GS450h Buck/Boost Converter control

Topics concerning the Toyota and Lexus inverter drop in boards
xp677
Posts: 435
Joined: Sat Jul 27, 2019 10:53 am
Location: UK
Has thanked: 1 time
Been thanked: 13 times

Re: GS450h Buck/Boost Converter control

Post by xp677 »

celeron55 wrote: Wed Jun 03, 2020 4:40 am
xp677 wrote: Tue Jun 02, 2020 10:35 pm Also note that this is not the first time I've seen a converter with the appearance of this failure.
...
or I was just unlucky and have had a faulty converter all along!
So has there been another case of this or not?
I saw one for sale with the same damage, from a GS. Which is why I said "appearance of this failure". This gives credit to the thought that it may be a fault with the unit rather than the method - if the same thing has happened in OEM use.
User avatar
drprox
Posts: 28
Joined: Sat Mar 07, 2020 12:50 pm
Location: England

Re: GS450h Buck/Boost Converter control

Post by drprox »

I would be interested to know if anyone has had long term success using this method.

The 330CI project which started off the GS450h trend did use the buck/boost converter for both charging (boost) and for powering the DC/DC (buck). The guy didn't report any long term issues but there was no detail on the method used.

Is there any context to the mods and what they are for? E.g Are we breaking the tracks from the original MCU control to insert our own? What happens if you do no mods, does it just buck down to 288v all the time? (This is what I actually want).
xp677
Posts: 435
Joined: Sat Jul 27, 2019 10:53 am
Location: UK
Has thanked: 1 time
Been thanked: 13 times

Re: GS450h Buck/Boost Converter control

Post by xp677 »

The modification to the PCB is to provide a ground path to the converter control PCB, this was previously switched via the MCU on the inverter board.

The 330Ci project had it's replacement MCU wired to the back of the PCB connector. It would be impractical to find and cut traces in that location. If traces needed cutting, a better option would be to cut and splice into the wiring harness.

Damien is doing a similar control setup on Prius converters right now. The IPM for those looks to be similar to the GS, likely the same/similar control setup.

I am unsure what caused the failure of my unit, having spoken to several electrical engineers about it, it was decided that the most likely cause was one IGBT failing short, allowing a path to ground when the other IGBT was triggered. The cause of this is unknown, the Toyota logic boards prevent this and should have detected the issue. The failure could be as simple as a routine failure of the unit - this was a junkyard inverter, after all.

I know that Damien & others in the Prius "cant kill an inverter" thread was looking into ringing within the inductor, and investigated adding deadtime to the two PWM signals to the IPM, however I don't know if that is relevant for this unit.

What I do know is that the wiring and code posted in this thread does work. For simple bucking to 288V the code could be simplified.

The main issue found with the code is that any cycle which includes serial writes (for diagnostic output) increases the cycle time for the code, which can allow the output voltage to rise or fall further than expected. I'd recommend using minimal diagnostic output during testing.

The important thing to take from this, is that the internal inverter <> converter bus bars should not be used, and instead a separate, fused power feed to the converter should be supplied. My inverter failed short, pulling 350A at 630V, if I had added a 20A fuse, I could have saved the converter.
User avatar
drprox
Posts: 28
Joined: Sat Mar 07, 2020 12:50 pm
Location: England

Re: GS450h Buck/Boost Converter control

Post by drprox »

Thank you for this information, it helps my understanding.

Do you know if the converter requires the main DC link capacitor?

I think it will be easier to supply the converter via a separate fused feed than to try and splice a fuse in-line with the original busbars. How did / would you do that?
I only need around 1kW max, so at 600v we are talking a few amps, though for that voltage the fuse is still not particularly small.


Also, how does the buck converter work under no load conditions - is there a static load built-in to keep it stable or is there a risk of it just rising to full DC voltage and blowing up?
User avatar
mfox
Posts: 146
Joined: Fri Apr 05, 2019 9:56 pm
Location: Croatia
Been thanked: 2 times

Re: GS450h Buck/Boost Converter control

Post by mfox »

Is it possible phisicaly remove buck-bost converter from inverter (wich is used to run drivetrain). Or both are using the same PCB, so is not possible ... just on diferent sides..
TNX
User avatar
arturk
Posts: 146
Joined: Wed Oct 02, 2019 3:58 am
Location: United States, MD
Has thanked: 1 time
Been thanked: 2 times

Re: GS450h Buck/Boost Converter control

Post by arturk »

It is possible to physically remove electronic components of the inverter such as PCB, Capacitor, Inductor, IGBTs.
However both: Inverter and Converter share "cold plate".

Good info and pictures here:
https://www.osti.gov/biblio/928684-eval ... ive-system

I wonder why you ask.
I was contemplating separating both at some point to make Inverter smaller since I have no need for Converter but it seems to much hassle but not impossible.
It is definitely recommended to disconnect HV bus bars between two.
1998 Jaguar XJR, GS450h drivetrain, 48kWh/96s BMW battery
xp677
Posts: 435
Joined: Sat Jul 27, 2019 10:53 am
Location: UK
Has thanked: 1 time
Been thanked: 13 times

Re: GS450h Buck/Boost Converter control

Post by xp677 »

You can easily remove all the converter components other than the inductor (which is potted).

