Wireless power transfer

Power Electronics / Power Management

29 March 2023 Power Electronics / Power Management

Technology advances in wireless power transfer is big news in the 21st century. However, wireless power was first proposed in the 19th century by physicist, Nikola Tesla. Tesla theorised that electricity could be transmitted wirelessly through the air and at long distances to power objects. Tesla’s innovative idea at the time, the Tesla coil, gave birth to how wireless power technology is shared and used today with modern engineers using a similar approach.

Whether it’s a smart phone or a smart watch, all wireless charging devices are designed with an electromagnetic coil positioned inside. These electromagnetic coils are basically an induction coil in a charging base, which creates an antenna-like magnetic field that sends energy to the phone. Inside the receiving device is an even smaller electromagnetic coil that receives the energy transmitted by the induction coil and transfers that energy back into the battery.

One risk of wireless power transfer is the electromagnetic interference (EMI), which can adversely affect other systems. The power transfer and any related EMI is controlled by the coupling of the coils. Uncoupled energy from wireless charging is just one example of unwanted electromagnetic energy. High-speed and high-frequency interconnects can act as antennas, either emanating or receiving said energy.

At Samtec, interconnect solutions are designed to minimise EMI/EMC susceptibility and emissions. Working both in-house at its Signal Integrity Group, and through various partners, Samtec simulates, tests and measures its interconnects using methods such as:

• Raw cable shielding tests.

• HFSS shielding performance.

• TRP simulation models.

• Shielding room/dual reverb chambers.

What does the future hold for wireless charging?

Advancements in wireless charging are being made each year. Eventually, phones and other wireless power devices with smaller and stronger receivers may be seen, allowing them to pick up energy even if the device is not aligned perfectly with the wireless charging coil.

Tesla had hoped to one day use his inductive charging on a broader scale to create a wireless power grid. While this never happened in his lifetime, it’s very close to the way we currently wirelessly charge our smart devices.

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Wireless power transfer

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