The Future: Wireless Power Transmission

Over the next decade, the most vibrant Wireless Power Transmission (WPT) markets will involve the contactless charging of portable and mobile equipment, in particular consumer electronics and electric vehicles. Today, development teams worldwide are stretching the boundaries of physics using available components to create systems that are able to compete with the efficiencies of wired solutions while offering the conveniences of wire free connections. In the 1890's famous scientist and engineer Nikola Tesla dreamt of wireless transfer of power. He envisioned a world, in which all electricity is transferred wirelessly, but the idea was more or less abandoned and highly efficient copper cables became the basis for modern electricity infrastructure. Then, a few years ago, Marin Soljačić, an assistant professor of physics at MIT, was dragged out of bed by the insistent beeping of a cell phone. In his exhausted state, he wished the phone would just begin charging itself as soon as it was brought into the house. So, Soljačić started searching for ways to transmit power wirelessly. Soljačić found magnetic resonance a promising means of electricity transfer because magnetic fields travel freely through air yet have little effect on the environment or, at the appropriate frequencies, on living beings. Working with MIT physics professors John Joannopoulos and Peter Fisher and three students, he devised a simple setup that wirelessly powered a 60-watt light bulb. The MIT work has attracted the attention of consumer-electronics companies and the auto industry. The U.S. Department of Defense, which is funding the research, hopes it will also give soldiers a way to automatically recharge batteries.

Types of WPT

1) Inductive coupling or magnetic induction Two conductors are referred to as mutual-inductively coupled or magnetically coupled when they are configured such that change in current flow through one wire induces a voltage across the ends of the other wire