Research On High Power Factor Rectifier Of On-Line UPS

With the development of power electronics, microelectronics and computer, uninterruptible power supply (UPS) which have been widely used in banking, securities, military, medical, aerospace and so forth, are widely selected for the protection of sensitive loads such as PC, communication systems and medical equipments. Meanwhile, high-performance digital signal processor (DSP) has been rapid development made the digital control more precise for the UPS. Thus the stability and the reliability of the whole UPS system have been enhanced.Advantages this thesis focused on the VSR (Voltage Source Rectifier) research and the technology of the PWM rectifier is summarized. It has completed the following work:1,In this paper, the status and future direction of the UPS are analyzed, After that , the development of the rectifier and the current situation and ways to improve power factor, on this basis, given the use-voltage rectifier technology.2,Three-phase VSR from the main circuit topology, based on the three-phase static coordinate system rectifier system model. In the model system on the basis of a new-for-flow analysis, a cycle of steady-state power grid to run when the three-phase VSR is divided into 12 working on the current and voltage control of the basic principles to further improve the Its control technology has a positive meaning.3,The characteristic chip is taken into account, in this dissertation ,Given the diagram of the system software, the main voltage and current detection circuit, driver circuit and the protection of the circuit design. Introduced the implementation of the system software, gives the PWM drive and A / D sampling arising from the process, the system's timing and structure of the interruption, as well as the important process flow chart.4,MATLAB software used to control the simulation methods and comparative analysis. The simulation results show that: In this paper, control, PWM rectifier can be a stable output voltage direct current, at the same time can be close to the rectifier input power factor of 1.