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IEEE Conference on Vehicle power and Propulsion (VPPC)

作者： Bo Feng Zhengming Zhao Yingchao Zhang Dejia Zhou Liqiang Yuan State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

LED lighting system supplied by batteries is one of effective solutions to vehicle and photovoltaic lighting systems. In order to improve lighting performance and prolong the life of LEDs and batteries, this paper proposes a novel intelligent controller for LED lighting systems. Stage constant current (SCC) control strategy is proposed, which determines the optimal working current of LEDs (I ref ) according to their ambient temperature and the capacity of batteries. For implementing SCC control strategy, a new control algorithm of double current loops and feedforward (DCLF) control is proposed based on Boost converter with constant current source. Both output current and inductor current are used as feedback control variables and input voltage is employed as feedforward compensation in the proposed algorithm. simulations have been conducted using PSIM software; and based on that, a 50 W photovoltaic LED lighting system has been developed to implement a serial of comparative experiments. The results show the advantages and validity of DCLF algorithm, such as excellent dynamic performance and good robustness.

关键词： Lighting control control systems Light emitting diodes LED lamps Photovoltaic systems Solar power generation Battery powered vehicles Optimal control Temperature control Inductors

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Discrete state Event-Driven Approach for High-power Converter simulations

Discrete State Event-Driven Approach for High-Power Converte...

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IEEE Energy Conversion Congress and Exposition

作者： Bochen Shi Zhengming Zhao Yicheng Zhu Zhujun Yu Jiahe Ju Liqiang Yuan Kainan Chen State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

Demands for high-power converters are increasing rapidly. Nevertheless, due to their complex structures and multi-time-scale features, accurate and efficient simulation of such systems has long been a huge obstacle. Aiming at improving the unacceptably slow simulation speed of high-power converters, this paper improves Discrete state Event-Driven (DSED) approach by implementing a decoupling method. Taking a 10kV 1MW electric energy router as an example, this paper evaluates the effectiveness of DSED with the proposed decoupling method in high-power applications. In the studied case, compared with commercially available tool for power electronics simulation, PLECS, DSED can achieve an up to 1000-fold improvement in simulation speed under the same accuracy: PLECS takes 6 hours while DSED only takes 18 seconds. DSED provides a powerful simulation tool for analysis, design and control of high-power converters.

关键词： event-driven simulation numerical algorithm circuit partitioning high-power converter electric energy router solid-state transformer

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A novel Modbus RTU-based communication system for adjustable speed drives

A novel Modbus RTU-based communication system for adjustable...

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IEEE Conference on Vehicle power and Propulsion (VPPC)

作者： Hu Sideng Zhao Zhengming Zhang Yingchao Wang Shuping State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

ISBN: (纸本)9781424418480

The communication protocol is important for applying adjustable speed drive (ASD) systems to an industry network. This paper proposes a novel scheme of communication system for the ASD system based on Modbus protocol. The most remarkable advantage of the approach lies in the tradeoff between performance and economic cost for a power converter system. The overall system is built on master-slave structure and easy for interacting with other networks. An additional study on the cyclic redundancy check (CRC) in Modbus RTU is introduced to obtain the optimization design in the actual application and the optimization method in software design is also presented. The performance of the communication system obtained from experiment conducted on the 15 kW ASD system validates the effectiveness of the proposed design method.

关键词： Variable speed drives Protocols Cyclic redundancy check Communication industry power system economics power generation economics Costs Master-slave Design optimization Application software

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Stabilization and assessment of interaction dynamics for More Electric Aircraft

Stabilization and assessment of interaction dynamics for Mor...

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International Conference on power Electronics and Motion control (IPEMC)

作者： Xuan Zhang Lie Xu Yongdong Li Zedong Zheng Kui Wang State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University Beijing China

ISBN: (纸本)9781509012114

This paper proposes a novel active stabilization method based on reshaping the output impedance of the source-side PWM rectifier for More Electric Aircraft (MEA) power system. A nonlinear compensation signal is injected into AC voltage command of PWM rectifier to adding a virtual resistor paralleled with DC bus capacitor. Thus, the instability caused by constant power loads (CPLs) can be neutralized. Compared to conventional active damping methods, the value of compensation signal can be expressed by the virtual resistor so that the physical mechanism of stability improvement can be clarified. Besides, all remote sensors providing load input voltages can be removed. Stability and sensitivity of the proposed active stabilization method are analyzed qualitatively. The interaction dynamics of passive devices, such as LC filters of CPLs and DC capacitors on source side are discussed. simulation results validate the effectiveness of the proposed method.

