We are using IKCM30F60GD for a 220V 200Hz 9A motor drive circuit with 8kHz sinusoidal PWM. We have the PCB ready and is driving the motor as desired.
However, we need to have protection for shorted motor windings, i.e. U-V or V-W or U-W shorted.
We have created a current sense circuit that creates a voltage well above 0.47V (limited to 3.1V) at I_TRIP pin in case of a high current(33mV/A), and this circuit rises I_TRIP voltage to 0.5V in 1.2usec. That trips the IPM successfully and shuts the output successfully. We have tested the circuit with down to 2 ohms instead of direct short, and it worked flawlessly.
However, when we go down near 1 ohm, or short, the IPM shuts down the output, however it dies. After it is dead, we have measured inbetween P,Nx,U,V,W and it seems like IGBTs are fine, we measure the same values as a non-faulty IPM. However, there is a diode reading of 1.7V on VDD to VSS with the multimeter(VSS on cathode lead).
And when we power the faulty IPM using only VDD and VSS pins with +15V, we have 200mA current drawn. And the heat on the package is coming from the point just in the upper side of pin 7.
Why is this happening?
Attached is the part of the package that heats up.Show Less
TLF35584 data sheet indicates "In case of over voltage at pin QTx, the corresponding tracker will be switched off, the event will be stored in an SPI status register (MONSF1) and an interrupt will be generated."
When the over voltage event ends, how/when does the tracker turns back on ?
- does tracker self recovers and turns on or
- does clearing the status register MONSF1 recovers the tracker ?