摘要
微电网系统中的电力电子接口变换器通常呈并联结构,且通过LCL滤波器连接到公共母线。LCL滤波器自身具有谐振问题,特别是在并联逆变器系统中,频域分析结果中存在额外的正向谐振尖峰和反向谐振尖峰。本文在分析微电网中带有LCL滤波器的并联逆变器系统谐振特性的基础上,采用基于双二阶滤波器的主动阻尼方法,在不引入额外的传感器和控制闭环的情况下,对并联系统中多对不稳定极点同时进行调整。该方法通过在控制系统中添加两对零极点,改变根轨迹的走向,使得多对不稳定极点均移动到z平面单位圆之内,因此系统稳定性得以保证。基于dSPACE1103搭建的实时仿真模型表明了理论分析结果。
The power electronics interfacing converters are usually parallel connected to the common bus via LCL filters in a microgrid. The LCL filters have resonance problems. Especially in a parallel inverter system, the additional resonance and anti-resonance peaks can be found in the frequency domain analysis result. In this paper, the frequency domain characteristic of the parallel LCL-filtered inverters is analyzed. Active damping method based on bi-quad filter is reached. By using this kind of method, the multiple poles leading to instability issues are damped at the same time without additional sensors and close-loops in the control system. The additional two pairs of zeros and poles are involved by the bi-quad filter. Hence, the original root locus is changed and the multiple pairs of unstable poles are moved into the unit circle in z domain. The system stability is thereby guaranteed. The theoretical analysis is showed by the model with three LCL filtered parallel inverters implemented in dSPACE1103.
出处
《电工技术学报》
EI
CSCD
北大核心
2013年第3期261-268,共8页
Transactions of China Electrotechnical Society
基金
国家自然科学基金资助项目(51177083)
