Paul & Sabrina's cheap DIY 144v motor controller - Page 590 - Fuel Economy, Hypermiling, EcoModding News and Forum

blacksun1989 · 10-25-2012, 08:49 PM

Thanks Paul i will trythat out tomorrow. But i think we have the wrong current sensor. We have the HAS 300-s and in the BOM is the HASS 300-s. Because the datasheet you linked me shows a sensor that works with a voltage with 5v and the one i have works with 15v(i forgot to mention that earlier) si i think that is our problem.... I will order one right now and tell you if it worked.

MPaulHolmes · 10-25-2012, 09:24 PM

Hello! Yes, that's exactly the problem. One time Digikey mailed me 25 of the Has 300-s sensors instead of the Hass 300-s sensors. They take 15v input instead of 5v. I had mailed them all over the stinking planet earth!!! It was a disaster. I just thought, oh weird, they sort of look different than normal.

MPaulHolmes · 10-27-2012, 01:05 PM

Here's the latest video of babysitting the mosfets, to discover what caused previous failures. It still could possibly be noise on the probe, being clamped by the 15v TVS diode:

http://www.youtube.com/watch?v=x14Xgbns1lA

I did some tests with the transient voltage suppresion diodes, and they get pretty warm at even 20-30mA continuous, when they are clamping to 18v. I just tested that on my little variable power supply. So, I glued on a thermistor to one of the TVS diodes on the driver board, and am now waiting for the glue to dry. Then I'm going to see under what conditions the tvs diode gets hot. If it does get hot, then the spikes are real, and I might need to move up to a higher powered TVS diode. I'm using a 600w peak, 1w continuous at the moment, so I figured a 6000w peak, 8w continuous would do it. haha. Those things are fast! It takes them less than 1 picosecond to start clamping the voltage. To give an idea how small that is, each horizontal division on the oscilloscope in the video is 20000 picoseconds.

MPaulHolmes · 10-28-2012, 02:10 AM

At 12v and 40 amps continuous motor amps (2 mosfets are installed out of the 12) the bus bar they are soldered to stays really cold, and the TVS diode temperature climbed really slowly, and then found its equilibrium 5 degrees above the temperature it started at. That could be the result of the spike on the gate exceeding 15v, allowing a bit of current to go through the TVS diode, or it could just be that it's above the bus bar, which probably warmed a couple degrees.

Now I'll see if the temperature of the TVS increases more at higher power section voltages.

EDIT: The TVS temperature climbs slowly even when the gate is well below the clamping voltage.

jamesweirick5 · 10-28-2012, 10:31 PM

Hi Paul

I bought one of your controllers and have had a hard time fixing it. Do you have a troubleshooting guide? Do you have a short expanation of hardware choices for one of your base dc models?

MPaulHolmes · 10-28-2012, 11:09 PM

The troubleshooting guide is a good idea, but right now it's just people email me, and then I try to help them get it working. What's happening right now with it? Without the equipment, it can be tough to track down bugs. You could mail it here and I could try to see what's going on.

jamesweirick5 · 10-29-2012, 01:05 AM

Quote:

Originally Posted by MPaulHolmes

The troubleshooting guide is a good idea, but right now it's just people email me, and then I try to help them get it working. What's happening right now with it? Without the equipment, it can be tough to track down bugs. You could mail it here and I could try to see what's going on.

I have a BS in Electronic Technology with equipment and get the theary and concepts. I do not have your valuable experience. Your huge threads are difficult to process easily. I have converted 8 cars cheaply and my 20A chargers cost about $10 by using just a full wave bridge.

Your 500A to 800A controller is to complex to troubleshoot readily. If I had measurements (V) of the micro processor inputs and outputs under success and different failures, then I could troubleshoot the simple circuits left.

I have built a 1000A controller using your power driver and fets with diodes. I have bought a cheap PWM control to drive it. I will use smaller wire resistance to current limit at first. I still have to find a simple current limit cricuit to connect to the driver chip. I have upgraded your fets and diodes and mounted them on big heat fins with a fan for supperior cooling. This contoller costs under $200 in parts. I do understand the dire need for your additional complexities and computer. I know I will be blowing some stuff up but hope that you can reduce the failures.

Jim

MPaulHolmes · 10-29-2012, 11:51 PM

Hello! I've never thought about what all the ports need to be. I'll figure that out and post it.

Just a quick video at 24v, going from 0amp up to 70amp, with 2 mosfets and 2 diodes installed. The board has room for 12 of each, so to get to 1000amp, I need around 84amp each. I'm still trying to decide if the spike is real. During this test, I monitored the temperature of a TVS diode, and it was staying cold, so it's not being overworked yet. Next I'll crank it a bit higher. But I'm just worried right now since I can't find my goggles, and I don't want molten metal blasting me in the face. haha.

http://www.youtube.com/watch?v=-Tg3fa-2WX8

MPaulHolmes · 10-30-2012, 03:58 PM

I cranked it all the way up to 100% duty at 24v, and it got to 146 amps. It's still with just 2 mosfets and 2 diodes. The bus bar stayed cool. I'm sure it will warm up with all 12, but I feel much more confident now that it won't be trouble to get the heat removed. The base plate was the same temperature as the bus bars, so the thermal transfer was very good.

http://www.youtube.com/watch?v=ijVLeixj2pM

Notice that the spike is clamped at around 18.5v or so. The TVS diode temperature was climbing at about 1 deg C every 5 seconds. It would probably find an equilibrium temperature at some point, but this represents about 876amp if it was all 12 mosfets. So, I wouldn't be putting much more current through them. 167amp represents max current the pair would ever see.

jyanof · 10-31-2012, 06:28 PM

Quote:

Originally Posted by MPaulHolmes

The TVS diode temperature was climbing at about 1 deg C every 5 seconds.

Sorry, can't watch the videos at work, but I was just curious about a couple of things - first, do you have a picture of the driver/power section? And second, does the TVS diode temp behavior change in anyway with the scope disconnected? If it's unchanged, that would at least eliminate the scope as a source of problems. Maybe you've already done that...

Also, I suspect the spiking may get worse with higher bus voltage - was there a difference between 12v and 24v?