Comprehensive Assessment of Safe Operating Regions and Methods for Enhancing Static Capacity in Hybrid Three-Level Topologies

The continuous development and utilization of new energy sources have underscored the increasing prominence of Voltage Source Converters (VSCs), emphasizing the need for efficient and cost-effective power conversion systems. The hybrid three-level topology, which optimally balances cost and efficiency, presents significant potential for future applications. However, the loss and junction temperature characteristics of hybrid three-level topologies remain inadequately understood. This paper introduces a novel loss analysis and junction temperature calculation method to determine the four-quadrant operating capabilities and output capacities at various voltage levels for hybrid three-level topologies. Furthermore, by analyzing the loss and junction temperature distribution patterns, an optimal capacity configuration method is proposed. To enhance performance further, a device capacity optimization configuration method tailored for hybrid three-level topologies is developed. Comprehensive simulations validate that the hybrid three-level topology achieves high efficiency at lower costs compared to the full SiC topology, while also offering the added benefit of static capacity expansion.