Next Prius Gen2 "ECU"

[johu]

I am slowly running out of stock on the Prius Gen2 inverter controller and to be honest it has never been a top seller. I now consider respinning it because the Gen2 is just such an awesome device. Here's what I thought:

- Base board that takes 1 or 2 mini mainboards to be able to control one or both inverters
- Better control of the various enable signals, including the DC/DC converter for more straight forward use
- ESP32 chip that talks to both mainboards

Now I'm dwelling over the best enclosure to use. The current one (Cinch ME) has the neat random feature that the bolt pattern is identical to that of the lid fasteners on top of the MG2 phase outlet:

The 40 pin version might offer enough pins but I haven't really gone over it.
Apart from that availability is poor and price is high. OH! And certainly it doesn't offer enough space for two mini mainboards

The Zombieverter enclosure would be another option. Apparently it can be had for 30€ but I only ever find it on Aliexpress. If I were to go for that I'd probably sell it without enclosure because they are bulky to stock. I was only given one half of our living room shelve for storage

Any input appreciated. Will be a winter project I guess.

[Ev8]

I love the gen2 inverter and plan to use more in the future, I like the idea of 2 boards sharing one esp32, currently im re using an old Bosch enclosure, as I couldn’t find a suitable new enclosure

[Jacobsmess]

What is particularly good with regards to the gen2 over other options?

[MattsAwesomeStuff]

What is particularly good with regards to the gen2 over other options?

https://openinverter.org/wiki/Toyota_Pr ... 2_Inverter

[MattsAwesomeStuff]

As with anything DIY, selling comes down to polish polish polish. This versus feature creep being the death of any successful project.

The more of a "buy me and your problems are solved" something is, and less of a "buy me and then figure the rest out", the more in demand it'll be. You have to presume that anyone using it cannot write software and cannot design hardware. It needs to be well documented, and well spelled out for people.

Honestly, I've heard lots of people still just wanting a plain DC controller and waiting on EV8's or Damien's or anyone to get around to that Gen 2 project too.

One thing I've noticed is that there just isn't much demand for FWD EVs.

The limited usability of the Gen2 (versus Gen3?) for charging certainly limits its prospects, though I suspect Damien all but never sells his Gen3 hardware either (not that it has charging available either).

[johu]

Yes much agreed. I modded the inverter and controller quite heavily to be able to charge reliably. Of course a controller can't take all of that away but it can be facilitated.

Mods for single phase boost charging:
- Swapped input and output of the buck/boost stage
- Removed 4 IGBTs of the A/C inverter and replaced them with a bridge rectifier (maybe making sure the gates are permanently low achieves the same)
- Fitted a current sensor to the cable going from said A/C inverter into the input of the boost converter to be able to measure charge current
- Disabling that current sensor with a relay while NOT charging
- Connected GSDN to the DC switch signal

What is particularly good with regards to the gen2 over other options?

It's the Hilux of inverters, virtually invincible unless I start mucking around with it

[RetroZero]

I personally find this a very interesting idea and lots has been learned from the Prius Gen2 setup.
I have a 2nd adapter board waiting to go in for dual motor setup.
Where I live, homebrew EV is a no-go, so I am doing this as a potential professional project, learning as much as I can from this 'basic and robust' set-up. A few things to note, especially if you are in a country where weight distribution and total weight are essential.
The Prius setup is too bulky for a small fwd as any battery modules need to be in the rear. Johu's A2 setup will not work here. Too bulky and heavy for 60-70kW when in dual motor mode (to be tested at full 380v battery pack voltage). If in MG2 mode, it's even worse as you're lugging about MG1 and it's all about weight from where I am.
If the inverter were to be placed next to the transaxle, then it becomes interesting, but again, small fwd solutions with original gearbox is the way forward in terms of a simple, repeatable solution, like the Leaf solution (in my opinion) as the transaxle is complicated to locate (especially in a golf MK1).
So I am already looking at where this great setup could be best used - I think light commercial is the way to go - VW Caddy, Renault Kangoo, Nissan NV200 and older fwd minivans circa 1970's from Peugeot and Citroen....or light rwd with enough ground clearance....
Whilst the inverter being used as a charger is a great solution, which thanks to Johu I have been using a few times, having to modify components opens us up for questionable reliability and safety when presenting to your local authorities.
I'm putting in an onboard OEM charger to solve that issue, so hopefully more to come from my project in next few months.

