Multiple parallel-connected dab-based solid-state transformer for hybrid dc/ac micrognd system

Abstract

To cater unceasing supply to the modern AC and DC loads, renewable energy resources integrated hybrid DC/AC microgrid (HMG) are considered as a viable technological solution. In this study, a multiple parallel-connected bidirectional converter (MPBC) topology has been proposed to enhance the solid-state transformer (SST) power handling capability with flexible control of the HMG. To improve the high-frequency AC-link power quality and to control the power transfer through the SST in each dual active bridge a split-step phase shift (SSPS) control technique has been used. A power management control strategy has also been proposed for efficient power transfer between the sources and loads of the HMG. The proposed MPBC- based SST is suitable for interconnecting multiple utility feeders. Multiple redundant utility feeders ensure stiff bus voltages and omit the power supply reliability issues. The operation of the proposed MPBC-SST converter system with corresponding control algorithm is verified through the simulation results in both grid feeding and grid fetching operating modes. Furthermore, experimental results are presented to validate the performance of the proposed MPBC-SST converter along with its proposed controller strategy.