows as Tesla effect.

FAR FIELD ELECTRICITY TRANSMISSION  This technology is used transmit power to large distances.  This can be achieved using the radio or microwave power transmission.  The main criterion here is also the efficiency.  There are two methods in this transmission. 1.Radio/Microwave Power transmission 2.Laser Power Transmission

RADIO/MICROWAVE POWER TRANSMISSION  The basic step up for this process is three components like a transmitter, Antenna and a charge pump.  The transmitter is used to transmit high frequency radio/microwave energy. The frequency is usually between 900 to 1200 MHz range.  The transmitted radio frequency (RF) is captured using an antenna.  The energy captured through antenna is fed to a charge pump which will convert this energy into DC current which can be used to run gadgets.  This stored in the capacitor can be converted to DC current. Usually this current is stored in a battery and then this battery is used to run electronic components.

LASER POWER TRANSMISSION  Laser is a concentrated beam of light with very high energy this can be used to transmit power with an efficiency of 40-45%.  The advantage of using Laser over RF power transmission is that Laser has more energy transmission capacity.

ADVANTAGES OF WIRELESS CHARGING  Resonance loss and atmosphere absorption loss.  Efficiency of current technology.  Biological Drawbacks.  Economic cost.

CONCLUSION  Transmission of power without wire is not science fiction but a reality now. Without any physical contacts we can transmit power to any distance and run appliances which can be controlled independently. Many companies now have wireless chargers as part of their standard accessory.

THANK YOU….