EV Conversion using prius gen 2 inverter/transaxle

Topics concerning the Toyota and Lexus inverter drop in boards
voti
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EV Conversion using prius gen 2 inverter/transaxle

Post by voti »

Hello everyone!
I'm excited to join this forum and connect with fellow EV enthusiasts and professionals. I'm currently working on
an EV conversion using a Gen 2 Toyota Prius transaxle].

pin 9 (start) and 10 (brake) from the VCU are said to be connected to positive side of the i9 connector right.

My question: is pin 9 and 10 also connected to the positive side of the 12v supply?
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by RetroZero »

Great to see another Gen 2 build starting. Looking back to the diagram, 12 supply to start switch and brake switch. When they are activated, they provide 12v signals on each pin for start and brake.

https://openinverter.org/wiki/File:VCU_ ... 2_v1.1.png
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by voti »

Thank you fc or the warm welcome Retro.

I've managed to supply 12v to all the 12v input and when I turn it on I here a hissing sound from the inverter.

I've done all the connections correctly "so I assume" but the inverter is not giving out 3 phase output.

Below I've attached pictures of the input high DC input (67.6 DC ) and the web Interface settings.
Please help me check what might be wrong.
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by RetroZero »

Thanks for the photos. So from the steps doculented in the wiki, from where does it not work?
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by RetroZero »

https://openinverter.org/wiki/Toyota_Pr ... Controller

Basically, do you get stuck at point 9?
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by voti »

Yes sir , I can't get pass that stage
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by voti »

Can it be that I connected 55w light bulb in delta instead of 21w ?.

Besides that I used a multimeter to test phase to phase but nothing.

After putting in all the settings for step 9 I clicked on "start inverter in manual mode" and I saw underneath written "inverter started". But still nothing
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by RetroZero »

Can't see my reply, so will resend. I think 3X21w bulbs would be a good start. That way we're staying with the "standard" set-up. I think you said somewhere that parts were removed from the inverter prior to buying it. Could you post some more photos pls.
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by voti »

No no. No parts were removed prior to buying it.

Besides the light bulbs for testing, I tested the three phase output phase to phase to see if I was getting any readings but nothing
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by voti »

Can all this be due to thst my boost was 2000 instead of 20000 ?.
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by RetroZero »

Yes it could. I saw @mattsawesomestuff explained it somewhere recently...Have you tried 20 000 then?
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by MattsAwesomeStuff »

Keeping in mind, I was powering mine off of a 12v battery as the "high voltage" traction battery, so I needed a truckload of boost.

Also, I think AMPNOM to 10 might be conservative. Try bumping it up 10 at a time until, I dunno, 50? 70?

Also, when troubleshooting, it's often of value to be as pedantic as possible, because 50% of the time the problem is that you thought you were following instructions and just getting the wrong result, we also thought you were following instructions and getting the wrong result, but those two things are different because you misunderstood them in the first place and there's no actual problem. You're (maybe) getting the correct result for the wrong solution. This went on for like, a year with me, because in my case I didn't flash the bootloader before firmware, because that's not mentioned anywhere in any instructions, until Johannes looked at a screenshot and picked up on it. So let's be more precise.

When you say: "I tested the three phase output phase to phase to see if I was getting any readings but nothing" let's just use the clearest language possible. Do you mean you put a multimeter across 2 of the 3 output phases on the Prius inverter itself (the place where you would plug in a motor, and to be even more thoroughly idiotproof, you might post a photo of what your interpretation of that is), the multimeter was set to AC volts, and it was reading 0 volts?

Also, show a picture of where you were plugging in your 70v to the inverter.

Sometimes it's useful to not be overly prescriptive, and to eliminate as many things as possible that it couldn't be.

You've probably done 99% of things correctly, we just don't know which are the 99 and which is the 1 you didn't.
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by voti »

Thank you again to MattsAwesomeStuff for redirecting me to my own post rather than being all over the place due to my desperation.

Well it's not just desperation but it's because I'm in the military and I'm not always home, so this projects helps me unwind when I'm off duty and I visit home.

OK let me start afresh from scratch.
I'll attach pictures below to show what i have currently.

