矿用LCL型三电平静止无功发生器控制策略

为适应煤矿井下特殊环境,减小矿用静止无功发生器(SVG)的体积和质量,采用LCL滤波器和三电平逆变器作为矿用SVG的主电路拓扑,并针对LCL滤波器电流谐振问题和三电平逆变器中点电位不平衡问题,提出了一种基于串联双电流环有源阻尼控制和动态比例空间矢量调制的矿用LCL型三电平SVG控制策略。串联双电流环有源阻尼控制在网侧电流外环PI控制的基础上,通过增加滤波电容电流内环反馈控制使LCL滤波器具有阻尼特性,有效抑制了电流谐振;动态比例空间矢量调制在基本空间矢量中引入动态比例调整因子,对单位开关周期内平均中点电流进行实时控制,从而实现对中点电位平衡的控制。仿真和实验结果验证了该控制策略在LCL滤波器无阻尼电阻和直流母线电容较小情况下的可行性和良好效果。

Control strategy of mine-used LCL three-level static var generator

In order to adapt to special environment of coal mine and reduce volume and quality of mine-used static var generator(SVG),LCL filter and three-level inverter were used as main circuit topology of mine-used SVG.For problems of current resonance of LCL filter and potential imbalancein three-level inverter,a control strategy of mine-used LCL three-level SVG based on series double current loop active damping control and dynamic proportional space vector modulation was proposed.On the basis of PI control of grid-side current outer loop,LCL filter has damping characteristics by adding feedback control of filter capacitor current inner loop,which can effectively suppress current resonance.Dynamic proportional space vector modulation introduces dynamic proportional adjustment factor into basic space vector to control average neutral-point current in unit switching cycle in realtime,so as to achieve balance control of three-level neutral-point potential.The simulation and experimental results verify the feasibility and good effect of the control strategy under condition of LCL filter without damping resistance and small DC busbar capacitance.