基于LCL型并网逆变器的二自由度控制技术研究

Research on two-degree-of-freedom control technology based on LCL-type gridconnected inverter

并网逆变器的交流侧大多都采用LCL型滤波器对系统进行滤波,相比于L型滤波器它可以达到更好的滤波效果,然而,由于LCL型滤波器容易产生高频谐振,系统的稳定性会因此而受到影响。为了解决这个问题,提出了多种解决方案,其中无源阻尼和有源阻尼是使用比较广泛的两种控制方法。该文将一种二自由度PID控制策略应用于光伏并网逆变控制系统之中,通过Matlab仿真分析了系统的性能,实验结果表明,该方法增强了系统的鲁棒性和跟随性,对系统的谐波有较好的抑制效果。

The LCL?type filter is used at the AC side of the photovoltaic grid?connected inverter to perform system filtering,and has more excellent filtering effect than that of the L?type filter.Since the system stability can be effected by the high frequency resonance produced by the LCL?type filter,various solutions are proposed by scholars at home and abroad to solve the prob?lem,in which the reactive damping control method and active damping control method are the two widelyused ones.A two?de?gree?of?freedom PID control strategy is applied to the photovoltaic grid?connected inverter control system.The system perfor?mance is analyzed with Matlab simulation.The experimental results indicate that the method has improved the robustness and following performance of the system,and has a better suppression effect for the system harmonic.