SCHEMATIC PSPICE SIMULATION OF A HALF BRIDGE SINGLE PHASE DC-AC INVERTER USING PWM SWITCHING WITH NON LINEAR LOAD

 

ENERGIZEI CAST COM DOUTOR ELETRÔNICA DE POTÊNCIA (UFC)LUIS DANIEL BEZERRA PROFESSOR NO IFCE MARACANAU CEARÁ BRASIL

 

Analysis of Phase-Locked Loop Filter Delay on Transient Stability of Grid-Following Converters by Chenglin Zhang *,Junru Chen and Wenjia Si-The College of Electrical Engineering, Xinjiang University,

 Abstract 

To ensure precise phase estimation within the q-axis of the phase-locked loop (PLL), integrating a filter into the q-axis loop is essential to mitigate grid-voltage harmonics. Nevertheless, the intrinsic delay characteristics of this filter impede PLL synchronization during significant grid disturbances. This study begins by developing mathematical models for three types of filters—moving-average filter (MAF) for eliminating odd harmonic components, dq-frame cascaded delayed signal cancellation (dqCDSC) filter, and notch filter (NF). Following the reduction in filter orders, a third-order nonlinear large-signal model of the PLL, incorporating an additional q-axis internal filter, is formulated. Using phase plane analysis, this study investigates the transient synchronism of the grid-following converter (GFL) and explores the influence of delay time constants from the three PLL filters on its behavior while delineating the boundaries of their basins of attraction. Theoretical findings indicate that, relative to the traditional SRF-PLL, incorporating an internal filter into the PLL compromises the transient synchronous stability of GFL. Specifically, greater filter delay time constants exacerbate the GFL’s vulnerability to transient instability amid substantial grid disturbances. Hence, careful consideration is essential when using MAF-PLL and NF-PLL in situations demanding high synchronization stability. The theoretical analyses are validated using Matlab/Simulink to verify their accuracy.

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DQ Impedance Reshaping of Three Phase Power-Controlled Grid Connected Inverter for Low-Frequency Stability Improvement Under Weak Grid Condition Zhou, Weihua; Wang, Yanbo; E. Torres-Olguin, Raymundo; Chen, Zhe-Department of Energy Technology, Aalborg University, Aalborg, Denmark

 DQ Impedance Reshaping of Three-Phase Power-Controlled Grid-Connected Inverter for Low-Frequency Stability Improvement Under Weak Grid Condition Weihua Zhou∗ , Yanbo Wang∗ , Raymundo E. Torres-Olguin† and Zhe Chen∗ ∗Department of Energy Technology, Aalborg University, Aalborg, Denmark 

 Abstract—Phase-locked loop (PLL) is commonly used to synchronize the phase angle of the injected current of voltage source grid-connected inverters (GCIs) with that of the voltage at point of common coupling. However, the quadrature-axis component of the dq impedance model of the GCIs presents negative resistance characteristics in low-frequency range due to the usage of the PLL, which may lead to low-frequency instability phenomena if the GCIs work under weak grid condition. This paper presents a dq impedance reshaping method of powercontrolled GCIs to eliminate the negative effect of PLL on lowfrequency stability. The dq impedance models of the GCIs under current and power control modes are first established using complex vector and complex transfer function theory. On its basis, the negative effects of PLL on current control loop and power control loop are theoretically derived. A grid voltage feedforward loop is then designed in the control system of the powercontrolled GCIs, where the parameters of the feed-forward loop are calculated. The effectiveness of the proposed dq impedance reshaping method is validated by frequency scanning results and time-domain simulation results.

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https://vbn.aau.dk/ws/portalfiles/portal/334511002/Manuscript_accepted_version.pdf

Analysis of linear Phase-Locked Loops in Grid connected Power Converters Steinkohl, Joachim; Wang, Xiongfei; Davari, Pooya; Blaabjerg, Frede-Department of Energy Technology, Aalborg University

 

Analysis of linear Phase-Locked Loops in Grid-Connected Power Converters Joachim Steinkohl, Xiongfei Wang, Pooya Davari and Frede Blaabjerg Aalborg University 

 Abstract

 Fast and accurate synchronization capability of grid-connected converters is becoming more and more important to ensure proper performance during transient events, such as grid faults. The higher requirements during the operation, as Fault-Ride-Through with reactive current injection, cause higher requirements on the operation during severe system conditions. This paper analyzes an addition to Synchronous-Reference-Frame Phase-Locked Loops for power electronic converters, that is linearizing the input signal. This enhances the tracking capabilities during abnormal transient events in the power grid. The improved control is analyzed and its increased performance is validated through simulations and experimental results.

