Wireless power has become a hot topic as wireless charging of mobile devices is get getting some popularity. Wireless charging isn’t something new; the technology exists since 1981 and Nikola Tesla has made first wireless power experiments over 100 years ago. Wireless charging for Qi technology is becoming the industry standard on smartphones (pushed by Wireless Power Consortium) as Nokia, HTC and some other companies use that. There is a competing AW4P wireless charging standard pushed by Samsung ja Qualcomm. And there is more standards coming. Power Matters Alliance is heavily pushing their own wireless charging standard. It seems there is going to be fight on wireless charging in near future. It seems that right now we’re in the midst of a battle between two standards for wireless charging – Qi from the Wireless Power Consortium and Power 2.0 from the Power Matters Alliance. It seems that a common Wireless Power Standard Years Off as Battle Heats Up.
As obviously useful as wireless charging is, it suffers from a Tower of Babel problem with incompatible standards and competing interests keeping it from truly going mainstream. Wireless charging continues to be a niche category until there’s a common standard. Heavyweights are backing the idea of wireless charging capabilities embedded in phones, and public charging stations are beginning to pop up. Differing standards, however, still make for a rocky adoption. Realistically there probably isn’t room for two or more standards, which do essentially the same to end user but are incompatible, so expect some technologies to disappear in the near future. Charging portable devices without needing to carry a power adapter sounds handy when we can agree on one standard. “Wireless charging continues to be a niche category until there’s a common standard,” said Daniel Hays, a consultant with PricewaterhouseCoopers. “The hassle factor is still high.”
Qi seems to be at the moment standard that gets most attention. The news that Nokia to join Qi party with wireless-charging Lumia 920 have given lots of publicity to it. Even if the Lumia isn’t a big seller, the publicity and visibility it will provide for Qi should be enough to make everyone forget there was ever an alternative, if indeed there ever was. Also some HTC phones and Nexus 4 phone use this standard. Toyota launches the world’s first wireless charging of mobile phones in the car. Toyota’s car will get wireless mobile phone charger using Qi standard.
Qi has been here for some years. Qi has been around for a while, gaining the name and logo back in 2009. The Qi standard came out of water filtration units, which needed wireless power, and has been widely endorsed but devices are still quite rare. Under the Qi specification, “low power” for inductive transfer means a draw of 0 to 5 W, and that’s where mobile device charging solutions most probably go. The system used inductive coupling between two planar coils to transfer power from the power transmitter to the power receiver. The distance between the two coils is typically 5 mm, but can be expanded to 40mm.
The Qi system uses a digital control loop where the power receiver communicates with the power transmitter and requests more or less power via backscatter modulation. Besides low-power specification up to 5 watts, there is also a medium-power specification will deliver up to 120 watts. The frequency used for Qi chargers is located between about 110 and 205 kHz for the low power Qi chargers up to 5 watts and 80-300 kHz for the medium power Qi chargers.
Qi
Method: inductive coupling between two planar coils
Frequency: 110-205 kHz (80-300 KHz)
Communication: backscatter modulation
WiPower was a technology start-up company that used the principles of inductive coupling to develop a near-field wireless energy transfer system. Qualcomm bought WiPower in 2010 and started quietly negotiating with manufacturers to get the technology embedded in their kit. Qualcomm argues that the additional range of WiPower (which can charge devices up to 45mm away) allows new possibilities. WiPower system is based on modified coreless inductive technology and dynamically adjusts power supplied by the transmitter to power demanded by the receiver without the need for control systems or communication. WiPower chargers are claimed to operate at about 60-75 percent efficiency.
WiPower
Method: inductive coupling
Communication: no need for specific communication
Samsung and Qualcomm’s Alliance for Wireless Power (A4WP) promises more flexibility in wireless charging. Instead of induction, this standard will use loosely-coupled (LC) wireless power transfer (a series resonance-tuned pair of magnetically-coupled coils) to transmit power. This construction allows that the transmitter and receiver don’t have to be in direct contact, which gives more flexibility to industrial designers. This designs will support simultaneous charging of multiple devices with different power requirements. A4WP specification takes advantage of Bluetooth 4.0. The biggest downside in this design is that currently there are no products with this technology are yet on the market.
A4WP
Method: series resonance-tuned pair of magnetically-coupled coils (loosely coupled)
Frequency: 6.78 MHz
Communications: Bluetooth 4.0
The Power Matters Alliance (PMA) is working on an open standard for wireless charging. A group of companies back up this initiative (including Google, AT&T, ZTE, Starbucks, ,McDonalds, PowerKiss). PMA uses inductive charging method used in Duracell’s Powermat product. It requires the transmitter and receiver be close together, placing the mobile device on the charging pad.
This is quite new alliance but it seems to get lots of backers: over the last few months, the PMA has seen a tenfold increase in membership. One very big thing is that AT&T is seeking from its handset vendors a commitment to one standard of wireless charging.
The PMA is working to advance the widespread acceptance of the wireless power paradigm in multiple sectors. PMA is intent on leading and organizing the Power 2.0 agenda to commercial realization, while working under the umbrella of the most trusted name in standards: the IEEE. Powermat is capable of delivering 5-to-50 watts of power. Powermat allows a built-in check for alignment via light and voice signals based on RFiD Handshake feature. When you place a Powermat-enabled device on one of its mats, the two exchange a “handshake” using RFID: The mat identifies the device, determines how much power it needs and transfers energy to it. Powermat operates at 277-357 kHz frequency. Once a device is fully charged, Powermat stops the electricity from flowing. But as much momentum as the PMA has achieved, it is far from clear whether it will be that bandwagon.
Power Matters Alliance (PMA)
Method: inductive charging
Frequency: 277-357 kHz
Communication: RFID
As obviously useful as wireless charging is, it suffers from a Tower of Babel problem with incompatible standards and competing interests keeping it from truly going mainstream. There are also attempts to support several standards on one product. Samsung Galaxy SIII wireless power supports both Qualcomm’s WiPower and Wireless Power Consortium Qi. The Samsung Galaxy S4 will support both PMA and Qi standards. NXP has developed a charging station, which allows you to use both the general mobile phone charging standards (as well as one rare third standard).
The technologies I mentioned are not the only ones trying to push to the market in the near future. Apple is trying to patent wireless charging, claiming its magnetic resonance tech is new and that it can do it better than anyone else. Digitoday writes that Finnish research organization VTT is planning to combine wireless power and NFC technologies. The reasearchers believe that in the future NFC devices could be made to work as way to get power into device and send power to other device cheaply. Technology is not ready yet, because today’s NFC antenna circuits are not optimized for power transfer and there is no standard that covers this kind of use yet. NFC operates within the globally available and unlicensed radio frequency ISM band of 13.56 MHz.
Wireless Power: Convenient, But Its Shortcomings Are Somewhat Sour article tells that close-proximity inductive coupling is commonly estimated to deliver 50 to 70% efficiency. That’s considerably worse efficiency that what you get with a well designed wired charger. Intel increases consumer-product power consumption 50% blog post says that a system that is 50% efficient on top of the ac-dc conversion, and pumps RF energy all over the place is far from ideal in world where some other parties try to conserve every single watt. In a world with 15 billion chargers, energy efficiency is a big deal. Based in that is makes me a little bit hard to believe the Power Matter Alliance claims that wireless charging could save a lots of power in the future. How Wireless Charging Will Keep Toxic Waste Out of Landfills article tries to describe how wireless power could be more eco-friendly, but it is hard to believe all those claims without good data. I can believe that wireless chargers can have better energy efficiency than some old chargers supplied with consumer devices, but I given the limitations wireless charging it is very hard to believe that wireless charger could ever be more efficient than well designed wired charger. But wireless charger could be well “good enough” to be acceptable.
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Tomi Engdahl says:
Tutkijat kehittivät huoneen, joka lataa kaikki laitteet langattomasti
https://etn.fi/index.php/13-news/12519-tutkijat-kehittivaet-huoneen-joka-lataa-kaikki-laitteet-langattomasti
Unohtakaa latausalustat ja muut kömpelöt ratkaisut! Michiganin ja Tokion yliopiston tutkijat ovat kehittäneet huoneen, joka toimii kokonaisuudessaan laitteiden langattomana latausalustana. Tehoa läppäreihin, älypuhelimiin ja muihin laitteisiin voidaan syöttää 50 watin verran.
