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Zhu N.,China EPRI Science and Technology Co. | Bai X.,China Electric Power Research Institute | Dong W.,China Electric Power Research Institute | Zhou Z.,State Grid Electric Power Research Institute of China
Dianwang Jishu/Power System Technology | Year: 2013

The research on DC-side voltage of active power filter (APF) are focused on how to implement the stable control of the voltage, and the minimum value of DC-side voltage of APF, by which the conditions could be met, is seldom researched. Allusion to the concrete setting of DC-side voltage of APF, referencing to the concept of voltage utilization ratio for inverters the DC-side voltage of APF under triangular PWM control and that under space vector pulse width modulation (SVPWM) control are calculated respectively, and then the difference between the two calculation results are attained. To determine conditions to be satisfied for the calculation of DC-side voltage of APF under SVPWM control, mathematical formulae describing the mechanism of action of DC-side voltages of single-phase and three-phase APFs are derived respectively, and finally the calculation formula for DC-side voltages of APF is obtained. Through a lot of simulation, the statistical optimal variation range of DC-side voltages of APF that basically copes with the result of theoretical calculation is achieved, thus the reasonableness of theoretical derivation is verified.


Wang X.,China EPRI Science and Technology Co. | Fu J.,Shanghai Municipal Electric Power Company | Teng L.,Shanghai Municipal Electric Power Company | Sun L.,China EPRI Science and Technology Co. | And 3 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2012

Based on small signal AC model of chain circuit static synchronous compensator (STATCOM), simplified STATCOM current control closed-loop system was proposed in this paper, the current regulator parameters of typical I and typical II model systems were optimized respectively, analysis shows that for current step response, the relative percentage of overshoot keeps unchanged in state of linear control, the absolute value of overshoot keeps unchanged in limiting nonlinear control state. The steady precision is a little poor but dynamic control precision is much better when applying proportional regulator to typical I model system, and it is suit for chain circuit STATCOM engineering installation. Simulation results in a-b-c coordinates show that with optimized control parameters of typical I model system the output current of chain circuit STATCOM can track reference changes fast, and the system has good stability and tracking precision. © 2012 Chinese Society for Electrical Engineering.


Wang X.,China EPRI Science and Technology Co. | Lin J.,Shanghai Municipal Electric Power Company | Teng L.,Shanghai Municipal Electric Power Company | Wang K.,China EPRI Science and Technology Co. | And 3 more authors.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2012

Mathematical model of chain circuit static synchronous compensator (STATCOM) in d-q-0 coordinates was deduced, simplified STATCOM model was proposed by linear control method. Decoupling control algorithm was designed, decoupling control model was given and simulated. Simulation results show that with optimized control parameters, 3-phase currents of chain circuit STATCOM have good tracking performance and control precision in d-q-0 coordinates, both in a-b-c coordinates and in d-q-0 coordinates current control has excellent fast tracking performance, that shows the current regulator design method and parameters setting are feasible and effective. © 2012 Chin. Soc. for Elec. Eng.


Li S.,JiangSu JianZhu Institute | Xu Y.,1687 ChangYang Road | Xu X.,China University of Mining and Technology | Zhu N.,China EPRI Science and Technology Co.
Applied Mechanics and Materials | Year: 2013

Multi-robot SLAM is a technology of multi-robot simultaneous localization and mapping cooperatively in unknown environment. We use information filters algorithm to solve multi-robot SLAM problem. Information filers use information matrix to describe the SLAM uncertain information, and multi-robot SLAM information matrix contains all robots poses and all the features observations which observed by all robots. We set up the multi-robot models, motion models and observe models, and set up feature-environment to simulation in computer. We set threshold to divide the features which are observed by robot k on current time, one part of features are used to relocalization as active maps, and the other features are used to update information matrix and information state. The simulation data shows that information filters can keep the accuracy of the robots poses, and keep the motion update and the observation update in the constant range, the algorithm improve the effective of multi-robot SLAM. © (2013) Trans Tech Publications, Switzerland.


Liu H.,China EPRI Science and Technology Co. | Zheng B.,China EPRI Science and Technology Co. | Zhan X.,China EPRI Science and Technology Co.
2016 IEEE 8th International Power Electronics and Motion Control Conference, IPEMC-ECCE Asia 2016 | Year: 2016

A passive shunt converter is usually used as an energy absorbing circuit in DVR. According to the location of passive shunt converter, DVR can be ascribed into two typical types: DVR with supply-side shunt converter and DVR with load-side shunt converter. They have differences in operation principle, comparisons focused on cost and performance between them will be helpful for the selection of system topology of DVR. In this paper, dc-link voltage range and parameter design procedure of these two types is analyzed, then a detailed comparison including inverter rating and passive converter rating between them is made under a unified compensation target. Both theoretical analysis and simulation results show that DVR with load-side passive converter has a smaller inverter rating compared to that of DVR with supply-side passive converter, thus DVR with load-side passive shunt converter has a lower cost. © 2016 IEEE.


