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Excavator Energy-saving Efficiency Based on Diesel Engine Cylinder Deactivation Technology

Chinese Journal of Mechanical Engineering 2012年第5期25卷 897-904页

作者： YANG Jing QUAN Long YANG Yang Key Laboratory of Advanced Transducers and Intelligent Control System of Ministry of Education Taiyuan University of Technology Taiyuan 030024 China The State Key Lab of Fluid Power Transmission and Control Zhejiang University Hangzhou 31002 7 China

The hydraulic excavator energy-saving research mainly embodies the following three measures： to improve the performance of diesel engine and hydraulic component, to improve the hydraulic system, and to improve the power matching of diesel-hydraulic system-actuator. Although the above measures have certain energy-saving effect, but because the hydraulic excavator load changes frequently and fluctuates dramatically, so the diesel engine often works in high-speed and light load condition, and the fuel consumption is higher. Therefore, in order to improve the economy of diesel engine in light load, and reduce the fuel consumption of hydraulic excavator, energy management concept is proposed based on diesel engine cylinder deactivation technology. By comparing the universal characteristic under diesel normal and deactivated cylinder condition, the mechanism that fuel consumption can be reduced significantly by adopting cylinder deactivation technology under part of loads condition can be clarified. The simulation models for hydraulic system and diesel engine are established by using AMESim software, and fuel combustion consumption by using cylinder-deactivation-technology is studied through digital simulation approach. In this way, the zone of cylinder deactivation is specified. The testing system for the excavator with this technology is set up based on simulated results, and the results show that the diesel engine can still work at high efficiency with part of loads after adopting this technology; fuel consumption is dropped down to 11% and 13% under economic and heavy-load mode respectively under the condition of driving requirements. The research provides references to the energy-saving study of the hydraulic excavators.

关键词： diesel engine cylinder deactivation hydraulic excavator energy-saving

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INFLUENCES OF BREAKDOWN CHARACTERISTICS OF DISCONNECT SWITCH GAP ON RESIDUAL VOLTAGE

INFLUENCES OF BREAKDOWN CHARACTERISTICS OF DISCONNECT SWITCH...

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The ⅪⅩ International Conference on Gas Discharges and Their Applications

作者： YUE GONGCHANG GUAN YONGGANG LIU WEIDONG CHEN WEIJIANG LI ZHIBING State Key Lab of Control and Simulation of Power System and Generation Equipments Department of Electrical EngineeringTsinghua University State Grid Corporation of China China Electric Power Research Institute

The very fast transient overvoltages(VFTO) are generated during operation of disconnect switch (DS) of gas insulated switchgear(GIS). After the opening operation of DS,the load side busbar is left at a residual *** residual voltage is determined by the opening phase and the breakdown characteristics of SF6 gap of DS. This study obtains the breakdown characteristic of the test DS,including the dielectric strength recovery speed and polarity effect factor of gap of testing *** the stochastic property of DS opening phase,the opening process of DS is simulated by computer under different dielectric strength recovery speeds and polarity effect *** results show that the dielectric strength recovery speed and polarity effect factor have big influences over the residual *** proper value of dielectric strength recovery speed and polarity effect factor could make the residual voltage minor

关键词： simulation INFLUENCES OF BREAKDOWN CHARACTERISTICS OF DISCONNECT SWITCH GAP ON RESIDUAL VOLTAGE

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Period distribution analysis of some linear maps

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Communications in Nonlinear Science and Numerical Simulation 2012年第10期17卷 3848-3856页

作者： Fei Chen Xiaofeng Liao Kwok-wo Wong Qi Han Yang Li State Key Lab. of Power Transmission Equipment and System Security College of Computer Science Chongqing University Chongqing 400044 PR China Department of Electronic Engineering City University of Hong Kong Hong Kong PR China Department of Automatic Control and Systems Engineering The University of Sheffield UK

This paper discusses period properties of some linear maps which are employed in various applications such as image encryption, public key cryptography and watermarking. Conditions for the bijectiveness of such maps and the existence of a period are presented. Period structure is also given. Then, the recurrence equation theory is adopted to address the period distribution problem. Finally, a framework to solve the problem is proposed with a demonstration of its effectiveness and efficiency into some applications.

