Design Of Hybrid High Voltage DC Circuit Breaker Based On IGBT

New energy is one of the important direction for the development of modern power grids.With the tremendous progress of flexible DC transmission technology in the past 30 years,the research of high-voltage DC circuit breaker has become a hot spot in international research.Hybrid high-voltage DC circuit breaker provides more selectivity for the safe and stable operation of HVDC system.However,there are too many devices used in the existing HVDC circuit breaker topology,which caused high cost.In order to reduce the cost,a topology structure of symmetrical hybrid HVDC circuit breaker based on IGBT is proposed in this paper.The working process in the steady-state and transient-state is analyzed,and the parameter values of the devices used in the topology are designed.In order to solve the unique problems of IGBT device in the short-circuit process,the RCD buffer averaging circuit and the compensation gate resistor current sharing measures are proposed based on the analysis for the uneven voltage and uneven current of the IGBT.The simulation software PSCAD/EMTDC is used to establish the simulation model of the proposed topology,focusing on the analysis of the action of the DC breaker when a short circuit fault occurs.And the control loop and main circuit are built to verify the topology proposed in this paper.Combined with the actual laboratory experimental condition,the experimental verification is carried out using a low voltage and small current mode.The experimentally monitored voltage-current conversion curve is consistent with the theoretical and simulation results,which verified the correctness of the theoretical analysis and simulation,and also verified the correctness of the experimental loop parameter setting.The simulation and experimental results prove each other,which proves the correctness of the proposed hybrid high-voltage DC circuit breaker topology.Under the premise of minimizing the number of devices used,it can effectively cut off the short-circuit fault and reduce the experimental cost.