Interleaved Split-switched Capacitor Boost Converter

Abstract

An interleaved split-switched capacitor (ISSC) boost converter for the photovoltaic energy storage system is proposed in this paper. The converter has the continuous input and output currents, and operates under two typical control methods: the symmetrical control (d1=d2) and the current sharing control (d2=1/(2-d1)), where d1 and d2 are the duty cycles of the two switches, respectively. Under the symmetrical control, the voltage gain is G=(1+d1)/(1-d1), and the voltage stresses across all the power semiconductors are half of the sum of the input voltage Uin and the output voltage Uo. Under the current sharing control with the continuous conduction mode (CCM), the current of the two-phase inductors can be shared within the full duty cycle range without detecting the input current. The voltage gain is twice of the conventional boost converter, and the voltage stresses across the power semiconductors are (Uin+Uo/2) and Uo/2, respectively. In this paper, the working principle and the steady-state characteristics of the proposed converter under the CCM and the two control methods are analyzed in detail, and the correctness of the theoretical analysis is verified in a 500W/50kHz prototype experiment.