I have a MPS 3003S MATRIX power supply for my 12v input to power the inverter and vcu.

Then I have a step down transformer that steps down my house outlet of 250v down to 70v and a capacitor bank that outputs 70v DC for my high voltage input.

I also have a MOS 620 OSCILLOSCOPE to test the three phase output from the inverter.

Please see attached pictures
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by voti »

From the pictures below
*The first one show the vcu board I'm using.
*The second one is the power supply that supplies the vcu and the inverter with 12v
*then comes the step down transformer from 250v to 70v DC for high DC Input
*then we have the vcu parameters
*then we have a multimeter to display the input high DC input to the inverter high voltage terminals

I wanted to attached a short video of the oscilloscope to display the output results of each phase but I couldn't and I ended up attaching screenshorts of each phase on the following comment.

I hope all this makes sense.
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by voti »

The attached pictures here show the waveform from each other the three phases of.

My question is if the output is OK why isn't it lighting the 12v 55w lightbulbs that's have connected in delta configuration, besides them.
I have also tried connecting the motor itself but still it won't run


What I also noticed is that the 250v 100w light bulb connected in parallel with a switch on the high voltage positive side cable that goes to the high voltage DC input didn't light up when I first connected it to the inverter to indicate the indicate the inverters pre charge.
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Screenshot_20250131_174616_Gallery.jpg
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by RetroZero »

Thanks for the detailed pictures.
Have you connected as per - Step 6 : Connect fused 12 volt and Ground to HV Inputs (battery), along with 55 watt light bulb in series (resistor) on the Positive line.

The 250v/100w bulb is connected in series at a later stage , when you are ready to connect High Voltage and start adjusting FOC.
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by voti »

Step 6 : Connect fused 12 volt and Ground to HV Inputs (battery), along with 55 watt light bulb in series (resistor) on the Positive line


Am I not supposed to connect the 12v with light bulb to the vcu's12v input positive to see if everything is connected correctly and there in no short circuit on the VCU connections like Damien said on the tutorial video ?.

What is the purpose of connecting the fused 12v to the high voltage (battery) along 55w light bulb?
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by MattsAwesomeStuff »

Just to rule some things out:

- Your 12v supply is probably fine. It's good for 3A, I think the board and inverter might draw 2 amps, so, shouldn't have trouble.

- You're connecting HV to the Prius inverter correctly, with the correct polarity, I doublechecked that.

- Your HV is probably fine? It's janky but you're knowledgeable enough to have built it. I don't think it's getting snuffed out.

- You seem to be measuring from the Prius's MG2 (the more powerful one). Is the rest of your control board also wired and configured to power up MG2, and not MG1? That is, you're using wires 9, 10, 11 on the inverter's receiving harness, not 4, 5 and 6? And you're using pin 25, not pin 20 for the shutdown disabler? And you're using pin 27, not pin 22 for the fail signal? And, I dunno, maybe there's others that slip my mind.

- Looks like you're getting a pretty clean AC waveform on the motor phase wires. Does the shape of this waveform change when you make changes to the parameters? Like increasing fslipspnt or whatever it is, to different numbers? Also does changing boost (by huge amounts, like, cut in half, or to 10%) change anything in the waveform?

...

All of this is just underlining for me that you're not having hardware problems. You've just never used the OI software and aren't familiar with it and what it does.

What I could do, is have you replace your 72v HV setup with a car battery, same as mine... go unbury the few hundred pounds of stuff I have blocking my motor and stuff, get a 100% working 12v HV setup on mine, send you the parameters, and have you copy exactly what I have when mine moves. That'd be idiotproof from my end. If mine moves, and yours doesn't, we'll know something else is wrong. Else if you can get yours to do something, then it's just a matter of changing only the things that are different about your setup than mine.

Only difference is I'm not using Johannes' board. And maybe I'm using an older firmware version. But we'll figure that out.
My question is if the output is OK why isn't it lighting the 12v 55w lightbulbs that's have connected in delta configuration, besides them.
What AC voltage do they see?

