论文部分内容阅读
双脉宽调制(pulse width modulation,PWM)交直交调速系统注入配电网的间谐波电流会引起配电网电压闪变,影响电网稳定运行.论文首先研究间谐波与基波耦合调制造成的频谱畸变及有效值波动规律.其次,以基于Bessel函数的时序开关函数,建立双PWM交流调速系统注入电网的间谐波电流数学模型.模型纳入电机工况变化及负载转矩的波动,精确得出双PWM系统注入电网电流中不同耦合调制项的数学表达式.通过仿真分析注入电网电流的频谱特征,及引起电网电压有效值波动的规律.最后,将研究结论与上海洋山深水港区配电网的实验数据相验证,证明数学模型及结论的正确性和有效性.“,”The dual PWM AC/DC/AC speed control system injects interharmonic currents into distribution networks. The injected interharmonic currents cause voltage flicker in distribution networks, affect the stable operation of power grids. Firstly, the distortions of spectrum and fluctuation of voltage effective values caused by coupling modulation were analyzed. Secondly, based on Bessel sequential switch functions, a mathematical model of interharmonic currents generated by the Dual PWM speed control system was established. The model, which takes account of motor operating conditions and load torque disturbance, consists of exact mathematical expression for interharmonic currents which were coupling-modulated by the dual PWM speed control system and were injected into power grids from the grid-side PWM. The spectrum characteristics of injected interharmonic currents and fluctuating laws of grid voltage effective values were presented by the simulation in this paper. Finally, the research conclusions were validated with the experimental data of distribution networks in Shanghai Deep water Port area. The feasibility and validity of the model and conclusions were verified.