50 wattia on kova lukema magneettisilla kentillä. Kannattaa muistaa, ettei esimerkiksi Apple pääse vastaavaan tehoon edes omilla latureillaan. Tutkijat ovat esitelleet ratkaisun Nature Electronics -lehdessä ja sen vakuutetaan olevan turvallinen.
Tokion yliopiston tutkijoiden johtama tiimi esitteli tekniikan tarkoitukseen rakennetussa alumiinihuoneessa, jonka koko on noin 3 x 3 metriä. He latasivat langattomasti lamppuja, tuulettimia ja matkapuhelimia, jotka olivat eri puolilla huonetta.
Avain järjestelmän toimivuuteen piilee Alanson Sampen mukaan resonanssirakenteessa, joka tuottaa huoneen kokoisen magneettikentän ja rajoittaa samalla haitallisia sähkökenttiä, jotka voivat lämmittää biologisia kudoksia.
Room-scale magnetoquasistatic wireless power transfer using a cavity-based multimode resonator
https://www.nature.com/articles/s41928-021-00636-3
Magnetoquasistatic wireless power transfer can be used to charge and power electronic devices such as smartphones and small home appliances. However, existing coil-based transmitters, which are composed of wire conductors, have a limited range. Here we show that multimode quasistatic cavity resonance can provide room-scale wireless power transfer. The approach uses multidirectional, widely distributed currents on conductive surfaces that are placed around the target volume. It generates multiple, mutually unique, three-dimensional magnetic field patterns, where each pattern is attributed to different eigenmodes of a single room-scale resonator. Using these modes together, a power delivery efficiency exceeding 37.1% can be achieved throughout a 3 m × 3 m × 2 m test room. With this approach, power exceeding 50 W could potentially be delivered to mobile receivers in accordance with safety guidelines.
Tomi Engdahl says:
EMI in Wireless Power Transfer Designs
Aug. 30, 2021
https://www.electronicdesign.com/power-management/whitepaper/21173868/electronic-design-emi-in-wireless-power-transfer-designs?utm_source=EG%20ED%20Auto%20Electronics&utm_medium=email&utm_campaign=CPS210909013&o_eid=7211D2691390C9R&rdx.ident%5Bpull%5D=omeda%7C7211D2691390C9R&oly_enc_id=7211D2691390C9R
At the heart of WPT, which charges and powers electronics like mobile devices, teapots, ebikes, and even robots, are receiver and transmitter coils using near-field inductive power transfer. This article focuses on inductor coils as they relate to EMI.
What you’ll learn:
Mitigating EMI in apps that use magnetic resonance.
How to reduce EMI when using WPT in UAVs and other drones.
Dealing with electric-vehicle EMI and its impact on those with pacemakers.
Shielding in electric trains.
Wireless power transfer (WPT) technology, an excellent technology for easier and safer battery charging, doesn’t use a wired electrical contact that can cause an unwanted electric spark or even deliver dangerous electric current to users. When transferring power from a source to a battery or other load, strong electromagnetic fields (EMFs) will be generated. The vehicle power inverter charger output will have a wide range of harmonics.
Designers are tasked with reducing the electromagnetic fields (EMFs) and electromagnetic interference (EMI) in WPT systems. What follows are some methods that will help designers create a robust and safe WPT design while minimizing EMI.
Magnetic-Resonance Method
WPT architectures that use a magnetic-resonance method between coils are employed for safety, wide distances, and high-power capabilities. This kind of system is perfect for electric vehicles, defense applications, and medical equipment. Advantages include high power-conversion efficiency, ability of fault tolerance, and wide operating capability even with coil misalignment.
EMI Risk in Pacemakers
EMI can be dangerous for people with pacemakers and implantable cardioverter defibrillators (ICDs) who are outside of an electric vehicle (EV) while it’s charging. This is caused by coil currents of WPT systems that can generate large, time-varying magnetic fields in the surrounding environment.
It’s been shown that the most severe fields will not be inside the vehicle cabin, but rather in the side areas close to the ground outside the EV. Vehicle power-supply devices must be compliant with EMF safety standards for human exposure as well as be electromagnetically compatible with ICDs and pacemakers.
The standard for automotive applications of WPT systems requires that at the operational frequency, f = 85 kHz, the magnetic flux density will need to be below B = 27 μT, to not exceed the reference levels of ICNIRP 2010 guidelines. And it must be lower than B = 188 μT (150 A/m) so as not interfere with the normal sensing operation of the pacemaker with unipolar leads. The induced peak-to-peak voltage, in the loop area formed by the unipolar pacing lead, will need to be lower than V p-p = 510 mV as well.
An active shielding coil can be designed to reduce the risk for patients with pacemakers or similar devices. It’s produced by a time-varying magnetic field generated via 85-kHz WPT coil currents. The design of the ferrite shield above the secondary coil (Fig. 2) will reduce the field on both external lateral sides of the EV without reducing the electrical performance of the WPT system. In addition, each side of the ground pad has an active coil with the shape of a partial annular sector that’s placed around the circular primary coil.
EMI Shielding in Electric Train WPT
WPT is being used in EVs, electric buses, and even in electric trains. In these high-power application cases, the systems have many existing electrical components, such as signal and control systems, which are directly responsible for human safety. EMI can wreak havoc on these safety systems in the presence of strong WPT fields that are powering electric trains, for example.
The power inverter in a WPT transmitter is usually the main source of EMI. To minimize the EMI in the power converter, focus must turn to the main source causing it—the switching transistor in the power inverter. The switching action of the power transistors generate harmonic components into the air that may affect nearby systems, such as electric train safety systems like crossing gates and safety signals for the trains.
Summary
Wireless power transfer is a technology that easily transfers power, from a source to a load, over the air without using wires. It improves safety with added convenience for users.
This article has suggested multiple scenarios discussing some various uses of WPT. There’s also a drawback in using WPT due to the generation of EMI. The good outweighs the bad here, since we can minimize that EMI in various ways.
Tomi Engdahl says:
https://www.uusiteknologia.fi/2021/09/10/langattomalla-laturilla-voi-ladata-useita-laitteita-samaan-aikaan/
Tomi Engdahl says:
How far can I Wirelessly Transfer Power? (Experiment) Better than at MIT?
https://www.youtube.com/watch?v=15HmW1K8MZY
In this video I will be once again having a look at wireless power transmission. But this time it is all about distance and power because I wanted to find out whether I could achieve the same results as MIT back in 2007. They transmitted 60W of power with an efficiency of 40% over 2m. During my experiment I will tell you lots about good coil designs and power electronics which are required to achieve such results. Let’s get started!
0:00 MIT’s wireless power results
1:49 Intro
2:25 Building the power electronics (half-bridge)
4:18 Coil design (diameter, windings)
5:54 Frequency selection for the coil design
7:14 Test 1 (windings)
8:50 Test 2 (diameter)
9:15 Test 3 (HF litz wire)
9:49 Final Test & Verdict
Tomi Engdahl says:
New Wireless Power Tech Could Transform How We Charge Mobiles
Sept. 20, 2021
https://www.electronicdesign.com/power-management/whitepaper/21175874/electronic-design-new-wireless-power-tech-could-transform-how-we-charge-mobiles?utm_source=EG%20ED%20Analog%20%26%20Power%20Source&utm_medium=email&utm_campaign=CPS210916090&o_eid=7211D2691390C9R&rdx.ident%5Bpull%5D=omeda%7C7211D2691390C9R&oly_enc_id=7211D2691390C9R
Approved by the EU, UK, and US, Ossia’s Cota over-the-air power system—according to its certifications—doesn’t have a distance limitation, and it complies with safety regulations in terms of RF exposure.
Ossia’s Sept. 9, 2021 announcement that its Cota Real Wireless Power technology has passed both EU and UK regulatory assessments may change the way tablets, phones, and other mobile devices keep their batteries topped up. It may also free remote sensors used by IoT applications from the tyranny of limited-life batteries.
Doug Stovall, Ossia’s CEO, says that the approval of its system, which delivers power over-the-air (OTA), at a distance, across the US and EU, will pave the way for additional global approvals. In turn, a single version of a product that uses Cota power technology could be quickly approved for sale in many major markets.
