scholarly journals Limitations of Small-Signal Modeling of Grid-Connected VSCs under Phase Jumps and Frequency Deviations

2020 ◽  
Author(s):  
Hongyang Zhang ◽  
xiongfei wang ◽  
östlund stefan
Keyword(s):  
Voltage Source ◽  
Frequency Variation ◽  
Small Signal ◽  
Voltage Source Converters ◽  
Signal Model ◽  
Small Signal Model ◽  
Frame Transformation ◽  
The Stability ◽  
Small Signal Modeling ◽  
Frequency Variations

The stability of grid-connected voltage source converters (VSCs) is commonly studied by the small-signal model in the synchronous reference (dq) frame. With phase-locked loop dynamic from VSCs, it is inevitable to convert the small-signal model to a common dq frame. When linearizing the frame transformation, the trigonometric functions of the angle are approximated by first-order terms. In this letter, the limitation of such linearization on the dq-transformation is discussed. The accuracy of the model, in presence of phase jumps and frequency variations, are examined. It is found that even under small phase jumps, mismatches are found between the small-signal model (SSM) and a nonlinear model (NM). It is further revealed that during the dynamics of frequency variation, significant mismatches can occur between the SSM and the NM.

scholarly journals Limitations of Small-Signal Modeling of Grid-Connected VSCs under Phase Jumps and Frequency Deviations

2020 ◽  
Author(s):  
Hongyang Zhang ◽  
xiongfei wang ◽  
östlund stefan
Keyword(s):  
Voltage Source ◽  
Frequency Variation ◽  
Small Signal ◽  
Voltage Source Converters ◽  
Signal Model ◽  
Small Signal Model ◽  
Frame Transformation ◽  
The Stability ◽  
Small Signal Modeling ◽  
Frequency Variations

The stability of grid-connected voltage source converters (VSCs) is commonly studied by the small-signal model in the synchronous reference (dq) frame. With phase-locked loop dynamic from VSCs, it is inevitable to convert the small-signal model to a common dq frame. When linearizing the frame transformation, the trigonometric functions of the angle are approximated by first-order terms. In this letter, the limitation of such linearization on the dq-transformation is discussed. The accuracy of the model, in presence of phase jumps and frequency variations, are examined. It is found that even under small phase jumps, mismatches are found between the small-signal model (SSM) and a nonlinear model (NM). It is further revealed that during the dynamics of frequency variation, significant mismatches can occur between the SSM and the NM.

Small-Signal Modeling of the LLC Half-Bridge Resonant Converter

2019 ◽  
Vol 28 (04) ◽  
pp. 1950063
Author(s):  
Jianguang Ma ◽  
Xueye Wei ◽  
Liang Hu ◽  
Junhong Zhang
Keyword(s):  
High Power ◽  
Experimental Result ◽  
Order System ◽  
Small Signal ◽  
Resonant Converter ◽  
Signal Modeling ◽  
Signal Model ◽  
Small Signal Model ◽  
Proposed Model ◽  
Small Signal Modeling

This paper proposes a small-signal modeling method for building an LLC half-bridge resonant converter. In recent years, the LLC half-bridge resonant converter has attracted the attention of many researchers because of its high-power conversion efficiency and high-power density. Generally, the LLC half-bridge resonant converter consists of many passive components, including stray and parasitic elements, resulting in a high-order system. Because the fundamental harmonic approximation (FHA) method for an LLC resonant converter only considers the fundamental harmonic and neglects higher harmonics, it is not accurate and introduces large errors in a higher-order system. In this paper, according to the operation principle of the LLC half-bridge resonant converter, a small-signal model is established. Based on the small-signal model, the input-to-output and control-to-output transfer function is derived. The experimental result verified that the proposed model yields a high accuracy, thereby highlighting the usefulness and versatility of the proposed model over other existing models.

Divided DQ Small-Signal Model: A New Perspective for the Stability Analysis of Three-Phase Grid-Tied Inverters

2019 ◽  
Vol 66 (8) ◽  
pp. 6493-6504 ◽  
Author(s):  
Zhikang Shuai ◽  
Yang Li ◽  
Weimin Wu ◽  
Chunming Tu ◽  
An Luo ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Small Signal ◽  
Signal Model ◽  
Small Signal Model ◽  
Three Phase ◽  
New Perspective ◽  
The Stability

scholarly journals Average and Small Signal Modeling of Negative-Output KY Boost Converter in CCM Operation

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Faqiang Wang ◽  
Jing Li ◽  
Xikui Ma
Keyword(s):  
Output Voltage ◽  
Averaging Method ◽  
Transfer Functions ◽  
Boost Converter ◽  
Small Signal ◽  
Signal Model ◽  
Boost Converters ◽  
Small Signal Model ◽  
Small Signal Modeling ◽  
Negative Output

