The thyristor model provided by common electromagnetic transient simulation software ignores the reverse tum-off characteristics of thyristor,resulting in inaccurate simulation of commutation failure of the thyristor converter.In order to improve the simulation accuracy of thyristor valve,we established a effect relationship of zero-crossing current change rate,positive current peak and junction temperature on the reverse recovery current peak,reverse recovery charge and turn-off time of thyristor turn-off characteristic parameters.Meanwhile,we proposed a characterization method of re-lated influencing factors in device modeling,and established a custom digital simulation model of thyristor including reverse blocking recovery process and forward blocking recovery process.Moerover,we constructed a refined electro-magnetic transient model of the converter considering the turn-off characteristics of the device.The comparison between the simulation results and the actual test values shows that the simulation error of the reverse recovery current peak is less than 5％,and the simulation error of the turn-off time is less than 4％.The proposed digital simulation model can accu-rately reflect the turn-off process of the thyristor.The converter simulation model can more accurately reflect the commutation failure characteristics of HVDC system.
维普
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