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https://vbn.aau.dk/files/319223001/Analysis_of_linear_Phase_Locked_Loops_in_Grid_Connected_Power_Converters.pdf

Small-Signal Stability Analysis and Optimization of Grid-Forming Permanent-Magnet Synchronous-Generator Wind Turbines by Guanghui Li ,Runqi Han ,Zhen Li,Bin Lui,

Small-Signal Stability Analysis and Optimization of Grid-Forming Permanent-Magnet Synchronous-Generator Wind Turbines by Guanghui Li 1,Runqi Han 2,*,Bin Liu 2,*ORCID andZhen Li 3ORCID National Key Laboratory of Renewable Energy Grid-Integration, China Electric Power Research Institute, Beijing 100192, China College of Artificial Intelligence, China University of Petroleum (Beijing), Beijing 102249, China School of Automation and Key Laboratory for Intelligent Control & Decision on Complex Systems, Beijing Institute of Technology, Beijing 100081, China 

 Abstract Due to the ability to improve the low-inertia characteristics of power systems and offer reliable voltage and frequency support, grid-forming permanent-magnet synchronous-generator wind turbines (PMSG-WTs) based on virtual synchronous-generator (VSG) technology are emerging se the direction for future developments. Previous studies on the small-signal stability of grid-forming PMSG-WTs that connect to the grid usually simplify them into grid-connected grid-side converters (GSC), potentially leading to errors in stability analyses. Therefore, this paper considers the machine-side converter (MSC) control and establishes impedance models for grid-forming PMSG-WTs. Based on the sensitivity calculation of controller parameters using symmetric difference computation based on zero-order optimization, the impact of the internal controller on outside impedance characteristics is quantitatively analyzed. Additionally, an optimization method to enhance the stability of a hybrid wind farm by adjusting the ratio of grid-forming and grid-following wind turbines is proposed.

LINK : https://www.mdpi.com/1996-1073/17/18/4560

Stability analysis of small signals under different ratios of grid-following to grid-forming converters sent via flexible DC delivery-Feng Li1, Zhijie Li2,*, Shuangmian Yang1, Jinyu Wang2 and Yibo Zhang1 1TBEA Science & Technology Investment Co., Ltd., Tianjin, 301700, China 2College of Electrical Engineering, Xi'an Jiaotong University, Xian, Shanxi, 712000, China

 Stability analysis of small signals under different ratios of grid-following to grid-forming converters sent via flexible DC delivery Feng Li1, Zhijie Li2,*, Shuangmian Yang1, Jinyu Wang2 and Yibo Zhang1 1TBEA Science & Technology Investment Co., Ltd., Tianjin, 301700, China 2College of Electrical Engineering, Xi'an Jiaotong University, Xian, Shanxi, 712000, China 

 Abstract: Under the "dual carbon" strategy, frequent wide-band grid oscillations caused by grid-following converters as the interface for renewable energy integration have become common. Existing studies suggest that the addition of grid-forming converters can address this issue, but few explain the reasons from a stability mechanism perspective. Additionally, most studies overlook the interaction between converters and sending-end converter stations. This paper first conducts sequential impedance modeling. Then, based on impedance network analysis, it examines the impact of sending-end converter stations on stability assessment. Finally, by adjusting the grid-following/grid-forming ratio, Nyquist curves under different ratios are generated to analyze the mechanism by which grid-forming converters enhance gridfollowing small-signal stability. Corresponding simulation models are also developed for validation.

LINK: https://iopscience.iop.org/article/10.1088/1742-6596/2896/1/012028

A Study on Internal Fault Simulation Methods for 345kV Autotransformers 345kV 단권변압기 내부고장 모의방법에 관한 연구 Jong-Kee Choi ․ You-Jin Lee ․ Jun-Ho Cho ․ Young-Hun Kwon ․ Ji-Hwan Park ․ Young-Hun Jang 최종기† ․ 이유진* ․ 조준호** ․ 권영훈*** ․ 박지환§ ․ 장영훈

 

SCHEMATIC DIAGRAM THREE-PHASE PHASE FAILURE DETECTOR CIRCUIT AND THREE-PHASE PHASE SEQUENCE-Simulation and Analysis Using PSpice

 

