I am trying to control a 1/3HP 12VDC motor using PWM, which is input into a dedicated IGBT driver(Vout -5 to +12), which then in turn should fire my IGBT. Without the IGBT connected everything seems to work fine, PWM signal is perfect and my IGBT gate drive signal is perfect.
My problem is that when the IGBT and motor are connected it only responds at 85% + PWM. Anything below 85% and the motor is totally off.
Has anyone experienced this before? Here are the links to he IGBT, driver IC, and my schematic.
i've got a fuji 1mbi300n that ive been using with a UCC27322 gate drive for a while, and its working great so far all the way up to 30 something kilohertz. first thing i would do is see if you can get an oscilloscope and view the waveform on the gate. second thing, where is your -5v and +12 coming from? do they have a common ground, because they need one, and that should connect to the emitter of the igbt.
The -5V and +12 have a common ground, which is connected to the emitter of the IGBT. Here are a few screen shots of the gate signal. The last one is of the IGBT actually connected the first two dont have the IGBT connected.