I am currently working on the gate driver system, I am a bit confused about the driving power and current requirements for IGBT driving. Are there any recommendations to the power supply required for a full 3-phase inverter? I am looking for 15V/-8V

[JKran.1]

I am working to create a 100KW 3-phase inverter to be used in an FSAE electric race car,I don't have much experience with bootstrapping and I am a bit confused about the driving power and current requirements for IGBT switching.

Thanks.

[Cristiana SCARAMEL]

Hello @JKran.1​ and welcome to the ST Community.

The bootstrap method allows to generate a voltage higher than the bus supply voltage and it is used to supply the high-side floating drivers. 

However for high power applications it is advisable to use isolated DC-DC power supply, one of each gate drivers.

The most used topology is the flyback converter with galvanic isolation between the input and any outputs.

An estimate of the power required for power supply sizing is given by: fsw x Qg x (VH-VL) where:

• fsw: swithcing frequency
• Qg: gate charge of you power transistor
• 'VH-VL': output volatge range, in you case '+15 - (-8)' --> 23 V

Let me know if these info are useful to your project, if so consider to mark it as best answer by clicking the label "Select as Best".

[JKran.1]

Thanks for the input, one thing I noticed from looking at the STGAP2HSCM eval board is that it uses some DC/DC to generate the 15V/-8.7V but the output current is only 80mA/40mA but the expected drive current is around 1A. Also if I were to find a high enough power supply would I be able to use just one to supply multiple drivers?

[Cristiana SCARAMEL]

Hello @JKran.1​,

the output current values for DC/DC converters mounted in the EVALSTGAP2HSCM board are rms current values.

The gate drivers works in switching mode so you have to consider the peak current an the duty cycle of PWM input signal.

Note that you will need to use a DC/DC to supply each gate drivers, so in your three-phase inverter you will need 6 DC/DC converters.