分频海上风电系统的不对称故障穿越控制

Ride-through Control of Fractional Frequency Offshore Wind Power System During Unsymmetrical Grid Faults

该文提出分频海上风电系统的不对称故障穿越控制策略。首先,介绍分频海上风电系统的基本结构与运行方式。其次,根据关键变频设备模块化多电平矩阵式换流器(modular multi-level matrix converter,M^(3)C)的数学模型,揭示电网电压不对称时M3C的运行特性,并提出分频海上风电系统的故障穿越控制策略。该策略在M3C双αβ0坐标变换控制的基础上,改进桥臂间均压控制策略,并引入M^(3)C-风电场联合电压–频率–功率下垂控制实现风电场减出力。最后,在MATLAB/Simulink中搭建分频海上风电系统电磁暂态仿真模型,对所提出的控制策略进行验证。仿真结果表明:提出的故障穿越控制策略能够在保证M3C运行安全的同时,满足风电场功率外送需求,实现风电场对工频系统的无功支撑目标。

This paper proposes a fault ride-through control strategy for fractional frequency offshore wind power system(FFOWPS)during unsymmetrical grid faults.First,the basic structure and operation mode of the FFOWPS are introduced.Secondly,according to the mathematical model of the key frequency conversion equipment,modular multi-level matrix converter(M 3 C),the operating characteristics of the M^(3)C under unsymmetrical grid voltage are revealed,and then the fault ride-through control strategy of the FFOWPS is proposed.Based on the classic doubleαβ0 coordinate transformation control of M^(3)C,the proposed strategy improves the inter-arm voltage balancing control strategy,and introduces the M 3 C-wind farm joint voltage-frequency-power droop control to reduce the output of the wind farm.Finally,the electromagnetic transient simulation model of FFOWPS is built in MATLAB/Simulink,and the proposed control strategy is verified.The simulation results show that the proposed fault ride-through control strategy can ensure the safety of M^(3)C,while meeting the power transmission requirements of wind farms,and achieving the goal of reactive power support for power systems by the offshore wind farm.