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Selection for Schottky Barrier Diodes with Various On-Resistance in Full-SiC Voltage Source Converters

IEEE Transactions on Industry Applications 2025年

作者： Chen, Yuzhi Li, Chi Liu, Jianwei Wu, Yifan Liu, Zicheng Zheng, Zedong Tsinghua University State Key Laboratory of Power System Operation and Control Department of Electrical Engineering Beijing100084 China Huazhong University of Science and Technology State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Wuhan430074 China

In Silicon Carbide based voltage source converters (VSCs), pairing Schottky barrier diodes (SBDs) presents trade-offs. While SBDs reduce the freewheeling loss and mitigate the adverse effects of bipolar conduction, their junction capacitance also contributes to increased switching loss. This paper proposes a systematic selection strategy for SBDs aimed at enhancing converter efficiency, using on-resistance as the design variable. A three-phase VSC with 1.2 kV MOSFETs and four sets of 1.2 kV SBDs is demonstrated as the case study. The static and switching characteristics for MOSFET/SBD pair are measured and analyzed over a wide temperature range. VSC efficiency is evaluated in both inverter and rectifier modes under different operating conditions. It appears that VSC using SBDs with 126% of the MOSFETs' resistance exhibits an overall superior performance. A 4 kW full-SiC VSC prototype is developed to validate the proposed selection strategy. Compared to other SBDs, using the recommended selection enhances VSC efficiency by up to 2% (± 0.5%) under light loads while maintaining high performance under medium and heavy loads. Compared to freewheeling by the body diode, using the recommended selection enhances VSC efficiency by an average of 0.4% (± 0.1%) across nearly the entire load range. © 1972-2012 IEEE.

关键词： Schottky barrier diodes

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High-frequency oscillation analysis of wind farm-side MMC station under no-load charging condition

High-frequency oscillation analysis of wind farm-side MMC st...

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20th International Conference on AC and DC power Transmission 2024 (ACDC 2024)

作者： Yongqing Yang Hua Ye Guanqun Li Jialun Yang Yujing Zhao Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education Shandong University 17923 Jingshi Road Jinan People's Republic of China State Grid Jinan Power Supply Company Jinan People's Republic of China

ISBN: (数字)9781837241552

Existing research on high-frequency oscillation indicates that the high-frequency oscillation during no-load charging of modular multilevel converter (MMC) station is primarily linked to time delay and the ground capacitance of AC lines. Nevertheless, a high-frequency oscillation around 2000 Hz has been observed in Rudong high voltage direct current project even when the AC lines are not connected. Except time delay, there still exists another key factor of the high-frequency oscillation, i.e., the transformer stray capacitance. This paper delves into the interaction among the dynamics of MMC station and the transformer. And the mechanism of high-frequency oscillation under no-load charging condition is determined. Firstly, the harmonic state space (HSS) model of MMC station considering the effect of stray capacitance is established. By plotting the eigenvalue trajectory, the essentiality of taking into account stray capacitance is elucidated. Subsequently, a simplified model is obtained by neglecting the dynamics of elements with low participation in the oscillation modes. Next, the mechanism of high-frequency oscillation is clarified according to impedance characteristics. Finally, the impact of proportional gain and shear frequency on small signal stability is revealed. The correctness and accuracy are identified by electromagnetic transient simulations.

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A Model-driven Early Warning Approach for Transmission Lines Failure under Wind Storms

A Model-driven Early Warning Approach for Transmission Lines...

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Sustainable power and Energy Conference (iSPEC)

作者： Haoran Chen Shibin Bai Zhihao Tian Gang Liu Changgang Li Qiulong Ni Chang Wu Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education Shandong University Jinan China State Grid Ningxia Electric Power Corporation Yinchuan China State Grid Zhejiang Electric Power Corporation Hangzhou China State Grid Quzhou Power Supply Corporation Quzhou China

The frequency and intensity of extreme wind storm events are gradually increasing due to global climate change, posing serious challenges to the security and stability of the power grid. Under this background, this paper proposes a model-driven early warning approach for transmission lines failure under wind storms. The mapping relationship between wind speed and line failure probability is established. Risk assessment is carried out for scenarios with high failure probabilities, and the early warning information is released. Case study is conducted based on the New England 39-bus system, and the issued early waring information can offer decision-making references for dispatchers during the storm.

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Response-Based Synchronization Stability Analysis of Multi-Converter power systems

Response-Based Synchronization Stability Analysis of Multi-C...

