摘要
LCL滤波器在大容量、低开关频率的并网逆变器系统中已广泛应用,但LCL容易发生谐振,特别是在多逆变器并联的新能源电力系统中。本文推导了LCL谐振的公式,根据并网电流谐振时滤波器网侧电感与电网等效电感为串联的特性,结合LCL的结构,提出采用网侧电感电压一阶微分和入网电流的双闭环控制策略,在不增加传感器数量条件下,网侧电感电压一阶微分反馈内环增加了系统阻尼,有效抑制了LCL的谐振;电流外环实现了对入网电流的直接控制,可保证较高的功率因数,提高逆变器的利用效率。与电容电流反馈控制的仿真对比结果表明,该控制策略在逆变器并网的环境中有更好的抑制电流谐振的效果,实现对并网电流质量的改善。
The LCL filter has been widely applied in the system with larger-capacity and lower switching-frequency gridconnected inverter.But resonance easily occurs in the LCL filter,especially in the new energy power systems with multiple inverters.In this paper,the LCL filter resonance formula is deduced.According to the characteristics of equivalent series inductance for grid-side inductor and power grid when the grid current resonates,and a novel control strategy with such double closed loop as the first differential of gridside inductance voltage and network current is proposed by combining with the structure of the LCL filter.In addition,without increasing the number of sensors,the system damping is added in inner loop of the first differential grid-side inductance voltage,which effectively restrains the resonance of LCL.In the outer current loop,the network current can be controlled directly to ensure higher power factor and improve the utilization efficiency of inverter.By comparing with the simulation of feedback control for capacitor current,the simulation results show that the control strategy has better effect on restraining current resonance in environment of grid-connected inverter,and improving network current quality.
出处
《现代电力》
北大核心
2015年第2期56-63,共8页
Modern Electric Power
基金
国家科技支撑计划(2011BAA01B03)
关键词
LCL型逆变器
等效电感
电感电压一阶微分
谐振阻尼
双闭环控制
inverter by using LCL filter
grid equivalent inductance
first differential of inductance voltage
resonance damping
double-loop control
