IGBT with X-Ray Machine

A 48kW resonated converter involves four power modules, per module contains two paralleled IGBTs and ant parallel diodes. They are arranged in a half-bridge or push-pull configuration depending on the input, at 400Vac or 200Vac. At maximum power, peak load current is 550A at 50 kHz, or 275A per module for 48kW out. The generator is zero-voltage switched to create a continuous series resonant output current that's transformer-isolated stepped up and rectified to the desired output level. The output voltage is regulated by a DSP based frequency modulated controller, with dual loop feedback on resonant current and load kV. For a range of output power, the system operates from 48 kHz up to 68 kHz with a resonant LC shunt across the load transformer. With fundamental series resonance at 48 kHz, the shunt resonates at 68 kHz. At low frequencies, the generator functions near resonance, with high power throughput. As frequency increases, the impedance rises the load being shorted by the resonant shunt. At 68 kHz, power is zero. Minimum size is important for state of the art X-ray equipment. In this version of the converter, the four ZVS modules with their tightly packed IGBT and FRED chips require only ¼ of the surface area formerly used. Integration of drivers, isolation, and ZVS logic circuitry further shrinks the footprint. Control signals have less distance to travel, which improves noise immunity and mechanical.