基于卸荷电路和无功优先控制的永磁同步风力发电机组低电压穿越研究

Low Voltage Ride-through Capability Improvement of PMSG Based on Chopper Circuit and Reactive Priority Control

为了改善2 MW二极管中点箝位式双三电平变流器直驱式永磁同步风力机组(PMSG)的低电压穿越(LVRT)性能,提出了新的稳态时单位功率因数控制、电网暂态故障时无功优先、有功受限复合控制策略。采用定量模拟的方法,对电网电压深度跌落时采用卸荷电路和改进控制策略实现风电机组低电压穿越进行了仿真研究。结合现场运行数据对内蒙古某风场永磁直驱式风电机组主要参数进行了数据处理和分析,并依据最新的风电场接入电力系统技术规定标准对该机组进行了低电压穿越现场测试。结果表明,卸荷电路和改进无功优先控制方式均可实现直驱式风电系统的低电压穿越运行,有功、无功的动态解耦和直流母线电压稳定控制,向电网发出友好型清洁电能。后者可向电网提供360 k VA的稳定无功支持,更有利于辅助电网电压的恢复和提升机组的低电压穿越能力。

Aiming at improving the low voltage ride through （LVRT） capability of 2 MW permanent magnet synchronous generator （PMSG） with diode neutral-point clamped type dual three-level converter, we proposed a novel control strategy for the gird side converter： during steady-state, a unit power factor control was adopted; and during transient fault state, a compound control strategy of reactive power priority and active power restriction was designed. The simulation on chop- per circuit and improved control strategy was made under the condition of the grid voltage fault. According to the operational data of PMSG from a wind farm in Inner Mongolia, the main parameters of the PMSG were analyzed. The PMSG-LVRT field test was made on the basis of the technical standard of wind power integration. The results reveal that the wind power system not only realizes low voltage ride through, active and reactive power dynamic decoupling and DC bus voltage stability, but also sends clean energy to the power grid based on chopper circuit and improved control strategy. The latter is more beneficial to recovering the grid voltage and improving LVRT ability by supplying 360 kVA reactive power to the grid.