Wireless power has made significant advancements in the last few years with many inductive technologies becoming mainstream and widely available – notably Qi and PowerMat products. Major players like Samsung are building wireless power receivers into their phones along with a huge number of transmitters widely available from companies like AirCharge, TYLT and of course Samsung themselves. Currently there are nearly 700 different products on the market that are Qi certified alone.
However, inductive wireless charging is not without its limitations – amongst them include slower charging speed and the requirement for precise alignment of the receiver (smartphone) and transmitter (wireless charger). This is where resonant technology can deliver a number of advantages and truly represents the future for charging wirelessly. Unlike inductive technologies, there are still zero finalized resonant products in the marketplace. A4WP has long promised an option and now the Wireless Power Consortium is in the process of developing a resonant specification called Resonant Qi. I’ve been working on the specification personally along with other top member companies at the WPC. The new Resonant Qi specification will overcome existing limitations with Inductive Qi and provide those consumer benefits which OEMs are looking to integrate into their devices.
What’s most important?
The discussion on how inductive and resonant perform must be framed in respect to what is valued by the end user. Specifically, what are the factors that will increase the appeal of wireless charging for the consumer?
Based on the above factors, how do inductive and resonant technologies stack up?
I have used examples of current inductive products that we find on the market today (Qi and PMA) to compare functionality and performance with the Resonant Qi specification, currently in the works – see Table 1 below:
Overall, resonant presents a wireless charging future with greater convenience, performance and flexibility. The main areas where we will see the greatest advantages are:
Resonant Qi technology provides the next evolution to an already widely available set of products. It will provide a noticeable step-up in performance over the current inductive solutions, and will help wireless charging technology become more pervasive. Today, inductive solutions continue to be the only option for consumers wanting to purchase their own wireless charging system despite a lot of noise from other rival resonant standards. One has to ask why there are no (zero!) A4WP products shipping in the market to date.
The key for the WPC, and arguably the industry at large, will be to deliver a Resonant Qi specification that remains fully compatible with the hundreds of millions of existing Qi products on the market, while also delivering greater user performance over inductive systems. This approach puts the consumer first, and the best technologies always do.