Optimal precalculation of the position-phase current projile for current feeding a 4-phase, 4 kW switched reluctance motor, results in a single input, linear. decoupled output torque controller, which provides low torque ripple. A bicubic spline interpolation was used to model the non-linear experimental data. The algorithm is bused 011 minimizing both the average and peak current hence improves the dynamic performance of the novel six switch, current fed, igbt 4 kW, 40 kHz inverter. Test results by instuntaneous speed measurement over the speed runge 100-300 rpm, ruted torque, open-loop optimizing technique are presented,

Torque ripple reduction of switched reluctance motors by phase current optimal profiling

This paperdescribes atechnique forstabilizing theopera- tionofvariable-reluctance stepping-motor drives operating without a shaft-position sensor. Insuchsystems there isatrade-off between the systemefficiency andthetorquemargin (orpull-out torque) which depends onthewidth ofthephase conduction pulse width. Thescheme described inthepaperpermits themotortoruninthesteady state with bothnarrow conduction pulse widths andhigh efficiency. Undertransient oroverload conditions theconduction pulse width isincreased inresponse toachange inthedclinkcurrent, providing anincrease inavailable torque. Tests onasmall motordrive haveproduced asteady-state torque margin ofover300percent andof200percent understep-change conditions.

RobustTorqueControl of Switched-Relucta nce MotorsWithout a Shaft-Position Sensor

Dramatic improvements have occurred since the large AC synchronous - wound field - conventionally cooled motors went to sea on Queen Elizabeth 2, podded propulsion motors not even having been discussed. Electric propulsion motors have become smaller, better and more affordable. Electric propulsion motor drives have followed a similar trend. Subsequent improvements, in both naval and commercial ships, are almost certainly going to be implemented using the systems and technologies which offer the best Life-Cycle Cost benefits; thus ocean-going ships, including naval combatants, will continue to most affordably transport either cargo or a military mission capability.

The state-of-the-art of integrated electric power and propulsion systems and technologies on ships

Extensive research in wide-bandgap material technology such as silicon carbide (SiC) has led to the development of medium-voltage (MV) power semiconductor devices with blocking voltages of 3.3 to 15 kV. When these devices are used in various applications, they are exposed to a high peak voltage stress and a very high $dv/dt$ (50–100 V/ns). These impose stringent requirements on the gate driving stage for these devices in terms of featuring a high isolation voltage capability along with a high $dv/dt$ ruggedness, which makes it necessary to have an ultralow coupling capacitance between primary and secondary sides of the gate drivers. One of the key issues in achieving this MV insulation pertains to the necessary clearance and creepage requirements, as defined in IEC 61800-5-1 standards. While the successful operation of these gate drivers is demonstrated in MV converter applications such as solid-state transformers, and MV grid-connected inverters, substantial research needs to be carried out to improve the gate drivers’ performance and provide a plug-and-play solution. This article aims to comprehensively review these gate drivers and consolidate various required design features concerning their galvanic isolation stage, based on normal and short-circuit operation of MV high-power converter systems. Different device short-circuit protection schemes for these gate drivers are explored in detail. Additional applications and functionalities of the gate drivers, including gate drivers used in the series-connection of MV devices and intelligent gate drivers, are also provided in brief. Based on prior research, this review aims to provide design choices and guidelines for the gate drivers, accelerating the growth and deployment of MV SiC devices for field applications.

Gate Drivers for Medium-Voltage SiC Devices

High-voltage and fast-switching silicon carbide (SiC) power modules are needed to construct high-voltage and high power-density converters. Stacking multiple low-voltage SiC devices to increase the equivalent blocking voltage shows advantages in on -state resistance, current capacity, and cost over one single high-voltage device. An indirect series-connected SiC MOSFET power module using quasi-two-level hybrid-clamp topology is proposed in this article. The voltages across the devices are automatically balanced with an open-loop modulation strategy to avoid sensors and control algorithm. Moreover, only ceramic capacitors are needed besides the MOSFETs and diodes in the topology. Thanks to this, the topology was highly integrated into a power module using SiC dies, which is equivalent to a general-purpose two-level medium-voltage SiC MOSFET power module. The switching losses of the power module show advantages over other stacking methods and even a single high-voltage switch and it can be evaluated with a two-level half-bridge (HB). To achieve this, the automatic voltage-balancing performance is analyzed in detail and the parasitic output capacitance in the topology is investigated, based on which the design considerations are presented. The simulation results from LTspice confirm the voltage-balancing and a 3600V/20A HB power module is built in the lab and the experimental results verify the design.

