Introduction: The modernization of power distribution systems is driven by the need for higher power density and improved controllability, further accelerated by the integration of Distributed Energy Resources (DERs). Traditional electro-mechanical circuit breakers are increasingly being replaced by semiconductor circuit breakers (SCCBs), which offer faster switching, higher reliability, and reduced wear and tear. This presentation explores the challenges and innovative solutions in this rapidly evolving field.
Challenges in High-Power Applications: While initial SCCBs effectively handle low-voltage and low-current applications, high-power systems such as AI data centers and e-marine applications demand higher voltages (up to 4kV DC) and currents. This necessitates semiconductor switches with ultra-low resistance (RDSon) and high blocking voltages, reaching up to 10kV, to ensure efficient and reliable operation.
Novel Solution: Super Cascode Switch (SCS): To address these challenges, we introduce the Super Cascode Switch (SCS), leveraging Silicon Carbide (SiC) JFET technology. The SCS incorporates five 1.2kV SiC JFETs, each with a low resistance of 2.3mΩ, controlled by a 1.2kV SiC MOSFET in a cascode configuration. This architecture achieves a blocking voltage of 7.2kV, with scalability to 10kV, making it suitable for high-voltage applications.
Enhanced Performance: An advanced gate drive circuit is implemented to reduce conduction losses by enhancing RDSon, a critical factor in minimizing energy dissipation. Additionally, a balancing network ensures even voltage distribution across the cascode stages, optimizing both static and dynamic performance.
Experimental Validation: Experimental results demonstrate the SCS's capability to interrupt a peak current of 1kA with peak voltages reaching 7.8kV by a single 10mΩ switch. This performance underscores the SCS's superior RDSon*A performance compared to conventional solutions, while maintaining the inherent robustness and control simplicity of SiC JFET technology.
Conclusion and Future Implications: The Super Cascode Switch represents a significant advancement in semiconductor circuit breakers, offering a reliable and efficient solution for high-power applications. Its potential to scale up to 10kV blocking voltage positions it as a key technology for future medium-voltage systems. This innovation not only addresses current challenges but also paves the way for further advancements in power distribution, enabling more efficient and resilient energy systems.