If Ossia’s ambitious performance claims can be demonstrated by the products in which its technology is licensed, Stoval’s analysis is most likely correct. Nevertheless, some of those claims gave rise to a number of questions about how the system achieves its remarkable functionality and performance. Our questions, and Ossia’s responses, are published later in this report.
Here’s what we know at the moment:
Previously, the Cota system was only authorized for sale in the US by the FCC. This new approval certifies that the Cota system complies with the UK and European Union essential requirements and can be licensed and sold with the CE marking in Europe and the UKCA mark in the UK. In addition, the certification doesn’t have a distance limitation for delivery of wireless power OTA, and effectively delivers power over air without any distance limitation. As we’ll see, this opens up the possibility for supporting multi-watt applications at one to two meters and milliwatt-level applications with ranges in the tens of meters.
The system mentioned in the company’s announcement operates in the 2.4-GHz band, also used by Wi-Fi, Bluetooth, and microwave ovens(!), but the material on its website focuses primarily on a second system being developed that operates in the 5.8-GHz band. I wasn’t able to obtain power levels for the 2.4-GHz system but Ossia says the 5.8-GHz Cota system can deliver 2 to 3 W to a receiver at one meter from the transmitter, 1 W at two meters, and 10 to 50 mW at 10 meters. Since attenuation and other losses tend to be lower at 2.4 GHz, I suspect that the system with EU/GB approval may offer somewhat better performance.
Ossia is making several unique claims that appear to push the state of the art for wireless power, which we’ll try to clarify here. For one thing, the company claims that its Cota system is the first RF-based non-line-of-sight, wireless-power technology, at-a-distance product to receive EU/UK Type Examination Certificates.
Electronic Design has covered several “long distance” wireless-power systems, including GuRu and Powercast, so we were a bit skeptical about the claim about being “first-of-type.” However, when we took a closer look, it turns out that while Powercast does transmit power via non-line-of-sight, the power levels it supports are much lower. And, while GuRu’s system does transmit multi-watt power levels (enough power to make me nervous), it relies on line-of sight-transmission, as shown in the video below, with the transmitter often located in the ceiling, over a desk, or conference room table.
Tomi Engdahl says:
ST tuo 70 watin langattoman latauksen eri pinnoille
https://etn.fi/index.php/13-news/12595-st-tuo-70-watin-langattoman-latauksen-eri-pinnoille
STMicroelectronics on esitellyt uuden integroidun ratkaisun langattomaan lataukseen. STWLC98-tehovastaanotin pystyy lataamaan erilaisia kannettavia ja mobiililaitteita 70 watin teholla yhdistettynä STWBC2-HP-lähetinpiiriin.
70 watin tehollaan STWLC98 voi ladata nykypäivän huippuluokan älypuhelimet alle 30 minuutissa. Lisäksi uusi laite laajentaa mahdollisuuksia erittäin nopeaan ja kätevään lataamiseen ilman kaapeleita, pistorasioita ja rajoittavia liitäntöjä moniin uusiin sovelluksiin ja yhteyksiin.
Laturipiiri on yhteensopiva Qi EPP 1.3 -latausstandardin kanssa. Piiriä ohjaa 32-bittinen Arm Cortex-M3 -suoritin, jonka mukana tulee sulautettu käyttöjärjestelmä. Tämä yksinkertaistaa laitteiden Qi 1.3 -sertifiointia. Lähettimen puolella STWBC2-HP kommunikoi vastaanottimen suojatun STSAFE-A110 -elementin kanssa ja tallentaa Qi-varmenteet. Tätä todennusta uusin latausprotokolla edellyttää.
STWLC98-piirillä ST on toteuttanut oman ARC-tilan (Adaptive Rectifier Configuration), joka parantaa järjestelmän tehonsiirtoa sekä vaaka- että pystysuunnassa muuttamatta laitteiston tai kelan optimointia.
Tomi Engdahl says:
How far can I Wirelessly Transfer Power? (Experiment) Better than at MIT?
https://www.youtube.com/watch?v=15HmW1K8MZY
In this video I will be once again having a look at wireless power transmission. But this time it is all about distance and power because I wanted to find out whether I could achieve the same results as MIT back in 2007. They transmitted 60W of power with an efficiency of 40% over 2m. During my experiment I will tell you lots about good coil designs and power electronics which are required to achieve such results. Let’s get started!
Tomi Engdahl says:
Sean Hollister / The Verge:
MagSafe wireless charging continues to underwhelm a year after its release, due to Apple’s lack of foresight and a limited ecosystem
A year later, Apple’s MagSafe continues to underwhelm
Apple’s charging ecosystem keeps revealing its limitations
https://www.theverge.com/2021/10/15/22728967/apple-magsafe-duo-wallet-cases-charging?scrolla=5eb6d68b7fedc32c19ef33b4
One year ago yesterday, I wrote how MagSafe could be the biggest reason to buy an iPhone 12. I believed it, too. It looked like Apple had cracked the code to effortlessly accessorize the iPhone and even add modular new capabilities. The company showed its pricey new MagSafe cases and wallets seemingly snapping into place, plus faster wireless charging. The future looked bright.
But if you became an early adopter like me, you might have wound up disappointed. As Bloomberg’s Mark Gurman points out, two of Apple’s first overpriced MagSafe accessories are already out of date. First, we just learned Friday that Apple’s $129 MagSafe Duo Charger can’t fast-charge an Apple Watch Series 7. Second, Apple has already replaced the $59 MagSafe Leather Wallet with a better version that supports Find My so your phone can remember where it was when it got removed.
The new Leather Wallet with MagSafe also doesn’t support Apple’s $49 Clear Case with MagSafe, so hope you didn’t buy one of those thinking it’d be futureproof — apparently, it blocks the NFC tags that MagSafe accessories like the Wallet use to passively ID themselves to the phone.
Tomi Engdahl says:
https://etn.fi/index.php/13-news/12705-mems-oskillaattori-nopeuttaa-langatonta-lataamista-selvaesti
Langattomat latausstandardit, kuten Qi ja AirFuel, perustuvat resonanssiseen voimansiirtoon läheisyyslatauksen mahdollistamiseksi. Ympäristön häiriöt voivat kuitenkin vaikuttaa dynaamisesti resonanssiseen lataustaajuuteen, mikä hidastaa latausprosessia. SiT3901:n ansiosta laturin resonanssitaajuus voidaan virittää digitaalisesti, mikä maksimoi tehonsiirron ja nopeuttaa sitä jopa 25 prosenttia. SiT3901-piirille integroitu digitaalinen ohjausominaisuus lisäksi eliminoi passiivisten komponenttien tarpeen piirikortilla.
https://www.sitime.com/products/mpower-oscillators-1-hz-26-mhz
Tomi Engdahl says:
Funny meme on wireless power ideas
https://9gag.com/gag/aD12oXZ
Tomi Engdahl says:
Rethinking Wireless Power: A Closer Look at Ossia’s Technology
Oct. 13, 2021
Can a small wireless power startup really use its “RF Holography” technology to charge personal electronics from several meters away, without irradiating their users? Join ED’s Lee Goldberg as he takes a deep dive into the theory behind the system.
https://www.electronicdesign.com/power-management/whitepaper/21178200/electronic-design-rethinking-wireless-power-a-closer-look-at-ossias-technology?utm_source=EG%20ED%20Analog%20%26%20Power%20Source&utm_medium=email&utm_campaign=CPS211004095&o_eid=7211D2691390C9R&rdx.ident%5Bpull%5D=omeda%7C7211D2691390C9R&oly_enc_id=7211D2691390C9R
What you’ll learn:
Ossia’s response to readers’ questions and skepticism regarding their longer-distance wireless power system.
The priniciples behind the company’s energy transmission system.
A demo of the technology, including a video presentation.
Our recent story “Wireless Power System Approved by EU and UK Claims to Charge Mobile Devices Without Frying Users” caused quite a stir amongst our loyal reader community. In fact, more of our sharp-eyed readers took the time to weigh in on the technology’s relative merits than any other story I’ve written in the last decade (or two).1 Nearly all of their responses were even more skeptical than I was of Ossia’s claims to be able to deliver meaningful amounts of power to devices multiple meters away via either 2.4- or 5.8-GHz RF beams, without exposing nearby users to unsafe energy levels.