Or do you see on the output without them?
What I also noticed is that the 250v 100w light bulb connected in parallel with a switch on the high voltage positive side cable that goes to the high voltage DC input didn't light up when I first connected it to the inverter to indicate the indicate the inverters pre charge.
The precharge is complete within a fraction of a second. And you're giving a 250v light bulb 72v. It might not even glow.

Conversely, you've got 12v light blubs on the motor phase output, and you're giving them 72v? Won't they, umm... instantly burn out?

Also, I don't know if there even is a pre-charge in manual mode. You'd have to manually charge the capacitors up. The lightbulb is just current limiting for the inrush. After that, you could remove it I guess, else you'll be limited to 100 watts, no? Maybe that's enough to see some results.
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by RetroZero »

voti wrote: Fri Jan 31, 2025 9:13 pm Step 6 : Connect fused 12 volt and Ground to HV Inputs (battery), along with 55 watt light bulb in series (resistor) on the Positive line


Am I not supposed to connect the 12v with light bulb to the vcu's12v input positive to see if everything is connected correctly and there in no short circuit on the VCU connections like Damien said on the tutorial video ?.

What is the purpose of connecting the fused 12v to the high voltage (battery) along 55w light bulb?
This is going way back for me too. The 12v setup for the VCU is correct.
The same setup was used with a 12v battery to the Inverter HV inputs on the first connection. This setup was to make sure everything was not going to short out. It also allowed to validate the AC output with low voltages.
The 250v/100w bulb was for foc tuning with higher voltages needed, and also could be used as a pre charge circuit for first
setups.

What voltage do you get on HV bus when testing your delta light bulb setup? When I started out, my first big problem was due to not having stable voltage supplies to both circuits. I went round in circles for a long time....
Lets try to get light bulbs flashing with good 12v battery to HV inputs....

As Matt said, your wiring and sine waves tends to say all is wired correctly.
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by voti »

RetroZero wrote: Sat Feb 01, 2025 9:39 am This is going way back for me too. The 12v setup for the VCU is correct.
The same setup was used with a 12v battery to the Inverter HV inputs on the first connection. This setup was to make sure everything was not going to short out. It also allowed to validate the AC output with low voltages.
The 250v/100w bulb was for foc tuning with higher voltages needed, and also could be used as a pre charge circuit for first
setups.

What voltage do you get on HV bus when testing your delta light bulb setup? When I started out, my first big problem was due to not having stable voltage supplies to both circuits. I went round in circles for a long time....
Lets try to get light bulbs flashing with good 12v battery to HV inputs....

As Matt said, your wiring and sine waves tends to say all is wired correctly.
my worry to the sive waves is that even before I set the parameters on the vcu web Interface the oscilloscope started showing the sine waves just soon after I connected the high voltage. When I went to the web Interface to change the settings to see if the wave will change, nothing happened

How to I test voltage on the HV bus because on the web it says the HV BUS is located glove compartment?
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by voti »

MattsAwesomeStuff wrote: Fri Jan 31, 2025 9:44 pm You seem to be measuring from the Prius's MG2 (the more powerful one). Is the rest of your control board also wired and configured to power up MG2, and not MG1? That is, you're using wires 9, 10, 11 on the inverter's receiving harness, not 4, 5 and 6? And you're using pin 25, not pin 20 for the shutdown disabler? And you're using pin 27, not pin 22 for the fail signal? And, I dunno, maybe there's others that slip my mind.

