This paper proposes a current control scheme for a grid-connected pulse width modulator(PWM) voltage source converter(GC-VSC) under imbalanced and distorted supply voltage conditions.The control scheme is implemented ...This paper proposes a current control scheme for a grid-connected pulse width modulator(PWM) voltage source converter(GC-VSC) under imbalanced and distorted supply voltage conditions.The control scheme is implemented in the positive synchronously rotating reference frame and composed of a single proportional integral(PI) regulator and multi-frequency resonant controllers tuned at the frequencies of 2ω and 6ω,respectively.The experimental results,with the target of eliminating the active power oscillations and current harmonics on a prototype GC-VSC system,validate the feasibility of the proposed current control scheme during supply voltage imbalance and distortion.展开更多
文摘随着海上风场规模的增大,全直流风场成为未来海上风电的发展趋势。模块化多电平变换器(modular multilevel converter,MMC)广泛应用在大功率、高电压的AC/DC电力变换领域,并且能够实现电能直接从低压交流到高压直流的转换,是一种适用于海上全直流风场的风力发电变流器拓扑。该文针对基于MMC的风力发电变流器的运行特性进行了分析,发现在低调制比的工况下MMC的子模块电容电压纹波会使交流输出电压产生畸变,通过对其机理的分析,提出一种改进的电流控制方法,改善受到电压畸变影响的电流动态控制性能。为了验证理论分析与控制方法,在RT-LAB中对一将6 k V永磁同步发电机连接到50 k V直流网的10 MW风力发电系统进行了建模和仿真,并在30k W的MMC实验平台上进行了实验验证。
基金supported by the National Natural Science Foundation of China(No.50907057)the National High-Tech Research and Development Program (863) of China(No.2007AA05Z419)
文摘This paper proposes a current control scheme for a grid-connected pulse width modulator(PWM) voltage source converter(GC-VSC) under imbalanced and distorted supply voltage conditions.The control scheme is implemented in the positive synchronously rotating reference frame and composed of a single proportional integral(PI) regulator and multi-frequency resonant controllers tuned at the frequencies of 2ω and 6ω,respectively.The experimental results,with the target of eliminating the active power oscillations and current harmonics on a prototype GC-VSC system,validate the feasibility of the proposed current control scheme during supply voltage imbalance and distortion.