关键词： Linear map Period distribution Periodic orbit Dynamical system Cat map

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Cascaded battery energy storage system based on dual active bridges and a common dc bus

Cascaded battery energy storage system based on dual active ...

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2010 9th International power and Energy Conference, IPEC 2010

作者： Jin, Yiding Song, Qiang Liu, Wenhua Sun, Weixin State Key Lab. of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing China

ISBN: (纸本)9781424473991

Along with the increasing system capacity, large-scaled energy storage systems are supposed to be connected into 10kV or higher networks. Urban network has strict criterions on power quality of the power electronic devices connected. Moreover, the occupancy and noise of industrial frequency transformers also become restraints to the promotion of urban network energy storage. For that reason, this paper proposes a battery energy storage system based on cascaded dc-ac converter, dual active bridges, and a common dc bus. High frequency transformers are used to replace the industrial frequency transformer for insulation, and battery groups are connected to the common dc bus with respective dc-dc interfaces. This multilevel converter system is easy to modularize, easy to extend, and allows different kinds of batteries to work together. The main circuit and proper control system are designed, with the soft-switching condition and current control issues of the dual active bridge analyzed in detail. The simulation results from EMTDC model verify the operation principles and corresponding control strategies. ©2010 IEEE.

关键词： Electric inverters

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A PI-based control scheme for primary cascaded H-bridge rectifier in transformerless traction converters

A PI-based control scheme for primary cascaded H-bridge rect...

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作者： Xinghua, Tao Yongdong, Li Min, Sun State Key Lab of Control and Simulation of Power System and Generation Equipments Dept. of Electrical Engineering Tsinghua University China Dept. of Electrical Engineering Naval Engineering University China

ISBN: (纸本)9788986510119

Cascaded H-Bridge rectifier (CHBR) is a more attractive solution in traction application for its transformerless structure. Because of the currents of different cells are exactly the same one, it is a challenge job to regulate the voltages of cells with only one current controller. In this paper, a PI-based control scheme is presented to deal with the voltages balance issue in CHBR. To satisfy the demand of rectifier such as unity power factor and regulated output DC voltages, the proposed control scheme consists of two parts. One is for shaping the grid current waveform and regulating the sum of DC-link voltages of all the cells;the other one is for balancing DC-link voltages. The latter is more concerned in this paper and is discussed in detail especially. Simulations and experiments are carried on. The results verified the feasibility and effectiveness of the proposed scheme.

关键词： Electric rectifiers

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A phase-disposition PWM method for DC voltage balance in cascaded h-bridge rectifier

A phase-disposition PWM method for DC voltage balance in cas...

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作者： Tao, Xinghua Li, Yongdong Sun, Min State Key Lab of Control and Simulation of Power System and Generation Equipments Dept. of Electrical Engineering Tsinghua University China Dept. of Electrical Engineering Naval Engineering University China

ISBN: (纸本)9788986510119

In this paper, a novel control scheme for cascaded H-Bridge rectifier (CHBR), which can be used as the primary end of high voltage high power multilevel converters, is presented. The controller is similar with the one for single phase rectifier. To improve the performance of the controller, notch filter and proportion resonance (PR) controller are employed and the discrete methods for them are discussed in detail. The different function of CHBR controller from the single rectifier is for voltage balancing. Therefore, the phase-disposition technology, which is used in the multilevel converter, is introduced to eliminate the voltage error from the expected value. With this approach, the states of the switches of the CHBR are decided correctly by the practical condition and then the DC-link capacitors of the cells are controlled to charge or discharge in the way which results to voltage balancing. The effectiveness of the proposed approach is verified by experimental results.

