Research On The Master-Slave Parallel Control Technology Of Three-Phase Inverter Based On CAN Bus

Multi-module paralleling is considered as one of the most important partin the field of inverter technology. The multi-module parallel inverter systemcan not only flexibly be used to expand power system capacities but built upparallel redundant systems to improve the reliability.Firstly, on the basis of analysis of parallel operation theories andtechnology, the paper develops mathematical models about three-phase inverter,analyzes the principle of parallel inverter system and proposes powercharacteristics and characteristics about closed loop regulation of voltage.Secondly, the paper studies the inverter control method "dual loop on voltageand inductor-current feedback with an outer average voltage loop", introducesthe characteristic of CAN bus, designs the hardware and software for the keytechnology of the parallel system: load sharing and synchronization control.A master-slave parallel control three-phase inverter system prototypebased on CAN bus is constructed. Theoretically, the newly designed systemhas the following merits: The using of DSP is adopted to realize full digitalcontrol;the system is designed under rotating coordinate, so the output ofparallel system can follow the reference without static error;thecommunication is achieved by CAN bus, with less mutual wires.The experimental results verify the parallel strategy. The resultsdemonstrate that the Master-slave parallel control technology of three-phaseinverter based on CAN bus has good dynamic current-sharing performance andstable synchronization. Besides, full digital control reduced the complexity ofthe parallel system and improved its reliability and feasibility.