Gravity DC to DC Boost using Rear Motor for Fast Charging from 500V Chargers

[Adnillien]

Can you elaborate a bit on the use of the rear motor to boost the DC? Physically, how is that accomplished?

I thought it would be better to create a new thread for this since it is Gravity technology rather than deliveries.

A basic DC to DC boost circuit requires an inductor, a switch and a smoothing capacitor. The circuit works by taking advantage of the property of an inductor where its voltage will rise as it tries to maintain a constant current. The switch is used to change the current through the inductor and thereby increase the voltage across the inductor. The switching frequency controls the amount of voltage boost. The smoothing capacitor helps make the output voltage constant so that it can be used for battery charging.

The stator of an electric motor is a large inductor, the motor inverter is multiple switches. Hence, most of the components for the DC to DC converter are already part of the motor. Lucid was issued patent US10505455B1 on Dec 10 of 2019 for this DC to DC boost methodology. A figure from their patent helps illustrate how it works. Contactor1 bypasses the motor boost circuit for high voltage chargers, Contactor2 engages the motor as a boost circuit. The advantage of having three stator windings is that currents can be interleaved and phased to minimize motor torque and reduce ripple on the boosted voltage.

 

[BS8899]

I thought it would be better to create a new thread for this since it is Gravity technology rather than deliveries.

A basic DC to DC boost circuit requires an inductor, a switch and a smoothing capacitor. The circuit works by taking advantage of the property of an inductor where its voltage will rise as it tries to maintain a constant current. The switch is used to change the current through the inductor and thereby increase the voltage across the inductor. The switching frequency controls the amount of voltage boost. The smoothing capacitor helps make the output voltage constant so that it can be used for battery charging.

The stator of an electric motor is a large inductor, the motor inverter is multiple switches. Hence, most of the components for the DC to DC converter are already part of the motor. Lucid was issued patent US10505455B1 on Dec 10 of 2019 for this DC to DC boost methodology. A figure from their patent helps illustrate how it works. Contactor1 bypasses the motor boost circuit for high voltage chargers, Contactor2 engages the motor as a boost circuit. The advantage of having three stator windings is that currents can be interleaved and phased to minimize motor torque and reduce ripple on the boosted voltage.


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Thank you for the insight and tutorial.

If I interpret your tutorial correctly,

> if the DCFC is capable of 1000V, Contactor 1 and Contactor 3 will close and charge the batteries directly.
> if the DCFC voltage is say, 500V, Contactor 2 (and contactor 3) will close. The DCFC current flows through the (3) motor windings (phased), acting as inductors to boost the voltage, and, them combined and filtered by CDC to generate a "slightly rippled" DC to charge the batteries.

Did I interpret it correctly?

Very clever!

 

[Adnillien]

Thank you for the insight and tutorial.

If I interpret your tutorial correctly,

> if the DCFC is capable of 1000V, Contactor 1 and Contactor 3 will close and charge the batteries directly.
> if the DCFC voltage is say, 500V, Contactor 2 (and contactor 3) will close. The DCFC current flows through the (3) motor windings (phased), acting as inductors to boost the voltage, and, them combined and filtered by CDC to generate a "slightly rippled" DC to charge the batteries.

Did I interpret it correctly?

Very clever!

Yes you are correct.

 

[BS8899]

Yes you are correct.

Does this approach "infringe" on (or plagiarize-from) the original (historical) "Tesla Coil"?

Don't take my comment seriously, it is a pun on history!

 

[Elfin]

How is this different than the E-GMP (Hyundai) system?

 

[Adnillien]

How is this different than the E-GMP (Hyundai) system?

From what I can tell, the Hyundai system is very similar.

 

[TahoeMichael]

How is this different than the E-GMP (Hyundai) system?

Assuming there's also a patent for the Hyundai system, you'd have to carefully read the claims to figure out what the unique "secret sauce" is of each approach. The main body of the patent describes how an invention works, and includes both whatever prior art and new invention is needed for the mechanism. The claims are specific to just what the new invention is. For these kinds of things, it's quite common for the bulk of a mechanism to be prior art, with just a few unique tweaks being the novel invention.

 

[Elfin]

Assuming there's also a patent for the Hyundai system, you'd have to carefully read the claims to figure out what the unique "secret sauce" is of each approach. The main body of the patent describes how an invention works, and includes both whatever prior art and new invention is needed for the mechanism. The claims are specific to just what the new invention is. For these kinds of things, it's quite common for the bulk of a mechanism to be prior art, with just a few unique tweaks being the novel invention.

Here is the circuit from Hyundai's patent. I think it's identical except for the placement of R3 which makes no functional difference.

US20200361323A1 - Multi-input charging system and method using motor driving system - Google Patents

A multi-input charging system and a multi-input charging method using a motor driving system can promptly compulsorily discharge a high charging voltage formed in a neutral point capacitor forming a neutral point voltage in a charging process and formed in a DC capacitor between an inverter and...

patents.google.com

 

[TahoeMichael]

Here is the circuit from Hyundai's patent. I think it's identical except for the placement of R3 which makes no functional difference.

...

The diagram doesn't really tell you anything about what's being patented. I don't have time to give the patents a full read right now, but a cursory look at the 1st claim of each patent seems to indicate that they claim almost exactly the same thing, with the key addition in the Hyundai patent (which came after the Lucid patent) is that that the neutral point capacitor will be drained once charging is complete. Welcome to the world of patents, where even tiny things can make the difference in what is covered and what is not.

Hyundai makes 18 total claims, all of which are expansions off the initial first claim. Lucid makes 20 total claims, with 3 independent claims in claim numbers 1, 12, and 17, and the rest being expansions of those three separate base claims. The three base claims are all relatively small variations of the fundamental idea. Doing that is pretty common when patents are drafted, because something doesn't infringe unless it does everything in the claim, and you specify a few minor variations to try and make it hard to work around the patent.

I could read more to tease out what else is going on with the patents. But really, you probably need someone with more expertise in power electronics than I have to understand what's been invented here. I'm an engineer, and have a lot of familiarity with how patents work, but this is not at all my field.

 

[borski]

Lucid’s solution shares similarities with the Hyundai solution. However, it’s a different architecture with significantly higher power output and better smooth current control and stability. Lucid filed this patent in 2018 and it was published in 2019, before any patent from Hyundai as far as I can tell. As a smaller player, I can pretty much guarantee Lucid has no interest in litigating against Hyundai, especially given the rumors of a potential eventual partnership.

 

[Adnillien]

Lucid’s solution shares similarities with the Hyundai solution. However, it’s a different architecture with significantly higher power output and better smooth current control and stability. Lucid filed this patent in 2018 and it was published in 2019, before any patent from Hyundai as far as I can tell. As a smaller player, I can pretty much guarantee Lucid has no interest in litigating against Hyundai, especially given the rumors of a potential eventual partnership.

Patents like these are protection from patent trolls and rarely used to litigate against others in the industry.

 

[borski]

Patents like these are protection from patent trolls and rarely used to litigate against others in the industry.

Right, totally agreed. I’ve got 8 patents to my name, and we’ve litigated precisely 0 of them, and likely never will. But VCs liked seeing them, and they were quite good protection against patent trolls.

Plus, we did actually have one case of a direct copy by a competitor, so we did send them a C&D, and that was the end of that.

 

[OCDC]

Anyone know if this tech is used in the Air? My weird brain is making the connection between this mechanism and the brief shudder that happens when the car is fast charging.

 

[borski]

Anyone know if this tech is used in the Air? My weird brain is making the connection between this mechanism and the brief shudder that happens when the car is fast charging.

It is not.