Dual-Hysteresis Control of Bi-directional Noninverting Buck-Boost Converter for Wide Voltage Range in Energy Interconnected Systems

The energy interconnection system (INS) connects multiple power systems to enable energy transfer among power Systems. By connecting two renewable energy systems with Bidirectional converters, the energy transfer of the systems can be realized. Bidirectional non-inverting buck-boost (BNBB) converter is widely used in this application. Energy interconnection system based on BNBB can not only achieve efficient energy transfer, but also achieve a wide range of input and output voltage conversion. Firstly, an energy interconnection system based on BNBB is presented, which can realize efficient energy transfer of power systems in a wide voltage range caused by long cables. Secondly, a Dual-Hysteresis Modulation (DHM) and a control strategy is proposed for BNBB, which enables BNBB to operate in buck mode, buck-boost mode, boost mode and filter mode according to the port voltage relationship and control signal. These four modes increase the overall efficiency of the converter. With the control strategy, the disturbance rejection while mode switching is optimized by hysteresis design and continuous voltage ratio. Finally, a prototype with an input of 80V ~ 120V and an output of 80 ~ 150V @ 1500W is fabricated to demonstrate the DHM and its corresponding control strategy. The experimental results have verified that the proposed control method can achieve smooth mode switching.