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IEEE Conference on Energy Internet and Energy system Integration (EI2)

作者： Yuren Zhou Zihan Wang Gengyin Li Shiwei Xia Le Zheng Linlin Ma Dingyi Cheng Ting Wang State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing China Shandong Electric Power Dispatching and Control Center State Grid Shandong Electric Power Company Shandong China State Grid Shandong Electric Power Research Institute Power Grid Technology Center Shandong China

With the increasing integration of renewable energy into the power grid, the application of converters in the electrical systems has grown significantly. Due to the nonlinearity, the complexity and the difficult availability of the system models, traditional methods of synchronization stability analysis have revealed limitations and challenges when confronted with modern power systems. Additionally, the prevalence of grid-following converters in the grid leads to a shortage of voltage sources within the system, significantly increasing the risk of grid instability. This paper addresses the issue of synchronization stability analysis of multi-converter power systems, and proposes a response-based method to assess the synchronization stability level of the entire system. Through an analysis of the synchronization stability mechanism of grid-forming converters, a relationship is established between electromotive force, power angle, and node voltages. A quantitative stability evaluation of the system is achieved using the sBTTC index. Case studies show that the proposed response-based method is effective to analyze the synchronization stability of multi-converter power systems, with great practical viability in engineering applications.

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Nickel Phase Invades Ysz Electrolyte Through Ysz/Ysz Grain Boundary During Long-Term Operation of Sofc

SSRN

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SSRN 2023年

作者： Liu, Jiawei Wang, Yige Lyu, Zewei Wang, Chenpeng Ma, Yue Ye, Hao Liu, Yinglong Liu, Yingli Xu, Xiaoru Chen, Zhicong Han, Minfang Liang, Bo School of Materials and Energy Guangdong University of Technology Guangzhou510006 China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Energy and Power Engineering Tsinghua University Beijing100084 China

A solid oxide fuel cell after long-term operation more than 5000 hours, nickel (Ni) phase is observed at YSZ/YSZ grain boundaries (GBs) within electrolyte. By using a humidified hydrogen, the single cell is electrochemically operated at 720℃ under 0.10 A·cm-2. The thickness of anode/electrolyte interface is thinned to less than 100 nm by a dual beam focused ion beam-scanning electron microscope (FIB-SEM). As-thinned electrolyte is analyzed by using High-Resolution Transmission Electron Microscopy (HR-TEM). The discrete nanostructures ranging from 50nm to 5nm are observed to have developed exclusively along the YSZ/YSZ grain boundaries. It is noted that the nickel phase is found in YSZ GBs of the electrolyte. FFT patterns shows that the invasion phase of nickel is FCC-Ni. A suggested mechanism has been put forth to explain the invasion of Ni phases into the electrolyte through YSZ/YSZ grain boundary. This mechanism takes into consideration the evolution of nanostructures, as well as the diffusion and nucleation of Ni, which involves the formation of Ni-OH species. © 2023, The Authors. All rights reserved.

关键词： Nanostructures

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MCMC Wind power Sequence Modeling Method Considering Climbing Direction

MCMC Wind Power Sequence Modeling Method Considering Climbin...

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power Science and Technology (ICPST), IEEE International Conference on

作者： Ling Hao Fei Xu Lei Chen Qun Chen Yong Min Yi Gu Yiming Chang Department of Electrical Engineering State Key Laboratory of Power System Operation and Control University Beijing China Department of Engineering Mechanics Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua University Beijing China State Grid Liaoning Electric Power Co. Ltd Liaoning China

Since the traditional Markov Chain Monte Carlo (MCMC) method has the problem that the wind power is stuck in a certain state and it is difficult to jump, this paper proposes an improved MCMC method considering the climbing direction, first dividing the state by the size of the output and the climbing direction, and then determining the duration of each state by changing the state, and then sampling and generating the corresponding number of output samples according to the duration of each state, and sorting these samples according to the climbing direction, and the sorted output is the output timing of the state. This method was used to generate wind power sequences from a wind farm in the Northeast China Sea, and the characteristics of a wind power sequence were compared and analyzed with the original wind power sequence, and the results were better than the wind power sequences generated by the traditional MCMC method.

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Spatial Fluctuation of the Electric Field within SF6 Streamer Channel in Highly Non-Uniform Fields: Phenomenon, Validation, and Mechanism

arXiv

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arXiv 2024年

作者： Feng, Zihao Wang, Xinxin Zou, Xiaobing Luo, Haiyun Fu, Yangyang Department of Electrical Engineering Tsinghua University Beijing100084 China State Key Laboratory of Power System Operation and Control Department of Electrical Engineering Tsinghua University Beijing100084 China

The electric field within the streamer channel is a critical parameter in the calculation model for the nonlinear breakdown voltage of SF6, motivating the research presented in this paper. By using a 2D fluid model, we investigate the microscopic characteristics of the SF6 streamer channel in highly non-uniform fields and uncover a previously unexplained coherent structure: the spatial fluctuation of the electric field (SFEF). We validate the physical validity of SFEF by modifying model parameters that could potentially introduce non-physical effects. Further comparative analysis reveals that SFEF is driven by an ion-conducting channel formed due to the strong electronegativity of SF6. This ion-conducting channel exhibits local characteristics, which fundamentally arise from the slow response of charged species to local charge relaxation. We identify that some charge separation originates from the accumulation of negative ions at the rear edge of the streamer head due to strong electric field shielding in this region. As the streamer propagates, charge separation is continuously generated and passively carried into the streamer channel, ultimately forming the SFEF. Finally, we confirm that SFEF does not occur in uniform fields, indicating that it is a phenomenon exclusive to highly non-uniform fields. These findings provide a deep insight into the electric field within the SF6 streamer channel and offer a potential avenue for further investigation into the mechanisms of SF6 nonlinear breakdown voltage. Copyright © 2024, The Authors. All rights reserved.

