Quasi-Proportional Resonance Control of Grid-Connected Inverter Based on Grid Impedance
With the large-scale integration of renewable energy to the grid, the problem of sub/super-synchronous oscillations caused by the interaction of renewable energy grid-connected inverters with the grid has drawn great public attention. Such oscillation problems are closely related to the output imped...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | zho |
| Published: |
State Grid Energy Research Institute
2019-12-01
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| Series: | Zhongguo dianli |
| Subjects: | |
| Online Access: | https://www.electricpower.com.cn/CN/10.11930/j.issn.1004-9649.201805135 |
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| Summary: | With the large-scale integration of renewable energy to the grid, the problem of sub/super-synchronous oscillations caused by the interaction of renewable energy grid-connected inverters with the grid has drawn great public attention. Such oscillation problems are closely related to the output impedance of the grid-connected inverter and the characteristics of grid impedance. Therefore, a small-signal output impedance model of the three-phase LCL–type grid-connected inverter is developed in this paper with harmonic linearization method, and the impacts of different current control strategies on its output impedance are evaluated, and the influence of grid impedance on system stability is analyzed with the impedance ratio Nyquist criterion. The inherent resonance peak of LCL filter is suppressed by combining passive damping with active damping, and the parameters of quasi-proportional resonance (QPR) controller and the feedback coefficient of capacitance current are adjusted according to the change of grid impedance at the point of common coupling, which enhances the robustness of the system without changing the system damping, and ensures the stable operation of the system. Finally, the effectiveness of the proposed control strategy is verified by combination of time-domain simulation and numerical analysis. |
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| ISSN: | 1004-9649 |