Power Electronics Research Research Articles

MMC-HVDC Simulation and Testing Based on Real-Time Digital Simulator and Physical Control System

Real-time simulation of modular multilevel converter (MMC)-based HVDC is one of the most important and difficult technologies in the area of utility-scale power electronics research. This paper describes an efficient modeling approach for real-time simulation of MMC-HVDC. Taking advantages of the full parallel architecture of the field-programmable gate array (FPGA), more than 1500 submodules are able to be simulated in a single FPGA. The design details of the physical MMC control system are also presented. The presented MMC-HVDC real-time simulator and physical control system are successfully performed in the Nan-ao Island MMC-HVDC project, which is the world’s first three-terminal MMC-HVDC system for research on operation and fault characteristics. The results validate the accuracy of proposed approach and real-time MMC simulator.

Characteristics Analysis and Simulation Testing on Modular Multilevel Converter VSC-HVDC Based on RTDS

Real-time simulation on the Modular Multilevel Converter (MMC) VSC-HVDC is one of the most important and difficult technologies in the area of power electronics research. After introduction and analysis on the RTDS simulation technologies for MMC VSC-HVDC study, this paper sets up the simulation model for MMC VSC-HVDC with inter control and researches on its operation and fault characteristics. Moreover, the simulation and testing system for MMC VSC-HVDC with physical control is also set up. The testing result should that, the voltage balancing method and phase disposition (PD) control strategy of the physical MMC control system perform well duing the test.

Survey on Reliability of Power Electronic Systems

With wide-spread application of power electronic systems across many different industries, their reliability is being studied extensively. This paper presents a comprehensive review of reliability assessment and improvement of power electronic systems from three levels: 1) metrics and methodologies of reliability assessment of existing system; 2) reliability improvement of existing system by means of algorithmic solutions without change of the hardware; and 3) reliability-oriented design solutions that are based on fault-tolerant operation of the overall systems. The intent of this review is to provide a clear picture of the landscape of reliability research in power electronics. The limitations of the current research have been identified and the direction for future research is suggested.

Growth and Trends of Power Electronics Research Literature (2001-2010)

This paper deals with the scientometric analysis on Power Electronics. The data is taken from the IEL database by using the keyword “Power Electronics” for search. The data were extracted from the IEL database for the period of 10 years from 2001 to 2010. This study was based of 109661 articles. The paper illustrates authorship pattern, growth of publications, source-wise distribution, authorship affiliation, title-wise distribution etc.

Study of a multiphase interleaved step-up converter for fuel cell high power applications

Abstract This paper presents a study of a high power dc distributed system supplied by a fuel cell generator. A proposed parallel power converter with interleaving algorithm is chosen to boost a low dc voltage of fuel cell to a dc bus utility level. The present interleaved step-up converters are composed of two and four identical boost converters connected in parallel. Converters are controlled by interleaved switching signals, which have the same switching frequency and the same phase shift. By virtue of paralleling the converters, the input current can be shared among the cells or phases, so that high reliability and efficiency in power electronic systems can be obtained. In addition, it is possible to improve the system characteristics such as maintenance, repair, fault tolerance, and low heat dissipation. During the past decade, power electronics research has focused on the development of interleaved parallel converters. For an interleaving technique with a real fuel cell source, this work is the first presentation; it is not just a fuel cell simulation. So, the design and experimental verification of 1.2-kW prototype converters at a switching frequency of 25 kHz connected with a NexaTM PEM fuel cell system (1.2-kW, 46-A) in a laboratory is presented. Experimental results corroborate the excellent system performances. The fuel cell ripple current can be virtually reduced to zero. As a result, the fuel cell mean current is nearly equal to the fuel cell rms current.

A DSP- and FPGA-Based Industrial Control With High-Speed Communication Interfaces for Grid Converters Applied to Distributed Power Generation Systems

New energy concepts such as distributed power generation systems (DPGSs) are changing the face of electric distribution and transmission. Power electronics researchers try to apply new electronic controller solutions with the capacity of implementing new and more complex control algorithms combined with internal high-speed communication interfaces. Thus, it is possible to monitor, store, and transfer a large number of internal variables that can be sent online to local or remote hosts in order to take new set points of different generation units. With this objective, this paper presents the design, implementation, and test of an industrial multiprocessor controller based on a floating-point digital signal processor (DSP) and a field-programmable gate array, which operate cooperatively. The communication architecture, which has been added to the proposed electronic solution, consists of a universal serial bus (USB), implemented with a minimum use of the DSP core, and a controller area network (CAN) bus that permits distributed control. Although the proposed system can be readily applied to any DPGS, in this paper, it is focused on a 150-kVA back-to-back three-level neutral-point-clamped voltage source converter for wind turbine applications.

Modeling And Circuit-based Simulation Of Photovoltaic Arrays

This paper presents an easy and accurate method of modeling photovoltaic arrays. The method is used to obtain the parameters of the array model using information from the datasheet. The photovoltaic array model can be simulated with any circuit simulator. The equations of the model are presented in details and the model is validated with experimental data. Finally, simulation examples are presented. This paper is useful for power electronics designers and researchers who need an effective and straightforward way to model and simulate photovoltaic arrays.

