Paul and Sabrina's Cheap 3 Phase Inverter (AC Controller) with Field Oriented Control

[metallica]

Hello everyone,

I am newly registered on the site, currently looking for a way to make a good quality BMS at a reasonable price, for electric vehicle project that I envisage in some time.

I spent a little time on this forum, with the idea to get the models of Paul & Sabrina’s BMS in order to manufacture them, as well as list of the components to buy.

But I did not succeed. Can one of you tell me where I can find that?

Thank you in advance for your help

[freebeard]

I just dropped by because of the email notification. My own EV dream is unrealized ...for now.

My understanding is that Paul and Sabrina's Cheap 3 Phase Inverter (AC Controller) with Field Oriented Control does just that. Maybe it does include battery management, that's for others to say.

I know EVTV are opinionated about BMS. ...since 2009.

GET RID OF THOSE SHUNT BALANCING CIRCUITS - EVTV Motor Verks

And they've had fires in their shop since during testing. Apparently bottom balancing > top balancing?

[thingstodo]

Originally Posted by metallica

Hello everyone

Hi! Welcome to the forum!

I am newly registered on the site, currently looking for a way to make a good quality BMS at a reasonable price, for electric vehicle project that I envisage in some time.

I don't recall a BMS that Paul has designed. He has designed a 500Amp DC controller, a 1200Amp DC Controller, a 1000Amp AC Controller, a Resolver to Encoder converter board, and a DC/DC converter board .. that I know of.

I would suggest using a BMS that has a good track record, of course. The Leaf BMS is good at monitoring from what I read. I have not heard much about the balancing for the Leaf BMS. The Tesla BMS also has a good track record.

Are you recycling surplus batteries? Or building your own? For your first build I would suggest recycling. It simplifies things and you get results a bit quicker ... if you have the room in your vehicle for pre-built packs.

To talk to the boards in each Leaf module, Woltronix has a 'Leaf Pack sniffer 2' that I have read good things about. Store

For Tesla modules, EVTV has a board that will talk, as master, to the BMS in each Tesla pack. EVTV Motor Verks Store:

Those are the most cost effective solutions that I know about.

I don't use a BMS - I bottom balanced my LiFePO4 pack and manually check the cells every 6 months or so, when I've run the pack low. The recycled cells have been rock solid.

My Leaf cells ... I foolishly damaged the boards while taking the pack apart. So I don't have an operable harness or the monitoring portions ... I check them about once a month. The controller on my Polaris Ranger EV won't start up below 42V. That's about 3V per cell. I didn't bottom balance the pack, I top balanced it so that all of the cells hit 4.1V at about the same time.
The voltage on the pack is not as stiff as the LiFePO4 cells, so when the Polaris shuts down, the cell voltage bounces back to about 45V. None of the cells is below 3V when I have let them cool down, before putting them on the charger.

But I'm just a hobbyist. I don't have a highway-capable vehicle running

Disclaimer: I am not affiliated anyone mentioned:
- Paul and Sabrina, I am a happy long-time customer
- Woltronix, I watch and enjoy his videos but have never purchased anything from him
- EVTV, I went to EVCON one year, and am a satisfied, long-term customer

[skyking]

Originally Posted by Quattro64

Hi,

Yeah, thanks I agree, I wont be putting any plane into the air without a lot of taxying, testing, redundancy etc. I'm new to this EV stuff and trying to wrap my head around it before deciding on a final engine. It seems that the EMRAX 348, which is rated at ~400hp is a capable engine to lift a small plane. I likely wouldn't have to get much over half of its capability. So even though it has a peak of 1100 amps I may only shoot for 600-700 max, and then it's continuous is just over 500 amps. I like that I can build a reasonably low voltage battery pack(s) and still drive the propeller, directly, at its target 2500 rpm. I like that these PM motors are very durable and safe for this type of application. The thing is though AC motor controllers/inverters are very expensive, for a plane I'd want two for redundancy. If I could build my own controllers and get the RPM, torque, CCAs to drive the motor that would be a start. Then what would I need for range? An ICE? Some sort of other tech like Free Piston? How exactly do I connect a range extender or serially driven motor? Hmm, interesting ideas, need to do more research, I found the thread over at endless sphere, will be looking there also.

curious why you'd build an ev plane, with the limitations to range and charging. the only use I see is a motorglider in good gliding country.

