摘要
实际电网阻抗的不确定性会严重影响并网逆变器的稳定运行,在并网逆变器控制中采用电网电压前馈策略会导致稳定性问题更加突出。首先建立了考虑电网阻抗时并网逆变器的数学模型,基于阻抗比稳定性判据,分析了电网电压前馈控制对并网逆变器在弱电网下稳定性的影响机理,指出弱电网下电网电压前馈造成系统稳定裕度下降的根本原因是前馈通道延时和脉冲宽度调制(PWM)控制延时的存在。提出了一种基于衰减因子的电网电压部分前馈控制策略。最终,仿真和实验结果验证了所提控制策略的有效性和可行性。
The uncertainty of the actual grid impedance will seriously affect the operation stability of the grid-connected inverter,and this stability problem will be aggravated by the grid-voltage feedfol"ward strategy which is widely used in the grid-eonneeted inverter control.First,the mathematical model of grid-connected inverter with the consideration of grid impedance is established.And based on the impedance ratio criterion,the influencing mechanism of the gridvoltage feedforward control on the inverter's stability in the weak grid is analyzed,and it has been pointed out that, in the weak grid,the fundamental reason of the stability margin reduction caused by grid voltage feedforward is the delay in the pulse width moduiation(PWM)control and grid-voltage feedforward path.Furthermore,a partial grid-volt- age feedforward control strategy with an attenuation factor is proposed.Finally,simulation and experimental results are provided to verify the feasibility and validity of the proposed strategy.
作者
刘乐
同向前
杨树德
宋辉
LIU Le;TONG Xiang-qian;YANG Shu-de;SONG Hui(Xi'an University of Technology,Xi'an 710048,China)
出处
《电力电子技术》
CSCD
北大核心
2019年第1期65-68,共4页
Power Electronics
基金
国家自然科学基金(51677151
51507139)~~
关键词
并网逆变器
弱电网
电网电压前馈
衰减因子
grid-connected inverter
weak grid
grid-voltage feedforward
attenuation factor
