Pub Date : 2024-06-03DOI: 10.30941/CESTEMS.2024.00013
Mehrage Ghods;Jawad Faiz;Ali A. Pourmoosa
The magnetic flux in a permanent magnet transverse flux generator (PMTFG) is three-dimensional (3D), therefore, its efficacy is evaluated using 3D magnetic field analysis. Although the 3D finite-element method (FEM) is highly accurate and reliable for machine simulation, it requires a long computation time, which is crucial when it is to be used in an iterative optimization process. Therefore, an alternative to 3D-FEM is required as a rapid and accurate analytical technique. This paper presents an analytical model for PMTFG analysis using winding function method. To obtain the air gap MMF distribution, the excitation magneto-motive force (MMF) and the turn function are determined based on certain assumptions. The magnetizing inductance, flux density, and back-electro-magneto-motive force of the winding are then determined. To assess the accuracy of the proposed method, the analytically calculated parameters of the generator are compared to those obtained by a 3D-FEM. The presented method requires significantly shorter computation time than the 3D-FEM with comparable accuracy.
{"title":"Winding Function Model-Based Performance Evaluation of a PM Transverse Flux Generator for Applications in Direct-Drive Systems","authors":"Mehrage Ghods;Jawad Faiz;Ali A. Pourmoosa","doi":"10.30941/CESTEMS.2024.00013","DOIUrl":"https://doi.org/10.30941/CESTEMS.2024.00013","url":null,"abstract":"The magnetic flux in a permanent magnet transverse flux generator (PMTFG) is three-dimensional (3D), therefore, its efficacy is evaluated using 3D magnetic field analysis. Although the 3D finite-element method (FEM) is highly accurate and reliable for machine simulation, it requires a long computation time, which is crucial when it is to be used in an iterative optimization process. Therefore, an alternative to 3D-FEM is required as a rapid and accurate analytical technique. This paper presents an analytical model for PMTFG analysis using winding function method. To obtain the air gap MMF distribution, the excitation magneto-motive force (MMF) and the turn function are determined based on certain assumptions. The magnetizing inductance, flux density, and back-electro-magneto-motive force of the winding are then determined. To assess the accuracy of the proposed method, the analytically calculated parameters of the generator are compared to those obtained by a 3D-FEM. The presented method requires significantly shorter computation time than the 3D-FEM with comparable accuracy.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10545422","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141494918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-03DOI: 10.30941/CESTEMS.2024.00019
Ye Zhang;Zixin Li;Fanqiang Gao;Cong Zhao;Yaohua Li
Cascaded H-bridge inverter (CHBI) with supercapacitors (SCs) and dc-dc stage shows significant promise for medium to high voltage energy storage applications. This paper investigates the voltage balance of capacitors within the CHBI, including both the dc-link capacitors and SCs. Balance control over the dc-link capacitor voltages is realized by the dc-dc stage in each submodule (SM), while a hybrid modulation strategy (HMS) is implemented in the H-bridge to balance the SC voltages among the SMs. Meanwhile, the dc-link voltage fluctuations are analyzed under the HMS. A virtual voltage variable is introduced to coordinate the balancing of dc-link capacitor voltages and SC voltages. Compared to the balancing method that solely considers the SC voltages, the presented method reduces the dc-link voltage fluctuations without affecting the voltage balance of SCS. Finally, both simulation and experimental results verify the effectiveness of the presented method.
