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New Electric Motor Could Boost Efficiency of EVs, Scooters, and Wind Turbines

spectrum.ieee.org

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Re: New Electric Motor Could Boost Efficiency of EVs, Scooters, and Wind Turbines

#41

Post by pjc50 »

phkahler wrote: post #32
MobileVet wrote: post #16

These guys have definitely spent some money on PR since closing their investment round in April. They have placed 4+ articles with many of the same talking points, pictures and video over the last 2 weeks: https://www.cnet.com/roadshow/news/linear-labs-electric-turb... https://jalopnik.com/a-texas-startup-claims-to-have-made-the... https://newatlas.com/linear-labs-hunstable-electric-motor/60... https://insideevs.com/…

And they don't really have anything useful. Their claims dont make any sense to someone in the field. Now I have to file ieee spectrum under "willing to pedal bullshit for money" like so many other publications.

It's probably not even money: it's just a reprinted press release. Once you know the style, it becomes obvious just how many articles everywhere about a new development from company X are just prints of company X's press release with some mild rewording.

It's mostly harmless; companies need to be able to announce products somewhere.

Re: New Electric Motor Could Boost Efficiency of EVs, Scooters, and Wind Turbines

#45

Post by mikepurvis »

jacquesm wrote: post #14
mikepurvis wrote: post #12

Earlier quoted context omitted.

50% range increase would be a huge boon to a vehicle like a Boosted Board. My V2 throws off a lot of heat and gets nowhere near the advertised 11km range.

> My V2 throws off a lot of heat and gets nowhere near the advertised 11km range. Heat losses come in many forms: - resistive losses in wiring - resistive losses in the batteries themselves (their Ri is nowhere near zero) - switching losses in the powertrain - slip losses between the field and the rotor If a piece of gear does not get its 'advertised performance' that can mean a defective product, deceptive advertisi…

It probably would go 11km on a straight and level run with no stopping for traffic lights or anything else. It's just that that's not realistic in an urban commute setting.

I don't feel cheated, I'm just saying that even a modest bump in efficiency could make a big difference to this kind of vehicle, especially if affected both the propulsion and regen side of things.

Re: New Electric Motor Could Boost Efficiency of EVs, Scooters, and Wind Turbines

#46

Post by magduf »

hinkley wrote: post #28
jacquesm wrote: post #4

10% is nothing to sneeze at but it also does not mean it is a game changer. I like the way the coil ends are described, they are 'dead' weight in a normal motor because they don't contribute to the flux but they do contribute to the resistive losses in the motor. But that 10% of the length of the winding that sits outside of the coil chambers is not responsible for 10% of the electric consumption of the motor, which…

My take was the transmission, DC-DC converter, and 10% efficiency gain were essentially the same conversation. Transmissions and converters all result in transmission losses. They're also more components to purchase, install, and maintain. So if they can build a motor that embodies some of those qualities, that's an improvement, even if the resulting motor were slightly less efficient (which they say is not the case)…

You can't run an electric car on straight battery voltage, unless you want the car to go a single speed. So you have two choices: DC-AC conversion to run a 3-phase AC motor, or DC-DC conversion to run a DC motor at variable voltage. Either one is going to have similar losses with modern power electronics.

Re: New Electric Motor Could Boost Efficiency of EVs, Scooters, and Wind Turbines

#47

Post by jacquesm »

fyfy18 wrote: post #37
hinkley wrote: post #28

Earlier quoted context omitted.

My take was the transmission, DC-DC converter, and 10% efficiency gain were essentially the same conversation. Transmissions and converters all result in transmission losses. They're also more components to purchase, install, and maintain. So if they can build a motor that embodies some of those qualities, that's an improvement, even if the resulting motor were slightly less efficient (which they say is not the case)…

The loses from AC/DC conversion must be pretty low. A typical solar installation with battery backup (e.g. Powerwall 2) would convert from DC to AC in the solar inverter, AC to DC when charging the Powerwall, DC to AC when discharging the Powerwall, then AC to DC when charging your electric car (and as you say, most likely DC to AC when driving it). The original Powerwall was DC, so they must have run the numbers and…

> The loses from AC/DC conversion must be pretty low.

For most applications on the order of 2-4%.

Re: New Electric Motor Could Boost Efficiency of EVs, Scooters, and Wind Turbines

#48

Post by hinkley »

magduf wrote: post #46
hinkley wrote: post #28

Earlier quoted context omitted.

