Thermal Performance Analysis of 10kV IGCT Based Three Level ANPC Converter in 7MW PMSG MV Wind Turbines

Abstract

The choice of power converter is driven by many parameters most commonly by higher efficiency. Over the years several topologies have been developed and made available commercially. The three level(3L) neutral point clamped (NPC) topology is widely accepted as a high-power wind energy grid interface due to its improved switching losses, harmonic distortion and common mode voltage/current. However, to address one of the major shortfalls of the NPC topology - the uneven junction temperature distribution - the active neutral point clamped (ANPC) topology, where the clamping diodes are replaced by bidirectional switches, was derived from the NPC topology. With the use of the correct switching model, the thermal distribution amongst the semiconductor devices can be modified and adjusted in the ANPC topology. In this paper comparative analysis of different switching strategies is conducted to understand their effect on the thermal performance of the recently developed 10 kV IGCT in a 3L ANPC converter under the given operating conditions of 7 MW-class PMSG wind turbines. The analysis is confirmed through PLECS simulations.