Interleaved converter with massive parallelization of high frequency GaN switching-cells using decentralized modular analog controller

Interleaving switching-cells is an appropriate approach to increase current capability of power converters and, at the same time, to increase the converter efficiency. Improvement in the power density of these converters can be achieved by the use of high-performance switches, such as wide bandgap semiconductors, with the consequent increase in the switching frequency. We develop here a fully decentralized analog controller which automatically generates “very” high frequency interleaved carriers for a buck converter with high number of switching-cells. Also, this controller regulates the output voltage (voltage regulation loop) and compensates current unbalance between the switching-cells (current sharing loop) using an innovative control technique. Furthermore, since the controller has a modular structure in a Daisy chain configuration, the number of switching-cells in operation can be automatically selected in order to maximize the converter efficiency for different output power. Besides that, Adaptive Voltage Positioning (AVP) technique is used in the controller in order to limit under and over voltage for different load variations and, at the same time, to increase the system dynamics. The controller operation is verified in a 12/5V buck converter having up to 25 interleaved switching-cells composed of Gallium Nitride transistors switching at 500kHz.