Transformerless Series-Connected Current-Source Converter With Less Switch Count

The existing series-connected current-source converters (SC-CSCs) require bulky and costly transformers at either input or output. A transformerless SC-CSC was recently proposed. On this basis, in this article, a modified version is proposed. Compared with the previous one, the new one has the same features, including the same voltage stress of used switches, gain, passive components, efficiency, and inherent current and voltage balancing, but it has less switch count. The operation principle is presented, and a new modulation scheme is proposed. Technical challenges and potential applications are also discussed. The performance is verified by both simulations and lab-scaled experiments.