What is wireless power transmission?
Wireless power transmission, also known as wireless
energy transfer (WET) or electric field coupling, is a process that transmits
electrical energy without wires. The technology has been around for decades but
it hasn’t been widely used in most applications because of high costs and other
technological barriers. However, recent advancements have brought down costs and
increased efficiency, spurring growth in many markets. Several technologies are being developed for WET; electromagnetic induction is one of them.
Electromagnetic induction utilizes an electromagnet near a moving ferromagnetic
conductor to generate an electric current in a nearby circuit.
Electromagnetic induction is based on
Faraday’s law of electromagnetic induction, which states that an electromotive
force (EMF) is generated in an electric circuit when a change in magnetic flux
through that circuit occurs. If you wrap an insulated copper coil around a
piece of a ferromagnetic metal, also known as a core, and place another coil
nearby, any change in current or voltage in your first coil will induce a
voltage (or induced current) on your second one. The transfer of energy takes
place over an air gap between your two coils. You can use electromagnetic
induction to produce electrical power from mechanical energy and vice versa. In
such applications, one device converts kinetic energy into electrical energy
while another uses that electrical power to generate movement.
How does this technology work?
Nikola Tesla, regarded as one of history's most brilliant
inventors and futurists, filed a patent in 1893 for an invention that allowed
electricity to be transmitted wirelessly. Unfortunately, his technology was
never fully developed. However, modern-day scientists have rediscovered his
original concept and given it a 21st-century upgrade using advancements in
nanotechnology and electromagnetic technology. The basic principle behind
wireless electrical power transmission is electromagnetic induction – when two
conducting objects are moved apart from each other a voltage is induced between
them through magnetic fields.
At its core, electromagnetic induction is based on a
simple principle of physics: changing magnetic fields create electric fields, and changing electric fields create magnetic fields. In a wireless power
transmitter, alternating high voltage in coil-shaped structures is converted
into pulsating direct current (DC) – otherwise known as an AC current – which
is then broadcast over a certain distance as radio waves or microwaves. As
these radio waves or microwaves bounce off any conductive material such as
metal or water, they induce varying voltages and currents in these materials,
depending on their size and shape. For example, if two copper coils are placed
one foot apart with the electrical cable attached to each coil’s ends then an
alternating current will flow through that cable when exposed to the
transmitter’s radio waves.
How do we receive energy from transmitting stations?
Most energy is transmitted from power plants. How
that happens depends on what type of plant you’re talking about and whether
it’s a coal, gas, or nuclear plant (nuclear plants provide about 20 percent of
all U.S. electricity). Different types of stations also require different tools
for transmitting their energy. And in most cases, as soon as you want to get
something away from a plant, like transformers and high-voltage lines, you need
wires—wires that can be very dangerous if they touch each other (see below). So
while wireless transmission has its place in powering devices like cell phones
and laptops, there aren’t many places where we can get our power without wires.
There are two
main ways for power plants to transfer energy: AC and DC. Alternating current
is delivered by high-voltage wires (usually 345,000 volts or higher) that can
go hundreds of miles from a plant. When that high-voltage energy gets closer to
your home or business, it travels along thinner wires, which step down its
voltage in transformers before delivering it on lower-voltage lines that
connect directly with your house or business. Direct current—like what comes
out of batteries—can only travel a small distance before you need an inverter
(or another transformer) that converts it back into alternating current.
Are there any health risks associated with wireless charging devices?
Sure, they are convenient, but while you may not
have been aware of them, wireless charging stations and pads can pose some
risks. The electromagnetic fields created by these devices can lead to memory
loss and insomnia in humans. For animals, there is also a risk for cancer. No
one has put an exact number on how many years you need to use a wireless
charging device to get any adverse health effects from it, but in
theory, if your exposure is great enough over a long enough period you
could be at risk for serious ailments like cancer or Alzheimer's disease down
the line. It's not something most people will ever experience because we're
probably never going to be subjected to those kinds of levels of radiation for more
than a couple years at best.
Because of
that, we should be extremely cautious about wireless charging. Obviously, we
can't banish our iPhones and Galaxy phones from our lives, but there are some
precautions we can take. For starters, use wired chargers whenever possible.
When you do have to use a wireless charger - or at least make sure your phone
is in direct contact with a pad so that its emissions will be at a minimum when
you're using it on your desk or nightstand. Also, keep in mind that these devices
are emitting radiation even when they're not charging your phone; if you don't
need them plugged in while they're just sitting there, unplug them as much as
you can.
The future of wireless charging - what lies ahead for us
We have a good idea of how wireless charging works
now, but that wasn't always the case. If you wanted your electronics charged up
back in 2013, then you had to hook them up to a wall charger with an annoying
cable. But fast forward six years, and suddenly wireless charging is everywhere.
There are even rumors that Apple will introduce wireless charging 2.0 in its
2019 iPhone lineup (along with triple-lens cameras). That said, if there's one
area where wireless charging still lags behind wired solutions, it's speed. So
what can we expect moving forward? And what can we do right now that would be
considered next-gen?
If you want to avoid fumbling for a charging cable each time you want to juice up your smartphone, then wireless charging is here for you. Several companies have introduced wireless chargers in recent years, and even Apple is rumored to be adding wireless charging capabilities to iPhones sometime in 2019. Right now, most new flagship smartphones support at least some form of wireless charging. And if there's one area where wires can still come out ahead of wireless, it's speed. So what does that mean for us moving forward? Are faster-charging solutions already on their way?
After more than five years of rumors, Samsung has finally unveiled its latest Notebook 9 laptops. While not revolutionary (they look pretty similar to last year’s model), these laptops are thinner than ever before (0.52 inches thick), and they’re lighter too (3.07 pounds).