Discrete-Time Modified UDE-Based Current Control for $LCL$-Type Grid-Tied Inverters
| Autor: | Qiangsong Zhao, Yuheng Wu, Yongqiang Ye, Cao Yongfeng, Yongkang Xiong |
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| Rok vydání: | 2020 |
| Předmět: |
Total harmonic distortion
Computer science 020208 electrical & electronic engineering Estimator 02 engineering and technology Grid Discrete time and continuous time Control and Systems Engineering Control theory Robustness (computer science) Control system Harmonics 0202 electrical engineering electronic engineering information engineering Electrical and Electronic Engineering |
| Zdroj: | IEEE Transactions on Industrial Electronics. 67:2143-2154 |
| ISSN: | 1557-9948 0278-0046 |
| Popis: | In $LCL$ -type grid-tied inverters, the lumped disturbance, including parameter uncertainties, unmodeled dynamics, and grid harmonics, will deteriorate the current tracking performance and lead to high total harmonic distortion (THD). The uncertainty and disturbance estimator (UDE) scheme provides an effective way to attenuate the lumped disturbance. However, UDE for the current control in $LCL$ -type grid-tied inverters is far from perfect. In this paper, a discrete-time modified UDE (MUDE) scheme is proposed to improve the current tracking performance and robustness. In MUDE, a reduced-order model of the $LCL$ filter, combined with an active damping scheme, is proposed. The stability performance is discussed in detail, and a rigorous stability condition is proposed for the first time. Moreover, the analysis of the controller sampling frequency and grid impedance, and their influences on the system stability is presented. A design case based on the stability condition is also given. Comparative experiments are conducted to verify the effectiveness of the proposed scheme. |
| Databáze: | OpenAIRE |
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