Design and Implementation of the Bidirectional DC-DC Converter with Rapid Energy Conversion

Abstract

The bidirectional DC-DC converters are widely used in the energy storage system (ESS) and DC distribution system. The power capacity is limited when the converter is operated with smooth power transfer. In addition, the directions of the inductor current and the capacitor voltage cannot change instantaneously. In this study, a rapid energy conversion technique for smoothing and accelerating the energy transfer under the same specification of the main components in steady state is proposed. Moreover, a bidirectional DC-DC converter with a high conversion ratio is proposed to overcome the commonly low voltage input from renewable energy sources. The operating principles of the proposed converter’s step-down and step-up modes are discussed in this study. Furthermore, to achieve rapid energy conversion, digital control is a crucial component in the converter system. A digital signal processor is used as the control platform, and a control strategy is formulated to achieve rapid energy conversion. The bidirectional DC-DC prototype converter with a 24 V battery, a DC bus of 200 V, and an output power of 500 W is constructed to confirm the feasibility of rapid energy conversion. The proposed converter can be operated in CCM, BCM, and DCM conditions. The transfer period can be completed within one switching cycle when the proposed converter is operated in BCM or DCM. The energy is freewheeled before energy conversion when the proposed converter is operated in CCM condition. In the experiment, the minimum transfer period is 6.29 µs on the DCM stage.

Development of a Bidirectional DC–DC Converter with Rapid Energy Bidirectional Transition Technology

“…Some previous publications briefly mentioned the transient time; however, the specification of transient time was not discussed in detail. The transition time discussed in our previous work was around 15.4 µs to 19.3 µs during the CCM stage [48]. Three different stages (DCM, BCM, and CCM) were discussed in the previous work.…”

“…Z. Chen et al presented an energy-conversion concept in a bidirectional DC-DC converter [48]. However, the transition period could not be balanced in two operation modes.…”

“…15, x FOR PEER REVIEW 16 of 20 in our previous work was around15.4 μs to 19.3 μs during the CCM stage[48]. Three different stages (DCM, BCM, and CCM) were discussed in the previous work.…”

A Common-Ground Bidirectional Hybrid Switched-Capacitor DC–DC Converter with a High Voltage Conversion Ratio

“…Multilevel [7] or quadratic [8] topologies can also be used in applications that require high voltage conversion ratios, but in comparison with them, hybrid converters usually have the advantages of a simpler structure and control. Bidirectional DC-DC converters with high voltage conversion ratios are used in electrical and hybrid vehicles [9][10][11][12], energy conversion and storage systems [13][14][15][16], and microgrids and distributed generation [17,18].…”