My take was the transmission, DC-DC converter, and 10% efficiency gain were essentially the same conversation. Transmissions and converters all result in transmission losses. They're also more components to purchase, install, and maintain. So if they can build a motor that embodies some of those qualities, that's an improvement, even if the resulting motor were slightly less efficient (which they say is not the case)…

You can't run an electric car on straight battery voltage, unless you want the car to go a single speed. So you have two choices: DC-AC conversion to run a 3-phase AC motor, or DC-DC conversion to run a DC motor at variable voltage. Either one is going to have similar losses with modern power electronics.

Couldn't you though?

This motor has 48 coils, and the ability to change what order and groupings they get powered. Doesn't that change the current substantially without altering voltage? I don't think you would ever run one coil alone, but that leaves at least 9 other patterns where all coils fire evenly.

And what is 'battery voltage'? Battery voltage is something like 2.8 volts, and that's not consistent across all cells at all levels of charge. Any voltage higher than that is due to composition. From what I recall, recharging multiple cells in series leads to some pretty big problems when some of the cells are aging faster than others. Being hard-wired is not a given.

With 48 coils on the motor and a battery pack of 120 or more cells, there are a lot of voltages and currents you could run through the system by reconfiguring instead of inverting.

Re: New Electric Motor Could Boost Efficiency of EVs, Scooters, and Wind Turbines

#49

Post by magduf »

hinkley wrote: post #48
magduf wrote: post #46

Earlier quoted context omitted.

You can't run an electric car on straight battery voltage, unless you want the car to go a single speed. So you have two choices: DC-AC conversion to run a 3-phase AC motor, or DC-DC conversion to run a DC motor at variable voltage. Either one is going to have similar losses with modern power electronics.

Couldn't you though? This motor has 48 coils, and the ability to change what order and groupings they get powered. Doesn't that change the current substantially without altering voltage? I don't think you would ever run one coil alone, but that leaves at least 9 other patterns where all coils fire evenly. And what is 'battery voltage'? Battery voltage is something like 2.8 volts, and that's not consistent across all…

>This motor has 48 coils, and the ability to change what order and groupings they get powered.

Ok, great, so now you have a bunch of discrete speeds you can run the motor at. How smooth a ride do you think that's going to provide?

If you can't run a motor at any arbitrary speed within its range, it's useless for any kind of vehicle.

>And what is 'battery voltage'? Battery voltage is something like 2.8 volts

No, that's cell voltage. A battery is a group of cells. That battery in your car that produces 12V is a group of 6 cells each producing 2V, with the cells all connected in series. As I understand it, Tesla batteries are rather high-voltage.

>From what I recall, recharging multiple cells in series leads to some pretty big problems when some of the cells are aging faster than others.

Yet somehow it works just fine for car batteries over the last 100 years, and for most every other battery we use these days (laptops, etc.).

>With 48 coils on the motor and a battery pack of 120 or more cells, there are a lot of voltages and currents you could run through the system by reconfiguring instead of inverting.

Yeah, again, if you just want to run at various discrete speeds. How many people are going to want a herky-jerky car like that?

Re: New Electric Motor Could Boost Efficiency of EVs, Scooters, and Wind Turbines

#50

Post by hinkley »

magduf wrote: post #49
hinkley wrote: post #48

Earlier quoted context omitted.

Couldn't you though? This motor has 48 coils, and the ability to change what order and groupings they get powered. Doesn't that change the current substantially without altering voltage? I don't think you would ever run one coil alone, but that leaves at least 9 other patterns where all coils fire evenly. And what is 'battery voltage'? Battery voltage is something like 2.8 volts, and that's not consistent across all…

>This motor has 48 coils, and the ability to change what order and groupings they get powered. Ok, great, so now you have a bunch of discrete speeds you can run the motor at. How smooth a ride do you think that's going to provide? If you can't run a motor at any arbitrary speed within its range, it's useless for any kind of vehicle. >And what is 'battery voltage'? Battery voltage is something like 2.8 volts No, that'…

My point is it could be done, and these guys specifically claimed they don't need a DC-DC converter, so either they're lying, or there's something you and I don't understand. I'm just speculating on ways they could solve that problem.

And you're giving so much salt back that I have to ask, do you believe they are lying? If so then don't beat around the bush. Just say it. You think they are frauds.

> Yet somehow it works just fine for car batteries over the last 100 years, and for most every other battery we use these days (laptops, etc.).

Every time I've replaced my car battery, it's been because one cell failed after I let it deep discharge. Except once where 2 cells failed.

I thought Tesla did something more sophisticated with their packs, but I'm looking at a picture here and there are for sure ~40 cells wired in series. At best there are 4 batteries per array (or they may be connected on the back side). But you don't have to use that bus architecture. It's mechanically simpler and more robust. It's the default. But it's a compromise, favoring physical robustness for reduced chemical robustness. Some day I hope to see other solutions, perhaps like what I described.

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