{"title":"High-gain DC-DC Converter with Ultra-low Input Voltage*","authors":"Shaoxiong Nie;Jiahua Zhang;Wenxun Xiao;Guiping Du","doi":"10.23919/CJEE.2025.000096","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000096","url":null,"abstract":"Energy-harvesting technologies enable the extraction of energy from environmental sources characterized by extremely low voltages. A high-gain DC-DC converter with an ultralow input voltage is necessary for voltage conversion to supply energy to sensors, batteries, and other devices. However, existing ultra-low-voltage boost converters typically exhibit limited output power, posing significant challenges in fully utilizing the available energy, particularly in applications such as high-voltage direct-current (HVDC) transmission line voltage-difference energy harvesting. To maximize the harvested energy, this study proposes a high-gain DC-DC converter designed for operation with ultra-low input voltage. The proposed converter utilizes a hybrid inductor-switch-capacitor (LSC) boost network, which offers advantages such as high voltage gain, increased output power, and straightforward control mechanisms. Experimental findings indicate that the converter achieves output power ranging from 10 to 210 mW with input voltages between 100 and 300 mV, delivering an output voltage of 5 V. This performance surpasses that of existing ultra-low-voltage boosting methods, providing a more effective solution for energy-harvesting applications.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 1","pages":"74-82"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10955347","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792911","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 Discrete-continuous Two-layer Optimization Methodology for Distribution Networks Considering Power Converter Embedded Hybrid On-load Regulator Transformers*","authors":"Xu Yang;Houyu He;Jin Zhu;Hongming Yang;Yu Zheng;Yu Lei;Zhuo Long;Yan Xu","doi":"10.23919/CJEE.2025.000105","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000105","url":null,"abstract":"In addressing voltage overruns and line losses in distribution networks with a high percentage of distributed photovoltaic (PV) connections, traditional on-load regulator transformers can achieve only fixed-step voltage regulation and have a limited switching lifespan. Consequently, a discrete-continuous two-layer optimization methodology for distribution networks, which accounts for power-converter-embedded hybrid on-load regulator transformers, has been proposed to adapt to rapid stochastic fluctuations associated with distribution networks having a high percentage of PV access. In the discrete layer, the mechanical ratio is employed as the decision variable at each moment. In the continuous layer, the power electronic converter ratio, STATCOM compensation capacity, and energy storage charging and discharging power are utilized as decision variables at each moment. A composite optimal allocation model is established with an integrated objective function comprising the PV consumption rate, operating costs, and line losses, while simultaneously ensuring that the voltage at each node remains within the prescribed limits. Based on this model, an improved particle swarm algorithm is employed to determine the optimal configuration. Finally, the efficacy of the proposed method is validated through enhancements of the IEEE 33 node system example.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 1","pages":"105-108"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10955305","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792905","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 Modeling and Analysis of Parasitics in Power Electronic Converters*","authors":"Jianing Wang;Mingkai Chen;Shaolin Yu;Xing Zhang","doi":"10.23919/CJEE.2025.000103","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000103","url":null,"abstract":"The generation of power semiconductor devices defines a generation of power electronic converters. The efficiency and switching speed of power devices continue to improve, leading to higher converter operating frequencies and a continuous increase in power density. In particular, the emergence and widespread application of wide-bandgap power devices, such as silicon carbide and gallium nitride, have accelerated the process of high-frequency converter operations, significantly improving the power density of converters, which still have considerable room for improvement. One significant change brought about by high-frequency operation of converters is the increased impact of parasitics on circuit operation. With the significant increase in the system switching frequency and the dv/dt and di/dt of device switching, parasitics have a greater influence on circuit operation. Over the past decade, several studies on the analysis and modeling of parasitics have been published for various devices in converters, such as transformers, inductors, capacitors, and power devices; however, there is currently a lack of a comprehensive review to summarize the above research. A detailed summary of parasitics in power electronic converters is included, providing a systematic understanding of past work and future prospects.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 1","pages":"151-173"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10955298","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792788","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}
Jiaqi Yu;Wenming Guo;Feng Zhou;Linjin Xie;Mingmin Zhang;Lihua Cao
