Hello, My name is Tom and I am looking to tap onto some knowledge of the members of this forum! I have some learning, but i'd like to expand on it.
The final goal is to build a speed controller for a light ev motor bike, nothing to complex, no reverse, regen braking, motor braking or soft start. Just to control the speed of a series wound motor, much the same as the older electronic rc esc's.
The planed motor will be in the values of 100v and 120A continuous so about 430A intermittent.
The way I intended on doing this is with a "bank" of parallel 100v power mosfets.
The problem is driving the "bank" I can not find any mosfet drivers that will handle that kind of load.
The first idea was to use a simple small low voltage PMW motor speed controller to drive the "bank", I'v seen this done but I doubt it was to affective as the square wave patten will have already been through a set of mosfets of some kind and not be so sharpe because of the charge and discharge capacitance and that will mean the "bank" will spend a much longer time in the half on-off stage wasting power and making lots of heat, as far as I can tell.
The next idea is to use a normal 20khz ish mosfet driver with potentiometer, to drive a simple audio style amp to then drive the "bank".
The question is this, will the wave pattern from a PMW speed controller have the effect i think it will have if i then use it to drive more MOSFETS?
Will an audio style amp keep the wave form from a MOSFET driver usable for driving the "bank" as I'm not familiar with different types of amp's and the full on full off speeds.
One last thing, I have seen many 100v power mosfets with high current ratings say 50-70, witch is fine, but they mesure about 1cm high, and the legs are 1mm x 0.5mm, I can not see how the legs can handle any usable current at all, these are from rs, I'v studied the data sheets but perhaps I'm missing something.
Any help or ideas are grately appreciated.
Thanks Tom.
The final goal is to build a speed controller for a light ev motor bike, nothing to complex, no reverse, regen braking, motor braking or soft start. Just to control the speed of a series wound motor, much the same as the older electronic rc esc's.
The planed motor will be in the values of 100v and 120A continuous so about 430A intermittent.
The way I intended on doing this is with a "bank" of parallel 100v power mosfets.
The problem is driving the "bank" I can not find any mosfet drivers that will handle that kind of load.
The first idea was to use a simple small low voltage PMW motor speed controller to drive the "bank", I'v seen this done but I doubt it was to affective as the square wave patten will have already been through a set of mosfets of some kind and not be so sharpe because of the charge and discharge capacitance and that will mean the "bank" will spend a much longer time in the half on-off stage wasting power and making lots of heat, as far as I can tell.
The next idea is to use a normal 20khz ish mosfet driver with potentiometer, to drive a simple audio style amp to then drive the "bank".
The question is this, will the wave pattern from a PMW speed controller have the effect i think it will have if i then use it to drive more MOSFETS?
Will an audio style amp keep the wave form from a MOSFET driver usable for driving the "bank" as I'm not familiar with different types of amp's and the full on full off speeds.
One last thing, I have seen many 100v power mosfets with high current ratings say 50-70, witch is fine, but they mesure about 1cm high, and the legs are 1mm x 0.5mm, I can not see how the legs can handle any usable current at all, these are from rs, I'v studied the data sheets but perhaps I'm missing something.
Any help or ideas are grately appreciated.
Thanks Tom.