Eon/Eoff datasheet values clarification

JohnSullivan

Hello,
I'm running simulations to compare losses on a three phase inverter using IGBT and SiC MOSFET.
I have three questions about the information presented on the SiC MOSFET  datasheet (C3M0015065D for example).
The datasheet presents the Eon and Eoff for either the switching process to a SiC diode or a MOSFET body diode as the FWD.
Does this switching energy (Eon/Eoff) contain both the v-i overlapping losses and Coss losses?
The Eon is higher for the case the FWD is a MOSFET body diode. Is it because the reverse recovery current in the body diode is higher than in a SiC diode?
Are the values of the body MOSFET reverse recovery energy available?
Thank you

Forum_Moderator

Thank you for your post, it has been approved and we will respond as soon as possible.

AAnders

Hello,

Thanks for your question. I'm not sure what platform you are using to do your simulations, but I wanted to make sure you are aware that we have PLECS and LTspice models available for download https://www.wolfspeed.com/tools-and-support/power/ltspice-and-plecs-models/

To answer your questions:

1. Eon does not include the Coss(er) losses as this energy is dissipated inside the device, and is not directly measurable in a double-pulse setup since the current to discharge the Coss does not flow through the external connections of the device. Eoff does include the impact of charging Coss since this current will be seen in the current shunt used to make the measurement.
2. Eon is higher when using just the body diode as the freewheeling path in the opposite switch position. As you suspected, this is due to the higher Qrr in a body diode compared to a SiC schottky diode which technically has no reverse recovery current, just junction capacitance.
3. Qrr is provided for 2 operating points in the table in the datasheet. If you would like data at other operating conditions, please submit the request through a private message on this forum.

One final note is that if your design is open to using other packages, you may consider using the TO-247-4 package which has lower switching loss due to the use of a kelvin source pin for the gate drive. Please let me know if you have any additional questions.

Thanks,

Adam

JohnSullivan

Thank you very much for your answer. It is very clear.

I'll contact you via private message for the Qrr data.

Best