A Phase-Shift-Modulated Resonant Two-Switch Boosting Switched-Capacitor Converter and Its Modulation Map

In this article, a phase-shift-modulated resonant two-switch boosting switched-capacitor converter (RTBSC) and its modulation map are proposed. Compared with the traditional RTBSC, all diodes are replaced by active switches and then phase-shift modulation is applied. The advantages of the modified topology are obtained as follows. First, the voltage gain can be regulated efficiently either below or above the nominal value within wide range (about ±20%) even at light-load condition, making it suitable for applications with voltage fluctuations, such as the battery charging/discharging system, photovoltaic system and battery/PV voltage equalizer. Second, the conduction loss is reduced by replacing all diodes in RTBSC with low turn-on resistance transistors and adopting phase-shift modulation, especially for high-order and high-gain configuration. Third, all switches achieve the zero-voltage-switching (ZVS) turn-on, reducing the switching loss significantly. Fourth, the soft-charging property smooths the current profile. Aside from the topology modification, a comprehensive analysis of operation principle, voltage gain, component stress and ZVS region is given. On the basis, a modulation map with the optimal operation region is proposed. It provides a guideline to operate and design such converters in the target gain range, low component stress and ZVS region, making up for the lack of modulation map and design guideline. A 120W prototype with low-voltage side 43-60 V and high-voltage side 150 V was designed in the optimal operation region to verify the above analyses.