Modern laboratory-based education for power electronics and electric machines

The study of modern energy conversion draws upon a broad range of knowledge and often requires a fair amount of experience. This suggests that laboratory instruction should be an integral component of a power electronics and electric machines curriculum. However, before a single watt can be processed in a realistic way, the student must understand not only the operation of conversion systems but also more advanced concepts such as control theory, speed and position sensing, switching signal generation, gate drive isolation, circuit layout, and other critical issues. Our approach is to use a blue-box module where these details are pre-built for convenience, but not hidden from the students inside a black box. Recent improvements to our blue-box modules are described in this paper and include a dual-MOSFET control box with independently isolated FET devices, a triple silicon controlled rectifier control box, a discretely built, high quality pulse-width modulation inverter, a small discrete brushless dc drive system, and a high-performance computer-controlled brushless dc dynamometer motor drive system. Complete details, sufficient to allow the reader to duplicate these designs, are publicly available.     

Unified power engineering laboratory for electromechanical energy conversion, power electronics, and power systems

This paper introduces a unified power engineering laboratory capable of various experiments for power systems, power electronics, and electromechanical energy conversion. It presents a flexible hardware setup, data acquisition (DAQ), and virtual instrumentation (VI). Some features of virtual instrumentation are shown with real-time phasor diagrams, sequence component analysis, and spectral analysis of AC data. We describe the general design of a single laboratory setup, which can be used for power electronics and electromechanical energy conversion experiments independently. We also present an example of power system operations, which can be implemented by the interconnection of several laboratory stations.     

Development, implementation, and assessment of a web-based power electronics laboratory

A Web-based laboratory exercise with remote access is presented, through which a student of Electrical/Electronic Engineering is introduced in both a theoretical and practical way, to many fundamental aspects of power electronics. The system is flexible and can expand the range of laboratory exercises where full-scale laboratories are not feasible. In the electrical environment, limits can be placed on voltages and currents for safety reasons. Prelaboratory investigations allow students to take an active involvement in the learning process by addressing some challenging and critical aspects of the design before approaching the physical system. Further understanding is gained by studying the circuit in a Web-based, interactive power electronics seminar (iPES) by simulating the circuit using PSpice and then analyzing the control and feedback issues with MATLAB. In the final stage, a real power converter is tested remotely over the Web, and the cycle of design, simulation, and test is completed using Web-based tools.     

Working group on dynamic performance and modeling of DC systems andpower electronics for transmission systems. Report on test systems forAC/DC interaction studies

This working group report presents DC benchmark models tailored to AC/DC interaction. This is to encourage comparisons of the performance of different control strategies or computational tools related to various AC/DC interaction phenomena and system dynamic performance (electromechanical oscillations, AC/DC recovery problems)     

Modern electric insulating materials for the insulation systems of rotating electric machines

Modern insulation systems of turbo- and hydrogenerators, large electric machines, and traction motors based on new electric insulating materials (EIMs) produced by the JSC Elinar Holding Company (Elinar HC) are described briefly. The technical characteristics of some new EIMs are given.     

Optimal tuning of linear controllers for power electronics/power systems applications

This paper presents a new method for tuning various linear controllers such as Proportional-Integral (PI), Proportional-Integral-Derivative (PID) and Proportional-Resonant (PR) structures which are frequently used in power electronics and power system applications. The linear controllers maintain a general structure defined by the Internal Model Principle (IMP) of control theory. The proposed method in this paper is twofold. The first perspective uses the well-known concept of the Linear Quadratic Regulator (LQR) to address the problem as a regulation problem. The Q matrix of the LQR design is then finely adjusted in order to assure the desired transient response for the system. The second perspective redefines the LQR in order to add capability to address the optimal tracking problem and is then generalized to systems with more than two states. These methods are then applied to two specific examples, one in an uninterruptible power supply (UPS) inverter system and the other one in a distributed generation (DG) system. In these examples, the tuning of PR and PI controllers is studied in great detail. These proposed design methods provide an easy and algorithmic procedure without jeopardizing stability or robustness. These tuning methods can also be utilized for linear state-space realization of any power converters. Both examples are supported via simulation and the results, which confirm analytical derivations, are presented and discussed.     