带有超级电容器（SC）和直流-直流级的级联 H 桥逆变器（CHBI）在中高压储能应用中大有可为。本文研究了 CHBI 内电容器（包括直流链路电容器和 SC）的电压平衡问题。每个子模块（SM）中的直流-直流级实现了对直流链路电容器电压的平衡控制，而混合调制策略（HMS）则在 H 桥中实施，以在 SM 之间平衡 SC 电压。同时，分析了 HMS 下的直流链路电压波动。引入了一个虚拟电压变量来协调直流链电容器电压和 SC 电压之间的平衡。与只考虑 SC 电压的平衡方法相比，所提出的方法在不影响 SCS 电压平衡的情况下减少了直流链电压波动。最后，模拟和实验结果都验证了所提出方法的有效性。
{"title":"Coordinated Capacitor Voltage Balancing Method for Cascaded H-Bridge Inverter with Supercapacitor and DC-DC Stage","authors":"Ye Zhang;Zixin Li;Fanqiang Gao;Cong Zhao;Yaohua Li","doi":"10.30941/CESTEMS.2024.00019","DOIUrl":"https://doi.org/10.30941/CESTEMS.2024.00019","url":null,"abstract":"Cascaded H-bridge inverter (CHBI) with supercapacitors (SCs) and dc-dc stage shows significant promise for medium to high voltage energy storage applications. This paper investigates the voltage balance of capacitors within the CHBI, including both the dc-link capacitors and SCs. Balance control over the dc-link capacitor voltages is realized by the dc-dc stage in each submodule (SM), while a hybrid modulation strategy (HMS) is implemented in the H-bridge to balance the SC voltages among the SMs. Meanwhile, the dc-link voltage fluctuations are analyzed under the HMS. A virtual voltage variable is introduced to coordinate the balancing of dc-link capacitor voltages and SC voltages. Compared to the balancing method that solely considers the SC voltages, the presented method reduces the dc-link voltage fluctuations without affecting the voltage balance of SCS. Finally, both simulation and experimental results verify the effectiveness of the presented method.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10545358","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141495122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-03DOI: 10.30941/CESTEMS.2024.00020
Bo Pang;Xiao Jin;Quanwang Zhang;Yi Tang;Kai Liao;Jianwei Yang;Zhengyou He
High-voltage direct current (HVDC) transmission is a crucial way to solve the reverse distribution of clean energy and loads. The line commutated converter-based HVDC (LCC-HVDC) has become a vital structure for HVDC due to its high technological maturity and economic advantages. During the DC fault of LCC-HVDC, such as commutation failure, the reactive power regulation of the AC grid always lags the DC control process, causing overvoltage in the AC sending grid, which brings off-grid risk to the wind power generation based on power electronic devices. Nevertheless, considering that wind turbine generators have fast and flexible reactive power control capability, optimizing the reactive power control of wind turbines to participate in the transient overvoltage suppression of the sending grid not only improves the operational safety at the equipment level but also enhances the voltage stability of the system. This paper firstly analyses the impact of wind turbine's reactive power on AC transient overvoltage. Then, it proposes an improved voltage-reactive power control strategy, which contains a reactive power control delay compensation and a power command optimization based on the voltage time series prediction. The delay compensation is used to reduce the contribution of the untimely reactive power of wind turbines on transient overvoltage, and the power command optimization enables wind turbines to have the ability to regulate transient overvoltage, leading to the variation of AC voltage, thus suppressing the transient overvoltage. Finally, the effectiveness and feasibility of the proposed method are verified in a ±800kV/5000MW LCC-HVDC sending grid model based on MATLAB/Simulink.
{"title":"Transient AC Overvoltage Suppression Orientated Reactive Power Control of the Wind Turbine in the LCC-HVDC Sending Grid","authors":"Bo Pang;Xiao Jin;Quanwang Zhang;Yi Tang;Kai Liao;Jianwei Yang;Zhengyou He","doi":"10.30941/CESTEMS.2024.00020","DOIUrl":"https://doi.org/10.30941/CESTEMS.2024.00020","url":null,"abstract":"High-voltage direct current (HVDC) transmission is a crucial way to solve the reverse distribution of clean energy and loads. The line commutated converter-based HVDC (LCC-HVDC) has become a vital structure for HVDC due to its high technological maturity and economic advantages. During the DC fault of LCC-HVDC, such as commutation failure, the reactive power regulation of the AC grid always lags the DC control process, causing overvoltage in the AC sending grid, which brings off-grid risk to the wind power generation based on power electronic devices. Nevertheless, considering that wind turbine generators have fast and flexible reactive power control capability, optimizing the reactive power control of wind turbines to participate in the transient overvoltage suppression of the sending grid not only improves the operational safety at the equipment level but also enhances the voltage stability of the system. This paper firstly analyses the impact of wind turbine's reactive power on AC transient overvoltage. Then, it proposes an improved voltage-reactive power control strategy, which contains a reactive power control delay compensation and a power command optimization based on the voltage time series prediction. The delay compensation is used to reduce the contribution of the untimely reactive power of wind turbines on transient overvoltage, and the power command optimization enables wind turbines to have the ability to regulate transient overvoltage, leading to the variation of AC voltage, thus suppressing the transient overvoltage. Finally, the effectiveness and feasibility of the proposed method are verified in a ±800kV/5000MW LCC-HVDC sending grid model based on MATLAB/Simulink.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10545418","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141494926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-03DOI: 10.30941/CESTEMS.2024.00016
Yuxuan Du;Wenxiang Zhao;Yihua Hu;Jinghua Ji;Tao Tao
In recent years, motor drive systems have garnered increasing attention due to their high efficiency and superior control performance. This is especially apparent in aerospace, marine propulsion, and electric vehicles, where high performance, efficiency, and reliability are crucial. The ability of the drive system to maintain long-term fault-tolerant control (FTC) operation after a failure is essential. The likelihood of inverter failures surpasses that of other components in the drive system, highlighting its critical importance. Long-term FTC operation ensures the system retains its fundamental functions until safe repairs or replacements can be made. The focus of developing a FTC strategy has shifted from basic FTC operations to enhancing the post-fault quality to accommodate the realities of prolonged operation post-failure. This paper primarily investigates FTC strategies for inverter failures in various motor drive systems over the past decade. These strategies are categorized into three types based on post-fault operational quality: rescue, remedy, and reestablishment. The paper discusses each typical control strategy and its research focus, the strengths and weaknesses of various algorithms, and recent advancements in FTC. Finally, this review summarizes effective FTC techniques for inverter failures in motor drive systems and suggests directions for future research.
