Parallel/Series Connected Standardized Active Switching Modules for High Power DCCBs in MVDC Networks

Solid-state dc circuit breakers (DCCBs) are increasingly employed across all power levels, including MVdc networks. Seamless integration of DCCBs into medium voltage direct current (MVdc) networks is challenging due to the diverse voltage and power levels. Furthermore, the limited current and voltage capability of semiconductor devices limits the full integration of solid-state DCCBs for MVdc applications. Series and parallel-connected insulated-gate bipolar transistor (IGBT) arrays can be employed to match the current and voltage levels required. However, with passive gate drives, devices may fail due to non-homogeneous current and voltage distribution across IGBTs. Closed-loop active gate drives (AGDs) provide a solution to overcome this. In the proposed standardized-active switching module (ASM) scheme, IGBTs are equipped with AGDs with status feedback. This control method enables the IGBTs to follow a defined current/voltage trajectory during the switching rather than being guided by the inherent characteristics of the device. Hence, with the ability to control dynamic current and voltage, an additional degree of freedom is enabled to connect several ASMs in series and parallel. DCCB architecture based on Standardized-ASMs is proposed as a flexible protection solution for MVdc networks. This paper describes the developed AGD scheme and behavioral analysis of the AGD-based ASMs. Experimental results show the dynamic voltage and current slope control capability of the proposed standardized ASMs. Finally, this paper assesses the ASM-based DCCB architecture for MVdc networks. An ASM-based DCCB prototype was developed and tested to verify the voltage and current sharing capability of modular ASMs in the proposed DCCB architecture.