Observer-Based Active Damping of $LCL$ Resonance in Grid-Connected Voltage Source Converters
Observer-Based Active Damping of $LCL$ Resonance in Grid-Connected Voltage Source Converters
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DOI：
10.1109/tia.2014.2317849
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发表时间：
2014-04
影响因子：
4.4
通讯作者：
Vlatko Miskovic;V. Blasko;T. Jahns;Anton H. C. Smith;Charles J. Romenesko
中科院分区：
文献类型：
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作者：
Vlatko Miskovic;V. Blasko;T. Jahns;Anton H. C. Smith;Charles J. Romenesko
带有$LCL$滤波器的电压源转换器(VSC)在并网应用中很有吸引力，因为它们大大减少了开关谐波对市电电压的污染。然而，$LCL$ 网络在接近谐振的频率下具有非常低的阻抗，因此，即使在这些频率下很小的电压幅度也会激发大量电流，甚至导致不稳定。本文提出了一种新颖的电流控制器结构，该结构使用Luenberger观测器作为传感器替代品和状态预测器来预测通过虚拟电阻器的滤波电容器电流以实现阻尼效果。通过虚拟电阻器的预测滤波电容器电流是内部快速环路，而包含适当前馈项的外部环路确保快速命令跟踪和零稳态误差。预测状态的使用减轻了计算和采样延迟的影响，从而大大提高了主动阻尼（AD）能力。所提出的解决方案无需额外的传感器。本文提供的仿真和实验结果证明了 AD 和虚拟电阻在接近谐振的频率下主动加强 AFE 驱动器输入阻抗的有效性。
Voltage source converters (VSCs) with $LCL$ filters are attractive in grid-connected applications because they greatly reduce the pollution of the utility voltage due to switching harmonics. However, $LCL$ networks have very low impedance at frequencies close to the resonance, and therefore, even small voltage magnitudes at those frequencies can excite currents of large magnitudes or even cause instability. In this paper, a novel current controller structure is proposed that uses a Luenberger observer as a sensor replacement and state predictor to predict the filter capacitor current which is passed through a virtual resistor to achieve a damping effect. The predicted filter capacitor current through a virtual resistor is the inner fast loop, while the outer loop containing the appropriate feedforward terms ensures fast command tracking and zero steady-state error. The use of the predicted states alleviates the impact of computational and sampling delays which greatly improves the active damping (AD) capability. The proposed solution eliminates the need for additional sensors. This paper presents simulation and experimental results which demonstrate AD and the effectiveness of the virtual resistance in actively stiffening the input impedance of the AFE drive at frequencies close to resonance.