Stationary-Frame Modeling of VSC Based on Current-Balancing Driven Internal Voltage Motion for Current Control Timescale Dynamic Analysis
Stationary-Frame Modeling of VSC Based on Current-Balancing Driven Internal Voltage Motion for Current Control Timescale Dynamic Analysis
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DOI：
10.3390/en11020374
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发表时间：
2018-02
期刊：
影响因子：
3.2
通讯作者：
Yabing Yan;Xiaoming Yuan;Jiabing Hu
中科院分区：
文献类型：
--
作者：
Yabing Yan;Xiaoming Yuan;Jiabing Hu
随着可再生能源的普及，电力系统中不断出现由电压源换流器（VSC）引起的高频振荡。电流控制时间尺度中的 VSC 模型在分析这些振荡问题中发挥着关键作用。传统的 VSC 模型很少显示系统振荡期间 VSC 动力学的物理机制。因此，本文从其内部电压（即VSC输出电压）的角度提出了一种VSC模型，该模型由静止坐标系中的电流基准和反馈之间的电流平衡驱动。该模型可用于以直观的物理方式研究VSC动态特性。基于所提出的模型，发现由于电流控制时间尺度内有功和无功电流控制的本质，静止坐标系中的VSC电流参考随内部电压动态变化。另外，在静止坐标系下，内部电压与误差电流之间的动态关系体现了广义积分特性，其中心频率由锁相环确定，自适应，保证了VSC电流控制的零稳态误差。所提出的模型和基于开关的模型之间的仿真比较验证了所提出的模型的有效性。
High-frequency oscillations caused by voltage source converters (VSCs) are constantly emerging in power systems with the increasing penetration of renewable energies. VSC models in current control timescale play a pivotal role in the analysis of these oscillation issues. Conventional VSC models show few physical mechanisms of VSC dynamics during system oscillations. Hence, this paper proposes a VSC model from the viewpoint of its internal voltage (namely, VSC output voltage), which is driven by current balancing between the current reference and the feedback in a stationary frame. The proposed model can be used to study VSC dynamic characteristics in an intuitionistic physical way. Based on the proposed model, it is found that VSC current reference in a stationary frame varies with internal voltage dynamic due to the essence of active and reactive current control in a current control timescale. Additionally, in a stationary frame, the dynamic relation between internal voltage and error current embodies a generalized integrating characteristic with adaptable center frequency determined by a phase-locked loop, which guarantees the zero steady state error of VSC current control. Comparisons of simulations between the proposed model and a switch-based model validates the effectiveness of the proposed model.