Research on control strategy for high power AC-DC-AC cascaded converter

Abstract

The high power AC-DC-AC cascaded converter consists several fundamental power blocks. The working principles have been described to draw the rectifier/inverter stage's noncascaded equivalent prerequisite, as well as the global dc-link capacitors' voltage balancing condition. Therefore, the control strategy could be designed hierarchically, such as cascaded voltage control, power factor control and voltage balancing control. The power factor at both front ends can be regulated at 1 or -1 depending on power delivery direction of the converter. The power flow alters automatically based on the given power flow. Both of simulation and experimental results verified the proposed control strategy.