Reliability planning for composite electric power systems

This paper proposes a reliability design approach using network flow technique, genetic algorithms, and Monte Carlo simulation for composite electric power systems. With increased emphasis on reliability design and cost control in electric power system planning and operation, particularly in composite electric power system, we are therefore striving to achieve an optimal reliability design solution under a reliability/cost implemented model. Because the floating-point representation is more efficient than the binary representation in genetic algorithms application, and the former also has more robust operators to locate near optimal solutions in most cases, we will employ the floating-point representation. The proposed method primarily finds out the optimal values of reliability indices for the components such that the objective function composed of interruption cost and installation cost is minimized. The reliability indices adopted include expected demand not served (EDNS) and forced outage rate (FOR). Application of the proposed method is demonstrated using a 23-bus test system.     

考虑传输线重构的电气综合能源系统分布鲁棒扩展规划模型

针对综合能源系统扩展规划模型多采用随机优化处理系统负荷需求增长不确定性问题,且场景信息缺失,易造成随机优化结果经济性与可参考性低的情况,提出一种以系统综合成本最小为目标函数、考虑传输线重构的两阶段电气综合能源系统分布鲁棒扩展规划模型.第一阶段为考虑综合能源负荷预测和传输线重构的扩展规划模型;第二阶段为计及机组调整出力与...     

Microprocessors in electric power systems

The present status of microprocessor applications in various fields of electric power systems is summarized. Special attention is directed towards development trends in the protection field where microprocessor applications are expected to cope with the increasingly stringent requirements for electric power supply reliability. Also discussed are the history, roles, design philosophy and basic schemes of microprocessor-based protective relaying systems. Only recently has their application reached a practical stage after long-term study and repeated field tests.     

An industry-university collaboration in power electronics anddrives

In 1997 Danfoss Drives A/S and the Institute of Energy Technology at Aalborg University in Denmark started an initial four-year collaboration called “The Danfoss Professor Program”. The main goal of the program is to attract more students to the multidisciplinary area of power electronics and drives by offering a world-class curriculum taught by world-class teachers. During the four years of the program distinguished professors will visit the university, giving advanced courses in their specialty areas and interacting with postgraduate students. A new curriculum in power electronics and drives is also now being implemented at the university, based on courses developed together with professors from the program. Another goal is to strengthen the research team at the university in the area by fostering new contacts and research areas. Finally, training and education of engineers in industry is a major aim of the program. After 2 1/2 yr, the Danfoss Professor Program has resulted in a significant increase in the number of students and research output of Aalborg University in the power electronics and drives area. It is beginning to be recognized world wide as a model of successful Industry/University collaboration. This paper describes the major goals, implementation and an evaluation of the program     

电力数据通信综合传输平台探讨

文章分析了电力系统各种业务对数据网络功能和带宽的要求;在比较各种数据网络组网技术后,提出了电力数据通信综合传输平台的方案;从业务网络划分、QoS定制和安全架构部署等方面阐述如何从功能、质量、安全上来保障平台实现,并指出了建设综合数据网所面对的重点和难点问题。最后依据技术演进的趋势,给出了网络平滑升级的发展策略。     

Optimal transmission expansion planning for electric power systems

This paper presents a new method for transmission expansion planning in which the utility loss revenue and the customer outage cost resulting from service outages are incorporated. A new algorithm based on the total probability formula is developed for evaluating the expected value of demand not served (EDNS) and the expected value of energy not served (EENS). These reliability indices are employed to determine the utility loss revenue curve. The system expansion cost curve is obtained by using a maximum reliability design algorithm. The optimal reliability level of a transmission expansion plan is determined by minimizing the sum of the investment cost, the utility loss revenue, and the customer outage cost. An example is presented for illustration of the proposed method.     

A distributed state estimator for electric power systems

The author develops a theoretically robust and computationally efficient distributed state estimator to solve the weighted least square state estimation problem by using distributed computation. This distributed state estimator is used in decentralized control and executes in a data communication network that is assumed to be topologically the same as and physically in parallel with the power network. Several attractive satellite functions can be obtained which include: (1) reduction of the time-skew problem; (2) freedom from the power network topological error; (3) easy identification of the unobservable states; and (4) bad data detection and identification. The computational complexity of this distributed state estimator was analyzed. This state estimator was simulated on several cases of the IEEE 30-bus system. The numerical accuracy of the simulation results is satisfactory, and the estimated computation time including the communication delay demonstrates the excellent computational performance of the distributed state estimator     

Long-term expansion planning for hydrothermal electric power systems

This paper shows some aspects of the applicability of mixed integer programming (MIP) in expansion planning for regional electric utility systems, considering both power plants and the transmission network. The hydrothermal generation system may include significant run-of-river and reservoir power stations, and also pumped storage stations. Some essential elements of the model are explained to demonstrate the MIP modelling. The application of the model to the long-term expansion planning problem of a hydrothermal power system is also described.