海上风电全直流汇集送出系统自适应振荡抑制策略

Adaptive oscillation suppression strategy for offshore wind power system with all-DC collection and transmission

海上风电全直流汇集送出系统中各DC/DC变换器以串并联形式组网,其控制之间相互耦合,极易诱发直流母线电压振荡。为抑制海上风电全直流汇集送出系统的直流母线电压振荡,提出一种基于直流镇定器的自适应振荡抑制策略。建立系统中各DC/DC变换器的阻抗模型。在风机机端升压端口处并联直流镇定器,通过提取直流电压的振荡频率,自适应地控制输出电流跟踪其参考值,实现输出电流与直流母线的振荡电压分量同频同相,重塑了风机机端升压端口对应谐振频率附近的阻抗。基于所提方法的振荡抑制机理,设计了期望输出导纳系数的取值界限并进行了直流镇定器的容量配置。通过阻抗稳定性分析和PLECS仿真,验证了所提方法抑制系统直流母线电压振荡的有效性。

The DC/DC converters in the offshore wind power system with all-DC collection and transmission are connected in series and parallel,and the control of them are also coupled with each other,which is easy to induce voltage oscillation of DC bus.In order to suppress the DC bus voltage oscillation of the off⁃shore wind power system with all-DC collection and transmission,an adaptive oscillation suppression strategy based on DC stabilizer is proposed.The impedance models of the DC/DC converters are established.The DC stabilizer is connected in parallel at the booster port of the wind turbine.By extracting the oscillation frequency of the DC voltage,the output current is adaptively controlled to track its reference value,so that the output current is in the same frequency and phase with the oscillation voltage component of DC bus,which reshapes the impedance at the booster port of the wind turbine near the corresponding resonant frequency.Based on the oscillation suppression mechanism of the proposed method,the value limit of the expected output admittance coefficient is designed and the capacity configuration of the DC stabilizer is carried out.Through impedance stability analysis and PLECS simulation,it is proved that the proposed method can effectively suppress the voltage oscillation of DC bus in the system.