调速传动用四象限级联中压变频器(下)

4-Quadrant Cascade Medium Voltage Frequency Converters for Variable Speed Drives

由于性能优良,H桥级联变频器在中压调速传动中得到最广泛应用。通常这类变频器H桥中的交-直变换都采用二极管整流,使之不能四象限工作。把二极管整流改为PWM整流(AFE),变频器就可以四象限工作,但需在整流输入端增加电感和电容,控制也复杂。本文建议改用IGBT整流/回馈单元,器件按同步开关模式工作,使变频器成为具有与常规H桥级联变频器同样性能的四象限变频器,且不必像AFE那样增加电感和电容,控制也特别简单。矩阵变换器MC是一类性能优良的PWM交-交直接变频器。通过三相/单相MC桥的级联可以实现四象限中压变频。文中介绍了安川公司的MC桥级联中压变频器,并把它和基于整流/回馈单元的H桥级联中压变频器进行比较。

H-bridge cascade frequency converters have been widely used for medium voltage variable speed drives due to their good features. Usually diode rectifiers are adopted in the H-bridges of this kind of converters, it makes the converters can not work in 4 quadrants. The converters can work in 4 quadrants if PWM rectifiers （AFE） are adopted instead of diode ones. But some inductors and capacitors have to be added to the input of the AFE and its control is complicated. A proposal replacing the AFE by IGBT rectifier/ regenerative units is made in this paper, it can make the converters have similar features with diode ones, but can work in 4 quadrants and do not need add inductors and capacitors like AFE. Matrix converter （MC） is a kind of PWM AC-AC direct converters with good performances. By means of cascade of 3-phasesingle-phase MC bridges, it can be built to a 4-quadrant medium voltage converter. This kind of MC bridge cascade medium voltage converter developed by Yaskawa Co. is introduced in this paper and comparisons have been made between it and the H-bridge cascade one with IGBT rectifier/regenerative units.