Grid current regulation of a three-phase voltage source inverter with an LCL input filter
Grid current regulation of a three-phase voltage source inverter with an LCL input filter
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DOI：
10.1109/psec.2002.1022337
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发表时间：
2002-11
期刊：
影响因子：
--
通讯作者：
E. Twining;D. G. Holmes
中科院分区：
文献类型：
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作者：
E. Twining;D. G. Holmes
许多并网电力电子系统，如STATCOMS、UPFC和分布式发电系统接口，都使用电压型逆变器(VSI)通过滤波器连接到电源网络。该滤波器通常是串联电感，用来减少进入配电网的开关谐波。一种替代的滤波器是LCL网络，它可以在较低的开关频率和较小的电感下实现较低级别的谐波失真，因此在更高功率的应用中具有潜在的优势。然而，包含LCL滤波器的系统需要更复杂的控制策略，并且在文献中并不常见。本文提出了一种用于调节通过LCL滤波器连接的三相VSI系统进入配电网的电网电流的稳健策略。该策略将外环电网电流调节器与内电容电流调节相结合，以稳定系统。外网电流控制环采用同步框架PI电流调节策略。利用线性分析、仿真和实验结果验证了控制算法在各种运行条件下的稳定性。最后，推导了系统“谐波阻抗”的表达式，研究了电源电压失真对系统谐波性能的影响。
Many grid connected power electronic systems, such as STATCOMs, UPFCs and distributed generation system interfaces, use a voltage source inverter (VSI) connected to the supply network through a filter. This filter, typically a series inductance, acts to reduce the switching harmonics entering the distribution network. An alternative filter is a LCL network, which can achieve reduced levels of harmonic distortion at lower switching frequencies and with less inductance, and therefore has potential benefits for higher power applications. However, systems incorporating LCL filters require more complex control strategies and are not commonly presented in literature. This paper proposes a robust strategy for regulating the grid current entering a distribution network from a three-phase VSI system connected via an LCL filter. The strategy integrates an outer loop grid current regulator with inner capacitor current regulation to stabilise the system. A synchronous frame PI current regulation strategy is used for the outer grid current control loop. Linear analysis, simulation and experimental results are used to verify the stability of the control algorithm across a range of operating conditions. Finally, expressions for "harmonic impedance" of the system are derived to study the effects of supply voltage distortion on the harmonic performance of the system.