Modeling and analysis of a three phase dual active bridge isolated bidirectional DC-DC converter

High power DC-DC converters have become very important with developments in especially electric vehicle, renewable energy conversion, aerospace, and railway applications. Most of these applications require DC-DC conversion stages that are also very important for the system efficiency. Since the energy conversion takes place at high power levels in these applications, DC-DC converter stages are very effective for the system efficiency and stability. In addition, bidirectional energy transfer and low weight requirements are common issues for most of these applications. This fact requires some considerations and system improvement activities to provide more stable and efficient systems. The dual active bridge (DAB) topology is one of the effective topology that contributes to overcome these problems. Dual active switching elements are used to provide bidirectional power transfer and high frequency isolation transformer is used to provide low weight system design. In this thesis a three phase dual active bridge isolated bidirectional DC-DC converter is modeled and analyzed. The input voltage is determined as 600 V the output voltage is determined as 800 V and the system nominal power is determined as 80 kW. The Input and the output voltages and the power range are determined based on railway operating ranges. Unstable conditions of voltage and the load are also considered in this system design.