scholarly journals Unified SISO Loop Gain Modeling, Measurement, and Stability Analysis of Three-Phase Voltage Source Converters

2021 ◽  
Author(s):  
Jianheng Lin
Keyword(s):  
Stability Analysis ◽  
Transfer Function ◽  
Power Systems ◽  
Linear Time ◽  
System Stability ◽  
Voltage Source ◽  
Domain Modeling ◽  
Loop Gain ◽  
Single Input Single Output ◽  
Three Phase

Frequency-domain modeling is an effective technique in the dynamic analysis of power electronic converters-based power systems. In this paper, a unified single-input single-output (SISO) loop gain modeling for the three-phase grid-tied VSCs under both symmetric and asymmetric ac grids is presented, which facilitates the physical measurement and stability analysis. Based on the linear-time-periodic (LTP) modeling technique, the harmonic admittance model of the three-phase grid-tied VSC is developed in the stationary (<i>αβ</i>)-frame. Instead of the transfer function matrix, the frequency-coupling effects are modeled by the transfer function vector, which simplifies the modeling process. According to the idea of mathematical induction, a two-by-two recursive admittance matrix (RAM) model that can accurately capture the coupling dynamics introduced by the power grid is derived. The RAM has an analytical form and is easy to include harmonic coupling components of arbitrary order. Furthermore, the RAM is converted to its equivalent SISO models following the concept of loop gain. The system stability is thus assessed by the SISO stability criteria (e.g., Nyquist stability criterion). In addition, the loop gain allows the traditional SISO perturbation and measurement scheme to be used for detecting the stability margin information. Finally, simulation results verify the feasibility and correctness of the theoretical analysis presented above.

scholarly journals Unified SISO Loop Gain Modeling, Measurement, and Stability Analysis of Three-Phase Voltage Source Converters

2021 ◽  
Author(s):  
Jianheng Lin
Keyword(s):  
Stability Analysis ◽  
Transfer Function ◽  
Power Systems ◽  
Linear Time ◽  
System Stability ◽  
Voltage Source ◽  
Domain Modeling ◽  
Loop Gain ◽  
Single Input Single Output ◽  
Three Phase

Frequency-domain modeling is an effective technique in the dynamic analysis of power electronic converters-based power systems. In this paper, a unified single-input single-output (SISO) loop gain modeling for the three-phase grid-tied VSCs under both symmetric and asymmetric ac grids is presented, which facilitates the physical measurement and stability analysis. Based on the linear-time-periodic (LTP) modeling technique, the harmonic admittance model of the three-phase grid-tied VSC is developed in the stationary (<i>αβ</i>)-frame. Instead of the transfer function matrix, the frequency-coupling effects are modeled by the transfer function vector, which simplifies the modeling process. According to the idea of mathematical induction, a two-by-two recursive admittance matrix (RAM) model that can accurately capture the coupling dynamics introduced by the power grid is derived. The RAM has an analytical form and is easy to include harmonic coupling components of arbitrary order. Furthermore, the RAM is converted to its equivalent SISO models following the concept of loop gain. The system stability is thus assessed by the SISO stability criteria (e.g., Nyquist stability criterion). In addition, the loop gain allows the traditional SISO perturbation and measurement scheme to be used for detecting the stability margin information. Finally, simulation results verify the feasibility and correctness of the theoretical analysis presented above.

scholarly journals Direct Method-Based Transient Stability Analysis for Power Electronics-Dominated Power Systems

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Yanbo Che ◽  
Zihan Lv ◽  
Jianmei Xu ◽  
Jingjing Jia ◽  
Ming Li
Keyword(s):  
Stability Analysis ◽  
Power Systems ◽  
Power Electronics ◽  
Transient Stability ◽  
Direct Method ◽  
System Modeling ◽  
System Stability ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Transient Stability Analysis

With the extensive application of power electronics interfaced nonsynchronous energy sources (NESs) in modern power systems, the system stability especially the transient stability is prominently deteriorated, and it is crucial to find a comprehensive and reasonably simple solution. This paper proposes a direct method-based transient stability analysis (DMTSA) method which concludes the key steps as follows: (1) the system modeling of Lyapunov functions using mixed potential function theory and (2) the stability evaluation of critical energy estimation. A voltage source converter- (VSC-) based HVDC transmission system is simulated in a weak power grid to validate the proposed DMTSA method under various disturbances. The simulation results verify that the proposed method can effectively estimate the transient stability with significant simplicity and generality, which is practically useful to secure the operation and control for power electronics-dominated power systems.

