Yes absolutely, you need large inductors and a mosfet or IGBT based controller. Large inductors are cheap and easy to make though.
Vicor modules is a good solution too. On Fri, Nov 7, 2014 at 11:16 AM, Lee Hart via EV <[email protected]> wrote: > Peter Gabrielsson via EV wrote: > >> One relatively cheap way of doing high power cycle testing is to cycle >> power between a large battery bank and the test battery using a >> bidirectional DCDC converter. >> >> The DCDC is simple since it's just a switching pole with an inductor and >> some controls. A DC motor controller with regen capability can be used as >> the DCDC converter, the controls should have a constant torque (current) >> mode for it to be useful. >> > > I've tried this. A motor controller has a significant amount of input > ripple current, and a *huge* amount of output ripple current. You have to > add inductors on the input and output to approximate DC. Since motor > controllers handle high currents and switch at relatively low frequencies, > these inductors are *big*. > > What I used instead were Vicor modules. They switch at high frequencies, > so the input and output filters are far smaller. Their internal filters are > already adequate for battery testing. The output voltage and current can be > adjusted with their TRIM pin. The output voltage can be higher or lower > than the input voltage; important if you're "ping-ponging" power between > two same-voltage batteries. For example, a VI-202 has a nominal 12vdc input > (10-20v), nominal 15v output (adjustable 7.5-16.5v), and 6.7 amp max > current. When I got mine, the VI-202 was $158 direct from Vicor. > > Vicors are built to operate in parallel, so you can use as many as needed > for high power. PS: I just checked eBay and see that someone has VI-202 > modules for $99 each or 15 for $479 if anyone is interested. I have no > connection with the seller. > > The DC/DC doesn't have to be bidirectional; it's much easier to simply > include a reversing relay that swaps input and output. > > -- > A designer knows he has achieved perfection not when there is > nothing left to add, but when there is nothing left to take away. > -- Antoine de Saint Exupery > -- > Lee Hart's EV projects are at http://www.sunrise-ev.com/LeesEVs.htm > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/ > group/NEDRA) > > -- www.electric-lemon.com -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20141107/e70a56e9/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
