This paper describes a ultra high power IGBT inverter. This inverter is the core component of a power supply intended to charge a 6.66 μF capacitor to 30kV (3kJ) in approximately 40 ms. The primary DC source voltage is approximately 500V. The topology of the IGBT inverter is an H-bridge rated at 1200V and 2400A. A step-up transformer and a rectifier bank are connected on the output of the H-Bridge. The IGBTs are high power modules made by Semikron. For compactness, the cooling fins of the modules have been removed down to the aluminum base-plate. This was possible due to the fact that the supply is only operated in short term burst mode. The inverter is controlled by Pulse Width Modulation (PWM) generated by a HC12 micro-controller made by Motorola. The micro-controller provides control flexibility for adaptation to the characteristics of the primary DC source. The IGBTs are switched at 10kHz.