关键词： Damping Pulse width modulation Rectifiers power system stability Capacitors Stability analysis Mathematical model

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A novel protection scheme for two-phase faults in power distribution system with neutral ungrounded

A novel protection scheme for two-phase faults in power dist...

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12th IET International Conference on Developments in power System Protection, DPSP 2014

作者： Shi, Shengxing Lei, Aoyu Li, Xin Dong, Xinzhou State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 10084 China Shibei Power Supply Company Shanghai Municipal Electric Power Company Shanghai China

ISBN: (纸本)9781849198349

A novel protection scheme for two-phase faults in power distribution system with neutral ungrounded is presented. The feasibility of tripping single-phase circuit when a phase-tophase or two-phase-to-ground fault occurs is studied with induction motor loads as the focus. The paper at first analyses the effect of a induction motor runs with one phase cut off theoretically. And then a real power distribution system model with 110kV, 35kV and 6kV voltage levels is built in PSCAD/EMTDC. Three feasibility criteria are proposed for motors in continuous operation with single-phase opened. At last, the novel protection scheme is testified in simulation with protection time and reclosing time as variables respectively. The results verify that the scheme is feasible and power supply reliability is improved.

关键词： Induction motors

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Effect of UV radiation aging on creepage discharge characteristics of high temperature vulcanized silicon rubber at high altitude

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Plasma Science and Technology 2019年第5期21卷 23-33页

作者： Fubao JIN Yuanxiang ZHOU Bin LIANG Xidong LIANG Zhongliu ZHOU Ling ZHANG Key Laboratory of Plateau Ecology and Agriculture College of Agriculture and Animal HusbandrySchool of Water Resources and Electric PowerQinghai UniversityXining 800016People's Republic of China State Key Lab of Control and Simulation of Power Systems and Gen eration Equipments Departme nl of Electrical EngineeringTsinghua UniversityBeijing 100084People's Republic of China

The physicochemical properties and creepage discharge characteristics of aged high temperature Vulca nized(HTV)silicone rubber materials were investigated by ultraviolet radiati on(UV)aging method in this *** experimental results show that as the aging time increases,the creepage discharge flashover voltage increases first and then *** the aging time has little effect on the creepage discharge inception *** the aging time prolonged,the discharge endurance time of HTV silicone rubber is shortened,and the creepage discharge development velocity is *** the short time of applying voltage to aging material,the magnitude of discharge in creases *** to the partial discharge characteristic parameters of creepage discharge,the whole creepage discharge process is partitioned into four *** with unaged HTV silicone rubber,the aged HTV silicone rubber has less fluctuation in performance parameters and a clear *** study found that UV aging not only affects the physicochemical and hydrophobic properties of the HTV silicone rubber,but also accelerates the development of creepage discharge under AC voltage.

关键词： high temperature vulcanized silicone rubber creepage discharge UV aging inception voltage flashover voltage high altitude characteristic parameters

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Research on Equalization Effect of Dynamic Reconfigurable Battery Management System

Research on Equalization Effect of Dynamic Reconfigurable Ba...

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2019 IEEE Sustainable power and Energy Conference, iSPEC 2019

作者： Wan, Yuxiang Cheng, Lin Jiang, Yi Wang, Zhidong Liu, Mei Tsinghua University State Key Lab. of Control and Simulation of Power System and Generation Equipment Beijing China State Grid Corporation of China State Grid Economic and Technological Research Institute Corporation Limited Beijing China

ISBN: (纸本)9781728149301

The battery differences not only affect the reliability and security of battery packs but also accelerate the decline of the packs' life. Although battery management systems (BMS) and equalization circuit can be used to balance the differences, only the whole battery pack can be protected with high-cost and complex circuits. Dynamic reconfigurable battery management system (DRBMS) based on networked control has a simple principle and can shield the differences of battery cells. This paper designs experiments for the dynamic reconfigurable battery network technology and makes a contrast with the traditional BMS. Through the analysis of voltage, SOC difference and dynamic resistance during charging and discharging, the results show that DRBMS has better voltage and capacity equalization effect than BMS. The cells of paralleled battery packs can be fully charged/released in DRBMS. It is also verified that DRBMS is applicable on decommissioned bus battery packs which are of larger differences and the ladder utilization. © 2019 IEEE.

