controller with built in boost dc dc converter possible?

[endomorphosis]

I was wondering if a controller with built in boost dc dc converter was possible?

I am fairly adept at EE, and understand the concepts okay, but was wondering if there were any open source controllers out there.

 

[Lebowski]

I once build that but realised it's a worthless idea. The energy conversion would be from voltage ( battery) to current ( boost converter inductor) to voltage ( output cap of converter) to current ( motor inductors). Much better to go straight from battery voltage to motor current. Note that every energy conversion carries a loss and that you can only go from current to voltage and vica versa. Current to current for instance is not possible.

 

[endomorphosis]

I'm confused by what your saying, but i know that there is a loss of efficiency. I have a 36v 100ah battery, and would like to have it stay at 36v until RPMS max out, then switch to a higher voltage and lower current (like 48/72v).

 

[dnmun]

you mentioned you are adept with EE so he thought you would understand how using a buck converter would not be advisable. how much EE have you studied?

why do you have such a huge battery and what does it go in?

 

[Doctorbass]

if your only way to boost your speed without having larger wheel, changing battery for higher Voltage or going downhill only, boosting the voltage of your battery with a DC-Dc might ve a good solution.

I already tried with couples 150W 5V 30A dc-dc connected in serie to gain 15V at 30A and it worked well.

The battery voltage was 48V ( 52V ping battery) that was connected to the input of all 3 DC-Dc, then the 15V output of these reconnected to the 52V ( the DC-Dc are isolated so no prob to connect in-out in serie)

Voltage climbed to 67V at 30A max and it worked well.

yes it is not the best efficient way but it's cheap and it work and require minimal part to acheive.. tese DC-Dc cost about 10$ each so for 30$ you get 15 more volt a 30A.

The current draw from your battery will also increase because it will have to supply current for the DC-Dc + the controller input...

But the max current of the controller get is limited by the DC-Dc so you MUST limit your controller battery current according to the DC-Dc max current due to their serie connection in the system.

It,s like tranmsforming current into volts for a part of the total power.

The speed gain is great and the powerband is extanded.

I have suggested this idea few years ago on that forum.

Doc

 

[endomorphosis]

you mentioned you are adept with EE so he thought you would understand how using a buck converter would not be advisable. how much EE have you studied?

why do you have such a huge battery and what does it go in?

I went to school for computer engineering, which is half computer science and half digital electronics. I got the part about the efficiency, but the english was what i have a problem understanding, specifically the use of voltage and current are wrong. What I was thinking of was building a circuit with either/or/both, a dc-dc converter to the input, a set of controller circuits switched between series and parallel.

 

[dnmun]

i think he was thinking you were gonna boost the voltage in one stage. seems like the inductor would be huge to buck that much current and the caps would be huge.

i had not thought of using several in series like doc said. mostly people wanna just have the battery in two parts so they can connect it in series to get more voltage,

 

[Lebowski]

my exploits, from when I was still very green, are documented here

http://endless-sphere.com/forums/viewtopic.php?f=30&t=31510&p=456474#p456474

 

[endomorphosis]

I just bought one of these at auction, and am going to try to make a controller. The plan is to have two sets of phase outputs, and have them switch between parallel and serial.

http://www.appc.fr/download-media/news/98/document/78.pdf