A power router based on modular multilevel converter integrating ultracapacitor energy storage system

In this paper, a modular multilevel converter (MMC) integrated ultracapacitors energy storage system (UCESS) and the control strategy are proposed for Power Router. Half bridges integrated with UC modules are utilized as the sub-module (SM) of the converter. Due to the integration of UCESS, the input power and output power can be decoupled, which means that the power relationship of the Power Router can be flexible. This paper analyzes the topology and mathematical model of a port power decoupling Power Router based on MMC-UCESS, and studied the top-down energy management strategy, including the rational allocation of power, port power decoupling control, energy storage capacitor status determination and voltage balance control, DC bus voltage control and circulating current control. The operation mode of the Power Router and the method of using the UCESS to adjust the power flow pattern is discussed. Finally, a Matlab/Simulink simulation has been built to verify the proposed system.