Analysis and Design of a Modular Switched Capacitor Converter With Adjustable Output Voltage in DC Microgrid

Abstract

A high conversion ratio, high efficiency and miniaturized switching power supply converter is an important part of DC microgrid. Switched capacitors have been widely used in low-power voltage conversion applications, for small size, light weight, high efficiency, etc. Due to the structural characteristics of the switched capacitor topology, the transformation ratio of the circuit cannot be adjusted continuously. In response to this need, some control methods are proposed, most of which require more complicated control circuits or parameter design. A modular switched capacitor converter with adjustable output voltage is proposed in this paper. The topology can be modularized as required. More switched capacitor module provides higher output power and higher efficiency. More voltage regulating module provides wider output adjustment range. Its control method is simple and can be expanded to a high-power power supply as needed. The advantages of small size and high efficiency of switched capacitor topology are also retained. A 4 to 1 prototype with 12V output is built to verify the proposed topology. The peak efficiency of the prototype is 95.34% and the full load efficiency is 93.82%.