基于有源阻尼的并网逆变器电流内环H_∞重复控制

H_∞ Repetitive Current Controllers for Grid-connected Inverters Based on Active Damping

该文首先根据两相静止坐标系下三相LCL型并网逆变器模型无耦合的特点,建立基于两相静止坐标系的电流内环控制系统。进而对采用电容电流反馈实现有源阻尼的LCL型并网逆变器进行状态空间方程建模,在此基础上利用H∞控制理论设计满足稳定性要求的并网电流内环重复控制器,实现在控制逆变器输出电流以较小的稳态误差跟踪基波参考值的同时,抑制各整数次谐波电流输出。最后在一10k W三相LCL并网逆变器样机上实现所设计的电流内环控制器,以验证其性能。通过与传统多谐振比例谐振(proportional-resonant,PR)控制器的实际控制效果相对比,实验结果证明采用该文提出的方法设计的H∞重复控制器能明显减小并网电流谐波含量,并有良好的稳态和动态性能。

The current-loop control strategy was proposed for LCL grid-connected inverters considering active damping. By adopting the H∞ control theory, a repetitive controller was designed to control the output current of the grid connected inverter and to guarantee the stability of the control system. The current-loop under the stationary frame which uses the controller based on the H∞ repetitive control strategy can track the given fundamental sinusoidal current and can eliminate harmonics of output currents. To verify the effectiveness of the current control strategy, a 10kW three phase grid-connected inverter was set up. By comparing with the experiment result of proportional resonant controllers, the proposed H∞ repetitive controller shows significant advantages in reducing the total harmonic distortion of output currents.