关键词： Negative ions

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Stability Analysis and Braking system Design of Icebreaker Propulsion system Based on 3L-NPC Inverter

Stability Analysis and Braking System Design of Icebreaker P...

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Smart power & Internet Energy systems (SPIES), International Conference on

作者： Nianzhou Liu Nan Fu Pengfei Xie Wenfeng Long Kui Wang Yongdong Li Science and Technology on Ship Integrated Power System Technology Laboratory Wuhan Institute of Marine Electrical Propulsion Wuhan China State Key Lab of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

The icebreaker is important in the polar scientific investigation and resource exploration. There will be pulse and periodic load during the continuous icebreaking process, which may affect the propulsion system of the icebreaker. This paper mainly analyzes the effect of the impact load on the three-level neutral point clamped (3L-NPC) inverter with diode front-end, and demonstrates the relationship between the impact load and the feedback energy. Moreover, the choice of the resistance of the braking resistor is briefly discussed. The simulation results are given at last, which verify the rationality and correctness of the theoretical analysis.

关键词： Resistors Resistance simulation Energy Propulsion Inverters Stability analysis

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Towards Non-Virtual Inertia control of Renewable Energy for Frequency Regulation: Modeling, Analysis and New control Scheme

SSRN

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SSRN 2024年

作者： Gao, Haishu Zhang, Feng Ding, Lei Zhang, Gang Salimu, Athuman State Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education Shandong University Jinan250061 China Yantai Research Institute Harbin Engineering University Yantai China

Currently, when renewable generation participates in frequency regulation, the traditional control method is to emulate synchronous generators through virtual inertia control. However, virtual inertia has a time delay, so essentially it is a kind of fast power response. Meanwhile, virtual inertia control is likely to be affected by frequency fluctuation, since it responds to the derivative of frequency. Hence, it’s worth exploring non-virtual inertia control for renewable energy when participating in frequency regulation. For this reason, a novel non-virtual inertia control scheme for renewable energy frequency regulation is proposed in this research. Firstly, the extended model of system frequency regulation (SFR), which contains virtual inertia with time delay, is built and analytically solved by order decrement on basis of Routh approximation method. Afterwards, according to analytical solution, it shows time delay really has an effect on the frequency response of renewable energy, and it can also be analytically proved that non-virtual inertia control, e.g., sole droop control, was capable to replace virtual inertia under the same frequency deviation, but more energy for frequency regulation may be needed. Furthermore, a novel two-segment droop control is presented, and to analytically prove its ability to replace virtual inertia, the impulse function balancing principle and the integration by parts algorithm were adopted to address the initial conditions of the differential equation. Based on the analytical expression, it can be analytically proved that under the same energy of frequency regulation, a lower frequency deviation can be obtained. Accordingly, a parameter setting method for two-segment droop control was proposed. Finally, the effectiveness of the proposed method is verified by using a two-area system frequency response model, and the results reveal that it can be used to replace virtual inertia and has better performance. © 2024, The Authors. All r

关键词： Time delay

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Analysis of multiple-faults of high-voltage circuit breakers based on non-negative matrix decomposition

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Global Energy Interconnection 2024年第2期7卷 179-189页

作者： Yongrong Zhou Zhaoxing Ma Hao Chen Ruihua Wang State Key Laboratory of Technology and Equipment for Defense against Power System Operational Risks Nanjing 211106P.R.China Nari Group Co. Ltd.Nanjing 211106P.R.China Qingdao University of Technology School of Information and Control EngineeringQingdao 266520P.R.China State Grid Nanjing Power Supply Company Nanjing 211000P.R.China

High-voltage circuit breakers are the core equipment in power networks,and to a certain extent,are related to the safe and reliable operation of power ***,their core components are prone to mechanical *** study proposes a component separation method to detect multiple mechanical faults in circuit breakers that can achieve online real-time ***,a model and strategy are presented for obtaining mechanical voiceprint signals from circuit ***,the component separation method was used to decompose the voiceprint signals of multiple faults into individual component *** on this,the recognition of the features of a single-fault voiceprint signal can be ***,multiple faults in high-voltage circuit breakers were identified through an experimental simulation and verification of the circuit breaker voiceprint signals collected from the substation *** research results indicate that the proposed method exhibits excellent performance for multiple mechanical faults,such as spring structures and loose internal components of circuit *** addition,it provides a reference method for the real-time online monitoring of high-voltage circuit breakers.

关键词： High voltage circuit breaker Signal separation Monitor Multiple faults power system

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