Study on Optimization of Low-Voltage Multi-Port Flexible Interconnection Device in AC/DC Hybrid Distribution

At present, the back-to-back multilevel modular converter (BTB-MMC) used in low and medium voltage flexible interconnection projects has the disadvantages of high cost and large footprint. Based on MMC, a multi-port flexible interconnection device for AC/DC hybrid distribution network is designed. Firstly, the topology structure and power regulation principle of the device are described by constructing the model of the low and medium port multi-port flexible device. Secondly, an improved inverter model based on independent center line module is proposed, and a multi-objective optimization compensation strategy for multi-function grid-connected inverters is proposed, which effectively improves the ability of independent inverters to carry unbalanced loads and optimizes power quality. Finally, a set of 750 V/50 kW experimental prototype is built, and the performance of the prototype is tested to verify the advantages of the voltage stability of the device.