單周期控制三相PWM整流器在不對稱電網下的研究

摘要：傳統的矢量模式單周期控制三相PWM整流器是基于對稱電網系統下研究的，功率因數約為1，輸入諧波低，且與雙極型單周期控制相比，具有更低的開關損耗。當三相電網不對稱時，三相輸入電流跟蹤電網電壓的非零序分量，采用傳統電網電壓選擇矢量區間不能保證三相PWM整流器具有較低的開關損耗，且在電網極端缺相故障時，系統不能正常工作。本文采用電網電壓非零序分量選擇矢量區間，并對矢量區間狀態進行分析比較，結果證明所采取的方法能保證系統在任何情況下開關損耗最低。最后對三相PWM整流器工作于不對稱電網情況下進行了仿真研究，仿真結果表明采用電網電壓非零序分量選擇矢量區間能保證電網電壓在缺相故障時系統仍能正常工作，并且所采用的單周期控制同時滿足對稱電網系統。 敘詞：單周期控制,不對稱電網,三相PWM整流器,非零序分量 Abstract：Research on three-phase PWM rectifier based on traditional vector model one-cycle control (OCC) is in balanced systems, which achieves unity power factor and low THD. And compared with bipolar mode one-cycle control, vector model one-cycle control has minimum switching losses. In unbalanced systems, three-phase input current track the non-zero sequence phase voltages. Selection region based on voltages cant ensure minimum switching losses and handle the extreme unbalanced system where one phase voltage is entirely zero. This paper employs the non-zero sequence phase voltages for region selection, and analyses vector region states, as a result, analysis verify the proposed OCC vector controller can ensure minimum switching losses in the any case. Finally, the simulation results show OCC controller with the non-zero sequence phase voltages for region selection ensure the system reliably work under extreme unbalance conditions, and also satisfy the balanced systems. Keyword：OCC unbalanced system three-phase PWM rectifier non-zero sequence