Cascaded Buck-Boost converter based on energy storage unit and its control method

With the integration of distributed power sources based on wind and photovoltaic power into the grid, due to the fluctuation and uncertainty of its output, the characteristics of distributed power generation and grid load demand characteristics are not uniform on the time scale, making the distribution network integrated the increased complexity of load characteristics brings a series of problems and challenges to the distribution network. This paper proposes a cascaded Buck-Boost converter and its control method based on the energy storage unit. First, analyze the energy storage unit structure of the cascaded Buck-Boost converter and the working principle of the converter; secondly, determine the three working modes of the cascaded Buck-Boost converter, and then select the droop according to the different operating modes of the converter Control is used as the control method of each energy storage unit module. Finally, a simulation model is built to verify the energy storage unit and the selected control strategy. The simulation results verify that the proposed converter structure and its control method can well solve the distribution network factors. The instantaneous power imbalance of the system caused by distributed power access.