弱电网下模型预测并网逆变器控制策略

针对有限控制集模型预测控制系统在弱电网并网时存在电网阻抗无法忽略、电网电压突变、系统有延时、电流跟踪精度低的问题,提出了利用参考电流矢量角补偿的方法加以开关权重系数约束方式。首先搭建传统三相并网逆变器有限控制集模型预测电流控制模型;其次运用参考电流矢量角补偿方法,对预测电流参考值存在误差进行补偿来弥补因电网阻抗与系统电流波动产生的误差,并加入开关函数优化权重系数,使得系统具备两目标兼顾优化的特点,同时在电网电压发生突变时,系统符合并网要求,动态电流跟踪精度准确;最后通过Matlab/Simulink仿真验证了方法的合理性以及有效性。

Model Prediction for Grid-connected Inverter Control Strategy under Weak Power Grid

According to the problems in limited control set model prediction control system, for example, when weak power grid is connected to the grid, the power grid impedance can not be ignored, when power grid voltage is changed abruptly and when the system has time delay, current tracking precision is low, this paper proposes the reference current vector angle compensation method and switching weight coefficient constraint method. Firstly, the traditional three-phase grid-connected inverter finite control set model is built to predict the current control model. Secondly, the reference current vector angle compensation method is used to compensate the error of predicted current reference value so as to make up the error from the grid impedance and system current fluctuation, the switch function optimization weight coefficient is added to make the system have the characteristics of two-objective optimization, at the same time, when the power grid voltage abruptly changes, the system meets the requirement for grid connection, and the dynamic current tracking precision is high. Finally, Matlab/Simulink simulation verified the rationality and effectiveness of the method.