Electronics Review

Haven't posted in a couple days, because not much has been done..
I've taken apart the controller and essentially analyzed the circuitry. Nothing major, they have one chip of their own brand, but essentially it's a PWM with two quad op-amps for error compensation and the accelerator input.. oh, and it's all hand drawn from the late 70s.. Retro

No ground plane, as they typically are not found on old circuit boards..

With some light.. on the upper right, the left is the PWM chip with the two quad op amps in the middle and far right.. Nothing really interesting is going on in here.. it's old..

I was able to dig up some 'old' LTSPICE files I had on my linux box (I run it using wine) and got the basic ones I was after to run on my work laptop (mac)..

So.. what is this circuit you may ask? It's a Back EMF Collector.. essentially it will be used as part of the controller.. an optical (rotary) encoder will tell me which phase to send a pulse of current through, when I am not sending a pulse, I can drain the induced current that is in it to do something useful rather than creating heat. The one downside to doing this, beyond needing to have the control circuitry to handle high voltage spikes, is that if there is no remaining induction taking place than the inductor (motor winding) has to start from 0 to charge up again, and comes across lots of resistance. you can see in the graph that the green line starts to taper off when it gets saturated.

Current pipe dream: Take some super capacitors, put it through a flyback with some feedback from the accelerator cable to get the right voltage.. hooked up with the rotary encoder to specify what rotor/stator phase to pulse, through some IGBTs, and when not pulsing take the current back in, buck it down to a charging/working voltage of the super capacitors, and feed it back in..

Oh.. this may become an electronics blog for a little while, and I'm okay with that.