Three-level boost converter based medium voltage megawatt PMSG wind energy conversion systems

For power rating of 2MW or higher, the medium voltage (MV) back-to-back (BTB) neutral-point clamped (NPC) converters are most preferable choice for wind turbine manufacturers as they reduce cost, size and complexity of the system compared to the BTB two-level converters. In this paper, a new MV topology using diode rectifier, three-level boost (TLB) and NPC converter has been proposed to further reduce the cost and size. The dc-link maximum power point tracking (MPPT) control scheme has been proposed with which the TLB performs MPPT and balancing of dc-link capacitors and thus provides a greater flexibility for NPC control. The simulation results for 3MW/3000V/53.33Hz non-salient pole PMSG wind energy system validate the proposed topology and control scheme.