340vDC to 750vDC input, 240v split phase or 208v-480v 3 phase output

MPaulHolmes

Hello, I noticed that Tesla is coming out with a battery bank/inverter, so in anticipation of more people going with more high voltage solar, I developed an inverter that is configurable (just press a button or 2) as 24kW 240vAC split phase output or 208v-480v 3 phase output.  The maximum power for 480v 3 phase would be about 80kW, and would require >= 680vDC input.  

I have developed 200kW 3 phase AC motor controllers, and am trying to expand some.  There are only so many people who are interested in doing EV conversions.  Does anybody here see a potential use for something like this?  I'm trying to figure out what it is worth, but most inverters I've seen are high voltage grid ties or low DC voltage input.  I'm honestly not a huckster or lame salesman.  It's just that my wife has M.S., and I need to work from home to help take care of her and our kids, and I'm trying to get things moving.  Here's my 3 phase AC motor controller for reference:
instructables.com/id/200kW-AC-Motor-Controller-for-Electric-Car/

BB.

I have a friend that is an electrician out here in SF Bay Area--He is busy wiring up houses for 1-2 Tesla quick charger systems (sometimes trenching for power cables). They are paying lots of money for this.

I would suggest that "we" do some paper designs for solar power (off grid?) that would support your charging system. And see if they are anywhere near cost effective.

And also need to address 680 VDC battery bus (and charge controller) configuration and safety.

-Bill

mike95490

Where does a person get a 700V battery charger ? would it be a Step-Up 400V MPPT to 700V?

MPaulHolmes

Since there are 3 half bridges to work with, and you have 3 inductors, you could use one of the half bridges plus its inductor as a boost MPPT, but then you would just have a full bridge left over, which would allow the 240vAC, but you would lose the 3 phase option.

Dave Angelini

The mppt's on these systems are limited to 600vdc and run typically at 350 to 450vmp. Available now world wide

MarkC

MPaulHolmes said:

Hello, I noticed that Tesla is coming out with a battery bank/inverter, so in anticipation of more people going with more high voltage solar, I developed an inverter that is configurable (just press a button or 2) as 24kW 240vAC split phase output or 208v-480v 3 phase output.  The maximum power for 480v 3 phase would be about 80kW, and would require >= 680vDC input.  

Have you inquired how Telsa plans to integrate their Powerwall 2 with solar PV when the grid is down?  The tech guy I talked with said that (maybe) by next summer they will have (I assume) a MPPT charge controller capable of charging their Li tech batteries - with required safe transfer from grid-tie to off grid battery backup. 

I have a Leaf and ~7000 watts of PV that would very much like to have a CHAdeMO based charge controller to direct DC charge the battery.  I certainly do not have the design skills to build such a charge controller, but does seem to be a "missing link" to tightly integrate the EV with solar PV - for my needs anyway.  Is this the type of project that interests you?  If so, PM me.

MPaulHolmes

Hey!  I've made a MPPT charge controller 4 years ago, and a few weeks ago modified it for my "ev" using our 5.6kW off grid solar array.  It's been running 24/7 for the last 4 years (not charging much at night.  haha).  I have since changed the panel wiring to be 400vDC in.  The EV  is only 93vDC, but is just a test bed for my Nissan Leaf motor/diy controller.  The batteries are A123, from a Spark EV.  I have a video of it on youtube.  My son and I did it around Christmas time, and we were playing around with the different recording speeds, so sometimes we sound a little like Alvin and the Chipmunks:
https://www.youtube.com/watch?v=dxp8kX_golA
I'll PM you.  My layout and wiring skills have improved in 4 years, so don't get too scared.  haha.
The spread spectrum switching was really just an experiment, so I had intentionally had the switching frequency in the 9-13KHz range, since I also do high power DC motor controllers in the 400kW range, and you need to switch them sort of slow (like 8kHz) since there are really big IGBTs, so I figured I'd work out the hiss that people would hear while driving rather than an 8kHz "stab yourself in the eyeball with a fork" frequency.  That way it blends in with the wind outside.  But in the case of an MPPT, it's probably better to switch above audible frequency.

MPaulHolmes

It's basically done now.  I ran my mill with it.  Both with a soft start where it ramps up voltage at whatever rate you want, as well as just hard turning on.  The mill used to always trip my breaker, since it's a big AC motor with a big startup surge.  I had left off the AC voltage monitoring, figuring that I could just infer the output voltage from the DC input and phase currents, but it was a little more variable than I would like, so I just did a board today that will monitor all 3 line voltages (Neutral probably won't be very interesting to monitor haha).  With this addition, this will be able to be used as a 3 phase grid tie as well.

MPaulHolmes

Here it is running right from the panels with no batteries:
https://www.youtube.com/watch?v=gSJUYZ178HY&feature=youtu.be
It just sags the panel voltage down toward max power.  As long as you don't go over max power it doesn't cause any problems.  I've been using it to charge my new wrecked Nissan leaf (only $2950!!), as well as window AC units.  I would have just done a grid tie, except that it would have been stupidly expensive to go through the right channels.  Also, the batteries don't last very long in that shop.