I have been lurking around the forum for some time now. Most threads have been of great help as I'm a noob in electronics. Currently I'm working in a project that consists of moving two 24V DC Motors (250W) with H-bridges. The motors will be driving a manual wheelchair by friction applied to the wheels. At the moment the problem arises at the h-brige.
The input signals of the h-bridge are PWM's. The duty cycle of the PWM is being varied by a pic18F1230. So far the programming is done, PWM's vary as commanded from 60% to 100%, and the motor can be run at 12V without heavy load with the current h-bridge circuit. Once constant heavy load is applied to the shaft the h-bridge breaks. My guess is that the currents passing through the MOSFETs are too high.
I want to raise the voltage to 24 volt in order to diminish the current. But I fear the Vgs of the MOSFET will be to high since R6 and R5 are the one creating the voltage drop to open and close the gates. I'm I right? Is raising the voltage a good idea to run the motors at full capacity and lower the current?
Please critique my work so far and help me in any way.
Thanks,
Kminant
P.S. The parts on the Schematic are the one being used.
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