Design Of Bidirectional AC/DC Converterbased On LLC Resonant

Energy storage system has broad applicat ion prospects. In addition to the applicat ion of renewable energy, as an emergency power systems, and the smart grid, and other new techno logy, energy storage techno logy is an integral part o f the core techno logy. Wit h the development of energy storage techno logy, the bidirectional AC/DC converter with the applicat ion o f energy storage system will also be widely concerned. Bidirectional AC/DC converter is very important for the energy conversion between the energy storage system and the grid. This paper mainly studies the main circuit and the key techno logy of the bidirect ional AC/DC converter for energy storage system.This art icle designed duty rat io feed-forward control scheme based on Simplified PWM modulat ion strategy. Simplified PWM contro l can effect ively reduce the switching losses o f the converter. The state-space averaged equat ion under Simplified PWM modulat ion is derived, and the dut y rat io feed-forward contro l scheme is designed. Then studied the circuits operat ing state o f full-bridge AC/DC converter using dut y rat io feed-forward control under the simplified PWM modulat ion, and gives simulation results.The forward and reserve direct ion mode operat ing charact erist ics of bidirectional LLC resonant converter is analysed, The synchronous rectificat ion contro l and Interleaved LLC scheme is designed. By the forward and reserve direct ion mode ac the equivalent model, the circuit characteristics o f the forward and reserve direction mode is derived, then the detail operat ing characterist ics o f bidirectional LLC resonant converter is analysed, the switching frequency range of the bidirect ional LLC resonant converter is set opt imal. The contro l program of the low vo ltage side synchronous rectifier driver and Interleaved LLC is designed.The system co mponents and the co mpensation loop parameters is designed, and a experiment system is set up. According to the design specificat ions, the main parameters o f the system design is completed, in order to ensure stabilit y o f the system, the contro l loop co mpensat ion o f full-bridge AC/DC converter and LLC resonant converter is designed. Experimental system is built to verify the so ft starter of bidirect ional AC/DC converter, power commutation control, the ZVS of the switches. Fro m experiment result, it is confirmed that the system have a good dynamic response. Finally, the efficiency of the bidirect ional AC /DC converter was test.Through theoretical analysis, simulat ion and experimen tal verificat ion showed that use the simplified PWM modulat ion and duty rat io feed-forward contro l can effect ively reduce the the switching losses o f full-bridge AC/DC converter; select opt imal switching frequency range o f the bidirectional LLC resonant converter, make the parameters is designed to make the converter work in ZVS region, can improve its efficiency obviously.