标题：Suppression effectiveness research on multi-level EMI filter in thermal electromagnetic interactive filed of explosion-proof three-level NPC converter
摘要：As a system, the explosion-proof three-level NPC (Neutral-Point-Clamped) converter has the characteristics of nonlinear, high complexity, and multiple thermal electromagnetic fields, among which multiple magnetic fields interfere with each other and affect the system stability. In order to solve this problem, the conducted electromagnetic interference principle was analyzed in the converter filed firstly in this paper, and transmission paths were illustrated as well. Secondly, on the basis of IGBT (Insulated Gate Bipolar Translator) transient state analysis, the EMI (Electro-Magnetic Interference) mechanism analysis of three-level converter power devices was completed for EMI filter design. Finally, a novel multi-level EMI filter was designed to weaken mutual interference of small magnetic field group in the system and to solve the EMI suppression problem of inner cavity interaction of explosion-proof three-level NPC converter. The research target is to optimize the filter and enhance the system ability of resistance to thermal and electromagnetic interference. The suppression effectiveness of multi-level EMI filter was proved by the experiment conducted on a 1 MW (Million Watt) explosion-proof three-level NPC converter platform.
