Abstract
This study presents a four-phase interleaved high voltage conversion ratio bidirectional DC-DC converter circuit based on coupled inductors and switched capacitors, which can eliminate the defects of conventional high voltage conversion ratio bidirectional DC-DC converters in terms of high-voltage/current stress, less efficiency and low-power limitation. Parallel channels are used to reduce current stress at the low-voltage side and series connected switched capacitors are used to enlarge voltage conversion ratio, reduce voltage stress and achieve auto current sharing. This paper proposes the operation principle, feature analysis and optimization design considerations. On this basis the objectives of high voltage conversion ratio, low voltage/current stress, high power density, high efficiency and high-power applications can be achieved. Some experimental results based on a 500 W prototype converter (24 V to 48 V at low-voltage side, 400 V at high-voltage side) are given to verify the theoretical analysis and the effectiveness of the proposed converter.
Highlights
The development of distributed renewable energy generation systems has become a foremost topic to save the fossil fuel consumption and protect the natural environment [1,2,3]
The output/input voltage acquisition is achieved by voltage-splitter resistances, and the inductor current acquisition utilizes a LAH 25-NP current transducer
The experimental results of channel current comparison shown in the following figures are just the results with the effect of auto current sharing (ACS) fulfilled by SCs, there is no other additional current-sharing controller
Summary
The development of distributed renewable energy generation systems has become a foremost topic to save the fossil fuel consumption and protect the natural environment [1,2,3]. Energy storage elements (ESEs) are adopted to smooth and stabilize the output power and improve the dynamic response of the system. The bidirectional DC-DC converter (BDC) links the ESEs to the DC voltage bus. The DC bus voltage could be as high as 800 V when the system includes three phase. PWM inverters for high-power applications [3,4]. As the most developed and widely used energy storage devices [5,6], the battery energy storage system typically includes numerous low-voltage battery cells. A storage battery series string can provide high enough voltage, slight mismatches or temperature differences will cause a charge imbalance when the series string is charged as a unit [7]
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