Bifurcation and Large-Signal Stability Analysis of Three-Phase Voltage Source Converter Under Grid Voltage Dips

2017 ◽  
Vol 32 (11) ◽  
pp. 8868-8879 ◽  
Author(s):  
Meng Huang ◽  
Yu Peng ◽  
Chi K. Tse ◽  
Yushuang Liu ◽  
Jianjun Sun ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Phase Voltage ◽  
Large Signal ◽  
Grid Voltage ◽  
Signal Stability ◽  
Three Phase ◽  
Voltage Dips

D–Q Impedance Based Stability Analysis and Parameter Design of Three-Phase Inverter-Based AC Power Systems

2017 ◽  
Vol 64 (7) ◽  
pp. 6017-6028 ◽  
Author(s):  
Wenchao Cao ◽  
Yiwei Ma ◽  
Liu Yang ◽  
Fei Wang ◽  
Leon M. Tolbert
Keyword(s):  
Stability Analysis ◽  
Power Systems ◽  
Parameter Design ◽  
Phase Inverter ◽  
Ac Power ◽  
Three Phase ◽  
Three Phase Inverter

Active Vibration Suppression With Time Delayed Feedback

2003 ◽  
Vol 125 (3) ◽  
pp. 384-388 ◽  
Author(s):  
Rifat Sipahi ◽  
Nejat Olgac
Keyword(s):  
Stability Analysis ◽  
Time Delay ◽  
Vibration Suppression ◽  
Linear Time ◽  
Direct Method ◽  
System Stability ◽  
Delayed Systems ◽  
Active Vibration Suppression ◽  
Active Vibration ◽  
The Stability

Various active vibration suppression techniques, which use feedback control, are implemented on the structures. In real application, time delay can not be avoided especially in the feedback line of the actively controlled systems. The effects of the delay have to be thoroughly understood from the perspective of system stability and the performance of the controlled system. Often used control laws are developed without taking the delay into account. They fulfill the design requirements when free of delay. As unavoidable delay appears, however, the performance of the control changes. This work addresses the stability analysis of such dynamics as the control law remains unchanged but carries the effect of feedback time-delay, which can be varied. For this stability analysis along the delay axis, we follow up a recent methodology of the authors, the Direct Method (DM), which offers a unique and unprecedented treatment of a general class of linear time invariant time delayed systems (LTI-TDS). We discuss the underlying features and the highlights of the method briefly. Over an example vibration suppression setting we declare the stability intervals of the dynamics in time delay space using the DM. Having assessed the stability, we then look at the frequency response characteristics of the system as performance indications.

scholarly journals Impedance Decomposition for Design-Oriented Analysis of Grid-Forming Voltage-Source Converters

2020 ◽  
Author(s):  
Yicheng Liao ◽  
xiongfei wang
Keyword(s):  
Stability Analysis ◽  
Controller Design ◽  
System Stability ◽  
Voltage Source ◽  
Voltage Source Converters ◽  
Multiple Control ◽  
Decomposition Approach ◽  
Control Loops ◽  
Nyquist Stability ◽  
Impedance Decomposition

<p>Grid-forming voltage-source converters (VSCs) tend to suffer from sideband oscillations in stiff grids. Conventional state-space eigenvalue analysis or impedance-based stability analysis based on generalized Nyquist stability criterion can only analyze how specific control parameters affect the overall system stability, which ends up with less insight into a controller design-oriented analysis. To tackle this challenge, this article starts with the impedance modeling and stability analysis of grid-forming VSCs in stiff grids. Then, an impedance decomposition approach to characterizing the impacts of multiple control loops is proposed, which benefits in a controller design-oriented analysis for stability enhancement. Finally, simulation and experimental results are provided to validate the approach.</p>

scholarly journals Impedance Decomposition for Design-Oriented Analysis of Grid-Forming Voltage-Source Converters

2020 ◽  
Author(s):  
Yicheng Liao ◽  
xiongfei wang
Keyword(s):  
Stability Analysis ◽  
Controller Design ◽  
System Stability ◽  
Voltage Source ◽  
Voltage Source Converters ◽  
Multiple Control ◽  
Decomposition Approach ◽  
Control Loops ◽  
Nyquist Stability ◽  
Impedance Decomposition

<p>Grid-forming voltage-source converters (VSCs) tend to suffer from sideband oscillations in stiff grids. Conventional state-space eigenvalue analysis or impedance-based stability analysis based on generalized Nyquist stability criterion can only analyze how specific control parameters affect the overall system stability, which ends up with less insight into a controller design-oriented analysis. To tackle this challenge, this article starts with the impedance modeling and stability analysis of grid-forming VSCs in stiff grids. Then, an impedance decomposition approach to characterizing the impacts of multiple control loops is proposed, which benefits in a controller design-oriented analysis for stability enhancement. Finally, simulation and experimental results are provided to validate the approach.</p>

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