Analysis of a High Power Low Voltage NPC Converter for Wind Turbines - Influence of Mechanical Design on Performance

Inhalt:
Development and research for power converters is concentrated on increasing power density, higher modularity, lower costs as well as higher reliability and efficiency. The use of multilevel converters, like Neutral Point Clamped (NPC) Converters, in high power applications in the range of 1.5MW can be favourable because of the filter size reduction and therefore reduction of weight and total volume of the system. The lifetime of a power module in a wind energy converter is closely related to its mean temperature and its temperature variation. This paper evaluates the stray inductances as well as the losses and the thermal cycling for two level and three level grid-side and generator-side connected converters with a apparent power of approximately 1MVA.