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基于五电平逆变器APF的控制与调制.doc

发布:2017-05-21约7.48千字共6页下载文档
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基于五电平逆变器APF的控制与调制 甘子松1,任洪强1,刘阳2 (,,210096044000) 关键词: APF;二极管钳位五电平逆变器;递归DFT;均压策略;SVPWM Control and Modulation of Three Phase APF Based on Five Level Inverter Gan Zi-song1, Ren Hong-qiang1, Liu Yang2 (1、Southeast University,Nanjing 210096,ChinaState Grid Yuncheng Power Company substation maintenance room, Yuncheng, 044000) Ahree-phase half-bridge APF is used for improving the power quality of three-phase three-wire power system, due to its limited number of output level, compensation result is not ideal. Based on the five-level npc inverter, this paper proposes a three-phase APF topology. Compared with ordinary three-phase half-bridge inverter, the number of the output levels of this topology can be increased to five, which can achieve the purpose of reducing values of the inverter outlet inductance at the same time. In addition, with SVPWM algorithm, the five-level npc inverters can reduce the switching losses, while the DC-side voltage utilization is improved. Finally, the effectiveness of five-level diode clamp APF is verified by building simulations in the MATLAB / SIMULINK. The Simulation results illustrate that five-level npc inverter with SVPWM modulation strategy for power quality improvement in three-phase three-wire system control is feasible. Keywords: APF;Five-level NPC Inverter;Recursive DFT;Balance of Voltage;SVPWM 引言 随着近几年电力电子技术的发展,整流电路、变频调速装置等各种电力电子设备在低压配电网中得到广泛应用。这些负荷虽然促进了工业的发展,但是由于其非线性产生的谐波电流对电网造成严重的污染,严重危害用户其他用电设备的用电安全。有源滤波器 (Active Power Filter,APF )因为其良好的动态性能和补偿特点,被广泛用于消除配电网中的谐波电流。 如何有效地消除电网中的谐波电流,是谐波抑制用的关键问题。文献[1]介绍了一种应用于补偿三相三线制系统的无功和谐波电流的三相半桥的拓扑,并分析了该拓扑数学模型、电路原理和调制策略等,但是由于两电平逆变器输出电压电平数和直流侧电压的限制,致使其谐波补偿效果并不理想。文献[2]提出了一种并联型的有源滤波器,该拓扑可以用于补偿电网中的无功和谐波电流,并且采用了前馈子控制,因此可以显著改善电流的输出波形,但是其谐波不能实现分次补偿。文献[3]提出了一种基于H桥级联的有源滤波器,其输出电平数多,补偿效果理想,但是其成本较高。针对补偿对象为谐波电流时,三相半桥逆变器的直流侧电压利用率低和H桥级联逆变器成本高的缺点,为此本文提出了一种基于二极管钳位五电平逆变器的三相APF的方案,采用预测电流和遍历冗余开关矢量的均压策略,使得电容电压保持平衡,同时采用SVPWM调制策略。本文给出了在αβ坐标系二极管钳位五电平逆变器SVPWM的谐波检测策略和均压策略,实现了基于递归的DFT算法的谐波检测方法,可以对负载谐波电流进行分次补偿,并在SIMULINK仿
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