CAJ | 학술논문

模块化多电平换流器(MMC)桥臂环流中的谐波直接影响 MMC 的工作特性和损耗。文中推导了 MMC 交流侧电流、桥臂电流和环流之间的内在联系，指出 MMC 在交流电网对称和不对称情况下桥臂环流中都含有二倍频谐波。为了对 MMC 谐波环流进行有效抑制，提出了一种基于比例-积分-谐振(PIR)控制的 MMC 新型环流控制器，无需二倍频负序坐标变换和相间解耦。最后，在 PSCAD/EMTDC 中搭建了包含该 PIR 环流控制器的双站 MMC 仿真模型，并与旋转坐标系下的环流控制器在交流电网对称和不对称情况下进行了对比仿真分析，仿真结果验证了所提出的PIR 环流控制器的有效性。
모괴화다전평환류기(MMC)교비배류중적해파직접영향 MMC 적공작특성화손모。문중추도료 MMC 교류측전류、교비전류화배류지간적내재련계，지출 MMC 재교류전망대칭화불대칭정황하교비배류중도함유이배빈해파。위료대 MMC 해파배류진행유효억제，제출료일충기우비례-적분-해진(PIR)공제적 MMC 신형배류공제기，무수이배빈부서좌표변환화상간해우。최후，재 PSCAD/EMTDC 중탑건료포함해 PIR 배류공제기적쌍참 MMC 방진모형，병여선전좌표계하적배류공제기재교류전망대칭화불대칭정황하진행료대비방진분석，방진결과험증료소제출적PIR 배류공제기적유효성。
The system losses and working performance of the modular multilevel converter(MMC) are directly affected by the harmonics in the circulating current.The inherent relation between the AC-side current,the leg current and the circulating current is first directly derived,which reveals that there always exists double-frequency harmonics whether under balanced or unbalanced grid conditions.Then,a novel circulating controller based on proportional-integral-resonant (PIR) control is proposed for effectively suppressing the harmonics in the circulating current,without the double-frequency negative-sequence transformation and the phase decoupling control.A MMC-HVDC simulation of a two-station model containing the PIR is created based on PSCAD/EMTDC.Simulation results have verified the availability of the control strategy when compared to the results from the circulating controller under double fundamental-line frequency negative sequence rotational frame.