Electric and Physical Chacteritics of a SiC-PiN Diode for High-Power Devices

Electric and Physical Chacteritics of a SiC-PiN Diode for High-Power Devices Nam-Oh Kim and Wan-Ki Min Department of Electricity, Chosun College of Science & Technology, Gwangju 501-759 Kyung-Min Sung Department of Electrical and Electronic Systems Engineering, Ibaraki National College of Technology, Ibaraki 312-8508, Japan Kazuma Suzuki Department of Arti cial System Science, Chiba University, Japan Yasunori Tanaka and Hiromichi Ohashi National Institute of Advanced Industrial Science and Technology Power Electronics Research Center, Japan (Received 26 February 2008) This paper is presented on a 2.5-kV silicon-carbide (SiC) PiN diode with a silicon injection enhancement gate transistor (IEGT) in an inductively loaded chopper circuit. The experimental switching characteristics of the SiC-PiN diode are presented under a DC 1200 V bias voltage and 40 A cuto current. Experimental results show that the reverse recovery time and the IEGT turn-on loss are signi cantly reduced by the combination of the SiC-PiN diode and the IEGT. To reduce switching losses and investigate the limitation of the switching frequency in high power converters, we newly present the design concept of an IEGT combined with a SiC-PiN diode. The proposed design concept is evaluated based on a device simulation. The result of the device simulation yields the possible switching frequency by using the comprehensive total devices loss in the test circuit. PACS numbers: 78.40.F, 78.55.F, 73.40.V

Control electronic platform based on floating-point DSP and FPGA for a NPC multilevel back-to-back converter

Modern energy concepts as Distributed Power Generation are changing the appearance of electric distribution and transmission and challenging power electronics researchers, which try to develop new solutions of electronic controllers. The aim is to enable the implementation of new and more complex control algorithms to verify the last standards related to the grid energy quality for new power converters, and, also, for equipments which nowadays are operating. This paper presents the design, implementation and test of a novel real-time controller for a Neutral Point Clamped (NPC) (three-level) multilevel converter based on a floating-point Digital Signal Processor (DSP) and on a Field-Programmable Gate Array (FPGA), by operating in a cooperative way. Although the proposed system can be readily applied to any power electronic application, in this work, it is focused on the next system: a 150 kVA back-to-back three-level NPC Voltage Source Converter (VSC) for wind power applications.

PWM Converter Power Density Barriers

Power density of power electronic converters in different applications has roughly doubled every 10 years since 1970. Behind this trajectory was the continuous advancement of power semiconductor device technology allowing an increase of converter switching frequencies by a factor of 10 every decade. However, today's cooling concepts, and passive components and wire bond interconnection technologies could be major barriers for a continuation of this trend. For identifying and quantifying such technological barriers this paper investigates the volume of the cooling system and of the main passive components for the basic forms of power electronics energy conversion in dependency of the switching frequency and determines switching frequencies minimizing the total volume. The analysis is for 5 kW rated output power, high performance air cooling, advanced power semiconductors, and single systems in all cases. A power density limit of 28 kW/dm3@300 kHz is calculated for an isolated DC-DC converter considering only transformer, output inductor and heat sink volume. For single-phase AC-DC conversion a general limit of 35 kW/dm3 results from the DC link capacitor required for buffering the power fluctuating with twice the mains frequency. For a three-phase unity power factor PWM rectifier the limit is 45 kW/dm3@810 kHz just taking into account EMI filter and cooling system. For the sparse matrix converter the limiting components are the input EMI filter and the common mode output inductor; the power density limit is 71 kW/dm3@50 kHz when not considering the cooling system. The calculated power density limits highlight the major importance of broadening the scope of research in power electronics from traditional areas like converter topologies, and modulation and control concepts to cooling systems, high frequency electromagnetics, interconnection technology, multi-functional integration, packaging and multi-domain modeling and simulation to ensure further advancement of the field along the power density trajectory.

DESIGN, MODELING, TESTING, AND SPICE PARAMETER EXTRACTION OF DIMOS TRANSISTOR IN 4H-SILICON CARBIDE

In this paper, an analytical model for a vertical double implanted metal-oxide semiconductor (DIMOS) transistor structure in 4H-Silicon Carbide ( SiC ) is presented. Simulation for transport characteristics of the SiC MOSFET with the exact device geometry is carried out using the commercial device simulator MEDICI. A rigorous experimental testing and characterization is done on a 4H- SiC DIMOS transistor test device. SPICE parameters are extracted from the measurements, and a SPICE model for the DIMOS transistor has been developed. The presented work is a part of team efforts of material, device, and power electronics researchers at the University of Tennessee and Oak Ridge National Laboratory.

Power electronics R&D funded in the UK by SERC and DTI

The most prominent UK government support for power electronics research originates from the Department of Trade and Industry (DTI) and the Science and Engineering Research Council (SERC). The importance of the power electronics sector in the UK was recognised in 1989 by the establishment of a dedicated LINK programme. This LINK programme is jointly funded by SERC and DTI and is entitled Power Electronic Devices and Derived Systems (PEDDS). A number of important projects have been supported under this programme, some of which are already completed, and further proposals are being considered. The author discusses the motor drives, power supplies, devices and process control applications which have been finded by the LINK PEDDS programme.

Serious Research and Undergraduate Projects in Power Electronics

Research is being carried out at Loughborough University to produce a range of solid state power supplies for high frequency induction heating applications. The research is based mainly on current and voltage fed inverters. This paper describes a cycloconverter built by an undergraduate project to complement the major research activity.