摘要
针对中压配电网中普遍存在的三相不对称现象,采用级联H桥分离直流母线结构的电力电子变压器,为了解决直流侧电压平衡问题,在输入电压和输出负载不对称时,提出了一种新的负序电压注入法控制相间直流电容电压平衡,建立了每相平均功率与负序电压之间的关系,在dq坐标系中对负序电压进行了计算,避免了复杂的三角函数求解。计算结果中不含电网电流,无需对电流进行正负序分离,只需采用单电流内环控制。另外,在输出级采用调节占空比的方法实现相内直流电容电压的平衡控制。仿真结果表明了所提控制策略的有效性。
The three-phase asymmetry phenomenon commonly exists in medium voltage distribution networks.In this paper,a cascaded H-bridge converter-based power electronic transformer with separated DC bus is applied.A new method with negative-sequence voltage injection is proposed to control cluster voltage balance of DC capacitors when the input voltages and output loads are asymmetric.The relationship between the active power of each phase and the negative-sequence voltage is established and the negative-sequence voltage is calculated in the dq frame to avoid the complicated trigonometric calculation.The calculation results do not contain the grid currents,therefore,only a single inner current loop is adopted and the positive and negative sequences of grid currents are not necessary to calculate.Besides,individual voltage balancing control is realized by trimming the modulation wave in the output stage.The effectiveness of the proposed control strategy is verified by simulation results.
作者
张海洋
王明渝
ZHANG Haiyang;WANG Mingyu(State Key Laboratory of Power Transmission Equipment&System Security and New Technology(Chongqing University),Shapingba District,Chongqing 400044,China)
出处
《现代电力》
北大核心
2020年第1期98-103,共6页
Modern Electric Power
关键词
电力电子变压器
级联H桥
负序电压
相间电压平衡控制
相内电压平衡控制
power electronic transformer
cascaded Hbridge
negative-sequence voltage
cluster voltage balancing control
individual voltage balancing control
