>You shouldn't need that. A motor can be its own filter. You can chop the >motor from substantially higher voltage than what it is intended to run at= , >just make really really sure the duty cycle is low enough so that the >average is right. Put another way, you need a buck converter, but the coils >in the motor can be the inductor and the final load at the same time. That's what I was hoping to hear! The idea is to be able to upgrade a battery bank simply by hooking up the new batteries in series. As I mentioned before it's for an open source E-bike design inspired by something in between Blade 04 and Erockit: http://www.youtube.com/watch?v=3DYPHThtr5GME http://www.youtube.com/watch?v=3DtzsHFka92X8 Thanks for your answers everyone! Have to admit I should not be the one designing this part, as thi= s is far beyond my expertise... This is more like a technology question, the effective wattage a cell array can provide is an obvious imitation, and I have no illusions that there won= t be losses, or that the batteries be cheap! But the issue at hand is to imagine a system that has flexibility and high reliability, and can start with a minimal battery and can be scaled to be an exciting tool! I have another interesting related engineering challenge: Braking Energy recovery: to stop an electric vehicle the initial voltage form the motor as generator is always the biggest when the speed is highest, but as one is getting closer to a stop, whatever is being used to receive the energy is fullest, and the voltage is the smallest - any suggestions what to do with that last bit of energy? Mechanical brakes I suppose ? On Fri, Feb 11, 2011 at 6:15 AM, Olin Lathrop wr= ote: > Isaac Marino Bavaresco wrote: > >> The question I have is, what kind of switching power supply > >> architecture would be recommendable to match lets say a 50V motor > >> (BLDC or Asynchronous) which would be fed by a 300V Bank that cant > >> really supply the max. power current of the motor? > > > > A buck step-down converter? > > You shouldn't need that. A motor can be its own filter. You can chop th= e > motor from substantially higher voltage than what it is intended to run a= t, > just make really really sure the duty cycle is low enough so that the > average is right. Put another way, you need a buck converter, but the > coils > in the motor can be the inductor and the final load at the same time. > > > ******************************************************************** > Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products > (978) 742-9014. Gold level PIC consultants since 2000. > > --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .