scholarly journals Impedance Modeling and Stability Analysis of DFIG-Based Wind Energy Conversion System Considering Frequency Coupling

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3243
Author(s):  
Shaojian Song ◽  
Peichen Guan ◽  
Bin Liu ◽  
Yimin Lu ◽  
HuiHwang Goh
Keyword(s):  
Stability Analysis ◽  
Coupling Effect ◽  
Impedance Model ◽  
Wind Energy Conversion ◽  
Proposed Model ◽  
New Type ◽  
Impedance Modeling ◽  
Frequency Coupling ◽  
Bus Voltage ◽  
Voltage Dynamics

Impedance-based stability analysis is an effective method for addressing a new type of SSO accidents that have occurred in recent years, especially those caused by the control interaction between a DFIG and the power grid. However, the existing impedance modeling of DFIGs is mostly focused on a single converter, such as the GSC or RSC, and the influence between the RSC and GSC, as well as the frequency coupling effect inside the converter are usually overlooked, reducing the accuracy of DFIG stability analysis. Hence, the entire impedance is proposed in this paper for the DFIG-based WECS, taking coupling factors into account (e.g., DC bus voltage dynamics, asymmetric current regulation in the dq frame, and PLL). Numerical calculations and HIL simulations on RT-Lab were used to validate the proposed model. The results indicate that the entire impedance model with frequency coupling is more accurate, and it is capable of accurately predicting the system’s possible resonance points.

scholarly journals Effect of Frequency Coupling on Stability Analysis of a Grid-Connected Modular Multilevel Converter System

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6580
Author(s):  
Yixing Wang ◽  
Qianming Xu ◽  
Josep M. Guerrero
Keyword(s):  
Stability Analysis ◽  
Coupling Effect ◽  
Modular Multilevel Converter ◽  
Stability Assessment ◽  
Analysis Method ◽  
Multilevel Converter ◽  
Single Input Single Output ◽  
Impedance Model ◽  
Frequency Coupling ◽  
The Stability

Due to the internal dynamics of the modular multilevel converter (MMC), the coupling between the positive and negative sequences in impedance, which is defined as frequency coupling, inherently exists in MMC. Ignoring the frequency coupling of the MMC impedance model may lead to inaccurate stability assessment, and thus the multi-input multi-output (MIMO) impedance model has been developed to consider the frequency coupling effect. However, the generalized Nyquist criterion (GNC), which is used for the stability analysis of an MIMO model, is more complicated than the stability analysis method applied on single-input-single-output (SISO) models. Meanwhile, it is not always the case that the SISO model fails in the stability assessment. Therefore, the conditions when the MIMO impedance model needs to be considered in the stability analysis of an MMC system should be analyzed. This paper quantitatively analyzes the effect of frequency coupling on the stability analysis of grid-connected MMC, and clarifies the frequency range and grid conditions that the coupling effect required to be considered in the stability analysis. Based on the quantitative relations between the frequency coupling and the stability analysis of the grid-connected MMC system, a simple and accurate stability analysis method for the grid-connected MMC system is proposed, where the MIMO impedance model is applied when the frequency coupling has a significant effect and the SISO impedance model is used if the frequency coupling is insignificant.

Input Impedance Modeling of Single-Phase Voltage Source Rectifier With Consideration of FrequencyCoupling Effect

2020 ◽  
Author(s):  
Jianheng Lin ◽  
Mei Su ◽  
Yao Sun ◽  
Shiming Xie
Keyword(s):  
Input Impedance ◽  
Single Phase ◽  
Coupling Effect ◽  
Voltage Source ◽  
Phase Voltage ◽  
Impedance Model ◽  
Grid Impedance ◽  
Impedance Modeling ◽  
Frequency Coupling ◽  
Time Periodicity

Time-periodicity and non-linearity pose a challenge to the precise input impedance modeling of single-phase power converters. In this study, a precise input impedance model with measurability of the single-phase voltage source rectifier (VSR), which considers the frequency-coupling effect (FCE), is established. Meanwhile, it is revealed that the rectifier input impedance is dependent of the grid impedance. In the proposed modeling approach, only Laplace transform and frequencyshifting operation are required, which avoids the complicated convolution calculation in the frequency domain. In addition, the influence of grid impedance on the input impedance is studied. Simulations are conducted to verify the effectiveness of the proposed method. <br>

scholarly journals Input Impedance Modeling of Single-Phase Voltage Source Rectifier With Consideration of FrequencyCoupling Effect

2020 ◽  
Author(s):  
Jianheng Lin ◽  
Mei Su ◽  
Yao Sun ◽  
Shiming Xie
Keyword(s):  
Input Impedance ◽  
Single Phase ◽  
Coupling Effect ◽  
Voltage Source ◽  
Phase Voltage ◽  
Impedance Model ◽  
Grid Impedance ◽  
Impedance Modeling ◽  
Frequency Coupling ◽  
Time Periodicity

