Uninterruptible Power Supply Control Strategy Research

This year as the electrical equipment in the military, industrial, communic-ations,transportation and other application popularization, the electrical equipment is more and moreused in many sophisticated, important occasions. With more and more dependent onproduction and living of electrical equipment, and electrical equipment can normal andreliable operation, every moment is related to people’s production and life. And more andmore important precision of electrical equipment is becoming more and more high to therequirement of power supply, no power, voltage transient and surge, harmonic and frequencydrift, etc, and these abnormal voltage often accompany in the power grid, thus theuninterrupted power supply was born. Along with the market requirements for uninterruptedpower supply of high performance, high efficiency, etc, for uninterrupted power supply hasbrought the development opportunity, but at the same time, the control strategy is also putforward the new challenge, this article will study of uninterrupted power supply controlstrategies.This article first to the kinds of uninterrupted power supply are introduced, includingreserve type UPS, on-line interactive UPS, pure on-line UPS, double on-line UPS invertervoltage compensation. This paper introduces the working principle of each UPS as well as theadvantages and disadvantages, and for all kinds of UPS to each other in terms of cost,performance advantage. And now typically pure on-line UPS, for example, the uninterruptedpower supply system structure and each part are introduced.Second, in the modern industry standard for uninterrupted power supply of rectifier andinverter standard requirements. In this paper, the high power factor rectifier, inverter controlstrategy were studied respectively, and its working principle, the establishment of themathematical model. Rectifier control method based on synchronous rotating coordinatesystem is introduced, the current can be astatic to track the input voltage and bus seriescapacitor in detail on pressure control, established the system control block diagram, andexpounds the rectifier controller design based on synchronous rotating coordinate systemtransform. In view of the inverter output voltage quality requirement, this paper designed theinverter voltage current double loop control strategy, the repetitive control technology. Onrepetitive control technology and its die design are studied, and the repetitive controller andcurrent loop PI controller is designed. In a power rating of100kva UPS on-line control of high power factor rectifier and inverter, a experiment is carried out to verify the rectification.Finally, in view of the on-line UPS for unloading process, middle busbar voltage on thecapacitor will appear relatively large fluctuations, increase the risk of uninterruptible powersupply operation phenomenon is studied. For unloading process, appear busbar voltagewaveform, the reasons for the proposed two-stage type cooperative control before and afterthe inverter control strategy, the control strategy are analyzed, and the controller design,feasibility and superiority of this method is verified by experiment.