The links below are to an Open Source Project that I've been working on over the last Month or two. Specifically for Perm Mag Brushed DC Motors upto 2,400Watts
In brief the PicOx is a PicAxe 08M based digital Controller that performs an ADC of a Hall-effect throttle and an ADC of a Hall-based current sensor. These two parameters determine the “Mark” value of a 15Khz PWM signal that does the switching to the Output stage.
http://www.theworkshop.ca/energy/picox/picox.htm
The link above details the general Design specification, and introduces the tools required, parts list, and some basics about the PicAxe family of processors.
http://www.theworkshop.ca/energy/picox/2/picox2.htm
The link above details the proto-typing process, development of a current sensor with recycled parts, and trouble shooting techniques when problems arise.
http://www.theworkshop.ca/energy/picox/3/picox3.htm
Part # 3 details the PCB fabrication process, and acts as an illustration of how to “Maximize” the ill-effects of Ground Noise to a sensitive digital circuit and how to diagnose the problem.
http://www.theworkshop.ca/energy/picox/4/picox4.htm
Part #4 is the complete revision of the PCB design to mitigate the Noise issues identified in Part # 3 as well as how to “Patch” a simple PCB Modification to the PCB design without scrapping the entire brd when proto-typing.
At the end of the project the Controller can sustain 48V @ 75 Amps repeatedly for approx 5 second bursts and is really only limited by the In-Line breaker that cuts the supply voltage, though the entire system’s overall design objective is met reliably at 48V 50Amp operation…
FrankG
www.theworkshop.ca
frank@theworkshop.ca