关键词： controllers

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A phase-disposition PWM method for DC voltage balance in cascaded h-bridge rectifier

A phase-disposition PWM method for DC voltage balance in cas...

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2010 International Conference on Electrical Machines and systems, ICEMS2010

关键词： Cascaded H-bridge rectifier Phase-disposition PWM PR controller Voltage balance

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Impact of electromechanical coupling on shaft torsional dynamics

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Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering 2010年第4期30卷 49-55页

作者： Chen, Wu-Hui Bi, Tian-Shu Yang, Qi-Xun Peng, Qian Key Lab. of Power System Protection and Dynamic Security Monitoring and Control Ministry of Edu. North China Electric Power University Beijing 102206 China State Nuclear Electric Power Planning Design and Research Institute Beijing 100094 China

The electromechanical coupling model is employed to define the all-mode shape and torsional mode shape, and deduce the linear solutions of torques. Based on the solutions of torques, mode shapes of torques and mode contribution factors of torques are defined. The above physical concepts can directly describe shaft torsional dynamics, and get more insights than the mode shapes previously defined. Moreover, the theoretical basis and the physical implications of free vibration and forced vibration models are analyzed in detail. In light of the difference between the electromechanical coupling model and the free vibration model, the deviations between the calculated and measured values are explained for mode shapes and natural torsional frequencies. The difference between the dynamics of the electromechanical coupling and forced vibration models is analyzed as well. © 2010 Chin. Soc. for Elec. Eng.

关键词： Electromechanical coupling

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Novel connection scheme of backup power supply adaptive to Distribution Line Non-Communication Protection and new criterion for high voltage and large capacity induction motor

Novel connection scheme of backup power supply adaptive to D...

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2009 Asia-Pacific power and Energy Engineering Conference, APPEEC 2009

作者： Liu, Kun Dong, Xinzhou Bo, Zhiqian State Key Lab of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing 100084 China AREVA T and D Automation Stafford ST17 4LX United Kingdom

ISBN: (纸本)9781424424870

This paper presents a new practical backup power supply connection scheme for Distribution Line Non-Communication Protection (DNCP). Simulation tests have been conducted using the Alternate Transient Program (ATP) with respect to a typical single circuit breaker multi-section system. The results prove that the new scheme is able to not only recover the power supply of loads on healthy lines automatically, but also create disturbances in favor of Accelerated Over Current (AOC) criterion. Aiming at the failure of Directional Under Voltage (DUV) criterion derived from high voltage and large capacity induction motor load, a novel criterion using the increment of reactive power is proposed. © 2009 IEEE.

关键词： Induction motors

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Novel Connection Scheme of Backup power Supply Adaptive to Distribution Line Non-Communication Protection and New Criterion for High Voltage and Large Capacity Induction Motor

Novel Connection Scheme of Backup Power Supply Adaptive to D...

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IEEE PES Asia-Pacific power and Energy Engineering Conference (APPEEC)

作者： Kun Liu Xinzhou Dong Zhiqian Bo State Key Lab of Control and Simulation of Power System and Generation Equipments Department of Electrical Engineering Tsinghua University Beijing China AREVA T&D Automation슠and Information Systems Stafford UK

This paper presents a new practical backup power supply connection scheme for distribution line non-communication protection (DNCP). Simulation tests have been conducted using the alternate transient program (ATP) with respect to a typical single circuit breaker multi-section system. The results prove that the new scheme is able to not only recover the power supply of loads on healthy lines automatically, but also create disturbances in favor of accelerated over current (AOC) criterion. Aiming at the failure of directional under voltage (DUV) criterion derived from high voltage and large capacity induction motor load, a novel criterion using the increment of reactive power is proposed.

关键词： Emergency power supplies Voltage Induction motors power system protection Circuit testing Circuit simulation system testing power system transients Circuit breakers power supplies

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