改进SVPWM在直驱型风电并网控制中的仿真研究

Simulation Study Based on Improved SVPWM of Direct-drive Wind Power Grid Inverter Control

目前大功率直驱永磁同步发电系统和三相PWM逆变器控制正成为风力发电技术研究的热点。主要针对直驱风电系统中网侧逆变器控制进行研究,为减小并网逆变器输出电流中的谐波,采用空间矢量脉宽调制技术;为维持直流环节电压的恒定和使输出电流快速跟踪给定电流,实现单位功率因数并网,采用电压外环、电流内环双闭环结构控制风电并网。给出一种改进SVPWM调制方法,可以消除偶次谐波,降低输出波形畸变率,并且分别采用传统SVPWM和改进SVPWM调制方法对风电系统的有源逆变部分进行了仿真,结果验证了改进SVPWM控制方法的可行性和有效性,从而为实践中完成较高电能质量风电并网提供理论基础。

Currently high-power direct-drive permanent magnet synchronous generating system and control of three-phase PWM inverter is becoming a hot spot in wind power generation technology.In this paper,grid inverter control of direct-drive wind power system is studied.To reduce output current harmonics of the inverter,space vector pulse width modulation is chosen.To maintain DC link voltage constant,make output current fast track the given current and integrate to grid with unity power factor,double loop structure of the outer voltage loop and the inner current control is used in wind power grid integration.An improved SVPWM modulation method is presented in this paper,even harmonics can be eliminated,the output waveform distortion rate can be reduced.The model of active inverter part of wind power system with the traditional SVPWM and the improved SVPWM modulation control strategies have been realized through the MATLAB software,the simulation results verify the feasibility and effectiveness of the proposed control strategy so as to provide theoretical basis on completing wind power grid integration of high power quality in practice.