For a Voltage Source Converter based High Voltage Direct Current Transmission(VSC-HVDC)system the most important part is the VSC part because it determines main performance of the whole system. This paper proposed a new topology of PWM AC/DC converter which is cascaded VIENNA rectifier. In addition, in this paper a current controller based on the working modes of three-phase VIENNA rectifier will be introduced to control input currents. By this current controller the input currents can follow the corresponding references to achieve the goal of unit power factor. When this current controller is applied on the proposed cascaded VIENNA rectifier the performance will be investigated too. In order to verify the correctness of the current controller and the cascaded VIENNA rectifier, the prototype of three-phase VIENNA rectifier and single-phase two modules cascaded VIENNA rectifier are developed. The current controller and the proposed topology is validated by the way of analysis of the experimental results.

Presently, the fringe-field switching (FFS) television is developing to larger size. With the increase in size, as one of noteworthy problem, the flowing behavior of liquid crystal (LC) was investigated in this paper. By quantifying the cell gap variation and corner partial yellow level, we researched the effect of electric field, LC amount, rubbing orientation and electrode structure. Accordingly, the theory model of LC flowing was clarified. By tuning the above mentioned factors, the larger margin of LC amount and more uniform cell gap was achieved.

No abstract

No abstract

No abstract