In this paper, high-efficiency, extremely high step-up and step-down bi-directional DC-DC converter is proposed. The proposed converter consists of a flyback and an isolated switched-capacitor cell to achieve high cost competitiveness for the extreme operation. The output of the flyback converter and that of the isolated switched-capacitor is connected in series to obtain a high voltage step-up. In the reverse direction, then, this converter can be an extremely voltage step-down one. For the design of the controller, the small-signal transfer functions of the converter are derived. Finally, a 100W hardware prototype of the proposed converter is implemented. To improve the efficiency of a PV system employing the proposed converter, a maximum Power Point Tracking (MPPT) method is applied with Perturb and Observe (P&O) method. To demonstrate the operation of the bidirectional converter, the main switch current is used for the power control. All of these controls are implemented with a digital signal processor (DSP).
[1]
Joung-Hu Park,et al.
Series-connected isolated-switched-capacitor boost converter
,
2012,
Proceedings of The 7th International Power Electronics and Motion Control Conference.
[2]
Joung-Hu Park,et al.
Controller design of power conditioning systems with energy storage device for renewable energy source under stand-alone operation
,
2012,
2012 Twenty-Seventh Annual IEEE Applied Power Electronics Conference and Exposition (APEC).
[3]
Joung-Hu Park,et al.
Influence of the Parasitic Inductor Resistance on Controller Design of Boost Converter for Renewable Energy System including an Energy Storage
,
2011
.
[4]
P. T. Krein,et al.
Differential Power Processing for Increased Energy Production and Reliability of Photovoltaic Systems
,
2013,
IEEE Transactions on Power Electronics.