High-power compact capacitor charger

We are reporting on a new design for a compact high power Capacitor charger with a power output that far exceeds the peak power of previously reported designs [1]. For this purpose we are evaluating parallel modular designs with separate inverters, transformers, & rectifiers and compare them with designs with a larger module size. For larger power implementations with a single inverter, transformer, & rectifier, the main challenge is the design of the inverter using parallel connected IGBT transistors and their current sharing. We are demonstrating an implementation were we are combining 2 H-Bridge inverters in parallel to feed the primary of a 100 kVA compact step-up transformer. Each H-Bridge is using current mode control to enforce current sharing. The oscillators in the current mode control IC's for each H- Bridge are synchronized for this parallel mode of operation. This topology could be expanded to more H-Bridges. In order to reduce the high-frequency impedance and the windings losses of the step-up transformer [2,3], litz wire is used for both the primary winding and the secondary windings.