ITER极向场变流器电源短路故障分析

ITER(international thermonuclear experimental rector)极向场电源系统是ITER磁体电源系统的重要组成部分。它由晶闸管相控变流器向极向场超导线圈供电,实现各种不同运行模式下等离子体的产生、加热、平衡与控制。通过利用PSCAD(power system computer aided design)软件建立了极向场变流器电源系统的仿真模型,并利用该模型对变流器电源系统进行了各种主要短路故障的分析,得出各种短路故障的电流峰值,并总结了短路故障的分析结果。这些分析结果可为今后变流器的结构设计和短路故障保护的研究提供重要的依据和参考。

浅析ITER变流器电源控制器项目管理

针对ITER变流器电源控制器项目特点,结合项目全过程管理的理论和方法,详细介绍了项目启动、计划、执行、控制及收尾过程中有效的管理方式,对项目开展过程的设计输入、沟通管理、过程质量控制等关键问题进行讨论。最后,提出重点开展设计输入评审,建立项目问题档案,完善沟通管理机制及运用制造检测计划进行过程质量控制等解决措施和优化建议。

用DSP实现高功率因数PWM整流器的控制

PWM整流器是一种高功率因数的电源变流器采用了电流追踪型控制方式对PWM整流器进行控制,并且设计了以高性能的DSP芯片TMS320F240为核心的全数字控制系统实验证明,该控制系统具有控制灵活,精度高,动态响应好。

Enhanced control of DFIG-used back-to-back PWM VSC under unbalanced grid voltage conditions

This paper presents a unified positive-and negative-sequence dual-dq dynamic model of wind-turbine driven doubly-fed induction generator(DFIG) under unbalanced grid voltage conditions. Strategies for enhanced control and operation of a DFIG-used back-to-back(BTB) PWM voltage source converter(VSC) are proposed. The modified control design for the grid-side converter in the stationary αβ frames diminishes the amplitude of DC-link voltage ripples of twice the grid frequency,and the two proposed control targets for the rotor-side converter are alternatively achieved,which,as a result,improve the fault-ride through(FRT) capability of the DFIG based wind power generation systems during unbalanced network supply. A complete unbalanced control scheme with both grid-and rotor-side converters included is designed. Finally,simulation was carried out on a 1.5 MW wind-turbine driven DFIG system and the validity of the developed unified model and the feasibility of the proposed control strategies are all confirmed by the simulated results.

Novel control scheme for 3-phase PWM current-source converters under unbalanced source voltage conditions

Under unbalanced source voltage supply, considerable output second harmonics and input low-order harmonics in 3-phase PWM current-source converters (PWM-CSC) are generated. This paper proposes a new deadbeat controller based on compensation for unbalanced source voltage and current. With the proposed scheme, the second harmonics of the output current are eliminated and low-order harmonics of the source current are reduced effectively. Simulation and experimental results con- firmed the feasibility of the proposed method.

A novel technology for control of variable speed pumped storage power plant

Variable speed pumped storage machines are used extensively in wind power plant and pumped storage power plant. This paper presents direct torque and flux control(DTFC) of a variable speed pumped storage power plant(VSPSP). By this method both torque and flux have been applied to control the VSPSP. The comparison between VSPSP's control strategies is studied. At the first, a wind turbine with the capacity 2.2 k W and DTFC control strategies simulated then a 250 MW VSPSP is simulated with all of its parts(including electrical, mechanical, hydraulic and its control system) by MATLAB software. In all of simulations, both converters including two-level voltage source converter(2LVSC) and three-level voltage source converter(3LVSC) are applied. The results of applying 2LVSC and 3LVSC are the rapid dynamic responses with better efficiency, reducing the total harmonic distortion(THD) and ripple of rotor torque and flux.

Power Transfer of PV Inverter from DC to AC Voltage Source

This paper presents a simple approach of a topology already known in the literature, applied in active power transfer from direct current source to any alternating current voltage source, whether the utility power or a voltage inverter that is forming an isolated AC grid. The photovoltaic inverter works as current controlled voltage source inverter that provides a sinusoidal current to the AC grid. The inverter is insulated from the grid by a transformer. The system is discussed and modeled. Simulation results of this application are presented and experimental results validate this topology.

Finite Set-Model Predictive Current Control of Three-Phase Voltage Source Inverter for RES （Renewable Energy Systems） Applications

This paper focuses on a combination of three-phase VSI （voltage source inverter） with a predictive current control to provide an optimized system for three-phase inverters that control the load current. A FS-MPC （finite set-model predictive control） strategy for a three-phase VSI for RES （renewable energy systems） applications is implemented. The renewable energy systems model is used in this paper to investigate the system performance when power is supplied to resistive-inductive load. With three different cases, the evaluation of the system is done. Firstly, the robustness of control strategy under variable DC-Link is done in terms of the THD （total harmonic distortion）. Secondly, with one prediction step, the system performance is tested using different sampling time, and lastly, the dynamic response of the system with step change in the amplitude of the reference is investigated. The simulations and result analyses are carried out using Matlab/Simulink to test the effectiveness and robustness of FS-MPC for two-level VSI with AC filter for resistive-inductive load supplied by a renewable energy system.

Flexible HVDC Transformer for Next Generation Renewable Energy Industry

The growing demand on non-fossil fuel energy has escalated the desire for mega-scale renewable energy power generation, which can no longer be satisfied solely by relying on onshore renewable energy power plants. Outcomes from a recent project funded by the Sixth European Union Framework Programme （FP6）, Project ＂Upwind＂ concluded that larger offshore wind turbines （i.e., 〉 10 MW） are feasible and cost effective. It will be beneficial for such future large scale renewable energy power generators （i.e., large offshore turbines） and plant （i.e., large offshore wind farms） to have a dedicated high efficiency, robust, flexible and low cost power collection, transmission and distribution technology. Proposed in this paper is a compact and effective hybrid HVDC （high voltage direct current） transformer that allows realisation of a highly robust and financially rewarding next generation multi-terminal HVDC system for future offshore renewable energy power plant. This concept, potentially, allows the elimination or minimisation of the need for a centralised local offshore HVDC platform or substation in each wind farm, solar farm, or tidal farm. This paper discusses the study outcome of the proposed hybrid HVDC transformer and the application of a multi-terminal HVDC system in the renewable energy industry, compared to the existing HVAC and VSC （voltage source converters） type HVDC systems.

微电网建设中的模型与应用(一)

分散而断续的发电是电力产业变化的一个重要发展方向,随着新能源的发展使电网变得更加复杂,微电网便是其中之一。微电网是由风、光等发电装置,加上开关电源变流器、由PC等控制器进行管理,与市电网并联后形成双电源、双向能流,并能完善运行、保护的小型电力系统。本文系统阐述了微电网的发展、含义、特征、运行和控制,重点对微电网变流器工作原理进行分析。

微电网建设中的模型与应用(二)

分散而断续的发电是电力产业变化的一个重要发展方向,随着新能源的发展使电网变得更加复杂,微电网便是其中之一。微电网是由风、光等发电装置,加上开关电源变流器、由PC等控制器进行管理,与市电网并联后形成双电源、双向能流,并能完善运行、保护的小型电力系统。本文系统阐述了微电网的发展、含义、特征、运行和控制,重点对微电网变流器工作原理进行论述。