适用于直驱风力发电系统的三电平两桥臂PWM整流器控制策略

Control Strategy of Three-Phase Two-Arm Three-Level PWM Rectifier Suitable for Direct-Driving Wind Power System

系统分析了新型三相两桥臂三电平中性点箝位脉宽调制(pulsewidthmodulation,PWM)整流器的数学模型和工作模式,提出了基于空间电压矢量的恒频控制策略,并将其应用于直驱风力发电系统整流变换中。该三电平PWM整流器不仅减少了一个桥臂,成本较低,而且控制简单。仿真结果表明,该整流器可以有效抑制注入电网的谐波,减小交流侧的电流波形畸变,实现单位功率因数控制以及能量的双向流动,适用于直驱风力发电系统。

The mathematical model and working modes of a novel three-phase two-arm three-level neutral-point-clamped （NPC） pulse width modulation （PWM） rectifier suitable for direct-driving wind power system are analyzed in detail, and the constant frequency control strategies based on space voltage vectors are proposed and applied to the rectification conversion of direct-driven power generation system. One bridge-arm of this three-phase two-arm three-level NPCPWM rectifier is removed, it makes its cost lower and its control strategy convenient for implementation. Simulation results show that this novel PWM rectifier can effetively eliminate harmonics injected into power system and mitigate current waveform distortion at AC side, implement unity power factor control and bi-directional flowing of energy. The novel PWM rectifier is suitable for direct-driven power generation system.