电网电压不平衡下的D-PMSWG系统 MPC-VSG时域优化控制

当电网电压不平衡时，传统的VSG恒定有功以及恒定无功控制策略，在电网电压跌落和恢复期间频率响应和暂态稳定性欠佳。为解决这一问题，提出了一种电网电压不平衡下的直驱永磁同步风力发电（D-PMSWG）系统MPC-VSG时域优化控制策略。该策略将不平衡电网电压下的虚拟同步机控制（VSG）与模型预测控制（MPC）相结合，并对VSG转子运动方程的转子角频率与转矩建立了MPC预测模型，通过优化预测时域，调整了频率环节、阻尼环节和反馈控制惯量环节系数，得到了最优预测时域输出向量以及下一时刻的控制输入向量。与传统方法相比，所提出的方法在电压跌落、电压恢复瞬间的频率响应，以及功率的暂态特性，都得到了良好的改善。最后，在Matlab/Simulink中验证了不同控制目标下该控制策略的正确性和有效性。

MPC-VSG Time Domain Optimal Control of D-PMSWG System Under an Unbalanced Grid Voltage

In view of the problem of a poor frequency response and transient stability during the power grid voltage drop and recovery found in traditional VSG constant active power and constant reactive power control strategies under the condition of an unbalanced grid voltage, an MPC-VSG time domain optimal control strategy has thus been proposed for direct driven permanent magnet synchronous wind power generation (D-PMSWG) system under an unbalanced grid voltage. With virtual synchronous machine control (VSG) under an unbalanced grid voltage combined with model predictive control (MPC), by optimizing the prediction time domain, the coefficients of frequency link, damping link and feedback control inertia link are adjusted to obtain the optimal prediction time domain output vector and the control input vector at the next moment. Compared with traditional methods, the proposed method is characterized with an improvement of the frequency response and power transient characteristics at the moment of the voltage drop and recovery. Finally, the accuracy and validity of the control strategy under different control objectives can be verified in Matlab/Simulink.