关键词： Battery management systems

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power Output Monitoring and Anomaly Identification of Photovoltaic systems Using Graphical Modeling 4

Power Output Monitoring and Anomaly Identification of Photov...

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4th International Conference on Sensing, Diagnostics, Prognostics, and control, SDPC 2020

作者： Chen, Yonghua Zhang, Xiaochen Liu, Gang Wu, Rui Liu, Chao Jiang, Dongxiang Nari Technology Co. Ltd Nanjing211106 China Tsinghua University Department of Energy and Power Engineering Beijing100084 China Tsinghua University State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Energy and Power Engineering Beijing100084 China

ISBN: (纸本)9781728170503

Photovoltaic cells are being increasingly installed worldwide as a type of important renewable resource for power generation. Among the installed photovoltaic systems, data are collected from the control and monitoring system, and the anomaly detection researches are mostly based on the individual photovoltaic cells and the systematic behavior in a group of photovoltaic systems is not well studied. Based on the assumption that the photovoltaic cells installed in the same location are with very close solar radiation, the power output of each subsystem is considered in this work for monitoring the operating status of the subsystem and identifying the anomalous subsystem, where spatiotemporal pattern network, a probabilistic graphical modeling approach, is applied. The results show that the presented framework is able to detect the anomaly and locate the anomalous subsystem. © 2020 IEEE.

关键词： Condition monitoring

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Numerical Analysis of Space Charge Characteristics in Low-density Polyethylene Nanocomposite Under External DC Electric Field

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高电压技术 2013年第8期39卷 1813-1820页

作者： ZHOU Yuanxiang ZHANG Ling SHA Yanchao TIAN Jihuan State Key Laboratory of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing 100084 China ABB Corporate Research Center Beijing 100015 China

The dynamic characteristics of space charge in nanocomposite of low-density polyethylene (LDPE) mixed with inorganic nano- fillers. Different from previous qualitatively theoretical works, we investigated the influence of trap depth, trap volume charge density and injection barrier height on the space charge and the electric field distribution in the nanocomposite under a DC external electric field (100 MV/m) systematically and quantificationally, through numerical simulations based on a bipolar charge transport model. The simulation re- sults showed that, the increase of trap depth would severely distort the balanced electric field distribution with the highest and the lowest electric field of 119 MV/m and 47 MV/m, respectively. It is concluded that the introduction of nanofillers creates more deep traps, which would block space charges by capturing most of them in the vicinity of electrode and hence reduce the local electric field largely. Further theoretical analysis of the simulation indicates that both the high permittivity and the low local electric field of the nanocomposite contri- buted to the increase of injection barrier height, and almost no charge could overcome an injection barrier higher than 1.25 eV. At last, a mechanism of space charge suppression in the LDPE nanocomposite was presented.

关键词：纳米复合材料低密度聚乙烯直流电场空间电荷电荷特性数值分析无机纳米填料陷阱深度

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Exergy Analysis of Electric Vehicle Heat Pump Air Conditioning System with Battery Thermal Management System

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Journal of Thermal Science 2020年第2期29卷 408-422页

作者： ZHANG Kexin LI Ming YANG Changhai SHAO Zhiyuan WANG Lihong State Key Laboratory of Automotive Simulation and Control Jilin UniversityChangchun 130025China College of Automotive Engineering Jilin UniversityChangchun 130025China School of Energy and Power Engineering Xi’an Jiaotong UniversityXi’an 710049China FAW-Valeo Climate Control Systems Co.Ltd. Changchun 130011China

The exergy analysis of an electric vehicle heat pump air conditioning system(HPACS) with battery thermal management system was carried out by studying the exergy loss of each component. The results indicate that the compressor is the main source of system exergy loss in all operation conditions. The exergy loss distribution of HPACS is almost the same when the battery thermal management system integrated into the HPACS in cabin and battery mixed cooling mode and the system exergy loss was linearly related to the compressor speed in cooling modes. The performance of the HPACS is better than that of the positive temperature coefficient(PTC) heater in cabin heating mode. The degree of exergy efficiency improvement of the alternative mode was discussed at all operation conditions in cabin heating mode. The results indicate that the optimization effect using the electric vehicle HPACS to replace the PTC heater is obvious at lower compressor speed, surrounding temperature and internal condenser air flow rate.

关键词： electric vehicle heat pump exergy efficiency battery thermal management

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