An Integrated Bidirectional Tri-port Microconverter for Hybrid Solar Plants

This paper presents a novel isolated bidirectional tri-port microconverter (TPMC) for hybrid solar plants that integrates solar panels with bidirectional energy sources, such as batteries. The proposed TPMC achieves high-performance tri-port functionality with minimal component count using the developed mode-sequence-based control scheme. It also features inherent ability to manage and recover the energy stored in leakage reactance leading to enhanced efficiency, and reduced stress on the switching devices. The mode-sequence-based control strategy realizes a simpler and low-cost implementation. Further, it provides flexibility in overall plant design by achieving an autonomous and system agnostic operation of TPMC. This paper presents the concept of proposed TPMC topology and its control scheme with a detailed discussion on its principles of operation, and verification using simulation and experimental results. The presented simulation results essentially highlight the operation of TPMC in various modes transferring power among its ports. A 1kVA prototype has been constructed with two 48V DC-ports and a three-phase current-source-inverter (CSI)-based AC-port connecting to a 480V AC load/source to validate the principle of operation of TPMC and its control. The presented experimental results demonstrate the efficacy of the TPMC in realizing inherent leakage energy management and power balance among its ports.