Fundamental study of a simple control ac-ac converter introducing delta-sigma modulation approach

A pair of a converter and an inverter is used for ac to ac power conversion as a usual way. But this method uses two power conversion circuits. This means increasing power conversion stage and leads to large size equipments. Moreover, series connection of power converters results in large conversion losses. On the other hand, direct ac-ac converter can converts ac power to ac power directly. But generally, ac-ac converter needs a complex control technique for generating converter switching pattern. Focusing on reduction high frequency noise peaks of the output voltage, this paper represents fundamental study of an ac-ac converter. The simple configuration is prior and avoiding complexity. The proposed converter uses delta-sigma modulators that are improved to apply to the converter. Comparing to PWM converter, it is indicated that the proposed scheme can reduce output voltage noise peaks.