{"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":"8 2","pages":"115-126"},"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}
{"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":"8 2","pages":"177-190"},"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}
{"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":"8 2","pages":"113-114"},"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}
{"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":"8 2","pages":"143-151"},"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}
{"title":"Design Optimization of a Self-Circulated Hydrogen Cooling System for a PM Wind Generator Based on Taguchi Method","authors":"Gaojia Zhu;Yunhao Li;Longnv Li","doi":"10.30941/CESTEMS.2024.00024","DOIUrl":"https://doi.org/10.30941/CESTEMS.2024.00024","url":null,"abstract":"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.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":"8 2","pages":"170-176"},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10579827","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141495325","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}
Lu Sun;Haoyu Kang;Jin Wang;Zequan Li;Jianjun Liu;Yiming Ma;Libing Zhou
{"title":"Analytical Model and Topology Optimization of Doubly-Fed Induction Generator","authors":"Lu Sun;Haoyu Kang;Jin Wang;Zequan Li;Jianjun Liu;Yiming Ma;Libing Zhou","doi":"10.30941/CESTEMS.2024.00022","DOIUrl":"https://doi.org/10.30941/CESTEMS.2024.00022","url":null,"abstract":"As the core component of energy conversion for large wind turbines, the output performance of doubly-fed induction generators (DFIGs) plays a decisive role in the power quality of wind turbines. To realize the fast and accurate design optimization of DFIGs, this paper proposes a novel hybrid-driven surrogate-assisted optimization method. It firstly establishes an accurate subdomain model of DFIGs to analytically predict performance indexes. Furthermore, taking the inexpensive analytical dataset produced by the subdomain model as the source domain and the expensive finite element analysis dataset as the target domain, a high-precision surrogate model is trained in a transfer learning way and used for the subsequent multi-objective optimization process. Based on this model, taking the total harmonic distortion of electromotive force, cogging torque, and iron loss as objectives, and the slot and inner/outer diameters as parameters for optimizing the topology, achieve a rapid and accurate electromagnetic design for DFIGs. Finally, experiments are carried out on a 3MW DFIG to validate the effectiveness of the proposed method.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":"8 2","pages":"162-169"},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10579828","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141494912","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}
Bo Pang;Qi Si;Pan Jiang;Kai Liao;Xiaojuan Zhu;Jianwei Yang;Zhengyou He
{"title":"Review of the Analysis and Suppression for High-Frequency Oscillations of the Grid-Connected Wind Power Generation System","authors":"Bo Pang;Qi Si;Pan Jiang;Kai Liao;Xiaojuan Zhu;Jianwei Yang;Zhengyou He","doi":"10.30941/CESTEMS.2024.00025","DOIUrl":"https://doi.org/10.30941/CESTEMS.2024.00025","url":null,"abstract":"High-frequency oscillation (HFO) of grid-connected wind power generation systems (WPGS) is one of the most critical issues in recent years that threaten the safe access of WPGS to the grid. Ensuring the WPGS can damp HFO is becoming more and more vital for the development of wind power. The HFO phenomenon of wind turbines under different scenarios usually has different mechanisms. Hence, engineers need to acquire the working mechanisms of the different HFO damping technologies and select the appropriate one to ensure the effective implementation of oscillation damping in practical engineering. This paper introduces the general assumptions of WPGS when analyzing HFO, systematically summarizes the reasons for the occurrence of HFO in different scenarios, deeply analyses the key points and difficulties of HFO damping under different scenarios, and then compares the technical performances of various types of HFO suppression methods to provide adequate references for engineers in the application of technology. Finally, this paper discusses possible future research difficulties in the problem of HFO, as well as the possible future trends in the demand for HFO damping.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":"8 2","pages":"127-142"},"PeriodicalIF":0.0,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10579809","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141495302","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":"A Loss-Model-Based Efficiency Optimization Control Method for Induction Traction System of High-Speed Train Under Emergency Self-Propelled Mode","authors":"Yutong Zhu;Yaohua Li","doi":"10.30941/CESTEMS.2024.00017","DOIUrl":"https://doi.org/10.30941/CESTEMS.2024.00017","url":null,"abstract":"Increasing attention has been paid to the efficiency improvement of the induction traction system of high-speed trains due to the high demand for energy saving. In emergency self-propelled mode, however, the dc-link voltage and the traction power of the motor are significantly reduced, resulting in decreased traction efficiency due to the low load and low speed operations. Aiming to tackle this problem, a novel efficiency improved control method is introduced to the emergency mode of high-speed train traction system in this paper. In the proposed method, a total loss model of induction motor considering the behaviors of both iron and copper loss is established. An improved iterative algorithm with decreased computational burden is then introduced, resulting in a fast solving of the optimal flux reference for loss minimization at each control period. In addition, considering the parameter variation problem due to the low load and low speed operations, a parameter estimation method is integrated to improve the controller's robustness. The effectiveness of the proposed method on efficiency improvement at low voltage and low load conditions is demonstrated by simulated and experimental results.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":"8 2","pages":"227-239"},"PeriodicalIF":0.0,"publicationDate":"2024-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10545326","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141495326","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":"Comments and Corrections","authors":"","doi":"10.30941/CESTEMS.2024.00801","DOIUrl":"https://doi.org/10.30941/CESTEMS.2024.00801","url":null,"abstract":"","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":"8 2","pages":"240-241"},"PeriodicalIF":0.0,"publicationDate":"2024-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10541945","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141494920","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":"Investigation on the Novel High-performance Copper/Graphene Composite Conductor for High Power Density Motor","authors":"Jiaxiao Wang;Tingting Zuo;Jiangli Xue;Yadong Ru;Yue Wu;Zhuang Xu;Yongsheng Liu;Zhaoshun Gao;Puqi Ning;Tao Fan;Xuhui Wen;Li Han;Liye Xiao","doi":"10.30941/CESTEMS.2024.00009","DOIUrl":"https://doi.org/10.30941/CESTEMS.2024.00009","url":null,"abstract":"High-performance Cu/Graphene composite wire synergistically strengthened by nano Cr\u0000<inf>3</inf>\u0000C\u0000<inf>2</inf>\u0000 phase was directly synthesized via hot press sintering followed by severe cold plastic deformation, using liquid paraffin and CuCr alloy powder as the raw materials. Since graphene is in situ formed under the catalysis of copper powder during the sintering process, the problem that graphene is easy to agglomerate and difficult to disperse uniformly in the copper matrix has been solved. The nano Cr\u0000<inf>3</inf>\u0000C\u0000<inf>2</inf>\u0000-particles nailed at the interface favor to improve the interface bonding. The Cu/Graphene composite possesses high electrical conductivity, hardness, and plasticity. The composite wire exhibits high electrical conductivity of 96.93% IACS, great tensile strength of 488 MPa, and excellent resistance to softening. Even after annealing at 400°C for 1 h, the tensile strength can still reach 268 MPa with a conductivity of about 99.14% IACS. The wire's temperature coefficient of resistance (TCR) is largely reduced to 0.0035/°C due to the complex structure, which leads the wire to present low resistivity at higher temperatures. Such Cu/Graphene composite wire with excellent comprehensive performance has a good application prospect in high-power density motors.","PeriodicalId":100229,"journal":{"name":"CES Transactions on Electrical Machines and Systems","volume":"8 1","pages":"80-85"},"PeriodicalIF":0.0,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10471246","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140342668","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}