And I don’t blame them. Wireless power has become a hot topic in the last few years. I’ve covered several of the many startups who claim to have a “breakthrough” technology but provide few, if any, details about how it works.
While most of these companies’ systems seem to be capable of transmitting power with varying degrees of efficiency, I’m less than confident in their purported safety mechanisms intended to avoid irradiating hapless users. As a result, wireless power systems (other than inductive) are currently on the same “no fly” list that bans any device containing Alexa, Siri, or other domestic spyware from my house.
Due to those experiences, I regarded the claims made by Ossia in a recent press release with equal skepticism. Nevertheless, as I try to do with any company, I gave them the benefit of the doubt and asked for additional details about their technology. My questions focused primarily on how their system achieves their unique capabilities, such as using multipath transmission for non-LOS power delivery, sensing obstacles (including people), and re-routing their power beam around them.
To my surprise, Ossia did reply, and some of their answers made an honest attempt to explain their technology without violating the laws of physics. Although I wasn’t completely satisfied with their answers, and a bit uncomfortable with some of the novel technical terms I wasn’t familiar with, such as “Reciprocal RF” and “retrodirective signal,” I thought it would be worthwhile to share what I’d learned
From a less allegorical perspective, Ossia’s Cota system consists of a base station (power transmitter) and one or more remote power receivers. The base station contains a large array of transceiver elements (typically 250+) that, depending on the model, transmit power at either 2.4 or 5.8 GHz. They’re normally off and only transmit in response to a request in the form of a “beacon” signal, generated by a power receiver embedded in a client device. The receiver’s beacon is a 5-mW pulse, transmitted up to 100 times/s. It contains a unit ID number plus other information about the client, such as its power requirements and state of charge.
Each of the base station antenna’s transceiver elements can accurately detect the phase and amplitude of the incoming beacon with respect to its internal reference. The Ossia system uses that information to understand the propagation characteristics of its environment on a moment-by-moment basis.
According to Ossia’s Mr. Zeine, the beacon signal seen by each receiver represents the unique sum of the various transmission paths reaching that particular point in space. That information can be extracted by using the receiver’s “phase detect mode” where the signal and an internal reference clock are combined and fed to an A/D. The resulting output value is used to calculate the negative or “complex conjugate” of the original phase value that can produce a signal with the inverse of the received phase.
We also discussed a few other issues I was unsure about. One involved their claims of being able to transmit multiple watts of power across several meters without the beamforming techniques often used to slow the dispersion that occurs as distance increases. Zeine’s answer was intriguing.
He reminded me of what any engineer with some background in RF already knows (but I’d forgotten). While the simple 1/R2 formula does a decent job of modeling propagation at relatively large distances from the transmitter, i.e., its far field, the field strength behaves in a much more complex manner close to the transmitter, i.e., in its near field.
Ossia takes advantage of some of the properties of the near-field effect to extend the distance its system can transmit enough power to charge phones, laptops, and other mobile electronics.
Within the near field, the signal’s near-field behavior can be modeled with an infinite series whose terms cause the value of the field strength to decrease more slowly with distance than the simpler far-field model (1/R2) would predict. But, as the signal radiates outward, it behaves more closely in accordance with the simpler 1/R2 formula until the far-field effects begin to dominate the beam’s behavior. This point is known as the Rayleigh distance
his means that the transmitter’s near-field distance can be increased by using a larger array or a higher frequency.
Zeine said that the near field of their current 2.4-GHz demo unit, which has a 60- × 60-cm antenna array, extends to 5.7 m. He also said that, once completed, the near field of their 5.8-GHz system (built to the same 60- × 60-cm dimensions) will extend nearly 2.5X further (12 to 13 m).
Note: This corrects a misunderstanding I had when I wrote the first article, which led me to speculate incorrectly that the 2.4-GHz system’s reach would exceed what they predict for their 5.8-GHz Cota system. In reality, the 2.4-GHz system I saw demoed has a range that’s somewhat less than the predicted performance of the 5.8-GHz system, which they say will be able to deliver 2 to 3 W to a receiver at one meter from the transmitter, 1 W at two meters, and 10 to 50 mW at 10 meters.
My understanding is that Ossia supports higher-power applications within the transmitter’s near field, but also delivers lower levels of power at greater distances. While the power levels at these distances are in the milliwatt range, they’re still very useful for applications such as charging the batteries of low-power wireless sensors, such as those used in security, asset tracking, or other IoT systems. Since both the beacon and the power beam can be used to transmit low-rate digital data streams, the technology also can power and update smart signage, such as those that contain product and pricing information in retail stores.
During the demonstration, Ossia also showed me how they have begun to put that theory to practical use, with a look at several commercial applications they’re currently developing for clients. This included a “smart price tag,” which retailers can update with price and product information using the same wireless channel that keeps its batteries charged. Each transmitter can support 1,000 or more of these low-power devices.
Questions about Certification
Several readers raised questions about Ossia’s recent statements regarding certification for its technology in the U.S. and the EU/UK. We were almost out of time before the topic came up, so I don’t have all the answers about how they achieved certification. Here is what I know:
The recent UK/European approvals that allow for operation over any distance the system can cover were achieved using a process known as “self-declaration.” Therefore, instead of having the government review a product’s test data for compliance with the radio, emissions, immunity, and RF safety standards, the company can review its own data and then submit a statement of compliance. I’m not enough of an expert in this area to weigh in on whether this leaves room for a company to skirt the intentions of the regulations with a non-compliant product or technology.
According to one source who contacted me, they were approved by an EU Notified Body and used those results to gain approval from the UKCA Conformity Assessment Body, which also uses the EU’s standards. My understanding is that this is well within the bounds of accepted practices, although I’m not sure how many companies choose to use it instead of going through direct certification with the EU/UK authorities.
Speaking of which, just to clarify Ossia’s statement regarding its U.S. approval, their current FCC certification limits their transmission to 1 m. This may change in the future since they’re vigorously pursuing approval to operate at longer or even unlimited distances. The FCC’s caution is understandable, given their novel technology, and numerous potential applications.
Conclusions
Although I entered the conversation as a skeptic, it does appear that what appeared to be “smoke and mirrors” is actually a novel, but plausible, application of standard RF theory. At least from my understanding of the simplified math that Dr. Zeine used to explain their complex conjugate process that generates the so-called retrodirective signal, the technology behind Ossia’s wireless power system seems to work in accordance with what I’m able to recall of the Fourier, Laplace, and radio propagation theory I learned in college.
Wireless Power System Approved by EU and UK Claims to Charge Mobile Devices Without Frying Users
Sept. 21, 2021
Approved by the EU, UK, and US, Ossia’s Cota over-the-air power system—according to its certifications—doesn’t have a distance limitation, and it complies with safety regulations in terms of RF exposure.
https://www.electronicdesign.com/power-management/whitepaper/21175874/electronic-design-wireless-power-system-approved-by-eu-and-uk-claims-to-charge-mobile-devices-without-frying-users
Ossia’s Sept. 9, 2021 announcement that its Cota Real Wireless Power technology has passed both EU and UK regulatory assessments may change the way tablets, phones, and other mobile devices keep their batteries topped up. It may also free remote sensors used by IoT applications from the tyranny of limited-life batteries.
Doug Stovall, Ossia’s CEO, says that the approval of its system, which delivers power over-the-air (OTA), at a distance, across the US and EU, will pave the way for additional global approvals. In turn, a single version of a product that uses Cota power technology could be quickly approved for sale in many major markets.
If Ossia’s ambitious performance claims can be demonstrated by the products in which its technology is licensed, Stoval’s analysis is most likely correct. Nevertheless, some of those claims gave rise to a number of questions about how the system achieves its remarkable functionality and performance. Our questions, and Ossia’s responses, are published later in this report.
Here’s what we know at the moment:
Previously, the Cota system was only authorized for sale in the US by the FCC. This new approval certifies that the Cota system complies with the UK and European Union essential requirements and can be licensed and sold with the CE marking in Europe and the UKCA mark in the UK. In addition, the certification doesn’t have a distance limitation for delivery of wireless power OTA, and effectively delivers power over air without any distance limitation. As we’ll see, this opens up the possibility for supporting multi-watt applications at one to two meters and milliwatt-level applications with ranges in the tens of meters.
