Sujet : A couple of problems with EV charging roads?
De : uucp (at) *nospam* crashelex.com (Crash Gordon)
Groupes : sci.electronics.designDate : 02. Jun 2024, 18:32:25
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <v3iab9$3efsn$1@dont-email.me>
User-Agent : Mozilla Thunderbird
I've seen a couple of articles about roads with embedded inductive charging for EVs. And there are a couple of issues that seem to me to make these roads unfeasible. (I'm not even going to get into any of the financial side)
My qualifications: I have a few decades experience in circuit design and have had the word "Engineer" in my job title at several different employers, but never went to college. So I have a lot of "wisdom-through-experience" but there are a lot of holes in my basic knowledge -- I tend to know a lot about the things I know, but nothing at all about other closely related things. So I am quite willing to accept that there's stuff going on here I simply don't understand. Feel free to educate me. Moving along...
First: Inductive charging is basically building a transformer where the primary is in one device (in this case, the road surface) and the secondary is in a different device (here, an EV). Ordinarily when we design transformers, we take great care to maximize the coupling between the primary and secondary because loose coupling is responsible for much of the loss in transferred power.
But in charging an EV there is necessarily going to be a considerable air gap between the primary and the secondary. Although we can optimize in other areas to account for this somewhat, it seems to me that there's going to be a lot of energy lost here, mostly as heat radiated into the air.
Second: In order to transfer significant energy, there's going to have to be some significant coupling of magnetic fields between the EV and the road. Wouldn't this be a source of substantial drag? Effectively the car would be driving "uphill" the whole time it's charging.
My thought is that if we're going to be shoveling huge amounts of electricity into a road surface, we could use it more efficiently by building a giant linear actuator with the EV as the moving part.
Opinions?
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