Power Transfer Stability Analysis of Grid Forming Converters-Seong-Jeon Lee ․ Joosik Kwak ․ Gyu-Sub Lee-Dept. of Electrical and Computer Engineering, Seoul National University (SNU), Seoul, Republic of Korea and Seoul National University Electric Power Research Institute (SEPRI),

 Power Transfer Stability Analysis of Grid Forming Converters SCR에 따른 그리드 포밍 인버터의 전력 전달 안정성 분석 Seong-Jeon Lee ․ Joosik Kwak ․ Gyu-Sub Lee 이성전* ․ 곽주식** ․ 이규섭†

 Abstract

 With the growth of renewable energy sources (RES) and energy storage systems (ESS), the number of distributed generators (DGs) integrated into power systems via voltage source converters (VSCs) has been increasing. VSCs are operated either in grid-following (GFL) or grid-forming (GFM) control modes. While the GFM mode offers the advantage of not requiring a phase-locked loop (PLL) for grid synchronization, it exhibits a stability issue when the grid impedance decreases. To analyze the stability concerns of GFM inverters, a PSCAD simulation-based study was conducted considering the short-circuit ratio (SCR) and the grid impedance X/R ratio (the ratio of inductive to resistive impedance). The results demonstrate that GFM inverters become more unstable as the SCR increases and the X/R ratio decreases. Key Words Grid forming converter, Short circuit ratio, Stability analysis, Voltage sourced converter, X/R Ratio † Corresponding Author : Dept. of Electrical and Computer Engineering, Seoul National University (SNU), Seoul, Republic of Korea and Seoul National University Electric Power Research Institute (SEPRI), Seoul, Republic of Korea. E-mail : lgs1106@snu.ac.kr https://orcid.org/0000-0002-6313-4685 * Dept. of Electrical and Computer Engineering, Seoul National University (SNU), Seoul, Republic of Korea. https://orcid.org/0009-0003-1996-001X ** Korea Electric Power Corporation Research Institute, Republic of Korea. Received : Oct. 30, 2024 Revised : Apr. 29, 2025 Accepted : Aug. 14, 2025 Copyright ⓒ The Korean Institute of Electrical Engineers This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ISSN 1975-8359 [Print] / ISSN 2287-4364 [Online]

VIEW ORIGINAL PAPER:

 http://journal.auric.kr/AURIC_OPEN_temp/RDOC/kiee01/kieet_202509_005.pdf

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Stability Analysis of Grid-Following and GridForming Converters Based on State-Space Modelling Xian Gao, Student Member, IEEE, Dao Zhou, Senior Member, IEEE, Amjad Anvari-Moghaddam, Senior Member, IEEE, and Frede Blaabjerg, Fellow, IEEE AAU Energy, Aalborg University, Aalborg, Denmark

 Stability Analysis of Grid-Following and GridForming Converters Based on State-Space Modelling

 Xian Gao, Student Member, IEEE, Dao Zhou, Senior Member, IEEE, Amjad Anvari-Moghaddam, Senior Member, IEEE, and Frede Blaabjerg, Fellow, IEEE AAU Energy, Aalborg University, Aalborg, Denmark

 Abstract - This paper conducts a comprehensive analysis and comparison of the control loops of the grid-following and grid-forming voltage source converters connected to the power grid. Eigenvalue trajectories are studied in order to obtain an accurate stability analysis. A timedomain simulation model of a 1.5 kW grid-connected converter is developed by using Matlab/Simulink to investigate the stability of the grid-following and gridforming control under different short-circuit ratios. The stability boundaries of the grid-following control and the grid-forming control are explored and compared with theoretical analysis. The result reveals that the gridfollowing control is better suited for a stiff power grid, while the grid-forming control is more suitable for a weak power grid. Finally, an experimental prototype is established to verify the effectiveness of the theoretical analysis.

