对于额定功率为2 MW或更高容量的变流器,背靠背(BTB)中点钳位型(NPC)变流器可以降低系统的成本、体积以及复杂性.文章提出一种新型拓扑结构,该结构采用二极管整流,三电平升压(TLB)和中点钳位型变流器,能够进一步降低系统的成本和体积.该结构在直流侧完成最大功率点跟踪(MPPT)控制计划,使TLB解决MPPT和直流侧电容平衡问题,为中点钳位控制提供更大的灵活性.最后以3 MW永磁风力发电系统为仿真对象,仿真结果验证了该拓扑结构和控制策略的正确性.%For power rating of 2 MW or higher, the back-to-back (BTB) neutral-point clamped (NPC) converters are most preferable choice for wind turbine manufacturers as its reduced cost, size and complexity of the system compared with the BTB two-level converters. In this paper, a new 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 in which the TLB performs MPPT and balancing of DC-link capacitors, which provides a greater flexibility for NPC control. The simulation results for 3 MW PMSG wind energy system validate the proposed topology and control scheme.
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