Hi Amir,

Your question seemed too general to me and I couldn't fully understand what details your question was seeking for. Nevertheless, you may find the following useful:

1) Along with all the merits that SiC switches have, there are some challenges that need to be considered when employing them (I can resemble it to driving a Ferrari race car vs. driving a Pinto car ! You can drive the race car very fast but you have to be a skilled driver or you'd crash it very bad!) One common challenge with regard to SiC based converters is managing the common-mode currents. Due to the fast switching edge rates of these devices, very high dv/dt can be generated that can charge/discharge stray capacitances from various parts of the system to the earth. Therefore, strong common mode currents can flow through the converter. These common mode currents must be managed (through proper filtering and layout design) or your converter would fail EMI compliance and you may even find controlling the converter quite challenging (e.g. you may have see ground bouncing etc.) Now, higher supply voltage can deteriorates common mode problem (due to generating higher dv/dt).

2) SiC MOSFETs have lower switching losses compared to their Si counterparts. So they can be operated at higher switching frequencies. If the switches are operated under hard-switching conditions, variation in supply voltage can directly impact the loss mechanisms. However, we should bare in mind that two loss mechanism in the switches needs to be collectively considered to judge about the effect of source variations on switch losses. Let's assume we are working under constant power conditions:

• Conduction loss of a switch should decrease if the source voltage is increased (due to decrease of drawn current) and vice versa.
• Switching losses can be either increased or decreased with increase of source voltage. Because on one hand switch voltage is increased and on the other hand the drawn current is decreased.

Therefore, we can't draw a general conclusion about the switch loss performance with regard to source variations and it should be studied for the specific case under study.

3) Load variations can directly affect the switch loss performance too. In this case, obviously the higher the load is, the higher the switch loss (conduction + switching losses) is too (again assuming hard-switching conditions.)

Good Luck!

Hi Ali.

Thank you for you response.

But I think that it is incomplete.