I have been dealing with l298 and mosfet driver lately and something happen which i do not understand.
MOSFETs that i am using are ifr9510 for upper bridge and irfz34 for lower bridge(all four are heat sink eqipped). I know the irf9510 commonly is paired with irf510. Since only irfz34 available to me, i used it for testing. My question is whether this kind of pairing will generated lots of heat. I could smell something if i put my nose nearer( not burn smell) and the driver is working(even can control the speed of the motor). However, i dare not to drive the motor too long. the MOSFETs are isolated by optocouplers 4n35. I'm not sure if this has anything to do with the overheating but i remember someone said that optocoupler cannot support the high speed of the PWM.
For l298, i am getting a insensitive speed control. l298 is controlled by PIC16F877a. the speed is set at range of 0 - 128(0 for 0% duty cycle and 128 for 100% duty cycle).
Direction = anticlockwise
Max speed = 0
Min speed = 128
Direction = clockwise
Max speed = 128
Min speed = 0
Above are results i suppose to get but what i got are:
Direction = anticlockwise
Max speed = 0
Min speed = around 30 - 40 ( >40 the motor completely off)
Direction = clockwise
Max speed = around 30 - 40 (>40 motor complety on / full speed)
Min speed = 0
i know it's hard without schematic but i'm in rush now. I'll post the schematic later. Hopefully, anyone can provide me some advices and assistance in the mean time. TQ
Eric
MOSFETs that i am using are ifr9510 for upper bridge and irfz34 for lower bridge(all four are heat sink eqipped). I know the irf9510 commonly is paired with irf510. Since only irfz34 available to me, i used it for testing. My question is whether this kind of pairing will generated lots of heat. I could smell something if i put my nose nearer( not burn smell) and the driver is working(even can control the speed of the motor). However, i dare not to drive the motor too long. the MOSFETs are isolated by optocouplers 4n35. I'm not sure if this has anything to do with the overheating but i remember someone said that optocoupler cannot support the high speed of the PWM.
For l298, i am getting a insensitive speed control. l298 is controlled by PIC16F877a. the speed is set at range of 0 - 128(0 for 0% duty cycle and 128 for 100% duty cycle).
Direction = anticlockwise
Max speed = 0
Min speed = 128
Direction = clockwise
Max speed = 128
Min speed = 0
Above are results i suppose to get but what i got are:
Direction = anticlockwise
Max speed = 0
Min speed = around 30 - 40 ( >40 the motor completely off)
Direction = clockwise
Max speed = around 30 - 40 (>40 motor complety on / full speed)
Min speed = 0
i know it's hard without schematic but i'm in rush now. I'll post the schematic later. Hopefully, anyone can provide me some advices and assistance in the mean time. TQ
Eric
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