{"title":"Novel Discrete-time Frequency-locked Loop for Three-phase Grid-connected Power Converters*","authors":"Jiaqi Yu;Wenming Guo;Feng Zhou;Linjin Xie;Mingmin Zhang;Lihua Cao","doi":"10.23919/CJEE.2025.000114","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000114","url":null,"abstract":"A novel discrete-time frequency-locked loop (FLL) for three-phase grid-connected power converters that features rapid dynamic response and low computational cost is introduced. Firstly, a simplified nonlinear frequency-estimation model that leverages the inherent orthogonality of voltage signals in the <tex>$a$</tex>β- frame, along with an optimal fixed-length delay, is proposed. Subsequently, a discrete-time FLL structure is developed based on this model. In addition, a convergence analysis and parameter design are presented. Finally, a comparative experiment with established methods is conducted, and the results demonstrate that the proposed FLL offers a faster dynamic response, requires fewer parameters to be tuned, ensures a smoother startup process, and maintains a relatively lower computational cost.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 1","pages":"174-183"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10955299","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792876","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":"N-phase Interleaved Boost Converter with Constant Power Loads Stabilized under Large Disturbances Using a Fractional-order Nonlinear Controller*","authors":"Yanfeng Chen;Shikai Chen;Yong Su;Bo Zhang;Dongyuan Qiu","doi":"10.23919/CJEE.2025.000122","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000122","url":null,"abstract":"In DC microgrid systems, interleaved boost converters (IBCs) are widely used to boost the output voltage of renewable energy sources on the source side of a DC bus owing to their high voltage gain and low current ripple. However, because power electronic converters on the load side behave as constant power loads (CPLs) with negative impedance characteristics, their high penetration can degrade the system stability. Therefore, this article proposes a fractional-order nonlinear controller integrated with an extended nonlinear disturbance observer (ENDO) for N-phase IBCs. First, the reduced-order model of the IBC is transformed into a canonical form using the differential geometric method. Subsequently, with the ENDO, the dynamic performance can be enhanced by estimating the disturbances, and a fractional-order nonlinear sliding surface is established to avoid the singularity problem and increase control flexibility. In addition, the stability of the proposed controller is analyzed using Lyapunov's theorem. In a CPL variation test, the proposed controller exhibited a faster dynamic performance and lower tracking error than conventional controllers, with at least a 27% improvement in the integral squared error (ISE). Both simulation and experimental results demonstrated the effectiveness of the controller, which can ensure large-signal stability and improved dynamic performance in DC microgrid systems.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 1","pages":"93-104"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10955307","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792906","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":"Study on the Optimization for Reactive Power Regulation of Synchronous Condenser Based on Single Neuron Adaptive PID*","authors":"Lin Wang;Honghua Wang","doi":"10.23919/CJEE.2025.000109","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000109","url":null,"abstract":"A synchronous condenser (SC) is used to maintain grid voltage stability owing to its bidirectional fast reactive power regulation ability and good dynamic characteristics. To address the issue of dynamic voltage instability in power system during failures or heavy inductive loads, an SC reactive power regulation optimization method based on single neuron adaptive PID (SNA-PID) combined with whale optimization algorithm (WOA) is proposed. This approach aims to overcome the limitations of normal PID controllers. A simulation model of the SC reactive power regulation system, based on SNA-PID combined with the WOA, is established using Matlab. The parameters of the SNA-PID are optimized by the WOA with the ITAE criterion under two typical operation situations of the power system: one is to set three different degrees of short-circuit ground faults, and the other is to access three different three-phase resistive loads. Compared to conventional PID control, as the degree of short-circuit ground faults increases and the three-phase resistive load resistance decreases, the SC reactive power regulation optimization method based on SNA-PID combined with the WOA can still reduce the voltage recovery time and voltage oscillation, while maintaining voltage stability. Simulation results show that the proposed method exhibits better dynamic adjustment characteristics and adaptive ability.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 1","pages":"184-193"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10955296","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792902","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}
Fan Xie;Ronglong Wang;Zhiqiang Yang;Haoyu Wu;Bo Zhang
