1. Frequency Coupling Suppression Control Strategy for Single-Phase Grid-Tied Inverters in Weak Grid
- Author
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Dongsheng Yang, Shiming Xie, Wenjing Xiong, Jianheng Lin, Mei Su, Yao Sun, Guanguan Zhang, Cyber-Physical Systems Center Eindhoven, Electrical Energy Systems, EIRES System Integration, and Power Conversion
- Subjects
Admittance ,Computer science ,Frequency coupling ,single-phase gridtied inverters ,MIMO ,Phase locked loops ,law.invention ,Admittance parameters ,Harmonic analysis ,Control theory ,law ,Voltage source ,Electrical and Electronic Engineering ,single-phase grid-tied inverters ,weak grid ,Impedance ,Inverters ,Systems modeling ,Grid ,phase-locked loop (PLL) ,Power system stability ,Control and Systems Engineering ,Frequency control ,Couplings ,Inverter ,Resistor - Abstract
In single-phase voltage source inverters (VSI) under a weak grid, the frequency coupling, caused by the asymmetrical system structure, poses a challenge to system modeling and controller design. In this article, a frequency coupling suppression control strategy is presented, where all the frequency coupling components in the current reference are eliminated. As a result, the single-phase grid-tied inverter is directly modeled as a simple single-input single-output (SISO) admittance rather than a complicated multiple-input multiple-output (MIMO) admittance matrix. The SISO admittance model is simple, compact, and accurate, which facilitates design-oriented analysis. The admittance characteristic analysis shows that the Sym-PLL has a critical impact on the system stability under weak grid conditions. To improve the system stability, a prefilter-based impedance-shaping control strategy is proposed by mitigating the negative resistor behavior of the Sym-PLL. Finally, simulations and experimental results validate the effectiveness of the frequency-coupling suppression control strategy.
- Published
- 2022
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