Analysis and control of partial power processing nonisolated bidirectional DC‐DC converter

Abstract

SummaryA partial power processing non‐isolated bidirectional DC‐DC converter is proposed, which is composed of non‐isolated bidirectional DC‐DC converter and direct power flow path. Part of the power of the system is transmitted from the power stage to the load through the non‐isolated bidirectional DC‐DC converter, while the other part is transferred via the direct path without processing by the non‐isolated bidirectional DC‐DC converter. This topology not only enhances the energy conversion efficiency but also has the remarkable advantages of high energy density, simple design, small volume, light weight, and low electromagnetic interference. It can be applied in various two‐way energy management scenarios such as photovoltaic, fuel cell, and super capacitor energy storage. The analysis of the operating principle reveals that the converter can realize the increase and decrease of input voltage and the bidirectional flow of current. When the bidirectional DC‐DC converter steps the voltage down, the partial power converter is in the step‐up mode of reverse transmission. As the bidirectional DC‐DC converter is steps input voltage up, the partial power converter is in step‐down mode of forward transmission. The differential equations and mathematical models of each operating mode are established, and the appropriate voltage feedback control strategy is proposed. Finally, a prototype is constructed and experiments verify the analysis.