Time-periodicity and non-linearity pose a challenge to the precise input impedance modeling of single-phase power converters. In this study, a precise input impedance model with measurability of the single-phase voltage source rectifier (VSR), which considers the frequency-coupling effect (FCE), is established. Meanwhile, it is revealed that the rectifier input impedance is dependent of the grid impedance. In the proposed modeling approach, only Laplace transform and frequencyshifting operation are required, which avoids the complicated convolution calculation in the frequency domain. In addition, the influence of grid impedance on the input impedance is studied. Simulations are conducted to verify the effectiveness of the proposed method. <br>

Recursive SISO Impedance Modeling of Single-Phase Voltage Source Rectifiers

2021 ◽  
Author(s):  
Jianheng Lin
Keyword(s):  
Transfer Function ◽  
Single Phase ◽  
Analytical Form ◽  
Voltage Source ◽  
Phase Voltage ◽  
Modeling Framework ◽  
Single Input Single Output ◽  
Impedance Model ◽  
Impedance Modeling ◽  
Frequency Coupling

<p>This paper proposes a recursive single-input single-output (SISO) impedance modeling framework for single-phase voltage source rectifiers, which can greatly simplify both the modeling procedure and the resulting impedance model. During the modeling process, frequency-coupling effects are modeled by the reduced-order transfer function vector rather than the transfer function matrix, so the modeling complexity is reduced. Moreover, the recursive SISO impedance model has an analytical form. And the recursive SISO impedance model can characterize the frequency-coupling dynamics of arbitrary order with a low computation burden. Experiments validate the accuracy of the recursive SISO impedance modeling.<br></p>

scholarly journals Recursive SISO Impedance Modeling of Single-Phase Voltage Source Rectifiers

2021 ◽  
Author(s):  
Jianheng Lin
Keyword(s):  
Transfer Function ◽  
Single Phase ◽  
Analytical Form ◽  
Voltage Source ◽  
Phase Voltage ◽  
Modeling Framework ◽  
Single Input Single Output ◽  
Impedance Model ◽  
Impedance Modeling ◽  
Frequency Coupling

<p>This paper proposes a recursive single-input single-output (SISO) impedance modeling framework for single-phase voltage source rectifiers, which can greatly simplify both the modeling procedure and the resulting impedance model. During the modeling process, frequency-coupling effects are modeled by the reduced-order transfer function vector rather than the transfer function matrix, so the modeling complexity is reduced. Moreover, the recursive SISO impedance model has an analytical form. And the recursive SISO impedance model can characterize the frequency-coupling dynamics of arbitrary order with a low computation burden. Experiments validate the accuracy of the recursive SISO impedance modeling.<br></p>

Output Impedance Modeling of Single-Phase Grid-Tied Inverters With Capturing the Frequency-Coupling Effect of PLL

2020 ◽  
Vol 35 (5) ◽  
pp. 5479-5495 ◽  
Author(s):  
Qiang Qian ◽  
Shaojun Xie ◽  
Jinming Xu ◽  
Kunshan Xu ◽  
Shenyiyang Bian ◽  
...  
Keyword(s):  
Single Phase ◽  
Coupling Effect ◽  
Output Impedance ◽  
Impedance Modeling ◽  
Frequency Coupling

Evaluation of thermal couple impedance model of power modules for accurate die temperature estimation up to 200 ◦C

2022 ◽  
Author(s):  
Yohei Nakamura ◽  
Naotaka Kuroda ◽  
Ken Nakahara ◽  
Michihiro Shintani ◽  
Takashi Sato
Keyword(s):  
Coupling Effect ◽  
Cross Coupling ◽  
Maximum Error ◽  
Oxide Semiconductor ◽  
Temperature Estimation ◽  
Impedance Model ◽  
Power Modules ◽  
Proposed Model ◽  
Practical Operation ◽  
Die Temperature

Abstract This paper presents an experimental evaluation of the thermal couple impedance model of power modules (PMs), in which Silicon Carbide (SiC) Metal-Oxide-Semiconductor Field-Effect-Transistor (MOSFET) dies are implemented. The model considers the thermal cross-coupling effect, representing the temperature rise of a die due to power dissipations by the other dies in the same PM. We propose a characterization method to obtain the thermal couple impedance of the SiC MOSFET-based PMs for model accuracy. Simulation based on the proposed model accurately estimates the measured die temperature of three PMs with different die placements. The maximum error between measured and simulated die temperatures is within 8.1 ◦C in a wide and practical operation range from 70 ◦C to 200 ◦C. The thermal couple impedance model is helpful to design die placements of high power PMs considering the thermal cross-coupling effect.

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