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PCB shop for hobby projects?
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<blockquote data-quote="Phil Graham" data-source="post: 96520" data-attributes="member: 430"><p>Re: PCB shop for hobby projects?</p><p></p><p></p><p></p><p>JR,</p><p></p><p>Thanks for the feedback.</p><p></p><p>Let me explain in more detail:</p><p></p><ol> <li data-xf-list-type="ol">The project/research I want to work on is battery charging/discharging control. The motor controller is a means to that end, as it provides for battery discharging and charging. I'm going to use brushed DC motors.</li> <li data-xf-list-type="ol">I'm using International Rectifier's IR21844 half-bridge MOSFET driver (<a href="http://www.irf.com/product-info/datasheets/data/ir2184.pdf" target="_blank">http://www.irf.com/product-info/datasheets/data/ir2184.pdf</a>). Feed it PWM and it automatically pumps out a high/low pair with resistor-adjustable switching deadtime.</li> <li data-xf-list-type="ol">Once I get the boards done and built, an Arduino (or Arduino-compatible) will provide the pulse and duty cycle control. I've got to derive power for the Aurduino regardless. On the motor side of the fence, I'm going to use an optical encoder to measure RPM directly, that way I can observe back EMF vs. RPM. The arduino will also take in V-I data from the battery side. I'll probably mount it on a bicycle or razor scooter.</li> <li data-xf-list-type="ol">Most of the time I expect the unit to operate via active rectification, with PWM duty cycle changing to alternate between ramp to current limiting under acceleration (low FET) and ramp to voltage limiting during regenerative braking (high FET). Near the top of the charge curve the unit should also exhibit current limiting behavior.</li> <li data-xf-list-type="ol">Once the batteries are near the top of their charge state, the high side FET might need to stay open for extended periods of time to act as a freewheeling diode. It is this usage state where I don't think the bootstrap is going to work, as the circuit might become charge depleted before the next low side cycle re-charges the bootstrap.</li> </ol><p>This project is not about me re-inventing the wheel on motor controllers, but rather about getting some practical circuit board layout experience, Arduino coding experience, and playing around with the battery and motor algorithms. At all points where I can use an off the shelf bit to get data into the Arduino, provide voltages, etc. I will.</p><p></p><p>Down the road I'd like to take what I've learned and apply it to a windmill/battery combination, or PV/battery combo in a practical home setting.</p></blockquote><p></p>
[QUOTE="Phil Graham, post: 96520, member: 430"] Re: PCB shop for hobby projects? JR, Thanks for the feedback. Let me explain in more detail: [LIST=1] [*]The project/research I want to work on is battery charging/discharging control. The motor controller is a means to that end, as it provides for battery discharging and charging. I'm going to use brushed DC motors. [*]I'm using International Rectifier's IR21844 half-bridge MOSFET driver ([URL]http://www.irf.com/product-info/datasheets/data/ir2184.pdf[/URL]). Feed it PWM and it automatically pumps out a high/low pair with resistor-adjustable switching deadtime. [*]Once I get the boards done and built, an Arduino (or Arduino-compatible) will provide the pulse and duty cycle control. I've got to derive power for the Aurduino regardless. On the motor side of the fence, I'm going to use an optical encoder to measure RPM directly, that way I can observe back EMF vs. RPM. The arduino will also take in V-I data from the battery side. I'll probably mount it on a bicycle or razor scooter. [*]Most of the time I expect the unit to operate via active rectification, with PWM duty cycle changing to alternate between ramp to current limiting under acceleration (low FET) and ramp to voltage limiting during regenerative braking (high FET). Near the top of the charge curve the unit should also exhibit current limiting behavior. [*]Once the batteries are near the top of their charge state, the high side FET might need to stay open for extended periods of time to act as a freewheeling diode. It is this usage state where I don't think the bootstrap is going to work, as the circuit might become charge depleted before the next low side cycle re-charges the bootstrap. [/LIST] This project is not about me re-inventing the wheel on motor controllers, but rather about getting some practical circuit board layout experience, Arduino coding experience, and playing around with the battery and motor algorithms. At all points where I can use an off the shelf bit to get data into the Arduino, provide voltages, etc. I will. Down the road I'd like to take what I've learned and apply it to a windmill/battery combination, or PV/battery combo in a practical home setting. [/QUOTE]
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