Alternative Source Port Tolerant Series-Connected Double-Input DC-DC Converter

The two input sources of a series-connected double-input dc/dc converter (SCDIC) can power the load simultaneouslyor individually. But the two sources must supply the load simultane-ously when the output voltage is greater than either of the two inputvoltages. This is a big issue, especially in double-input alternativepower systems in which two input ports are, respectively, inter-faced with a renewable energy source and a storage element dueto the randomness and intermittency of renewable energy sources.This paper proposes a topology scheme using a combination of acharging switch and an SCDIC. In the case of one port poweringor one input being short-circuit, the proposed topology forms abootstrap circuit with the help of the charging switch and SCDICswitches to charge the powered off port and maintain the expectedoutput voltage, which enhances the reliability of double-input con-version, making it robust against one input powering off and faulttolerance against one input short-circuit. The operation principleand the corresponding power management strategy are presentedin detail. In addition, charge–discharge feature of the bootstrapmode is analyzed and the charging loss is calculated. Experimentalresults validate the feasibility of the proposed scheme.