邓孝祥 戴超凡

摘 要：针对5MW永磁直驱风力发电机的特点，详细研究了二极管中点钳位式（neutral point clamped，NPC）三电平中压全功率变流器的控制系统、主回路设计、定子磁链估算与不连续脉冲调制discontinuous pulse-width modulation，DPWM）。网侧变流器采用电网电压定向和空间电压脉冲宽度调制（space voltage pulse width modulation，SVPWM）策略，机侧变流器采用转子磁场定向和DPWM策略，并基于低通滤波器补偿的方法进行定子磁链的幅值及角度的估算。热仿真软件结果表明：网侧开关频率为1.55kHz时，IGBT结温与温升满足器件设计规范;25kW 样机实验结果表明，采用该文所提调制策略和定子磁链估算方法，并网电流谐波含量能够满足国标要求，转子位置估计误差小，具有较好的稳态性能和转矩动态响应性能，能够很好满足系统控制要求。

关键词：中压三电平变流器;矢量控制;断续脉宽调制

DOI：10.15938/j.jhust.2018.06.013

中图分类号： TM614

文献标志码： A

文章编号： 1007-2683（2018）06-0070-07

Abstract：The diode three-level neutral-point-clamped3L-NPC） converter with full power is a promising multilevel topology in the application of wind power generation system. In view of the 5MW direct-drive wind power generator with permanent magnet this paper investigated the control system main loop parameters stator flux estimation and discontinuous pulse-width modulationDPWM） of the full-power 3L-NPC converter. The grid-side converter emploied the grid voltage oriented control and space voltage pulse width modulationSVPWM） strategy while the rotor field orientated vector control and DPWM strategy were adopted in the rotor-side converter. In addition low-pass-filter-compensation-integratorLPFCI） based rotor flux position estimation control method is proposed. The result of thermal simulation indicates that when the switching frequency of the grid-side converter is 1.55kHz the junction temperature and temperature rise of IGBT conform with design regulation. Furthermore the 25kw experimental prototype illustrates that based on the technique and stator flux estimation as mentioned in the paper the harmonics content is quanlified with international standards，and the system has small rotor position estimation error excellent steady-state performance and torque dynamic response meeting with systematic control requirements.

Keywords：medium voltage three level converter; vector control; discontinuous pulse-width modulation

0 引 言

與陆上风力发电相比，海上的风资源更好，离岸10km的海上风速是沿岸陆上风速的1.25倍，且风机布置在海上，风机布局可以更加灵活，因此海上风电与大功率风电变流器是风电的发展趋势[1]。目前国内外均已经开始5MW以及以上功率等级海上风电变流器研究;其中ABB公司已经在国内外小批量使用，采用二极管中点钳位式（NPC）三电平拓扑与中压系统（3000VAC）;国内一些厂家如阳光电源和国电南瑞等企业也进行了试验样机的研制与样机的地面对托试验。由于国外机型成本较高，因此5MW海上风电变流器具备很大的进口替代优势。综合国内外厂家的变流器设计参数，均采用了中压型NPC三电平拓扑[2-3]，设计难点为中性点电压平衡控制、内管电压不钳位抑制、谐波与热损耗平衡等问题。……