Getting your mobile devices juiced up is set to become even more convenient in the coming years
Can you imagine charging your mobile phone simply by entering a room?
That’s right - no wires or charging pads are involved because the energy is, quite literally, transferred from a power source to your phone through the air.
Sounds like a scene straight out of a science fiction movie? Well, it’s not.
Types of wireless charging
1. Contact-based wireless charging
Today, most people perform wireless charging by placing a device on a charging pad, most of which operate on the basis of inductive charging. In this method, the coil within the charging pad generates a magnetic field. When the coil inside a device like a mobile phone comes into close proximity with the magnetic field, a transfer of energy takes place.
The thing about inductive charging is that the magnetic field radiates in all directions. This means that a device like your phone needs to be extremely close to the power source. In most cases, your device must be no more than 4cm from the charging pad.
Contact-based wireless charging
2. Contactless wireless charging
Resonant charging is another way we can transfer power to our devices. Although similar to inductive charging in the sense that an electromagnetic field is also created, resonant charging involves the use of coils operating at identical resonant frequencies. Because of the strong coupling that occurs between resonant coils, the distance between the charger and the device can be considerably larger compared to inductive charging.
Another plus point of resonant charging is that more devices can be charged at a single time.
This may come as a surprise, but the premise of such technology was discovered more than a century ago, when Serbian American inventor Nikola Tesla, aka the “father of modern electricity”, demonstrated the key principles of wireless power transfer that form the foundation of modern resonant charging technology.
His goal? To create a “Worldwide Wireless System” in which the Earth and its ionosphere are used to transfer energy wirelessly around the planet.
Imagine a world in which there are no electricity cables; where homes are powered wirelessly by a power source located kilometers away.
Yes, super ambitious. Unfortunately, he never found success, even though he did manage to illuminate some lights located outside the building located near the Wardenclyffe Tower (also known as the Tesla Tower), which was used as a transmission station.
Nikola Tesla envisioned a “Worldwide Wireless System” that could transfer energy wirelessly around the planet
Over the last few years, however, companies from around the world have come up with innovations that suggest the ambitious dream Nikola Telsa had may very well be achievable.
In 2021, Motorola showed that a smartphone could be wirelessly charged up to 3m away from a power source. Several years later, in 2024, Tesla gave the public a glimpse of its wireless charging station at the Robotaxi unveiling.
Magnetic resonance charging for the SCDF
As an agency that always keeps pace with the latest tech trends, in 2024 HTX installed an Undercarriage Charging System (UCS) at Punggol Fire Station that works using resonant charging.
The goal? To test if this technology could improve the operational responsiveness of Singapore Civil Defence Force (SCDF) ambulances and enhance the safety of emergency responders.
Managed by HTX’s Vehicle and Weapon Systems Centre of Expertise (VWS CoE), the project was born with the aim of addressing current challenges faced by first responders.
According to VWS CoE lead engineer Chan Ka Keong, the fire station had previously relied on an overhead cable charging system to maintain operational readiness of the Mobile Data Terminal (MDT) and medical supply refrigeration units within ambulances.
The MDT is the dispatch system for frontline resources, while the medical supply refrigeration units contain medical supplies like lifesaving drugs.
The prototype UCS at Punggol Fire Station. The system generates an electromagnetic field (EMF) which is transmitted from the Wireless Transmitter Pad (WTP). When in range, the EMF charges the devices in the ambulance. The IP Enclosure (IPE) contains the power converters that conditions the electrical energy to appropriate alternating signal to be conducted into the WTP. (Photo: HTX)
As you can imagine, the cable charging mechanism must be decoupled before the ambulance can depart the station, and although there is an auto-decoupling feature that kicks in when the engine is started, LTC Foo Yiing Kai, Commander Punggol Fire Station, SCDF, shared that there have been a few instances where the charger cable got entangled.
Moreover, wire cables or charging heads are more susceptible to wear and tear as well as physical damage.
As such, the UCS prevents entanglements as well as minimises the need for repairs or replacements of other parts of the charging components like loose connectors or retractable cable reels.
The UCS has two main components – a wireless transmitter pad (power source) and a receiver unit located on the undercarriage of the ambulance. According to Ka Keong, charging will take place as long as the two components are within 13cm of one another.
The UCS will automatically start charging as soon as the ambulance is parked. It will automatically stop charging when it drives off. Charging will start even if the transmitter and receiver units are not perfectly aligned. (Photo: HTX)
“The UCS prototype represents a significant advancement for our operations. It has not only enhanced our working relationship with HTX, who have been incredibly responsive to our feedback, but it also addresses several operational pain points. I firmly believe that this is the beginning of innovative developments collaboratively created by SCDF and HTX, and the insights gained from the UCS project will lead to significant advancements in such technologies,” said LTC Foo.
MAJ Lee Jun Qi, Senior Staff Officer Land Systems, Transformation & Future Technology Department, SCDF, shared the same sentiments.
“Our collaboration with HTX led to a breakthrough in electromagnetic technology – creating an IOT-powered product that surpassed expectations with an intuitive interface. The outcome not only fulfilled the original vision but set a new standard in functionality and usability,” he said.
What the future holds
Wireless charging could bring exciting new developments to the world in the coming decades.
The Renault Group, for example, suggests that wireless charging could radically change the way we drive in the future. It even posits a possible scenario in the future in which charging coils are installed in the roads, allowing electric cars to be charged while on the move.
Wireless charging could change the way we drive in the future
Such technology could also revolutionise the medical industry. At present, implantable medical devices like neurostimulators and pacemakers are still powered by batteries, which eventually run out of charge. When this happens, a patient must undergo intrusive operations to replace the device. With wireless charging, this would no longer be an issue.
While Ka Keong believes that wireless charging will become more commonplace in the coming years, he noted that scientists and researchers still have many hurdles to overcome if such tech is to become ubiquitous in society.
Among the hurdles are efficiency – wireless charging is still less efficient than wired charging. Another obstacle is the cost of wireless charging infrastructure. He noted that such infrastructure is still too expensive and complex to implement on a massive scale.
“And then there’s regulatory requirements and making sure that such tech is safe to humans and does not cause electromagnetic radiation and interference,” he said.
“But there’s much to be excited about. Given how fast science and tech is evolving today, it could very well be a matter of sooner rather than later that we see more revolutionary inventions in this field.”