marcos
1 kW
- Joined
- Nov 19, 2016
- Messages
- 348
Slowing down the switching won't hurt much if you don't use very high switching freq like 25+kHz. High end VESCs often switch at 25 or 30khz because the observer works better with more sampling per second, but you can halve that by sampling on both V4 and V7.
Its important to take a look at the gates voltages to make sure miller capacitance is not turning ON your mosfet due to high dV/dt.
With high power stuff its not a problem because gate driver OFF is like -8V, you are far away from a turn on (Vth=3V for example).
But cheap gate drivers turn OFF with 0V, and with an Rg!=0 so they kind of suck holding the gate OFF. Small fets can turn on at only 2.5V so its worth taking a look. If it fully turns ON you get a shoot through!
The 50A waveform looks great!
Its important to take a look at the gates voltages to make sure miller capacitance is not turning ON your mosfet due to high dV/dt.
With high power stuff its not a problem because gate driver OFF is like -8V, you are far away from a turn on (Vth=3V for example).
But cheap gate drivers turn OFF with 0V, and with an Rg!=0 so they kind of suck holding the gate OFF. Small fets can turn on at only 2.5V so its worth taking a look. If it fully turns ON you get a shoot through!
The 50A waveform looks great!