A Two-Phase to Single-Phase Frequency Changer Using Power Modulation

This paper extends the novel application of the principle of pole-amplitude modulation to that in time for ac to ac conversion resulting in a single-phase frequency changer. A general method of suppressing a sideband frequency of the modulated public system and the results of the initial work carried out with a view to realizing a frequency changer are described. Herein is shown that for a given modulation ratio, depending on the modulating wave sequence, either of the sideband frequencies in relation to the public supply could be realized with the other completely eliminated. It is concluded that the amplitude-modulated power supply may well prove to be complimentary to the conventional cycloconverter in addition to the frequencies obtainable which are outside the frequencies available from a normal cycloconverter.