Development of a 10kV solid-state DC circuit breaker based on press-pack IGBT for VSC-HVDC system

With the rapid development of power electronics technology, the voltage source converter-high voltage DC (VSC-HVDC) has been drawn more attention. DC circuit breaker, which can cut off the short current immediately while DC fault occurs, is a key equipment for DC grid of VSC-HVDC, avoiding the whole DC systems shut down. This paper presents the development and test of the prototype of a solid-sate DC circuit breaker for a bipolar VSC-HVDC system based on insulated gate bipolar transistor (IGBT) series-connected technique. The dynamic characteristics of IGBT and the principle of voltage balance circuits for series-connected IGBTs are analyzed in detail. This paper not only illustrates the breaking operation of the solid-state DC circuit breaker, but also solves the press-pack (PP) IGBT mechanical design being no available in the literature of similar application. With a Saber simulation model of series-connected IGBTs, the characteristics of unbalanced voltage-sharing caused by the gate resistor, tail current and gate charge of IGBT are simulated. The simulation results show that the static and dynamic circuits can greatly improve the performance of voltage balance. At last a ten series-connected IGBTs for solid-state DC circuit breaker and its test system are developed, which successfully turns off 5.1 kA under 10 kV DC, which shows the feasibility of the solid-state DC circuit breaker based on series-connected IGBTs. This paper provides a practical engineering application of the solid-state DC circuit breaker for the medium and high VSC-HVDC systems in future.