Research On Digital Control Technology Of Online UPS Based On DSP

With the pervasive application of IT, IC industry and PC, the security conscious of the data has been greatly improved for individuals and businesses. Various kinds of communication equipment and storage devices need to steadily run 24 hours a day, thus it results in the expansion of the great demand for uninterrupted power supply(UPS). At the same time, in terms of technical level, the progress of modern information technology is driving rapid pace of constant voltage and constant frequency(CVCF) power supply towards digital direction. This dissertation focuses on the study of the digital online UPS of three-phase input and output under the power of 20 KVA. This dissertation puts forward a new control strategy for PFC control and new method for designing the inverter controlling parameters, the simulation and experiments are achieved good performance.First of all, the classification of UPS, the current situation of the development, industry dynamics and the future development direction are introduced. And the topology of the online UPS is depicted. The average state space method is used to abstract out the controlled model, then, the control methods are proposed, analyzed and compared. The detailed control structure diagrams and bode charts are used to analyze the dynamic and steady performance. The specific control consists of the following two aspects, PFC control as AC/DC control, inverter control as DC/AC control. Simulation and experiment are used to prove the validity and feasibility of the proposed the control methods. Many times of test data meets the national standard. It shows that the proposed control scheme can decrease the THDI and THDV and stabilize the output 50 Hz sine wave well.