| The multi_module and intelligent UPS system isn't restricted by power capacities.Therefore,it can not only flexibly be used to expand power system capacities and build up parallel redundant systems to improve the reliability,but it can also find and deal with the fault of UPS in no time ,and shorten the time caused by the fault or inspect,which make it become a true UPS. Six single-phase double-conversed on-line UPSs are designed in this paper.And we realized parallel operation of two and three and six 3KVA UPS, At the same time,we build the monitor-net on the base of CAN in this system. In order to satisfy the engeering need and take the advantage of digital and simulate control ,the outer voltage loop is digitally controlled and the inner current loop is controlled by hysteresis band with simulate circuit for PFC control in the sect of rectifier.and the design of controller parameters is introduced.The circuit of half-bridge inverter is adopted in the sect of inverter,The models of SPWM inverter are established and an example is given to explain how to design PI controller parameters with voltage RMS feedback. This paper introduce the characteristic,the general situation of development and the net buildup of CAN BUS.and analyze the five key technology of the CAN ,such as the communication protocol,the format of frame,the arbitration,the Acceptance Mask filter and the BUS syhchronization,At last,this paper also introduce the hardware and software of the intelligentization of the system.Models of parallel system are establishied to analyze the speciality of the circumfluence ,then the principle of the parallel operation is analyzed in detail if.the infuence of inverter's output impedance to load-sharing in parallel operation is thought or not .An new way to adjust the amplitude and phase of output voltage independently is given at last.The experimental results about PFC rectifier ,inverter and parallel operation are given and analyzed at the end of this paper. |
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