A Study of Virtual Resistor-Based Active Damping Alternatives for LCL Resonance in Grid-Connected Voltage Source Inverters
A Study of Virtual Resistor-Based Active Damping Alternatives for LCL Resonance in Grid-Connected Voltage Source Inverters
复制标题
针对并网电压源逆变器中 LCL 谐振的基于虚拟电阻的有源阻尼替代方案的研究
DOI：
10.1109/tpel.2019.2911163
复制
发表时间：
2020-01-01
影响因子：
6.7
通讯作者：
Liu, Zipeng
中科院分区：
文献类型：
--
作者：
Liu, Teng;Liu, Jinjun;Liu, Zipeng
LCL谐振使电流控制回路的设计复杂化，甚至可能威胁其稳定性。已经提出了广泛的方法来处理这种谐振，其中主动阻尼（AD）计划的基础上反馈的一个单一的滤波器变量已被证明是有效的和成本效益。本文提出了这样的AD技术的研究，其中提出了一种通用的方法来开发一个AD控制器的控制图的等效电路。基于这种方法，AD控制器的形式与四个常用的滤波器变量中的任何一个，以实现虚拟电阻（VR）在六个不同的连接到LCL滤波器推导。然后，通过考虑AD控制器的实施复杂性、测量传感器的数量以及AD控制器对功率级的影响，对这24种AD控制器替代方案进行比较。因此，选择电网侧电流反馈AD以实现与滤波电容器并联的VR作为考虑的替代方案。接下来，讨论并解决了由二阶微分表达式和数字时间延迟引起的与所选择的电网侧电流反馈AD的实际实施相关联的两个问题。最后，在离散z域对所选AD方法进行了分析，并通过实验验证了其有效性。
LCL resonance complicates the design of a current control loop and can even threaten its stability. Extensive approaches have been proposed to deal with this resonance, among which active damping (AD) schemes based on the feedback of a single filter variable have been shown to be effective and cost-efficient. This paper presents a study of such AD techniques, where a generalized approach to developing an AD controller by relating a control diagram to an equivalent circuit is proposed. Based on this approach, AD controller forms with any one of four commonly used filter variables to realize virtual resistors (VRs) in six different connections to the LCL filter are derived. Comparisons are then made between these 24 AD controller alternatives by considering the implementation complexity of the AD controller, the number of measuring sensors, and the effect of the AD controller on the power stage. Consequently, grid-side current feedback AD to realize a VR in parallel with the filter capacitor is selected as a considered alternative. Next, two issues associated with the practical implementation of the selected grid-side current feedback AD, caused by the second-order differential expression and the digital time delay, are discussed and solved. Finally, the selected AD method is analyzed in the discrete z-domain, and its effectiveness is experimentally verified.