港区桥吊双PWM交流调速系统间谐波数学模型及仿真分析

Modeling and Simulation for Inter-harmonics of Double PWM AC Speed Control System for Port Bridge Crane

配电网中双PWM可逆调速系统的总容量占电网容量的比例较大时,双PWM产生的间谐波会引起电能质量污染,严重时引起配电网电压闪变,影响电网稳定运行。通过对上海洋山深水港配电网桥吊系统的研究,建立了双PWM交流调速系统多象限运行间谐波数学模型。利用MATLAB依照双PWM可逆调速系统桥吊的运动规律,对不同转速的用电和馈电状态下注入电网间谐波进行了仿真,仿真与测试结果均表明该模型的可靠性。模型揭示了洋山深水港区配电网电压闪变的原因,成功地在洋山深水港区电网电能质量控制中得到应用,有效地解决了电压闪变问题。

When the total capacity of double PWM reversible speed control system in distribution network accounts for a larger proportion of power grid capacity, the power quality pollution, or even voltage flicker is generated by interharmonics of double PWM system. Therefore the stable operation of the power grid is affected. Based on the studies on bridge crane system in Shanghai Deep water Port area, a mathematical model of multi-quadrant double PWM reversible speed control system was established. In accordance with the operating characteristics of motor, the inter-harmonic currents, injected into grid were simulated at different speeds respectively in the power and feed state. Simulation outcomes and measured results both proved the feasibility and validity of the model. The reasons for voltage flicker in distribution network were revealed by the model, and the model has been applied successfully in the power quality control system of Shanghai Deep water Port areaand themicro-grid voltage flicker problems have been successfully solved.