{"title":"Review of Fault-Tolerant Control for Motor Inverter Failure with Operational Quality Considered","authors":"Yuxuan Du;Wenxiang Zhao;Yihua Hu;Jinghua Ji;Tao Tao","doi":"10.30941/CESTEMS.2024.00016","DOIUrl":"https://doi.org/10.30941/CESTEMS.2024.00016","url":null,"abstract":"In recent years, motor drive systems have garnered increasing attention due to their high efficiency and superior control performance. This is especially apparent in aerospace, marine propulsion, and electric vehicles, where high performance, efficiency, and reliability are crucial. The ability of the drive system to maintain long-term fault-tolerant control (FTC) operation after a failure is essential. The likelihood of inverter failures surpasses that of other components in the drive system, highlighting its critical importance. Long-term FTC operation ensures the system retains its fundamental functions until safe repairs or replacements can be made. The focus of developing a FTC strategy has shifted from basic FTC operations to enhancing the post-fault quality to accommodate the realities of prolonged operation post-failure. This paper primarily investigates FTC strategies for inverter failures in various motor drive systems over the past decade. These strategies are categorized into three types based on post-fault operational quality: rescue, remedy, and reestablishment. The paper discusses each typical control strategy and its research focus, the strengths and weaknesses of various algorithms, and recent advancements in FTC. Finally, this review summarizes effective FTC techniques for inverter failures in motor drive systems and suggests directions for future research.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10545419","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141494911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Content","authors":"","doi":"","DOIUrl":"https://doi.org/","url":null,"abstract":"","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10579823","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141495300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.30941/CESTEMS.2024.00027
Xinshou Tian;Yongning Chi;Longxue Li;Hongzhi Liu
Based on the complementary advantages of Line Commutated Converter (LCC) and Modular Multilevel Converter (MMC) in power grid applications, there are two types of hybrid DC system topologies: one is the parallel connection of LCC converter stations and MMC converter stations, and the other is the series connection of LCC and MMC converter stations within a single station. The hybrid DC transmission system faces broad application prospects and development potential in large-scale clean energy integration across regions and the construction of a new power system dominated by new energy sources in China. This paper first analyzes the system forms and topological characteristics of hybrid DC transmission, introducing the forms and topological characteristics of converter-level hybrid DC transmission systems and system-level hybrid DC transmission systems. Next, it analyzes the operating characteristics of LCC and MMC inverter-level hybrid DC transmission systems, provides insights into the transient stability of hybrid DC transmission systems, and typical fault ride-through control strategies. Finally, it summarizes the networking characteristics of the LCC-MMC series within the converter station hybrid DC transmission system, studies the transient characteristics and fault ride-through control strategies under different fault types for the LCC-MMC series in the receiving-end converter station, and investigates the transient characteristics and fault ride-through control strategies under different fault types for the LCC-MMC series in the sending-end converter station.