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Metodologia de projeto de filtros de emissão conduzida aplicada a conversores CA/CC monofásicos Maicon W. M. de Carvalho 1,* , Djonny Weinzierl 1 , Sérgio V. G. Oliveira 1,2 1 Universidade do Estado de Santa Catarina, Programa de Pós-Graduação em Engenharia Elétrica, Santa Catarina, Brasil 2 Universidade Regional de Blumenau, Departamento de Engenharia de Telecomunicações, Elétrica e Mecânica, Santa Catarina, Brasil

Metodologia de projeto de filtros de emissão conduzida aplicada a conversores CA/CC monofásicos Maicon W. M. de Carvalho1,*, Djonny Weinzierl1, Sérgio V. G. Oliveira1,2 1

 Universidade do Estado de Santa Catarina, Programa de Pós-Graduação em Engenharia Elétrica, Santa Catarina, Brasil 2 Universidade Regional de Blumenau, Departamento de Engenharia de Telecomunicações, Elétrica e Mecânica, Santa Catarina, Brasil 

 ABSTRACT Electromagnetic interference filter design specifies circuit topology and elements, inductors, and capacitors of an electrical network whose purpose is to reduce interferential signals. This work presents an iterative methodology of EMI filter design for switched power supplies based on the sequential element theorem and the concept of the dominant effect in electromagnetic compatibility. This design methodology was proposed based on experiments with three commercial off-the-shelf power supplies and knowledge about common, differential, and mixed-mode emissions, as well as the non-idealities of the elements and the power supply's input impedance characteristics. In practical tests, the effect of the EMI filter resonance and the power supply's mixed-mode input impedance was observed, which served as a guideline for determining which component should be included or whether its value should be increased in the EMI filter structure. The most restrictive requirements were met with a few iterations and fewer components than the original filters, demonstrating that the concepts used as a reference are valid and valuable.

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Electronic Load for Parameter Characterization in Equivalent Circuit Models of Lithium-Ion Batteries-Suelen Bampi 1,* , Gierri Waltrich 1 , Anderson Vaccari 2 1Federal University of Santa Catarina, Postgraduate Program in Electrical Engineering, Florianopolis - SC, Brasil. 2Vale S.A, Development and Innovation Sector, Vila Velha - ES, Brasil.

 Electronic Load for Parameter Characterization in Equivalent Circuit Models of Lithium-Ion Batteries Suelen Bampi1,*, Gierri Waltrich 1, Anderson Vaccari2 1 Federal University of Santa Catarina, Postgraduate Program in Electrical Engineering, Florianopolis - SC, Brasil. 2 Vale S.A, Development and Innovation Sector, Vila Velha - ES, Brasil. 

 ABSTRACT The applications and implemented volume of lithium-ion batteries have been gaining momentum each year. Aiming to contribute to the development of research in this area, this paper presents the design and implementation of an electronic load focused on characterizing parameters inherent to equivalent circuit models (ECM). ECMs are commonly applied for estimating the State of Charge (SoC), State of Health (SoH), and Remaining Useful Life (RUL) of lithium batteries. In this paper, an electrical design of an electronic load was implemented and validated through laboratory instrumentation to obtain characteristic data from a lithium titanate cell. The data from the tests performed on the cell were used as input for a SoC estimation algorithm based on the Extended Kalman Filter (EKF) to help corroborate the prototype's performance. The results comprise the performance of the electronic load, the results associated with the parameterization tests of the lithium cells, and the results obtained for the cell’s SoC estimation using the EKF.

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Analysis and Implementation of a Single-Phase Bridgeless Hybrid Switched-Capacitor Rectifier in Discontinuous Conduction Mode for Power Factor Correction-

 

Analysis and Implementation of a Single-Phase Bridgeless Hybrid Switched-Capacitor Rectifier in Discontinuous Conduction Mode for Power Factor Correction

 Chrystian Mumic 1,∗, Marcus V. Soares 2, Yales R. de Novaes 1, Alan J. Watson 3 1Santa Catarina State University, Dept of Electrical Engineering, Joinville, Brazil. 2Silicon Austria Labs, Division Power Electronics, Graz, Austria. 3University of Nottingham, Dept. Electrical and Electronic Engineering, Nottingham, United Kingdom.

ABSTRACT 

This work presents the quantitative and qualitative analysis, as well as the experimental results of a practical implementation of the Single-Phase Bridgeless Hybrid Switched Capacitor Rectifier operating in discontinuous conduction mode (DCM) to achieve a high input power factor. Operating in DCM provides several advantages, including natural power factor correction (PFC) behavior of the input current and reduced semiconductor switching losses. The paper begins with a literature review on key studies of hybrid switched-capacitor converters with a high power factor. Subsequently, the converter analysis, including its modulation scheme, operational stages and design methodology, is detailed. The proposed approach is validated with results from a practical prototype implementation, achieving an output voltage of 1200 V and an output power of 315 W from an input voltage of 220 V. The converter demonstrated an efficiency of 97.3%, a power factor of 0.99, and harmonic distortion levels within the limits specified by IEC61000-3-2.

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