The system mentioned in the company’s announcement operates in the 2.4-GHz band, also used by Wi-Fi, Bluetooth, and microwave ovens(!), but the material on its website focuses primarily on a second system being developed that operates in the 5.8-GHz band. I wasn’t able to obtain power levels for the 2.4-GHz system but Ossia says the 5.8-GHz Cota system can deliver 2 to 3 W to a receiver at one meter from the transmitter, 1 W at two meters, and 10 to 50 mW at 10 meters. Since attenuation and other losses tend to be lower at 2.4 GHz, I suspect that the system with EU/GB approval may offer somewhat better performance.
Ossia is making several unique claims that appear to push the state of the art for wireless power, which we’ll try to clarify here. For one thing, the company claims that its Cota system is the first RF-based non-line-of-sight, wireless-power technology, at-a-distance product to receive EU/UK Type Examination Certificates.
Tomi Engdahl says:
OSSIA WHITEPAPER
OSSIA’S COTA® VERSUS OTHER WIRELESS POWER TECHNOLOGIES
https://cdn2.hubspot.net/hubfs/2870932/Content%20Offers/Whitepapers/Cota%20vs%20Other%20Wireless%20Power%20Technologies.pdf
Tomi Engdahl says:
Nopeampi langaton lataus tulee autoon
https://etn.fi/index.php/13-news/12731-nopeampi-langaton-lataus-tulee-autoon
NXP Semiconductors on julkistanut markkinoiden ensimmäisen Wireless Power Consortium eli WPC:n sertifioiman ja Qi 1.3 -tekniikkaa tukevan autojen langattoman latauksen referenssialusta. Alusta koostuu Qi-sertifioidusta kortista, sekä valinnaisesta NFC:stä, suojaelementistä ja CAN/LIN-lähetinvastaanottimesta.
Tomi Engdahl says:
Small Inductive Coil and 10 Wireless LED Kit – 5V
https://www.adafruit.com/product/5140
Sounds magical! That’s what makes this Small Inductive Coil and 10 Wireless LED Kit so nifty. It uses electromagnetic fields and inductive coupling to pass power through the air to light up lil LEDs soldered onto coils.
Each order comes with one driver board (you’ll need a 5V power supply to power it) and ten miniature LED inductors in an assortment of colors (two each of white, blue, yellow, green, and red)
Tomi Engdahl says:
Sähköautoon 200 kilowatin lataus langattomasti
https://etn.fi/index.php?option=com_content&view=article&id=12381&via=n&datum=2021-07-30_14:10:39&mottagare=31202
Sähköauton akuston lataaminen on tällä hetkellä suurin sähköautoilua hidastava tekijä. Saksalainen Tesvolt on esitellyt ongelmaan uuden ratkaisun: induktiivisen langattoman lataamisen, joka voisi syöttää akkuun virtaa ajon aikana tienpinnasta 200 kilowatin teholla.
Langaton lataus tarkoittaa sähköenergian siirtämistä induktiivisessa, toisin sanoen kontaktittomassa prosessissa lattiassa tai lattialla olevasta magneettikäämisestä sähköajoneuvon vastaanottokäämin. Tämä mahdollistaa monia lyhyitä mutta nopeita latausprosesseja – esimerkiksi kauppakeskusten pihapiireillä, monikerroksisissa pysäköintialueissa sekä kotona. Autonvalmistajat, kuten Audi ja BMW, asentavat jo latauskäämiä uusiin automalleihin.
Toistaiseksi ainoa sarjatuotantoon sopiva langaton lataus on vain teholtaan vain 3,2 kilowattia ei käytännössä lataus onnistuu samalla nopeudella kuin normaalissa suomalaisessa kodin sähköverkossa.
Tesvolt haluaa tuoda markkinoille induktiivisen latausaseman, jonka latausteho on 44 kilowattia. Nykyisiin ratkaisuihin verrattuna lataaminen onnistuisi siis 14 kertaa nopeammin. Ratkaisu perustuu piikarbiditehopuolijohteisiin, jossa hyötysuhde on 95 prosenttia. Se mahdollistaa lataamisen jopa 20 senttimetrin etäisyydellä lähettimen ja vastaanottimen kelojen välillä. Tesvoltin latausasemat sisältävät myös älykkään ohjelmiston, joka näyttää kuljettajalle oikean pysäköintiasennon ajoneuvolle magneettikäämin yli.
Tomi Engdahl says:
Trio collaborate to promote 5.8-GHz wireless power
https://www.edn.com/trio-collaborate-to-promote-5-8-ghz-wireless-power/
Ossia, NGK, and Torex have joined forces to create a 5.8-GHz wireless power transfer (WPT) power receiver development kit. The offering combines Ossia’s Cota Real Wireless Power technology with NGK’s EnerCera lithium-ion rechargeable batteries and Torex’s micro DC/DC XCL series of power supply ICs.
Tomi Engdahl says:
https://www.edn.com/teardown-pixel-stand-offers-faster-than-qi-wireless-charging-for-some-google-fans/
Tomi Engdahl says:
Electrically connected spin-torque oscillators array for 2.4 GHz WiFi band transmission and energy harvesting
https://www.natureindex.com/article/10.1038/s41467-021-23181-1
Tomi Engdahl says:
Watin langaton latausteho NFC-linkin yli
https://etn.fi/index.php?option=com_content&view=article&id=12940&via=n&datum=2021-12-10_14:47:09&mottagare=31202
ROHM-konserniin kuuluva LAPIS Technology on esitellyt piirisarjan, joka pystyy syöttämään jopa 1 watin lataustehon langattomasti 13,56 megahertsin linkin yli. Tämä tuo langattoman latauksen moniin pienikokoisiin NFC-radiolla varustettuihin laitteisiin, kuten puettavat laitteet ja teollisuuden laitteisiin.
ML7661- (lähetin) ja ML7660-piirit (vastaanotin) eliminoivat ulkoisen MCU:n tarpeen sisällyttämällä lähetykseen/vastaanottoon tarvittavan ohjauspiirin, mikä johtaa alan pienimpään järjestelmäkokoon 1W-luokassa. Tämä tekee ratkaisusta ihanteellisen puetettaville laitteille, joissa on suuri akkukapasiteetti ja jotka on suunniteltu käytettäväksi pitkiä aikoja. Tyypillisiä tuotteita ovat esimerkiksi aktiivisuusrannekkeet, verenpainemittarit, kuntomittarit, älykellot ja kuulolaitteet.
LAPIS Technology kehitti jo aiemmin ML763x-piirisarjan, joka hyödyntää 13,56 MHz:n taajuuskaistaa 200 mW:n tehon tuottamiseksi ja langattoman viestinnän mahdollistamiseksi.
13.56MHz (NFC) wireless charging chipset supporting up to 1W power supply
” ML7661 / ML7660 ”
https://www.lapis-tech.com/en/semicon/wpt/landing/ml7660_61.html
By increasing the power supply capacity to 1W (five times that of the conventional product), it is possible to charge wristband blood pressure monitors with large battery capacity, and to charge smartwatches and hearing aids at high speed
Using the 13.56MHz frequency band, the antenna size can be reduced by 83% compared to Qi (Qi)* (110kHz to 205kHz), a common feeding method used in smartphones.
Or, the antenna size can be reduced by 36% compared to discrete component configurations (several hundred kHz), allowing it to be mounted on smaller devices.
Power supply control can be achieved without a microcontroller by simply supplying power.
This not only eliminates the need for software development for the microcontroller, but also contributes to miniaturization by reducing the mounting space for the microcontroller.
For the addition of a new SPI interface, it enables microcontroller-less control of digital sensors and other devices with SPI interfaces.
Tomi Engdahl says:
In Search for the BEST Wireless Power Coil! (Experiment) My Coils can act like Capacitors?
https://www.youtube.com/watch?v=S3mLHpzzcTU
In this video we will be having a closer look at my wireless power coils in order to optimize them. That means I will show you exactly how to measure the most important characteristics of any coil and how to turn these values into the coil quality which I should keep as big as possible for my wireless power transmission. Along the way we will learn about LCR meters, how coils act at higher frequencies and ultimately (maybe) create my best wireless power coil so far. Let’s get started!
0:00 We need the Coil Quality!