{"title":"Hopf Bifurcation and Coexisting Attractors in Power Electronic Converters: An Overview of the Mechanisms of Occurrence and Case Studies*","authors":"Fan Xie;Ronglong Wang;Zhiqiang Yang;Haoyu Wu;Bo Zhang","doi":"10.23919/CJEE.2025.000097","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000097","url":null,"abstract":"Power electronic converters are commonly used in daily life, and the nonlinear phenomena that arise during their operation have garnered significant attention. Several classical nonlinear phenomena are introduced, and their causes are discussed. Then, the Hopf bifurcation phenomenon is analyzed in detail through specific examples. In addition, the causes and cases of coexisting attractor phenomena in power electronic converters are analyzed. Based on these discussions, potential directions for studying nonlinear system dynamics in power electronics are presented.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 1","pages":"119-137"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10955308","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792907","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 HVDC Tap","authors":"Chong Qiu;Songtao Huang;Yihua Hu","doi":"10.23919/CJEE.2025.000110","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000110","url":null,"abstract":"The development of high-voltage direct current (HVDC) systems has been pivotal to the evolution of modern power systems, particularly in terms of providing an effective solution for long-distance, high-capacity power transmission, which has become increasingly important in the integration of renewable energy technologies. The integration of renewable energy sources into the grid requires the use of sophisticated tap-changing technology to ensure efficient extraction of power from HVDC lines. A critical review of the current status of the HVDC technology is presented in this paper. It synthesizes research findings on power flow optimization, grid expansion, and the challenges of designing HVDC grid substations. The development of modular multilevel converters (MMCs) and DC-DC converters, particularly for use in hybrid alternating current (AC)/direct current (DC) grids, is highlighted. These findings emphasize the importance of continuous research on the HVDC tap technology to improve the efficiency, reliability, and scalability of future power systems.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 1","pages":"1-15"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10955304","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792954","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":"Multi-rate Co-simulation Framework with Taylor-series-based Variable-step Solver for Grid-connected Power Converters*","authors":"Weicheng Liu;Zhengming Zhao;Han Xu;Yangbin Zeng;Liqiang Yuan","doi":"10.23919/CJEE.2025.000111","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000111","url":null,"abstract":"Grid-connected converters (GPC) are playing an increasingly important role in distribution networks. Performing electromagnetic transient (EMT) simulations on power electronics and distribution networks can significantly improve the analysis accuracy. However, the existing simulation software struggles to handle distribution networks with a large number of power electronic switches, leading to unacceptable simulation times. To address this issue, a system-hierarchical multi-rate co-simulation framework is proposed. The system is hierarchically divided into different rate subsystems based on timescales, and solvers with different simulation rates are used to solve them separately. A Taylor-series-based variable-step solver is proposed for power electronic systems, and numerical compensation algorithms are designed for multi-rate interfaces to improve the system stability and accuracy. Compared with commercial software, the proposed framework increased the simulation speed by more than 200 times in the studied case, involving 576 switching devices and 14 bus distribution networks, while contributing less than 1% to the relative error.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 1","pages":"59-73"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10955323","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792903","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 Lightweight Oriented Offshore Wind Power Transmission Schemes*","authors":"Yanfeng Wang;Shuxin Luo;Mengze Yu;Lingyun Yang;Jun Huang;Zhicong Huang","doi":"10.23919/CJEE.2025.000098","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000098","url":null,"abstract":"The use of renewable energy is essential for addressing global climate change, and offshore wind power plays a critical role in achieving this goal. As nearshore resources become saturated, the focus of offshore wind power development is shifting to deep-sea areas. Deep-sea wind power transmission schemes must prioritize lightweight designs and low costs to enhance overall economic and technical feasibility. Currently, four lightweight offshore wind power transmission schemes have been identified: low-frequency alternating current (LFAC) transmission, high-voltage direct current (HVDC) transmission utilizing uncontrolled diode rectifier units (DRU-HVDC), DRU-MMC parallel-connection hybrid rectifier transmission (PCDRU-MMC), and DRU-MMC series-connection hybrid rectifier transmission (SCDRU-MMC). Four schemes are examined, advantages and disadvantages in various scenarios are outlined, technical performance are analyzed. A comprehensive economic assessment of each scheme is conducted for deep-sea environments far from load centers. The results indicate that LFAC transmission effectively reduces transmission losses, whereas DRU-HVDC has limitations in terms of voltage support and black-start capability. In contrast, hybrid rectification solutions such as PCDRU-MMC and SCDRU-MMC combine the economic benefits of DRU-HVDC with the flexibility of modular multilevel converters (MMCs), thereby enhancing system reliability and efficiency.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 1","pages":"16-39"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10955301","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792909","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}