| Mobile power supplies provide great convenience for people to use electricity for travel and field operations.Distributed mobile power supplies based on battery energy storage are even more popular.The dual active bridge CLLLC resonant DC/DC converter with high-frequency transformer has the advantages of high-frequency electrical isolation,bidirectional energy flow,high voltage conversion gain,and high conversion efficiency.It is a typical example of energy storage converters commonly used in mobile power supplies.Topology.This article focuses on the study of the operation control strategy of the energy storage converter based on the CLLLC resonant DC/DC converter,in order to improve the operation time and load capacity of the mobile power supply.First,the working mechanism of the CLLLC resonant converter under variable frequency control is analyzed.After the fundamental equivalent circuit model of the converter is established,the gain characteristics of the converter and the influence of the resonant component parameters on the gain are analyzed.In order to improve the operating time and load capacity of mobile power supplies,two droop operation characteristics of the output voltage U of the energy storage converter with the battery state of charge SOC and the output voltage U with the output power P are designed,and the specific droop parameters are given.In the selection method,a CLLLC parameter design method suitable for variable frequency control is proposed based on the voltage droop variation range.The output voltage droop control strategy of the energy storage converter based on the principle of variable frequency voltage regulation and its control system structure are studied,and the Matlab/Simulink simulation model of the energy storage converter system and the hardware-in-the-loop simulation model based on the RT-Box real-time simulator are built.,Under different working conditions,the two droop control strategies of U-SOC and UP are simulated and compared.The simulation results show that the U-SOC droop control of the energy storage converter can increase the load time of the mobile power supply,and the U-P droop control can expand the load capacity of the mobile power supply.A set of CLLLC resonant energy storage converter experimental platform was developed,and the operating characteristics of the energy storage converter under two droop control strategies,U-SOC and U-P,were tested.The experimental results show that the two droop control strategies proposed in this paper can effectively extend the working time of the mobile power supply or improve the carrying capacity of the mobile power supply. |