{"title":"Review of the Configuration and Transient Stability of Large-Scale Renewable Energy Generation Through Hybrid DC Transmission","authors":"Xinshou Tian;Yongning Chi;Longxue Li;Hongzhi Liu","doi":"10.30941/CESTEMS.2024.00027","DOIUrl":"https://doi.org/10.30941/CESTEMS.2024.00027","url":null,"abstract":"Based on the complementary advantages of Line Commutated Converter (LCC) and Modular Multilevel Converter (MMC) in power grid applications, there are two types of hybrid DC system topologies: one is the parallel connection of LCC converter stations and MMC converter stations, and the other is the series connection of LCC and MMC converter stations within a single station. The hybrid DC transmission system faces broad application prospects and development potential in large-scale clean energy integration across regions and the construction of a new power system dominated by new energy sources in China. This paper first analyzes the system forms and topological characteristics of hybrid DC transmission, introducing the forms and topological characteristics of converter-level hybrid DC transmission systems and system-level hybrid DC transmission systems. Next, it analyzes the operating characteristics of LCC and MMC inverter-level hybrid DC transmission systems, provides insights into the transient stability of hybrid DC transmission systems, and typical fault ride-through control strategies. Finally, it summarizes the networking characteristics of the LCC-MMC series within the converter station hybrid DC transmission system, studies the transient characteristics and fault ride-through control strategies under different fault types for the LCC-MMC series in the receiving-end converter station, and investigates the transient characteristics and fault ride-through control strategies under different fault types for the LCC-MMC series in the sending-end converter station.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10579810","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141495301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.30941/CESTEMS.2024.00030
Haifeng Lu;Qiao Wang;Jianyun Chai;Yongdong Li
For electric vehicles (EVs), it is necessary to improve endurance mileage by improving the efficiency. There exists a trend towards increasing the system voltage and switching frequency, contributing to improve charging speed and power density. However, this trend poses significant challenges for high-voltage and high-frequency motor controllers, which are plagued by increased switching losses and pronounced switching oscillations as consequences of hard switching. The deployment of soft switching technology presents a viable solution to mitigate these issues. This paper reviews the applications of soft switching technologies for three-phase inverters and classifies them based on distinct characteristics. For each type of inverter, the advantages and disadvantages are evaluated. Then, the paper introduces the research progress and control methods of soft switching inverters (SSIs). Moreover, it presents a comparative analysis among the conventional hard switching inverters (HSIs), an active clamping resonant DC link inverter (ACRDCLI) and an auxiliary resonant commuted pole inverter (ARCPI). Finally, the problems and prospects of soft switching technology applied to motor controllers for EVs are put forward.
{"title":"Review of Three-Phase Soft Switching Inverters and Challenges for Motor Drives","authors":"Haifeng Lu;Qiao Wang;Jianyun Chai;Yongdong Li","doi":"10.30941/CESTEMS.2024.00030","DOIUrl":"https://doi.org/10.30941/CESTEMS.2024.00030","url":null,"abstract":"For electric vehicles (EVs), it is necessary to improve endurance mileage by improving the efficiency. There exists a trend towards increasing the system voltage and switching frequency, contributing to improve charging speed and power density. However, this trend poses significant challenges for high-voltage and high-frequency motor controllers, which are plagued by increased switching losses and pronounced switching oscillations as consequences of hard switching. The deployment of soft switching technology presents a viable solution to mitigate these issues. This paper reviews the applications of soft switching technologies for three-phase inverters and classifies them based on distinct characteristics. For each type of inverter, the advantages and disadvantages are evaluated. Then, the paper introduces the research progress and control methods of soft switching inverters (SSIs). Moreover, it presents a comparative analysis among the conventional hard switching inverters (HSIs), an active clamping resonant DC link inverter (ACRDCLI) and an auxiliary resonant commuted pole inverter (ARCPI). Finally, the problems and prospects of soft switching technology applied to motor controllers for EVs are put forward.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10579825","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141494919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.30941/CESTEMS.2024.10051
As with the continuous advancement of the low-carbon energy development, the wind power generation experiences fast growth with 441.3 GW installed capacity by Dec. 2023. The high penetration of renewable energy, together with high penetration of power electronic equipment (namely, “double high”), has been altering the steady-state and transient characteristics of wind power generation in a profound way, resulting in the different risk of instability. These stability issues will seriously affect the consumption of renewable energy and threaten the safe supply of electricity. Along with rapid deployment of wind power generation, together with the solar photovoltaic generation, it is expected to be over 1200 GW by 2030.
