Zilla FAQ19 Feb 2007 11:34 pm

How to build a controller

I figure it’s time to get some of the FAQs answered.

Since some recent discussion has been around how to build a controller and how they work I figure I’d share a pretty good link that someone shared with me.
http://homepages.which.net/~paul.hills/SpeedControl/SpeedControllersBody.html

OK, so maybe I’m not sure of how good the link is, the truth is I only skimmed the text, but the images and concept all seem right on (as long as the reversing is taking about PM motors).

-Otmar

3 Responses to “How to build a controller”

  1. on 20 Feb 2007 at 9:22 pm   John

    Hello,

    I am an engineering student working on a hypothetical high voltage/current power supply for a semester project. My current design uses IGBTs to regulate rectified mains voltage down to a lower voltage level. However in learning about IGBTs I came upon the problem that they require a second much lower gate voltage. Someone on a different forum told me about your controller and that it uses IGBTs and doesn’t have a secondary voltage input. In seeing your website and how generous you have been with helping people understand the technology behind your controllers, I was just wondering if you could possibly point me in the right direction in regards to how you produce the lower gate voltage from the single high voltage source.

    Much thanks for your time, and also I wanted to mention how reading about your controllers makes me see EVs in a whole new light, they can be more like building a hotrod than an hippy wagon..ha! I think I’ve got the itch to build one someday soon.

    thanks again.

  2. on 20 Feb 2007 at 9:35 pm   Otmar

    Hello John,

    Hmmm, why do I get the feeling this post may end up with a lot of comments? 🙂

    It is common in any controller design to need a low voltage supply to run the logic and gate drive. In your case where you have AC mains power you might use a wall wart type transformer, though it may not be terribly reliable. Another common method that often will work on DC controllers as well is to use a universal input switching power supply similar to a laptop power supply.
    I now build my own custom supply which coincidentally I spent much of today improving, but the first controllers I made used a Cosel Gorilla power supply which also happened to run fine on 70-370 VDC. Not cheap at about $80, but simple and effective.

    A great place to further discuss such technical issues might be the EV tech list which can be found at http://evtech.org/

    Good luck with your project!
    -Otmar

  3. on 20 Feb 2007 at 9:42 pm   John

    Thanks very much, that was truly helpful. It was exactly the straight forward info I needed to put me in the right direction.

    Couldn’t thank you enough!