Bang-bang control of three-level bidirectional DC-DC supercapacitor energy storage system with midpoint potential self-balance

In this paper, the working principle of three level bidirectional DC-DC converter was introduced. The relationship between output voltage and input voltage was deduced. From this, the relationship between inductance current and duty cycle was received. Then, the influence of switching states on the inductance current in supercapacitor energy storage system was analyzed. Bang-bang control method was proposed from this. The charging and discharging control of the three-level super capacitor energy storage system were completed, in which bangbang control method was adopted, and the midpoint potential was balanced by redundant switching vectors in time. Finally, the simulation of three level bidirectional DC-DC super capacitor energy storage system was carried on PSIM simulating software. The correctness and effectiveness of this method are verified. Its structure is simple, its response is faster, and the midpoint potential in DC side is balanced perfectly by itself.