{"title":"Message from Editors","authors":"","doi":"10.30941/CESTEMS.2024.10051","DOIUrl":"https://doi.org/10.30941/CESTEMS.2024.10051","url":null,"abstract":"As with the continuous advancement of the low-carbon energy development, the wind power generation experiences fast growth with 441.3 GW installed capacity by Dec. 2023. The high penetration of renewable energy, together with high penetration of power electronic equipment (namely, “double high”), has been altering the steady-state and transient characteristics of wind power generation in a profound way, resulting in the different risk of instability. These stability issues will seriously affect the consumption of renewable energy and threaten the safe supply of electricity. Along with rapid deployment of wind power generation, together with the solar photovoltaic generation, it is expected to be over 1200 GW by 2030.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10579826","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141495327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Virtual synchronous generators (VSGs) are widely introduced to the renewable power generation, the variable-speed pumped storage units, and so on, as a promising grid-forming solution. It is noted that VSGs can provide virtual inertia for frequency support, but the larger inertia would worsen the synchronization stability, referring to keeping synchronization with the grid during voltage dips. Thus, this paper presents a transient damping method of VSGs for enhancing the synchronization stability during voltage dips. It is revealed that the loss of synchronization (LOS) of VSGs always accompanies with the positive frequency deviation and the damping is the key factor to remove LOS when the equilibrium point exists. In order to enhance synchronization stability during voltage dips, the transient damping is proposed, which is generated by the frequency deviation in active power loop. Additionally, the proposed method can realize seamless switching between normal state and grid fault. Moreover, detailed control design for transient damping gain is given to ensure the synchronization stability under different inertia requirements during voltage dips. Finally, the experimental results are presented to validate the analysis and the effectiveness of the improved transient damping method.
虚拟同步发电机（VSG）作为一种有前途的电网形成解决方案，被广泛引入可再生能源发电、变速抽水蓄能机组等领域。人们注意到，VSGs 可以为频率支持提供虚拟惯性，但较大的惯性会恶化同步稳定性，即在电压骤降时与电网保持同步。因此，本文提出了一种 VSG 瞬态阻尼方法，以增强电压暂降期间的同步稳定性。研究表明，VSG 的同步损失（LOS）总是伴随着正频率偏差，而当平衡点存在时，阻尼是消除 LOS 的关键因素。为了增强电压骤降期间的同步稳定性，提出了由有功功率环路频率偏差产生的瞬态阻尼。此外，所提出的方法还能实现正常状态和电网故障之间的无缝切换。此外，还给出了暂态阻尼增益的详细控制设计，以确保电压暂降期间不同惯性要求下的同步稳定性。最后，介绍了实验结果，以验证分析结果和改进的暂态阻尼方法的有效性。
{"title":"Transient Damping of Virtual Synchronous Generator for Enhancing Synchronization Stability During Voltage Dips","authors":"Shitao Sun;Yu Lei;Guowen Hao;Yi Lu;Jindong Liu;Zhaoxin Song;Jie Zhang","doi":"10.30941/CESTEMS.2024.00021","DOIUrl":"https://doi.org/10.30941/CESTEMS.2024.00021","url":null,"abstract":"Virtual synchronous generators (VSGs) are widely introduced to the renewable power generation, the variable-speed pumped storage units, and so on, as a promising grid-forming solution. It is noted that VSGs can provide virtual inertia for frequency support, but the larger inertia would worsen the synchronization stability, referring to keeping synchronization with the grid during voltage dips. Thus, this paper presents a transient damping method of VSGs for enhancing the synchronization stability during voltage dips. It is revealed that the loss of synchronization (LOS) of VSGs always accompanies with the positive frequency deviation and the damping is the key factor to remove LOS when the equilibrium point exists. In order to enhance synchronization stability during voltage dips, the transient damping is proposed, which is generated by the frequency deviation in active power loop. Additionally, the proposed method can realize seamless switching between normal state and grid fault. Moreover, detailed control design for transient damping gain is given to ensure the synchronization stability under different inertia requirements during voltage dips. Finally, the experimental results are presented to validate the analysis and the effectiveness of the improved transient damping method.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10579824","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141495287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-01DOI: 10.30941/CESTEMS.2024.00024
Gaojia Zhu;Yunhao Li;Longnv Li
With the continuous improvement of permanent magnet (PM) wind generators' capacity and power density, the design of reasonable and efficient cooling structures has become a focus. This paper proposes a fully enclosed self-circulating hydrogen cooling structure for a originally forced-air-cooled direct-drive PM wind generator. The proposed hydrogen cooling system uses the rotor panel supports that hold the rotor core as the radial blades, and the hydrogen flow is driven by the rotating plates to flow through the axial and radial vents to realize the efficient cooling of the generator. According to the structural parameters of the cooling system, the Taguchi method is used to decouple the structural variables. The influence of the size of each cooling structure on the heat dissipation characteristic is analyzed, and the appropriate cooling structure scheme is determined.
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