An innovating topology of power converter: serial and parallel auto regulated configuration (SPARC)

The authors propose a new topology of insulated converter. Two converters, one on the primary side (input) and a second one on the secondary side (output), allow the combination of several transformers in series (for high voltage) and/or in parallel (for high current). The converters used have a "ladder" structure, thus distributing the voltage and/or the current in the switches. A particular control mode ensures an alternating voltage at the transformer terminals. Indeed, a circular shift of the instructions sent to the switches leads to various kinds of commutations, such as a hard-switching with voltage and current divided by two: the commutation losses will, therefore, be reduced by a factor of 4. The interlacing of the switches orders removes the discontinuities in the input and output electric signals, which present a weak ripple signal at high frequency, reducing the size of the associated filters. The principle of operation is illustrated, with steady-state analysis. The effectiveness of the proposed converter topology is verified by implementing a 1.5-kW 20-kHz prototype using insulated gate bipolar transistors and fast-recovery diodes.