The paper is dedicated to the study of methods related to improvement of functional/operating characteristics of a frequency converter with circular voltage phase rotation. In order to improve frequency conversion quality, the use of multichannel switching circuits is proposed. To implement the multichannel principle, matching transformers have been developed, as well as control laws for the proposed devices. The study results show the effectiveness of the proposed method for improving the characteristics of the frequency converter and the possibility of using these type devices for organizing controlled intersystem connections on alternative current to combine power systems operating with different frequency standards.