1:22 Intro
2:08 High Frequency Inductor Problem
3:55 Real Coil Explained (LCR)
5:00 DIY Coil Measurements
7:33 DIY Coil Quality Analysis & New Test
8:21 New Litz Wire Coil
9:45 Final Test & Verdict
Tomi Engdahl says:
Vahva tunnistus langattomalle lataukselle autoissa
https://etn.fi/index.php/13-news/12979-vanha-tunnistus-langattomalle-lataukselle-autoissa
Infineon Technologies on kehittänyt turvaratkaisun mobiililaitteiden langattomaan lataukseen autoissa. OPTIGA Trust Charge automotive on Wireless Power Consortiumin Qi-standardin version 1.3 mukainen eli se tukee vahvaa kryptografista todennusta langattomalle lataukselle 15 watin tehoon saakka.
Latauksen aloittamiseksi teholähettimen on autentikoitava itsensä tehovastaanottimelle, kuten matkapuhelimelle, suojatulla tallennusalijärjestelmällä. Infineon suunnitteli OPTIGA Trust Charge -autot täyttämään tämän prosessin tarvittavat sovellusvaatimukset ja tukee seuraavan sukupolven latausratkaisujen kehitystä.
Tomi Engdahl says:
https://hackaday.com/2021/11/29/wireless-leds-arent-really-magic/
Tomi Engdahl says:
Delivering Wireless Power to Table Tops, Mobile Devices, and More
Jan. 21, 2022
Ossia implements a wirelessly powered table using its wireless power technology. Find out how it works.
https://www.electronicdesign.com/power-management/power-delivery/video/21214487/electronic-design-delivering-wireless-power-to-table-tops-mobile-devices-and-more?utm_source=EG%20ED%20Analog%20%26%20Power%20Source&utm_medium=email&utm_campaign=CPS220113008&o_eid=7211D2691390C9R&rdx.ident%5Bpull%5D=omeda%7C7211D2691390C9R&oly_enc_id=7211D2691390C9R
Ossia has some neat long-distance, wireless power transmission technology that’s ideal for delivering power to mobile and IoT devices. At the Consumer Electronics Show, they were demoing a wirelessly powered table that could in turn charge short-range, wireless charging devices like smartphones. While the latter typically must essentially be in close contact with the charging unit, Ossia’s system works within rooms.
There are a number of wireless power transmission techniques. Ossia’s patented methodology transmits power to a device using a number of paths rather than one high-power, focused transmission. How it determines this multipath transmission is interesting as well. It does so by sending signals from the source; the transmitter receives some of these signals and sends back power based only on the signals it receives
Tomi Engdahl says:
https://etn.fi/index.php/13-news/13102-pieni-antenni-keraeae-energian-kaikilta-kaennykkaetaajuuksilta
Tomi Engdahl says:
https://www.uusiteknologia.fi/2022/02/01/katevat-latausmoduulit-pienlaitteisiin/
Tomi Engdahl says:
https://www.uusiteknologia.fi/2022/02/01/aallossa-kehitetty-tekniikka-voisi-ladata-robotin-liikkuessaan/
Tomi Engdahl says:
Suomessa kehitetty langaton lataus toimii myös liikkeessä
https://etn.fi/index.php/13-news/13114-suomessa-kehitetty-langaton-lataus-toimii-myoes-liikkeessae
https://www.uusiteknologia.fi/2022/02/01/aallossa-kehitetty-tekniikka-voisi-ladata-robotin-liikkuessaan/
Tomi Engdahl says:
https://www.aalto.fi/fi/uutiset/yksinkertaisen-hienostunut-uusi-virransiirtotekniikka-mullistaa-langattoman-latauksen
Tomi Engdahl says:
”Yksinkertaisen hienostunut” – uusi virransiirtotekniikka mullistaa langattoman latauksen
Julkaistu: 1.2.2022
https://www.aalto.fi/fi/uutiset/yksinkertaisen-hienostunut-uusi-virransiirtotekniikka-mullistaa-langattoman-latauksen
Oli kyseessä sitten varastorobotti, kodinkone tai matkapuhelin, lataus toimii missä tahansa latausalueella ja jopa laitteen liikkuessa.
Tomi Engdahl says:
Electreon, Ford Developing In-Road Charging System Near Mobility Tech Hub
https://www.forbes.com/sites/greggardner/2022/02/01/electreon-to-develop-in-road-charging-system-near-fords-mobility-tech-hub/
Ford Motor Co. is working with Israeli startup Electreon to construct a mile-long road near Detroit’s Michigan Central Terminal that will charge electric vehicles as they travel on it.
The pilot program will deploy an inductive in-road charging system in partnership with the Michigan Department of Transportation, the Michigan Office of Future Mobility and Electrification and the Michigan Economic Development Corp.
“We are proud and thankful to be selected by the Michigan Department of Transportation to lead and implement the first wireless electric road system in the United States,” said Stefan Tongur, vice president of Electreon.
Electreon’s technology can wirelessly charge EVs whether they are moving or stationary. This project will be one of the first to be installed on public roads in the United States.
The company currently has pilot projects in Germany, Sweden and Italy. Recently it signed an agreement to develop a plug-free charging network for 200 transit buses in Tel Aviv.
Inductive charging has the potential to ease range anxiety for EVs owners and reduce their cost of charging at home or at public charging stations.
Tomi Engdahl says:
https://emrod.energy/short-range-vs-long-range-wireless-power-transmission/
Tomi Engdahl says:
What’s Up with Wireless Power?
Feb. 4, 2022
Energous’ CEO Cesar Johnston talks about the company’s wireless power chipset and technology.
https://www.electronicdesign.com/power-management/power-delivery/video/21215419/microwaves-rf-whats-up-with-wireless-power?utm_source=EG%20ED%20Analog%20%26%20Power%20Source&utm_medium=email&utm_campaign=CPS220127064&o_eid=7211D2691390C9R&rdx.ident%5Bpull%5D=omeda%7C7211D2691390C9R&oly_enc_id=7211D2691390C9R
Wireless power delivery within a room, instead of being in contact with a charger, is something that can benefit everything from IoT devices to mobile devices. I spoke with Energous’ CEO Cesar Johnston about the firm’s wireless power chipset and technology that were on display at this year’s Consumer Electronics Show.
Tomi Engdahl says:
What’s Up with Wireless Power?
Feb. 4, 2022
Energous’ CEO Cesar Johnston talks about the company’s wireless power chipset and technology.
https://www.mwrf.com/technologies/systems/video/21216029/microwaves-rf-whats-up-with-wireless-power?utm_source=RF%20MWRF%20Today&utm_medium=email&utm_campaign=CPS220211031&o_eid=7211D2691390C9R&rdx.ident%5Bpull%5D=omeda%7C7211D2691390C9R&oly_enc_id=7211D2691390C9R
Wireless power delivery within a room, instead of being in contact with a charger, is something that can benefit everything from IoT devices to mobile devices. I spoke with Energous’ CEO Cesar Johnston about the firm’s wireless power chipset and technology that were on display at this year’s Consumer Electronics Show.
Tomi Engdahl says:
Metasurface-based antenna turns ambient radio waves into electric power
by The Optical Society
https://phys.org/news/2022-02-metasurface-based-antenna-ambient-radio-electric.html
Tomi Engdahl says:
https://www.edn.com/wigl-a-design-intro-and-how-it-complements-wireless-charging/
Tomi Engdahl says:
Volvo lataa langattomasti 40 kilowatin teholla
https://etn.fi/index.php/13-news/13270-volvo-lataa-langattomasti-40-kilowatin-teholla
Sähköauton lataus on monen mielestä edelleen koko konspetin Akilleen kantapää. Jos autoa joutuu lataamaan yön yli, se laskee käyttömukavuutta, johon olemme polttomoottoriautoissa tottuneet. Nyt Volvo Cars testaa uutta langatonta latausteknologiaa aidossa kaupunkiympäristössä.
Seuraavan kolmen vuoden aikana pientä joukkoa Volvo XC40 Recharge -täyssähköautoja käytetään Pohjoismaiden suurimman taksiyrityksen, Cabonlinen, takseina ja niitä ladataan langattomasti Göteborgissa sijaitsevilla asemilla.