[thingstodo]

Originally Posted by freebeard

I know EVTV are opinionated about BMS. ...since 2009.

GET RID OF THOSE SHUNT BALANCING CIRCUITS - EVTV Motor Verks

And they've had fires in their shop since during testing. Apparently bottom balancing > top balancing?

Yup. But what I read .. and listened to in the videos .. is that Jack and EVTV are still against BMS for LiFePO4 - they appear to take care of themselves for the most part.

I'd have to go back and look. I thought the fire was on a pack that was suspect ... a Better Place pack that had low capacity or something like that. I'm too lazy to go look

The Lithium polymer cells - Leaf Cells - EVTV don't deal with much. They still have a couple of the Better place packs around the shop. You see them in the background (or parts of them, I guess) in some of the shop videos.

The Tesla cells EVTV actually USE the BMS that came with the packs, just replace the master that gets the data. I think their master even activates the top-balance circuitry if you charge up the batteries past a certain voltage.

So things do evolve

[freebeard]

https://www.youtube.com/watch?v=O-PaSSTA2YE

November 9th, 2015 episode has the details.

[Quattro64]

Originally Posted by skyking

curious why you'd build an ev plane, with the limitations to range and charging. the only use I see is a motorglider in good gliding country.

Hi, Yes all of that is true. My idea, and it is ambitious, is to use a small, light diesel to generate the electricity to drive one of the EMRAX motors. With batteries to assist the way they would in an EV Auto, as boost, emergency drive etc. I wouldn't need reverse or brake regen but otherwise I would think I could use a pair of Paul's controllers. I'm still learning but I think it is doable. So Far it looks like a GM 1.6L Turbo Diesel, some combo of EMRAXs for both AC generation and final prop drive, some type of AC-DC converter, a DC battery charger, a pair of tandem resolvers also from EMRAX and a couple of Paul's AC controllers. There is a similar Series-Hybrid Electric drive for planes in development by Siemens and Pipistrell. The total $$ of this drive system could be put together for less that any of the Aircraft engines that I was looking at and would sip Diesel or Jet-A in comparison.


I'm looking at two possible kit planes, both are in development and would be good platforms for this. One looks like it will be doing flight testing this summer, the other in a couple years. I'll try to supply more details after I do some more research and have more posts so I'll be allowed to create links.


Both Aircraft can have very high performance with this setup and therefore range.

[skyking]

ok, thanks for the explanation.
Do the math for weight of the components, and compare with an engine driven propeller using a reduction gear to get the optimum tip speeds, and see what the added weight will cost. Then factor in generator losses.
I think your idea lends itself to low speed high lift aircraft, where the weight penalty gets absorbed better.
High speed regime, weight is king. Inline losses alone make it impractical.

[Quattro64]

Indeed yes the weight of all of this Aircraft hybrid drive has to be equal to or less than the original engine/fuel weight. I think this can be achieved given the much lower need for fuel. No need for a reduction drive with the right EMRAX motor. The real weight would be in the batteries, GM 1.6 Turbo Diesel, Generator/Drive Motors. Also true that a plane that can land slow and take off quick has an advantage, better yet if it also has a good/great top speed.

[Quattro64]

Yes one of the things I am trying to wrap my head around is the inline losses. Starting with a 1.6L Turbo Diesel that can deliver ~100kw power is key, pick then an EMRAX motor to use as a generator - 40% performance as it isn't optimized to be used this way without a controller. Match that with a tandem pair of Emraxs to drive the propeller. Then I'm not sure how much is lost when going from AC-DC to the controller, then also back from DC-AC. All has to be factored to keep losses at a minimum.