3 level topologies for windmill converter

Abstract:
In wind industry, to achieve lower cost per kW, bigger and bigger wind turbine is becoming clear trend on market today. For new offshore installation, 5MW and higher power wind turbine is common. Traditional 2 level low voltage topology in multi MW wind converter are facing the challenge of higher current stress and cable cost. Because of this new trend, major market players in China are considering to apply 3 level topologies in wind converter. By using 3 level topology, the output voltage of converter can be increased even with same rated voltage IGBT. Higher output voltage can reduce the cable losses and therefore save the cost of cable inside tower. This paper compared NPC and ANPC topologies from different aspects and proposed IGBT module solution for wind converter.