基于动态触发卸荷电阻的风电低电压过渡技术的仿真分析

电网导则要求风电机组在电网电压跌落时要保证在一定范围内不脱网运行。针对背靠背的永磁直驱风电系统,分析了双PWM变流器的网侧控制策略,并设计直流侧卸荷电阻式Crowbar电路的硬件电路和控制策略,在此基础上对电网3种典型的电压跌落故障进行了仿真分析。结果表明,直流侧卸荷电阻式Crowbar电路的投入能够使风电机组在不同类型的电压跌落故障时保持不脱网运行,并使发电系统的恢复更加迅速,控制简单,成本低,能够保障变流器稳定安全的运行,有效提高永磁直驱风力电系统的低电压过渡能力。

Simulation on Low Voltage Ride Through of Wind Power Based on Dynamic Triggered Unloading Resistance

Grid-connection standards require the wind turbine to ensure no off-grid operation within a certain range when the grid voltage drops. Based on the back-to-back direct drive permanent magnet wind power system, the author analysed the control strategy of the grid-side converter. The DC side unloading resistive Crowbar circuit and control strategy were designed. On this basis, three typical voltage drop fault of grid was simulated and discussed. The results showed that unloading resistance of DC side can deal with issues existing in different voltage drop faults.