Yang S.,China EPRI Science and Technology Co. | Wu S.,China EPRI Science and Technology Co. | Dai C.,China EPRI Science and Technology Co.
Dianwang Jishu/Power System Technology | Year: 2013

With rapid development of power grids in China, the fact that short-circuit currents exceed specified limits becomes a troubled problem. Fault current limiter (FCL) can restrict short-circuit current under the prerequisite of not changing power flow distribution in power grid, so it possesses a good application prospect. It is one of key factors influencing the application effect of FCL to recognize short-circuit fault rapidly and accurately. Based on the feature that there is abrupt change of line current during the short-circuit fault, a method to rapidly recognize fault current by use of curvature of line current waveform is proposed. An equivalent system of FCL used in 500 kV East China power grid is built by PSCAD software, and the fast fault signal recognition method based on the curvature of line current waveform is simulated by the built system. Simulation results show that the proposed method possesses the ability of recognizing abrupt change of line current and the recognition speed is fast. Finally, simulation results are verified by on-site recorded fault data come from controllable series compensation for a UHVAC transmission system project.


Zheng B.,China Electric Power Research Institute | Wu S.,China EPRI Science and Technology Co. | Dai C.,China EPRI Science and Technology Co. | Liu H.,China EPRI Science and Technology Co. | And 2 more authors.
Dianwang Jishu/Power System Technology | Year: 2013

Most of the current control for modular multilevel converters (MMC) is based on the rotating d-q coordinate system, in which the upper and lower bridge-arms are regarded as a whole to be controlled. In this paper, an individual bridge-arm current control strategy is proposed. Firstly, a switching cycle mean value model and a small signal model of single bridge arm in MMC are derived, and on this basis a closed-loop control system for bridge arm current is designed. Using such a control strategy not only the AC output current and DC current of MMC can be controlled flexibly, but also the AC circulating current between the upper and the lower bridge arms can be eliminated. Results of PSCAD/EMTDC-based simulation show that the proposed control strategy is effective and can fast respond to current control system.


Ma Q.,North China Electrical Power University | Cui X.,North China Electrical Power University | Zhang W.,North China Electrical Power University | Liu H.,China EPRI Science and Technology Co.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2013

Sparkover of the bypass gap and isolation of the disconnecting switch on the 1000 kV fixed series capacitors (FSC) platform will cause electromagnetic transient phenomena including transient overvoltage in the primary equipment circuit and induce electromagnetic interference (EMI) into the secondary circuit on the platform. To investigate the electromagnetic transient characteristics, a simulation method incorporating the 3-D finite element method (FEM) and the time-domain partial-element equivalent circuit (PEEC) was presented and verified based on the reduced-size experimental model and the life-size 1000 kV FSC experimental platform. Simulation results of the overvoltage, platform potential rise (PPR) in primary circuit and disturbance in the secondary circuit on the platform due to bypass gap sparkover and disconnecting switch operation were obtained with the method. To mitigate the overvoltage in the primary circuit on the platform due to bypass gap breakdown, a suppressing scheme was evaluated and already implemented in actual 1000 kV FSC projects. Further application aspects of simulation results were analyzed and discussed as well. © 2013 Chin. Soc. for Elec. Eng.


Meng N.,China EPRI Science and Technology Co.
2011 International Conference on Electrical and Control Engineering, ICECE 2011 - Proceedings | Year: 2011

This paper took lithium battery as the energy storage system of PV grid-connected system, which introduced two forms of energy storage system access to PV, and analyzed the power and energy management of PV-energy storage system. it has also proposed the solutions. © 2011 IEEE.


Zhao B.,China EPRI Science and Technology Co. | Guo J.,China Electric Power Research Institute | Zhou F.,China EPRI Science and Technology Co.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2012

Chain structure is widely used in static synchronous compensator (STATCOM), which is composed of several H-bridge modules with identical structure. The stability of DC voltage of each converter determines the stability of the device. This article analyzed the converter chain power equation, sets forth the basic mathematical principles to achieve DC voltage balance control among the converter chains, and put forward an averaging DC voltage control strategy based on negative sequence current. The scheme also took system unbalanced voltage into consideration. Simulation results and industrial prototype tests show the high steady-state control accuracy and excellent transient and dynamic performance of the proposed control strategy, thus proves it to be an effective solution to the chain converter DC voltage control problems. © 2012 Chin. Soc. for Elec. Eng.

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