Conversores cc-cc não isolados com ampla taxa de conversão de tensão baseados nas células de comutação de múltiplos estados

Abstract

This paper presents the study and development of non-insolated DC-DC converters with high voltage conversion rate based on multi-state switching cell. The twelve proposed converters are used in applications where a high voltage conversion rate is required. Typically, the low voltage at the terminals is found in photovoltaic panels, small wind generators, fuel cells and battery banks. These voltage values should be raised to levels around 200 V, 400 V or 800 V. The main haracteristics of these converters with a high voltage conversion rate are: reduced current stress in the switches due to current splitting; High power processing capacity; Possibility of associating other secondary windings depending on the output voltage requirement; The multiphase transformer secondary can have two types of connections (star or polygon); Low current ripple in the inductor, which implies in the eduction of volume of the magnetic element; Low voltage ripple in the capacitors, which implies in reducing the size of the capacitor. The converter with four-state cell and high voltage conversion rate has three operating regions where the first operating region, with the duty cycle less than 1/3, has a lower static gain compared to the other two operating regions due to nonvoltage induction in the secondary of the transformer in one of its stages of operation. To validate the theoretical study, a prototype with 3 kW output power, 96 VDC input voltage, and 400 VDC output voltage, was implemented in the laboratory.