The space left behind is a nice spot for a DC junction box or even just a HV fuse or whatever.

I was thinking of maybe looking at designing an alternate VCU which could mount where the converter hardware used to live, and wire through to the inverter PCB. This would give an "all in one" solution. But then I figured it just changes which connections you need to the outside world, and doesn't really help all that much in the end.
User avatar
mackoffgrid
Posts: 93
Joined: Thu Jan 02, 2020 10:18 am
Location: Brisbane Australia
Has thanked: 4 times

Re: GS450h Buck/Boost Converter control

Post by mackoffgrid »

xp677 wrote: Sat Feb 15, 2020 5:31 pm
To complement the work on the GS450h inverter, here is the control method for the 30kW Buck/Boost converter.

I control this converter using a bare Arduino Nano mounted to the inverter control PCB.

The following pins need to be connected (for the attached sketch)
  • +5v
  • GND
  • HV Voltage Read (A0)
  • LV Voltage Read (A1)
  • PWM High (D6)
  • PWM Low (D5)

XP677,

Because of this project / Topic I have been able to fill many gaps in the pinout information of a GS450/Camry breakout board I'm putting together. So I have included your Nano project into the breakout board-
https://github.com/mackelec/LexusGS450_ ... r_Breakout
I hope this in both Correct and interesting.
https://github.com/mackelec/SolarUte
meFDCAN Arduino Library 3 FDCAN port stm32G4xx
meCAN Arduino Library 2023 version 2/3 CAN port stm32F0xx, stm32F1xx, stm32F4xx, stm32L4xx
xp677
Posts: 435
Joined: Sat Jul 27, 2019 10:53 am
Location: UK
Has thanked: 1 time
Been thanked: 13 times

Re: GS450h Buck/Boost Converter control

Post by xp677 »

Nice work!
TonyV
Posts: 87
Joined: Sat Nov 14, 2020 9:00 pm
Location: Toronto
Has thanked: 1 time
Been thanked: 8 times
Contact:

Re: GS450h Buck/Boost Converter control

Post by TonyV »

I'm about to embark on my EV conversion soon and been collecting some parts but, I've been reading alot about charging EV batteries using the 450h inverter,(and I must say I'm more confused then ever 8-) ), question is, to charger the batteries do we need another inverter to charge the batteries or do we use the one that drives the MG1 and MG2 and somehow convert it to charge the battery?
If its the later is there a wiring diagram?

Thanks in advance for your time.
I'll figure this out sooner or later
User avatar
ggeter
Posts: 133
Joined: Wed Nov 18, 2020 1:56 pm
Location: Houston, TX
Has thanked: 4 times
Been thanked: 15 times

Re: GS450h Buck/Boost Converter control

Post by ggeter »

mackoffgrid wrote: Sun Oct 18, 2020 8:13 am
Because of this project / Topic I have been able to fill many gaps in the pinout information of a GS450/Camry breakout board I'm putting together. So I have included your Nano project into the breakout board-
https://github.com/mackelec/LexusGS450_ ... r_Breakout
I hope this in both Correct and interesting.
mackoffgrid, do you have experience or recommendations to run the GS450h transmission and do charging and dc/dc with the Camry or GS450h inverter?
Houston, Texas, USA
EV Newbie
1979 MG Midget + GS450h = "Mexus?"
IT Consultant
Dilbert
Posts: 410
Joined: Mon Aug 12, 2019 7:21 pm
Location: Dublin, Ireland
Been thanked: 4 times

Re: GS450h Buck/Boost Converter control

Post by Dilbert »

Outlander charger and dc to dc is cheap and readily available, not worth doing a diy if you can source one of them
User avatar
mackoffgrid
Posts: 93
Joined: Thu Jan 02, 2020 10:18 am
Location: Brisbane Australia
Has thanked: 4 times

Re: GS450h Buck/Boost Converter control

Post by mackoffgrid »

I made that breakout for other purposes but added the boost control because I could. I've not had any chance to power this board up because of other projects :D

So I'm sorry I can't advise, but Dilbert makes good sense - I'd like to get a outlander charger but they are not so cheap in Oz.
https://github.com/mackelec/SolarUte
meFDCAN Arduino Library 3 FDCAN port stm32G4xx
meCAN Arduino Library 2023 version 2/3 CAN port stm32F0xx, stm32F1xx, stm32F4xx, stm32L4xx
Jacobsmess
Posts: 441
Joined: Thu Mar 02, 2023 1:30 pm
Has thanked: 226 times
Been thanked: 55 times

Re: GS450h Buck/Boost Converter control

Post by Jacobsmess »

Out of curiosity has there been any more developments with this?
Post Reply