Modeling and Analysis of a Digitally Controlled Grid-Connected Large-Scale Centralized PV System

Liu, Jinhong; Zhou, Lin; Li, Bin; Chen, Zheng; Xie, Bin

doi:10.1109/tpel.2017.2712910

Cited by 34 publications

(21 citation statements)

References 26 publications

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“…8. To improve system stability reducing the influence of digital control delay, some methods have been put forward, such as enlarging the positive damping region [39,83,84], modifying active damping by other control strategies [85][86][87], and compensating the digital delay time [88,89]. Existing works have greatly reduced the influence of digital delay on system stability, but have not totally eliminated the effect.…”

Section: Non-linear Analysis Of Invertersmentioning

confidence: 99%

Stability problems of PV inverter in weak grid: a review

Zhang

Mao

Guo

et al. 2020

IET Power Electronics

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Photovoltaic (PV) power generation, as one important part of renewable energy, has been greatly developed in recent years. The stability of PV inverters is very important for the normal operation of PV systems. However, most PV systems, especially the large PV plants, locate in rural areas. The corresponding equivalent grid impedance is rather large and easy to lead to stability problems of grid-connected inverters and many researches have been done focusing on the stability problems. In this study, a survey of stability problems of PV inverters on weak grid condition is given. The stability problems are mainly divided into two parts, i.e. the control loops instability and inverter output voltage instability. The control loops cover the current loop and dc voltage loop. The output voltage instability refers to the voltage phasors relationship and the application of reactive power compensation. The non-linear parts of inverter dead-time, digital control delay, and phase-locked loop are explored. Future trends and challenges are given.

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Section: Non-linear Analysis Of Invertersmentioning

confidence: 99%

Stability problems of PV inverter in weak grid: a review

Zhang

Mao

Guo

et al. 2020

IET Power Electronics

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“…Facing the increasingly serious problems of fossil energy shortage and environmental pollution, the photovoltaic (PV) power generation has achieved remarkable growth [1]. As one of the utilisation forms of PV power generation, the large‐scale PV plant has advantages of higher generation efficiency and reactive power compensation [2, 3]. Fig.…”

Section: Introductionmentioning

confidence: 99%

“…For multi‐parallel inverters loaded through long wiring cables, the inverters are coupled due to the grid impedance, which exacerbates the influence of grid impedance [5, 8]. In addition, when considering the digital control delay of grid‐connected inverters, the phase characteristics of the system will become worse and the system stability is threatened [3, 11].…”

Section: Introductionmentioning

confidence: 99%

Modelling and robust control of digitally controlled large‐scale PV plants

Xie

Mao

Guo

et al. 2020

IET Power Electronics

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Large-scale photovoltaic (PV) plants may be destabilised by the large grid impedance introduced by transformers and long transmission lines. When considering the digital control delay of grid-connected inverters, the problem will become more serious. In this study, the equivalent impedance model of digitally controlled large-scale PV plants is established, considering that the values of the parameters of the LCL filter follow Gaussian distributions. Then, the system stability can be analysed conveniently, and the stability analysis shows that the digital control delay will make the system robust to large grid impedance worse. To enhance the stability-robustness of the system, an H ∞ robust controller is proposed in this study. By properly selecting the weighting functions, the desired tracking error performance and robustness are achieved on the basis of the mixedsensitivity optimisation control design. Compared with the traditional dual current loop control strategy, the H ∞ robust controller improves significantly the system stability-robustness against large grid impedance. Finally, simulation and experimental tests are carried out in this study, and the results demonstrate the effectiveness of the proposed H ∞ robust controller.

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“…Today, distribution generation-based PV systems make a major contribution to total global electricity production. It has been reported that PV capacity in 2016 had increased by a factor of 43.14% from just 7.0 GW in 2006 to a new record figure of 303GW worldwide [1]. However, the power produced from distributed generation systems such as PV panels is in the form of DC voltage, which necessitates the use of a pulse-width modulation (PWM) inverter for conversion into AC components and hence connected to the utility network [2].…”

Section: Introductionmentioning

confidence: 99%

Resonance Frequency Detection Technique in Gridconnected Inverter Systems Based on Double-order Digitalized Filter

Khalfalla¹,

Ethni

Kadandani³

et al. 2019

2019 10th International Renewable Energy Congress (IREC)

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Voltage source inverters (VSI) employed in distribution generation systems are usually interfaced to the grid via a low-pass LCL filter. This filter has a resonance frequency peak which can vary with respect to grid impedance, leading to instability issues if not properly suppressed. This paper proposes a resonance detection method based on a double-order digital band-pass filter. The digital filter extracts only the harmonic components around the resonance frequency from the injected grid current waveform while attenuating other frequencies outside its passband. The range of resonance frequencies has been determined by a grid impedance estimation technique. The detection method has been implemented in an experimental singlephase grid-connected inverter system and the practical results validate the effectiveness of the proposed method.

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Modeling and Analysis of a Digitally Controlled Grid-Connected Large-Scale Centralized PV System

Cited by 34 publications

References 26 publications

Stability problems of PV inverter in weak grid: a review

Stability problems of PV inverter in weak grid: a review

Modelling and robust control of digitally controlled large‐scale PV plants

Resonance Frequency Detection Technique in Gridconnected Inverter Systems Based on Double-order Digitalized Filter

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