Dc-bus voltage control of three-phase ac/dc converter using load predictive method

A three-phase AC/DC converter should extract the pure sinusoidal current from the AC source, and maintain the DC-bus voltage at a demand level when the dc load varies. In this paper, a novel control method is presented to match these requirements. At the AC side, a real-time voltage and current predictive methods are used to reduce the influence of control delay and voltage harmonics, so that AC current quality can be maintained at a very high level. At the DC-bus side, a predictive load and DC voltage are used to decide the converter output DC current control. Based on load correct prediction, when the DC load varies, its influence on the DC voltage is reduced to the minimum.