Negative-output KY Boost converter, which can obtain the negative output voltage and could be driven easily, is a good topology to overcome traditional Boost and Buck-Boost converters and it is believed that this converter will be widely used in engineering applications in the future. In this study, by using the averaging method and geometrical technique, the average and small signal model of the negative-output KY Boost converter are established. The DC equilibrium point and transfer functions of the system are derived and analyzed. Finally, the effectiveness of the established model and the correctness of the theoretical analysis are confirmed by the circuit experiment.

scholarly journals Small-Signal Modeling of Phase-Shifted Full-Bridge Converter Considering the Delay Associated to the Leakage Inductance

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7280
Author(s):  
Diego Ochoa ◽  
Antonio Lázaro ◽  
Pablo Zumel ◽  
Marina Sanz ◽  
Jorge Rodriguez de Frutos ◽  
...  
Keyword(s):  
Voltage Drop ◽  
Power Converter ◽  
Open Loop ◽  
Small Signal ◽  
Random Delay ◽  
Signal Model ◽  
Leakage Inductance ◽  
Small Signal Model ◽  
Natural Response ◽  
Small Signal Modeling

This paper demonstrates that in the Phase-Shifted Full-Bridge (PSFB) buck-derived converter, there is a random delay associated with the blanking time produced by the leakage inductance. This random delay predicts the additional phase drop that is present in the frequency response of the open-loop audio-susceptibility transfer function when the converter shows a significant blanking time. The existing models of the PSFB converter do not contemplate the delay and gain differences associated to voltage drop produced in the leakage inductor of the transformer. The small-signal model proposed in this paper is based on the combination of two types of analysis: the first analysis consists of obtaining a small-signal model using the average modeling technique and the second analysis consists of studying the natural response of the power converter. The dynamic modeling of the Phase-Shifted Full-Bridge converter, including the random delay, has been validated by simulations and experimental test.

scholarly journals Analysis and Experimental Verification of New Power Flow Control for Grid-Connected Inverter with LCL Filter in Microgrid

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Herong Gu ◽  
Yajuan Guan ◽  
Huaibao Wang ◽  
Baoze Wei ◽  
Xiaoqiang Guo
Keyword(s):  
Flow Control ◽  
Power Flow ◽  
Voltage Source ◽  
Small Signal ◽  
Distributed Energy ◽  
Signal Model ◽  
Power Flow Control ◽  
Small Signal Model ◽  
Grid Connected Inverter ◽  
Good Agreement

Microgrid is an effective way to integrate the distributed energy resources into the utility networks. One of the most important issues is the power flow control of grid-connected voltage-source inverter in microgrid. In this paper, the small-signal model of the power flow control for the grid-connected inverter is established, from which it can be observed that the conventional power flow control may suffer from the poor damping and slow transient response. While the new power flow control can mitigate these problems without affecting the steady-state power flow regulation. Results of continuous-domain simulations in MATLAB and digital control experiments based on a 32-bit fixed-point TMS320F2812 DSP are in good agreement, which verify the small signal model analysis and effectiveness of the proposed method.

АЛГОРИТМ АВТОМАТИЧЕСКОГО ПОСТРОЕНИЯ МАЛОСИГНАЛЬНОЙ МОДЕЛИ GAAS PHEMT- ТРАНЗИСТОРА И ЕГО РЕАЛИЗАЦИЯ В САПР

2020 ◽  
Vol 96 (3s) ◽  
pp. 330-336
Author(s):  
А.А. Калентьев ◽  
А.А. Попов ◽  
Д.В. Билевич ◽  
И.М. Добуш ◽  
А.Е. Горяинов ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Small Signal ◽  
Signal Modeling ◽  
Design Environment ◽  
Signal Model ◽  
Microwave Transistor ◽  
Small Signal Model ◽  
Transistor Model ◽  
Small Signal Modeling ◽  
Good Agreement

Показаны результаты разработки алгоритма построения малосигнальной модели GaAs pHEMT-транзистора. Алгоритм реализован в виде плагина для САПР СВЧ-устройств NI AWR Design Environment. Алгоритм представляет собой комбинацию различных методик построения малосигнальных моделей. Он позволяет получить модели СВЧ-транзисторов в автоматическом режиме непосредственно в САПР. Экспериментальные исследования показали хорошее совпадение модели, полученной прямой экстракцией, с результатами измерений. The paper highlights the results of developing a GaAs pHEMT small-signal modeling algorithm. The algorithm has been implemented in the microwave EDA NI AWR Design Environment. The algorithm is a combination of the different techniques for small-signal model extraction. It allows automatically getting the microwave transistor model directly in the EDA. Experimental studies have shown a good agreement between directly extracted model and measurements results.

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