A Quasi-Two-Level Medium-Voltage SiC MOSFET Power Module With Low Loss and Voltage Self-Balance

LLC resonant converter can help achieve soft switching for both primary side and secondary side devices, which makes it a great candidate for today’s high-frequency, high-efficiency and high power density solid state transformer (SST) applications. For cases to achieve a constant DC output voltage, it is desired that the LLC converter works in the zero-voltage-switching (ZVS) region that the switching frequency (fs) is smaller than the resonant frequency (fr). However, when a much wider frequency modulation range with ZVS guaranteed is needed to achieve a wide output voltage range and a variable load, the region that fs is larger than fr is the better choice. This region, which is rarely analyzed in the literature, is investigated in this paper. Detailed analysis for charging/discharging process during deadtime is shown. A simple but accurate model to determine fully ZVS condition in this region is proposed, which can also be used for deadtime optimization. Moreover, a 1 MHz/2 kW GaN based LLC converter prototype is built and presented for verification.

An Investigation on Fully Zero-Voltage-Switching Condition for High-Frequency GaN Based LLC Converter in Solid-State-Transformer Application

The SiC MOSFETs are replacing Si IGBTs in power electronics applications due to its several intrinsic features, such as higher temperature operation availability, higher breakdown electric field and higher switching speed. However, for the medium voltage range above 1.7 kV, the SiC MOSFETs are still at their early development stage and are not ready for commercialization. This paper presents the characterization and evaluation of 3.3 kV, 5 A SiC MOSFETs. They are the samples from GeneSiC and are not commercialized yet. Static and dynamic tests are performed for the device at different working conditions. For static tests, I-V characteristics, Rds(on) and parasitic capacitors characteristics were recorded for different temperatures. The dynamic tests were done with a Double Pulse Tester (DPT) with an inductive load up to 1.8 kV. The switching speed and switching loss are evaluated and analyzed for different conditions. A simple energy effective and charge effective Coss calculation method through DPT test results is proposed. The test results show its potential in medium voltage applications, especially in multistage cascaded topology.

Characterization and Evaluation of 3.3 kV 5 A SiC MOSFET for Solid-State Transformer Applications

Switched reluctance machines (SRMs) sidestep many of the issues with permanent magnet and induction machines and embody the lowest cost and simplest manufacturing of the motor technologies. Major drawbacks to SRMs have been (1) the need for failure-prone electrolytic capacitors, (2) large torque ripple, and (3) acoustic noise. Conventionally, these drawbacks have been addressed independently either through (1) excitation control or (2) machine design, but not as a holistic system or solution. This paper presents a design for high-efficiency low-cost SRM while producing smooth output torque and avoiding pulsating inverter input current and the associated electrolytic capacitor. We propose a comprehensive approach which combines both phase excitation control and machine design to cooperatively address the excursions of input and output powers from their average values.

Switched reluctance motor without torque ripple or electrolytic capacitors

This paper presents a wind-driven DC power generation and control system modified by a doubly fed induction generator (DFIG), which stator is connected with a full-power diode rectifier to supply DC power to a stand-alone load and rotor is connected to the DC link with a PWM converter in charge of regulation of frequency and voltage on stator side. The transient character and behavior of current, voltage and electro-magnetic torque are studied under different frequency condition as the control system responds to sudden change of the DC load. The stator flux orientation control method is applied in this paper, which d-axis rotor current is used to regulate the flux and frequency of the stator, and q-axis rotor current is used to keep the dc voltage constant. Simulation results show that frequency regulation can be realized with stator flux leakage, and meanwhile the dc voltage can be kept. Load change will cause different dc voltage variation under different frequency conditions.

Behavior of responding to sudden change of standalone dc load supplied by a DFIG with different frequency in AC side

The HFO phenomena have been frequently reported in various VSC-HVDC projects, such as the 1.7kHz oscillation incident in France-Spain end-to-end VSC-HVDC project, the 1.2kHz oscillation incident in Luxi back-to-back VSC-HVDC project, the HFO range from 250Hz to 350Hz in Borwin1 VSC-HVDC project connecting to offshore wind farms, the 1.8kHz oscillation incident in YuE back-to-back VSC-HVDC project, the high frequency oscillation ranges from 750Hz to 4000Hz in Zhangbei VSC-HVDC grid project, the 2KHz and 2.5kHz oscillation incident in Rudong offshore VSC-HVDC system. These high frequency oscillation phenomena significantly disturb the normal operation of the power system. In order to reveal the mechanism of this type of high frequency oscillation, the process of the typical high frequency oscillation and their following suppression or optimization approaches used in the VSC-HVDC projects are presented. And then, the impedance model analysis and eigenvalue analysis approach regarding the high frequency oscillation are also demonstrated. The high frequency oscillation prevention and suppression approaches are categorized based on the active and passive aspects. The effectiveness of the active filter and the passive filter are also demonstrated. Finally, the difficulties and the future research perspective of the high frequency oscillation in VSC-HVDC system are discussed. 

A review of the high frequency oscillation phenomena in VSC-HVDC power transmission system

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Jason Lai

Author Tools

Chat about Author