CAJ | 학술논문

分析了直驱风电变流器在电网不对称情况下的表现,提出一种适用于该情况的网侧变流器控制策略,并将其与直流侧Crowbar电路配合,实现电网不对称故障下的低电压穿越.直驱风电机组与电网间的功率交换完全通过变流器实现,电网不对称故障引起的有功功率波动在变流器上表现为直流侧电压大幅波动.控制策略以稳定输出有功功率为目标,基于同步旋转坐标系和正负序分解得出控制模型,并综合考虑电流安全限值、系统复杂程度等问题,给出额定功率附近运行时发生不对称故障的穿越方案.使用MATLAB建立仿真模型,给出不对称故障下的仿真结果,证明方案可行性.
분석료직구풍전변류기재전망불대칭정황하적표현,제출일충괄용우해정황적망측변류기공제책략,병장기여직류측Crowbar전로배합,실현전망불대칭고장하적저전압천월.직구풍전궤조여전망간적공솔교환완전통과변류기실현,전망불대칭고장인기적유공공솔파동재변류기상표현위직류측전압대폭파동.공제책략이은정수출유공공솔위목표,기우동보선전좌표계화정부서분해득출공제모형,병종합고필전류안전한치、계통복잡정도등문제,급출액정공솔부근운행시발생불대칭고장적천월방안.사용MATLAB건립방진모형,급출불대칭고장하적방진결과,증명방안가행성.
The response of direct-drive wind turbine converters under unbalanced grid conditions is analyzed.A control strategy in this condition is proposed,which coordinates the converter with the DC side Crowbar circuit during unbalanced voltage dips.Since the direct-drive wind turbines exchange full power with grid via converters,the fluctuation of active power caused by unbalanced voltages will lead to DC-link voltage ripples.The control strategy aims to stabilize the active power outputs.The control model is based on the rotating frame,decomposition of positive and negative sequence vectors.The current limit and complexity of the control system are also taken into account.When operating in the vicinity of rated power,wind turbines can pass through unbalanced voltage dips.Simulation results using MATLAB verify the correctness of the proposed control strategy.