Capacitor mainly acts as the rectifier filter in the Inverter circuit.
Power input using three-phase AC through the bridge rectifier output the DC pulse. In this part we can use C43/C45 that can better withstand the high pulse current and resistance high voltage.
In the circuit, using the IGBT snubber capacitor (C51/C54) can do a good buffer absorbing. After the IGBT the output voltage in secondary reduction voltage it needs a coupling blocking capacitor (C74/C75) to rectifier filter and output. That realizes the whole inversion process from low frequency to high frequency.