A Novel Control Technique for Grid-Tied Inverters Considering Unbalanced Grid Voltage Conditions and Control Input Saturation
A Novel Control Technique for Grid-Tied Inverters Considering Unbalanced Grid Voltage Conditions and Control Input Saturation
复制标题
DOI：
10.1109/tste.2018.2883863
复制
发表时间：
2019-10
影响因子：
8.8
通讯作者：
R. Errouissi;A. Al‐Durra
中科院分区：
文献类型：
--
作者：
R. Errouissi;A. Al‐Durra
提出了一种在电网电压平衡和不平衡两种情况下并网逆变器电流控制器的设计方法。该控制器由反馈输出控制器和干扰观测器(DO)相结合构成。控制设计在$\α\β$参照系中进行。因此，复合控制器的目标是确保系统的输出跟踪无稳态误差的正弦参考信号。由于模型不确定性和未知扰动的存在，反馈控制器不能获得良好的跟踪性能。为了考虑实际系统与数学模型之间的自然失配，首先在系统动力学中增加一个表示扰动的状态变量，并基于扰动输入可用于反馈的假设设计反馈控制器。然后，构造观测器估计扰动，假设扰动是在电网频率处振荡的正弦波。DO的另一个特点是它能够补偿在瞬变过程中限制控制输入所需的饱和区块的影响，从而提高动态性能。为了验证该控制器的有效性，进行了多次实验测试，结果表明该控制器能够实现准确、快速、稳定的响应。
This paper presents a new method to design a current controller for grid-tied inverters under both balanced and unbalanced grid voltage conditions. The proposed controller consists of combining a feedback-output controller with a disturbance observer (DO). The control design is carried out in the $\alpha \beta$ reference frame. Thus, the objective of the composite controller is to ensure that the output of the system tracks a sinusoidal reference signal with zero steady-state error. A feedback controller only cannot achieve a good tracking performance because of the presence of model uncertainties and unknown disturbances. To account for the natural mismatch between the actual system and the mathematical model, the system dynamics are first augmented with an additional state-variable, representing the disturbance, and the feedback controller is designed based on the assumption that the disturbance input is available for feedback. Then, an observer is constructed to estimate the disturbance, which is assumed to be a sine wave oscillating at the grid frequency. Another feature of the DO is its ability to compensate for the effect of the saturation blocks required to limit the control input during transients, leading to improved dynamic performance. Several experimental tests were conducted to verify the effectiveness of the proposed controller, and the results demonstrated its capability to achieve accurate fast stable responses.