A high-frequency, low-voltage stackable full bridge module for modular mutli-level cascade converters (MMCC) research

A new small full-bridge module for mutli-level cascade converter (MMCC) research is presented. Each full-bridge converter cell is a single small (65 x 30 mm) multilayer PCB with two low-voltage high-current (22 V, 40 A) integrated half-bridge ICs and the necessary isolated control signals and auxiliary power supply (2500 V isolation). All devices are surface-mount, minimising the cell height (4 mm) and parasitic inductance. Each converter cell can be physically stacked with PCB connectors propagating the control signals and inter-cell power connections. Many cells can be trivially stacked to create a large multilevel converter leg with isolated auxiliary power and control signals. Any of the MMCC family members is then easily formed. With a change in the placement of the stacking connector, a parallel connection of bridges is also possible. The operation of a nine-level parallel full bridge is demonstrated at 12 V and 384 kHz switching frequency, delivering a 30-W 2-kHz sine wave into a resistive load. A number of new applications for this novel module (aside from MMCC development) are listed.