A Novel AM Modulation Technique for Solid-State Transformers with Reduced Conversion Stages and Enhanced Efficiency

Recent advancements in smart grid technology and the increasing adoption of renewable energy sources highlight the need for an alternative to conventional transformers. Traditional transformers suffer from issues such as lack of controllability, large size, and weight, making them less suitable for modern grid applications. Solid-State Transformers (SSTs) have emerged as an attractive solution due to their controllability, compact size, and power density. In this paper, a novel SST structure is proposed with a new modulation technique, which reduces one of the conventional energy conversion stages by directly converting DC voltage into a medium-frequency waveform with a controlled amplitude. The proposed structure simplifies the control system and enhances power density compared to traditional SSTs. The effectiveness of the proposed structure is validated through both simulation and experimental results, which demonstrate improved performance in terms of efficiency, harmonic reduction, and reduced system cost.