My connections on the vcu are based from the wiring diagram on.
https://openinverter.org/wiki/Toyota_Pr ... Controller
MattsAwesomeStuff wrote: Fri Jan 31, 2025 9:44 pm All of this is just underlining for me that you're not having hardware problems. You've just never used the OI software and aren't familiar with it and what it does.
I agree with you hence why im here looking for your help brother
MattsAwesomeStuff wrote: Fri Jan 31, 2025 9:44 pm Looks like you're getting a pretty clean AC waveform on the motor phase wires. Does the shape of this waveform change when you make changes to the parameters? Like increasing fslipspnt or whatever it is, to different numbers? Also does changing boost (by huge amounts, like, cut in half, or to 10%) change anything in the waveform?
I was a bit disappointed testing this out.
The oscilloscope showed the waves even before I set any parameters on the web Interface. As soon as I power the vcu with 12v and supplied the high voltage 70v DC, the oscilloscope started showing sine waves. When I make changes in terms of fslipspnt and ampnom to higher figures the wave didn't show any changes.
MattsAwesomeStuff wrote: Fri Jan 31, 2025 9:44 pm What I could do, is have you replace your 72v HV setup with a car battery, same as mine... go unbury the few hundred pounds of stuff I have blocking my motor and stuff, get a 100% working 12v HV setup on mine, send you the parameters, and have you copy exactly what I have when mine moves. That'd be idiotproof from my end. If mine moves, and yours doesn't, we'll know something else is wrong. Else if you can get yours to do something, then it's just a matter of changing only the things that are different about your setup than mine.
I have a car battery with me, please share me your parameters so I can just use them and see what output we get from that because sy this point I'm sad and confused
RetroZero wrote: Sat Feb 01, 2025 9:39 am Also, I don't know if there even is a pre-charge in manual mode. You'd have to manually charge the capacitors up. The lightbulb is just current limiting for the inrush. After that, you could remove it I guess, else you'll be limited to 100 watts, no? Maybe that's enough to see some results
I did remove the 250v 100w light bulb and tried testing without it but nothing happened.
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by johu »

voti wrote: Sat Feb 01, 2025 6:02 pm The oscilloscope showed the waves even before I set any parameters on the web Interface. As soon as I power the vcu with 12v and supplied the high voltage 70v DC, the oscilloscope started showing sine waves. When I make changes in terms of fslipspnt and ampnom to higher figures the wave didn't show any changes.
Something is not right with your scoping, probably you didn't ground the probe. You could ground it to HV-. Right now it picks up grid frequency.

The cables you put into the white connector look like they are to thick for it. Are you sure they make good contact?
Have you pulled MSDN to 12V?
After starting the inverter and specifying fslipspnt and ampnom both >0 you should see an increase in current draw from your 12V supply by 200 mA or so. Otherwise there is no PWM going on.
Is the inverter still in some run mode after reloading?
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by MattsAwesomeStuff »

johu wrote: Sat Feb 01, 2025 8:34 pmSomething is not right with your scoping, probably you didn't ground the probe. You could ground it to HV-. Right now it picks up grid frequency.
That's my thoughts, is why I asked if it changes. I suspected it's just 60hz AC from the wall.
voti wrote: Sat Feb 01, 2025 3:12 pmHow to I test voltage on the HV bus because on the web it says the HV BUS is located glove compartment?
On the web where? Gotta be specific so we're all on the same page. The root of all of this is some assumption being made wrong.

Also, that's nonsensical. The "HV" is your battery pack that moves the car. So in your case, right now it's the 72v you're hooking up. Whatever you're powering the HV power inputs on the Prius Inverter with.

Also, your other link was broken, looks like you pasted a text string instead of the actual link, and OI abbreviates the links if you copy them as text rather than the link.
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by voti »

johu wrote: Sat Feb 01, 2025 8:34 pm Something is not right with your scoping, probably you didn't ground the probe. You could ground it to HV-. Right now it picks up grid frequency.
You are right, when testing the sine wave my ground from the oscilloscope was not connected on anything
johu wrote: Sat Feb 01, 2025 8:34 pm The cables you put into the white connector look like they are to thick for it. Are you sure they make good contact?
Have you pulled MSDN to 12V?
the cables make good contact witht the output terminal of the ups.
johu wrote: Sat Feb 01, 2025 8:34 pm After starting the inverter and ṭ fslipspnt and ampnom both >0 you should see an increase in current draw from your 12V supply by 200 mA or so. Otherwise there is no PWM going on.
I understand
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Re: EV Conversion using prius gen 2 inverter/transaxle

Post by voti »

MattsAwesomeStuff wrote: Sat Feb 01, 2025 9:09 pm Also, your other link was broken, looks like you pasted a text string instead of the actual link, and OI abbreviates the links if you copy them as text rather than the link.
Noted thank you.

https://openinverter.org/wiki/Toyota_Pr ... Controller
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