[Ev8]

Possibly an aux pwm output could be useful

[arber333]

Possibly an aux pwm output could be useful

Yes to send output RPMs to dash. But it should be selectable either const freq variable duty pwm or variable freq fixed duty pwm.

[johu]

Hmm.... The Prius board doesn't have the over current comparator so I could indeed use the free timer for variable frequency PWM

[arber333]

Hmm.... The Prius board doesn't have the over current comparator so I could indeed use the free timer for variable frequency PWM

That could either drive RPM indicator with true RPM function or use the same indicator to show inverter DC Amp draw.
Hm... or it could process CAN bus SOC information from sensor such as ISA to show fuel status using original fuel dial.

[0tik]

It's the Hilux of inverters, virtually invincible unless I start mucking around with it

I know that nobody asked or wants to know but I can't keep thinking about how high of a voltage can stock Prius 2 car take before failing. The way the car handles NiMH is wild and one source says it can go up to 302v(with cells at low soc I bet)!

[RetroZero]

Depends, the 'battery' is a glorified accumulator. It stores energy quickly and uses it up just as fast. Voltage before Inverter, as in battery pack voltage is around 200vdc. The inverter buck/boost controls voltage in and out if it, from what I worked out. Damien made a video showing the voltage after the buck/boost converter, as in Bus Voltage to be as high as 500vdc! From what I understand, the Prius handles about 100 amps for mg2 (50kW) and
55 amps for mg1(30kW) max at these voltages.
If we want to keep to standard EV battery pack voltages around 380vdc, there won't be any problems on the HV bus side. However, the buck/boost converter must be bypassed. Total kW is also compromised, but it's still good for a comfortable 55 kW from my guesstimation.

[Jacobsmess]

Depends, the 'battery' is a glorified accumulator. It stores energy quickly and uses it up just as fast. Voltage before Inverter, as in battery pack voltage is around 200vdc. The inverter buck/boost controls voltage in and out if it, from what I worked out. Damien made a video showing the voltage after the buck/boost converter, as in Bus Voltage to be as high as 500vdc! From what I understand, the Prius handles about 100 amps for mg2 (50kW) and
55 amps for mg1(30kW) max at these voltages.
If we want to keep to standard EV battery pack voltages around 380vdc, there won't be any problems on the HV bus side. However, the buck/boost converter must be bypassed. Total kW is also compromised, but it's still good for a comfortable 55 kW from my guesstimation.

Pretty sure Damian for 350A out of mg2 and 230A out of mg1 before the inverter shut down on his stress tests of the inverter. Once you bypass the boost stage you can get much higher power outputs as it's the boost stage that actually limits this. Also efficiency is much higher when bypassing the boost stage.

[MattsAwesomeStuff]

As the main proprietor of the Gen 2 wiki page, there's lots of this stuff that is ... I don't know the word for it. It's kind of known, but there's multiple ways of interpreting it, and nothing's really concrete or ever explained well. The page would be well served by anyone with a confident grasp of the limits explaining them in a introductory manner.

[jrbe]

As the main proprietor of the Gen 2 wiki page, there's lots of this stuff that is ... I don't know the word for it. It's kind of known, but there's multiple ways of interpreting it, and nothing's really concrete or ever explained well.

Tribal knowledge. It's also hard to document from someone said on the internet to safe, realistic, reliable info into a wiki. Testing and sharing the tests, specs, and results helps with this a lot.

It would be great to crowdsource these efforts with something like the report button but have it be a marker for wiki info. Not sure that's doable though. Maybe a wiki icon?

[turnip73]

- Removed 4 IGBTs of the A/C inverter and replaced them with a bridge rectifier (maybe making sure the gates are permanently low achieves the same)

Very interesting that it might be possible to use the A/C inverter for charging without modification.

[johu]

Where can I find a KiCAD footprint for that 56-pin connector? None of the designs that use it seems open

[turnip73]

@johu let me know if you need any help with testing, OEM logs/values or anything else. I plan to try the A/C inverter for charging without modification and external rectifier.