摘要
三相电力电子负载在系统不平衡或模拟不平衡负载、非线性负载的工况下,直流母线会包含丰富的谐波电压,这些谐波分量通过PWM调制过程和电压外环控制器会引入到并网指令电流中,导致馈网电流质量的下降。针对这一问题,根据瞬时功率理论,建立了三相电力电子负载功率平衡方程,推导出三相电力电子负载在不同工况下直流母线谐波电压的表达式,揭示了负载模拟变换器和并网变换器对直流母线电压的影响机理,并提出一种基于滞环控制的直流电压控制方案,以抑制直流母线谐波电压对并网输出电流的影响,改善馈网电流的质量。仿真和实验都验证了理论分析的准确性以及谐波抑制方法的有效性和可靠性。
Power electronic load is a device used to test the power supply quality. When three-phase power electronic load worked in unbalanced or nonlinear condition,dc bus capacitor contained abundant harmonic,which led to the decrease of the quality of the grid current through the PWM modulation and the voltage loop controller. According to the theory of instantaneous power,the power balance equation of power electronic load was established and the expressions of dc bus harmonic voltage were deduced. The influence mechanism of dc bus capacitor from simulation load converter and grid converter was also discussed. After analyzing the characteristics of several kinds of filter,a dc voltage control scheme based on hysteresis current control strategy was proposed to suppress the effect on grid output current from dc bus voltage harmonic and to improve the quality of feed network current. The simulation and experiment verify the accuracy of theoretical analysis,the validity and reliability of the algorithm.
出处
《电工电能新技术》
CSCD
北大核心
2015年第2期25-33,共9页
Advanced Technology of Electrical Engineering and Energy
基金
"十二五"国家科技支撑计划重大项目(2013BAG19B00-04-01)
关键词
三相电力电子负载
并网变换器
直流母线
滞环控制
瞬时功率理论
three-phase power electronic load
grid connection converter
dc bus
hysteresis control
instantaneous power theory