Testissä käytettävät latausasemat toimittaa Momentum Dynamics, joka on johtava langattomien latausjärjestelmien tarjoaja. Lataus käynnistyy automaattisesti, kun yhteensopiva auto pysäköi katuun upotetulle latausalustalle, ja kuljettajat voivat kätevästi ladata autonsa siitä poistumatta.
Täyssähköisissä XC40 Recharge -autoissa langaton latausteho on yli 40 kW, mikä tekee lataamisesta noin neljä kertaa nopeampaa kuin johdollisen 11 kW:n AC-laturin kanssa ja lähes yhtä nopeaa kuin johdollisen 50 kW:n DC-pikalaturin kanssa.
Tomi Engdahl says:
Kiinnostaako NFC-lataaminen? Tarjolla ilmainen webinaari
https://etn.fi/index.php?option=com_content&view=article&id=13275&via=n&datum=2022-03-08_14:54:27&mottagare=31202
Yhä useammin laitteet halutaan ladata langattomasti. Tähän on tarjolla erilaisia ratkaisuja. Mikäli tarvitaan vain pieniä, tyypillisesti alle yhden watin lataustehoja, myös lähimaksamisesta tuttu NFC-tekniikka voi olla toimiva ratkaisu.
Mikäli esimerkiksi aktiivisuusrannekkeeseen langattoman lataamisen tuominen NFC:llä kiinnostaa, voi aiheeseen tutustua STMicroelectronicsin webinaarissa. Ensi viikon tiistaina klo 16 järjestettävässä webinaarissa käydään läpi tekniikan perusteet, esitellään ST:n omia piiriratkaisuja molempiin päihin latauslinkkiä ja demotaan, miten tekniikka toimii käytännössä.
NFC charging:
the tiniest solution
for wireless charging
https://content.st.com/nfc-wireless-charging-solution-webinar.html?ecmp=tt25327_em_enews_feb2022
Tomi Engdahl says:
Spotify kaatui – syy vaikuttaa karun yksinkertaiselta https://www.is.fi/digitoday/art-2000008669441.html
Tomi Engdahl says:
Wireless Power is Already Changing the World
March 14, 2022
It may sound like futuristic technology from a sci-fi movie to many people, but wireless power is already transforming the logistics industry, and soon it will improve healthcare and unleash a wave of innovation in the consumer sector.
https://www.electronicdesign.com/power-management/whitepaper/21236042/ossia-wireless-power-is-already-changing-the-world?utm_source=EG%20ED%20Analog%20%26%20Power%20Source&utm_medium=email&utm_campaign=CPS220302028&o_eid=7211D2691390C9R&rdx.ident%5Bpull%5D=omeda%7C7211D2691390C9R&oly_enc_id=7211D2691390C9R
What you’ll learn:
How wireless power is already transforming the logistics industry.
How wireless power will change healthcare.
How wireless power will ramp up innovation in the consumer sector.
We live in a world that’s continuously increasing in devices that help us with our safety, security, entertainment, productivity, and health. These electronic devices may be connected—today called the Internet of Things (IoT)—but many devices are not connected, such as our electric toothbrush, kid’s thermometer, and numerous other applications everywhere.
Each of those devices requires a power source, and we’ve been using wires and batteries for over 150 years to meet their power needs. The 21st century brings a third type of power to devices: wireless power.
Imagine a world where devices are powered wirelessly, from a power source—not conceptually different from the Wi-Fi hub—delivering the power needs of those sensors, smartphones, and other types of industrial or consumer devices as seamlessly as our Wi-Fi experience. As a relatively small number of people know, we already live in that world, but soon, the broader public will become aware of the possibilities.
https://www.ossia.com/
Tomi Engdahl says:
Autoon jopa 50 watin langaton lataus
https://etn.fi/index.php/13-news/13301-autoon-jopa-50-watin-langaton-lataus
Renesas on julkistanut seuraavan sukupolven referenssimallin autojen langattomille latausasemille. Mallimerkinnällä P9261-3C-CRBv2 esitelty ratkaisu sisältää autoteollisuudelle sopivan langattoman tehonohjaimen P9261, jossa on MP-A13 3-käämin referenssirakenne langattomana teholähettimenä.
Ratkaisu tarjoaa suuren aktiivisen latausalueen korkealla hyötysuhteella ja poikkeuksellisella EMC/EMI-suorituskyvyllä. Referenssimalli tarjoaa Wireless Power Consortiumin Qi 1.3 -standardin EPP (Extended Power Profile) -yhteensopivuuden 15 watin lataukseen. Se tukee myös patentoituja latausprofiileja ja pystyy toimittamaan 50 W tehoa.
Tomi Engdahl says:
NFC-lataus on pienten laitteiden Qi
https://etn.fi/index.php/13-news/13307-nfc-lataus-on-pienten-laitteiden-qi
Yhä useammassa kalliimmassa älypuhelimessa on jo langaton lataus ja käytännössä se aina perustuu Qi-standardiin. Pienempiin laitteisiin Qi ei kuitenkaan sovi jo sen takia, että antenni on liian iso. Monessa laitteessa NFC-lataaminen on parempi ratkaisu.
STMicroelectronics esitteli eilen webinaarissaan NFC-lataamista ja omia piiriratkaisujaan alueelle. Teknisesti NFC-lataaminen ei ole erityisen monimutkaista. Tarvitaan vain ohjain ja antenni, 13,56 megahertsin kenttä ja vastaanotin, niin induktiivisen linkin yli voidaan siirtää tehoa.
NFC Forum hyväksyi langattoman lataamisen WLC 1.0 -standardin toukokuussa 2020. Sen rajoituksena on 1 watin maksimiteho. Uusi 2.0-standardi on valmistumassa lähiviikkoina ja siinä teho kasvaa maksimissaan 3 wattiin. Tämä nopeuttaa pienten laitteiden lataamista merkittävästi.
Nykyinen standardi määrittelee kaksi eri moodia. Staattisessa moodissa teho on rajattu 100 milliwattiin, joten käyttö on rajoitettua. Ns. neuvotellussa linkissä (negotiated mode) teho voidaan määritellä 0,25 – 0,5 – 0,75 tai 1,0 watiksi. Yhden watin teho riittää jo esimerkiksi aktiivisuusrannekkeen lataamiseen.
NFC-lataamista ei oikeastaan pitä verrata Qi-tekniikkaan. Qi toimii 100-200 megahertsin taajuudella ja tukee nyt 15 watin tehoa. Teho on kasvamassa pian 45-50 wattiin. Qi-antennit ovat kuitenkin selvästi suurempia (10-20 neliösenttiä), mikä rajaa ne pois useimmista pienistä laitteista. Lisäksi Qi mahdollistaa vain 2 kilobitin datalinkin, kun NFC:llä voidaan siirtää dataa 26-848 kilobittiä sekunnissa. Tämä avaa NFC-linkille sovelluksia, joihin Qi ei taivu.
https://www.st.com/content/st_com/en/support/learning/essentials-and-insights/connectivity/nfc/nfc-for-wireless-charging.html
Tomi Engdahl says:
https://hackaday.com/2022/03/17/wireless-charging-for-border-patrol-drones/
Tomi Engdahl says:
Design kit addresses in-cabin wireless charging
https://www.edn.com/design-kit-addresses-in-cabin-wireless-charging/
Tomi Engdahl says:
Ladattava Qi-laite pitää nyt tunnistaa varmasti
https://etn.fi/index.php/13-news/13370-ladattava-qi-laite-pitaeae-nyt-tunnistaa-varmasti
Qi on noussut pienten laitteiden langattoman lataamisen de facto -standardikdi. Wireless Power Consortiumin uusin standardi on jo viime vuonna hyväksytty Qi 1.3. Se edellyttää, että latauslaite tunnistaa varmasti ladattavan laitteen. Microchip on tuonut tarjolle näiden laitteiden turvallisen autentikoinnin.
Microchip on lanseerannut TrustFLEX ECC608- ja autoteollisuuden Trust Anchor TA100-piirit Qi 1.3 -lähetinpiirien rinnalle. Kyse on suojatusta all-in-one -tallennusalijärjestelmä, joka tukee suojattujen avainten käyttöä laitteiden autentikoinnissa. Tämä pitää sisällään X.509-varmenteet, joilla voidaan varmistaa salausteknisesti sertifioidun teholähettimen lähde ja laatu.
