GaN technology for wireless charging - high-power automotive scenarios first!

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GaN technology for wireless charging - high-power automotive scenarios first! [Copy link]

Judging from the current consumer experience, the advantages of wireless charging in terms of charging distance, conversion rate, etc. are not prominent, so most consumers are still waiting and watching.

But from an objective point of view, the purpose of wireless charging technology is not to replace wired charging, and its future advantages will not be charging distance and conversion rate, but will be reflected in safety, convenience and scientificity.

For example

① The terminal device does not require an interface and has stronger waterproof and dustproof performance;

② Unification of interfaces and protocols;

③ Suitable for special applications such as underwater power supply, coal mine power supply, drone power supply, human pacemaker power supply, etc.

On the other hand, when embedded wireless charging transmitters are installed on a large scale in the future, people can experience convenient wireless charging at restaurant dining tables, on the armrests of cinema seats, and on high-speed rail window sills.

Image source: Paixin.com official photo library

01. GaN’s applicability in wireless charging

There is currently no mass-produced GaN wireless fast charging on the market, mainly due to GaN cost issues.

Taking mobile phone chargers as an example, the current price of Baseus' 65W GaN wired fast charger is RMB 129. If GaN is integrated into a wireless charger that supports the Qi standard, the price will be far beyond the consumer's acceptance range. Mobile devices are very sensitive to costs, forcing GaN to be difficult to play in a short period of time.

In fact, the core application of GaN technology in the field of wireless charging is not mobile devices, but medium and high power scenarios such as electric vehicles and robots. If the high-frequency and high-power characteristics of GaN are forcibly used in low-power scenarios such as mobile phones, it can be said to be a waste of resources.

02. Opportunities and Challenges of Wireless Charging for Electric Vehicles

Last year, the National Standardization Administration issued four national standards for wireless charging of electric vehicles, marking a key step for my country's wireless charging of electric vehicles from technology research and development and engineering demonstration to industrialization. However, it will take some time and a lot of money to truly implement wireless charging of electric vehicles. Currently, there is no mass-produced model in the domestic market that supports wireless charging.

According to a report by market research firm MarketsandMarkets, the global electric vehicle wireless charging market size will increase from US$16 million in 2020 to US$234 million in 2027, with a compound annual growth rate of 46.8%.

Although the data is good, car manufacturers are not unanimously optimistic. Many car manufacturers, including NIO, believe that the current user experience of wired charging is already very good, and it is not cost-effective to spend money on research and development just to save the plug-in and unplug steps of the charging gun. Another part of the manufacturers expressed support for wireless charging because in the era of automation, wireless charging can be combined with autonomous driving and can be remotely operated through an APP, so that electric vehicles can be well connected to the power grid.

03. Analysis of typical applications of GaN in wireless charging of electric vehicles

In June this year, Italian wireless equipment manufacturer Eggtronic launched GaN-based electric vehicle wireless charging technology, which does not require a power adapter and can achieve up to 95% charging efficiency at up to 300W power and 40mm distance, completing a real breakthrough in inductance standards.

It uses a hybrid wireless AC power patented technology E2WATT. The internal GaN technology is provided by Navitas Semiconductor. It integrates monolithic analog drive circuits and digital logic circuits on the same chip with a rated frequency of 2MHz, greatly reducing the size of the fast charging system and the power conversion cost.

E2WATT technology energy efficiency and output power relationship (Source: Eggtronic)

The E2WATT transmitter (shown below) uses logic circuits to convert AC power from the grid to another AC frequency to activate the coil. The base consists of a GaN half-bridge circuit from Navitas Semiconductor to excite the LC tank, which complies with the Qi standard. This architecture allows high input voltages, eliminates the need for a series AC/DC converter, and achieves zero voltage switching (ZVS) without the use of a resonant LC tank, ensuring ZVS under most load conditions and reducing capacitive switching losses during turn-off and turn-on.

E2WATT technology block diagram (Source: Eggtronic)

04. Conclusion

At this stage, leading car manufacturers have begun to deploy wireless charging technology. Last month, there was news that the well-known Taiwanese foundry, World Advanced, invested in a wireless charging company in China, Sichuan Yi Chong Technology. Considering that World Advanced is involved in GaN power device foundry business, it is unknown whether there is any connection. But what is certain is that as wireless charging gradually becomes popular in various fields, GaN technology will have great potential.