直驱风力发电系统三电平变换器控制策略研究

针对基于NPC型三电平变换器的永磁直驱风力发电系统存在的直流侧电容中性点电位不平衡问题继续研究。根据NPC型三电平变换器的特点,采用简化SVPWM调制算法,采用实时电流监测(Real-time Current Detection,RCD)电位平衡控制策略,结合机侧变换器、网侧变换器所采用转子磁场定向控制策略和电网电压定向控制策略,建立了三电平永磁风力发电系统变换器控制策略,在实现最大风能跟踪、有功无功解耦控制的同时抑制了中性点电位不平衡。基于MATLAB/Simulink仿真环境搭建系统模型,通过仿真验证控制策略的可行性和正确性。

Control Strategy Study on Three-level NPC Converters of Direct-driven Wind Power Generation System

Researches on the direct-driven wind power generation system based on the permanent magnet synchronous generator, using the diode neutral-point-clamped three-level converters were made continuously, and the problem about the DC-link Capacitor neutral point Voltage Unbalance (CVU) got the most attention. According to the feature of the diode neutral-point-clamped three-level converter used in the system, simplified Space Vector Pulse Width Modulation was utilized and the Real-time Current Detection control strategy (RCD) was proposed. In consideration of the fact that the generator side adopted rotor flux linkage oriented vector control strategy and the grid voltage orientation vector control was applied to the converter at power grid side, an overall strategy about the control of the converters used in the wind power generation system was created to realize the maximum wind energy tracking. The active power and reactive power could be decoupled and controlled separately and capacitor neutral point voltage unbalance had been brought under effective control. The whole system simulation model was established in MATLAB/Simulink software environment and simulation results verified the correctness and feasibility of the control strategy.