Mechanism and Analytical Model for Switching Transient Process in SiC 3L-ANPC Converter

Silicon carbide three-level active neutral point clamped converters (SiC 3L-ANPC) have emerged as promising solutions for medium-voltage high-capacity applications. However, compared to traditional two-level converters, they exhibit a relatively higher presence of stray parameters. The combined impact of high $\text{d}v/\text{d}t$ , $\text{d}i/\text{d}t$ and multiple stray parameters during the switching transient process can lead to non-ideal behaviors, including voltage and current overshoots, along with oscillations. These issues contribute to increased switching losses and limitations in power handling. Therefore, a thorough evaluation of the switching transient process becomes imperative to ensure the proper design and protection of 3L-ANPC converters. An analytical model is proposed in this article that accurately characterizes the switching transient process of SiC 3L-ANPC converters. The model is developed based on a comprehensive analysis of the switching transient mechanism. By focusing on specific pivotal moments within the transient process, the model significantly reduces computational time. Moreover, these distinct moments carry explicit physical significance and possess universal applicability. Experimental results validate the effectiveness of the proposed model, showcasing a maximum calculation error of less than 6% for transient overshoots. The insights presented in this article provide guidance for designing circuit parameters in SiC 3L-ANPC converters, aiding in the mitigation of overvoltage issues.