Vastaanotin esimerkiksi matkapuhelimessa, joka on sijoitettu Qi 1.3 -teholähettimeen, voi aluksi hyväksyä 5 watin latauksen tai hylätä sen. Onnistuneen X.509-pohjaisen ECC-todennuksen jälkeen, joka osoittaa, että laturi on hyväksytty, puhelin voi hyväksyä latauksen 15 watin teholla. Tämä tietenkin lyhentää latausaikaa merkittävästi.
15W Multi-Coil Wireless Power Transmitter
https://www.microchip.com/en-us/solutions/power-management-and-conversion/intelligent-power/wireless-power/15w-multi-coil-wireless-power-transmitter
Tomi Engdahl says:
https://hackaday.com/2022/03/29/led-kaleidoscope-uses-induction-power-magic/
Tomi Engdahl says:
Wireless power transfer modules (with schematic)
https://www.youtube.com/watch?v=hZ8PqQWyUR8
Some very small modules designed to transfer power wirelessly for battery charging or direct powering of sealed devices. The power transfer is low, but perfectly suitable for low current devices.
Standby current with no load is about 24mA at 5V, so about a tenth of a watt.
For best coupling the antennas have to be close together, so cases should be thin and flat, preferably with an alignment guide.
The reason the normal wireless LEDs wouldn’t light with this coil is due to their tuned LC circuit being optimised for a different frequency. My simple coil with inverse parallel LEDs will work at a wide range of frequencies.
Tomi Engdahl says:
Wireless Charging for EV Taxis Launches in Gothenburg
April 1, 2022
https://www.electronicdesign.com/markets/automotive/article/21237878/electronic-design-wireless-charging-for-ev-taxis-launches-in-gothenburg?utm_source=EG+ED+Analog+%26+Power+Source&utm_medium=email&utm_campaign=CPS220330047&o_eid=7211D2691390C9R&rdx.ident%5Bpull%5D=omeda%7C7211D2691390C9R&oly_enc_id=7211D2691390C9R
Volvo Cars will leverage wireless induction charging pads installed into the pavement. Charging begins automatically when a compatible EV parks over the installed pad, which provides over 40 kW of power.
Charging pads from Momentum Dynamics—whose wireless tech was used in an Oslo taxi charging pilot project a few years ago—were installed in two taxi stands in Gothenburg, Sweden. While Momentum’s technology has been in full commercial use for more than four years on various types of electric vehicles, this program, part of the Gothenburg Green City Zone, will allow a small fleet of fully electric Volvo XC40 Recharge cars to be used as taxis.
Over a three-year period, the small fleet of fully electric taxis will be in service for Cabonline, the largest taxi operator in the Nordic region. Its fully operational taxi environment will include charging wirelessly at taxi stations in Gothenburg, Sweden.
Inductive Charging
The inductive-charging technology to be used is based on the scientific principle of resonant magnetic induction. It promises to provide fast, automated charging for electric vehicles with no moving parts.
“Automated charging provides unlimited driving range for high-intensity driving and our system enables Gothenburg cab drivers to stay in revenue service all day,” said Momentum Dynamics CEO Andy Daga. “We are pleased that the system was integrated by Momentum and Volvo Cars engineers into the fully electric XC40 Recharge so efficiently, even with the difficulties of COVID-19.”
The charging starts automatically when a compatible vehicle parks over a charging pad embedded in the street, allowing drivers to conveniently charge without getting out of their car. To easily align the car with the charging pad, Volvo Cars will use its 360-degree onboard camera system.
For the fully electric XC40 Recharge cars, the wireless charging power will be more than 40 kW. Thus, charging speeds are around 4X faster than a wired 11-kW ac charger and almost as fast as a wired 50-kW dc fast charger.
How Does It Work?
The vehicle side of the wireless-charging system comprises a receiver pad and an electronics module. High-frequency ac is converted to dc, which directly charges the vehicle’s battery. An alternating current is fed into a resonant transmitting coil that creates a magnetic field. The magnetic field is captured by a resonant receiving coil, creating an alternating current in that coil.
The ground side of the wireless-charging system consists of a charging pad installed in the pavement, which is connected to an electronics cabinet. High-frequency ac power is generated by the electronics cabinet and transmitted by the charging pad to the vehicle.
Tomi Engdahl says:
Metasurface Enables High-Efficiency Harvesting of Ambient RF Energy
April 6, 2022
By constructing a resonant metamaterial antenna, researchers have captured and used a meaningful amount of ambient RF energy in the low-gigahertz range of the electromagnetic spectrum.
https://www.electronicdesign.com/power-management/whitepaper/21237735/metasurface-enables-highefficiency-harvesting-of-ambient-rf-energy?utm_source=EG+ED+Analog+%26+Power+Source&utm_medium=email&utm_campaign=CPS220415020&o_eid=7211D2691390C9R&rdx.ident%5Bpull%5D=omeda%7C7211D2691390C9R&oly_enc_id=7211D2691390C9R
Tomi Engdahl says:
Trukkirobotit voi ladata langattomasti
https://etn.fi/index.php/tekniset-artikkelit/13540-trukkirobotit-voi-ladata-langattomasti
Lataus langattomaksi
Langattomaan lataukseen siirtymisen etuna on, että se mahdollistaa sekvenssimuotoisen latauksen (kuva 1) ja lisäksi eliminoi perinteisten laturien kytkentä- ja irrotusvaiheessa syntyvät kipinät. Jaksoittain tapahtuva sekvenssilataus tarkoittaa akkujen varaamista työtehtävien aikana, mikä pidentää AMR-robotin akun käyttöaikaa ja kasvattaa kokonaistyöaikaa.
Magneettiresonanssi avuksi
WPX1000 on TDK:n kehittämä kapasiteetiltaan keskitasoinen 1 kW-luokan langaton teholähdejärjestelmä (kuva 2), joka hyödyntää magneettiresonanssia siirtomenetelmänä. Tämä innovatiivinen tekniikka siirtää tehoa resonanssipiirien kautta, jotka on muodostettu sekä tehonsyötön että vastaanoton puolelle virittämään molemmat puolet resonoimaan samalla taajuudella.
Menetelmän avulla voidaan saavuttaa keloille ±30 mm sallittu siirtymäalue robotin kulkusuunnassa ja 20-40 mm etäisyys tehoa siirtävien kelojen välillä, mikä laajentaa tehonsiirtoaluetta. Järjestelmä kykenee myös reagoimaan kelojen mahdollisiin siirtymiin, ja se on optimaalinen sekvenssimuotoiseen lataukseen.
Koska kelayksikön rakenne on suojattu pölyltä ja vedeltä (IP65) sekä tehonsyötön että vastaanoton puolella, tämä langaton latausjärjestelmä sopii käytettäväksi ankarissakin ympäristöoloissa sekä sisä- että ulkotiloissa. Lisäksi akun lataamisen optimoiva vakiojännite/vakiovirtaohjaus (CV-CC) mahdollistaa akun suoran latauksen, ja sarjaportin (RS-232) avulla latausjännitettä/virtaa voidaan säätää.
Vaihtoehtoinen lataustapa
Magneettiresonanssia hyödyntävän langattoman tehonsyöttöratkaisun lisäksi TDK on kehittänyt myös sähkömagneettisen induktiomenetelmän. Tätä tekniikkaa käytetään ensisijaisesti puettavassa elektroniikassa ja mobiililaitteissa. Yhtiö on kaupallistanut siihen perustuvia langattomia latausjärjestelmiä mobiililaitteille ja keskitehoisia järjestelmiä teollisuuslaitteisiin.
TDK kehittää myös suuritehoisia tehonsyöttöjärjestelmiä sähköautoja/PHEV-ajoneuvoja varten (kuva 3). Laajan tuotevalikoiman ytimenä on ferriittiteknologia, joka on yhtiön koko tuotannon perusta. Ferriitti on tehonsyöttö- ja vastaanottokelojen ydinmateriaali, jonka ominaisuudet vaikuttavat merkittävästi langattoman latausjärjestelmän siirtotehokkuuteen.
Tomi Engdahl says:
https://www.hackster.io/news/when-will-wireless-power-transfer-redefine-the-industrial-iot-f4326b07daa8