电网发生故障时，风电机组的有功/无功动态特性是影响机组穿越特性及并网点电压的关键因素。为解决传统比例-积分（proportional-integral, PI)控制跟踪速度较慢及控制回路设计复杂的问题，提出了基于模型预测控制（model predictive control, MPC）的低电压穿越控制策略。采用MPC代替网侧换流器控制回路中的电流内环来提升故障穿越时的暂态特性，在电压不对称跌落情况下，结合最新入网标准推导指令值并设计了更为简洁的控制回路，在MATLAB/Simulink平台上分别进行了对称故障、不对称故障两组仿真验证：对称故障情况下，对比传统控制、模糊PI控制（fuzzy PI control），验证了所提控制策略具有更好暂态特性，能够更好地为应对电网故障提供无功支撑。不对称故障情况下，通过仿真验证所提控制策略能够有效降低三相电压不平衡度。
英文摘要:
The active/reactive dynamic characteristics of the wind turbine are the key factors affecting the fault ride-through characteristics and the grid-connected voltage when a fault occurs in the power grid. To solve the problems of slow tracking speed and complex control loop design of traditional proportional-integral（PI) control, a model predictive control (MPC)-based LVRT control strategy is proposed. Firstly, MPC is used instead of the current inner-loop in the control loop of the network-side converter to improve the transient characteristics during fault ride-through. Then, in the case of asymmetric voltage dips, a more concise control loop is designed by combining the latest grid entry standards to derive the command values. Finally, two sets of simulations are carried out on MATLAB/Simulink platform to verify the symmetrical and asymmetrical faults. In the case of symmetrical faults, it is verified that the proposed control strategy has better transient characteristics and can better cope with grid faults and provide reactive power support compared with the traditional control and fuzzy PI control. In the case of asymmetric faults, the proposed control strategy is verified to be effective in reducing the three-phase voltage unbalance through simulation.