Circulating current analysis in the parallel-connected windings of synchronous generators under abnormal operating conditions

2003 ◽  
Author(s):  
A. Foggia ◽  
J.-E. Torlay ◽  
C. Corenwinder ◽  
A. Audoli ◽  
J. Herigault
Keyword(s):  
Operating Conditions ◽  
Current Analysis ◽  
Synchronous Generators ◽  
Circulating Current ◽  
Abnormal Operating Conditions

scholarly journals A Novel Hybrid LDC Converter Topology for the Integrated On-Board Charger of Electric Vehicles

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3603
Author(s):  
Vu-Hai Nam ◽  
Duong-Van Tinh ◽  
Woojin Choi
Keyword(s):  
Low Voltage ◽  
Operating Conditions ◽  
Maximum Efficiency ◽  
Battery Charger ◽  
Forward Converter ◽  
Vehicle To Grid ◽  
Circulating Current ◽  
In Series ◽  
Converter Topology ◽  
Output Capacitor

Recently, the integrated On-Board Charger (OBC) combining an OBC converter with a Low-Voltage DC/DC Converter (LDC) has been considered to reduce the size, weight and cost of DC-DC converters in the EV system. This paper proposes a new integrated OBC converter with V2G (Vehicle-to-Grid) and auxiliary battery charge functions. In the proposed integrated OBC converter, the OBC converter is composed of a bidirectional full-bridge converter with an active clamp circuit and a hybrid LDC converter with a Phase-Shift Full-Bridge (PSFB) converter and a forward converter. ZVS for all primary switches and nearly ZCS for the lagging switches can be achieved for all the operating conditions. In the secondary side of the proposed LDC converter, an additional circuit composed of a capacitor and two diodes is employed to clamp the oscillation voltage across rectifier diodes and to eliminate the circulating current. Since the output capacitor of the forward converter is connected in series with the output capacitor of the auxiliary battery charger, the energy from the propulsion battery can be delivered to the auxiliary battery during the freewheeling interval and it helps reduce the current ripple of the output inductor, leading to a smaller volume of the output inductor. A 1 kW prototype converter is implemented to verify the performance of the proposed topology. The maximum efficiency of the proposed converter achieved by the experiments is 96%.

Process Safety for Sustainable Applications

2021 ◽  
pp. 2150033
Author(s):  
Alexander Stolar ◽  
Anton Friedl
Keyword(s):  
Risk Management ◽  
Operating Conditions ◽  
Process Safety ◽  
Implementation Effort ◽  
Wide Range ◽  
System Improvement ◽  
Management Techniques ◽  
Universal Applicability ◽  
Abnormal Operating Conditions ◽  
Business Sectors

Process safety techniques have been used in industry for decades to make processes and systems safer and to optimize them, and thus to improve sustainability. Their main aim is to prevent damage to people, equipment and the environment. In this overview, process safety and risk management techniques are shown that can be applied in the different life cycle phases of an application without much implementation effort. A broad and universal applicability in a wide range of business sectors is set as the main focus. In addition to the application of system improvement techniques, a number of additional considerations, such as maintenance and the consideration of abnormal operating conditions, are included in order to be able to comprehensively improve a system or application.

Circulating Current Suppression for Parallel Three-Level Inverters Under Unbalanced Operating Conditions

2019 ◽  
Vol 7 (1) ◽  
pp. 480-492 ◽  
Author(s):  
Changwei Qin ◽  
Chenghui Zhang ◽  
Alian Chen ◽  
Xiangyang Xing ◽  
Guangxian Zhang
Keyword(s):  
Operating Conditions ◽  
Circulating Current

scholarly journals Indirect Vector-Controlled Brushless Doubly-Fed Twin-Stator Induction Generator for Wind Energy Conversion Application

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4174
Author(s):  
Mona I. Abdelkader ◽  
Ahmed K. Abdelsalam ◽  
Ahmed A. Hossameldin
Keyword(s):  
Wind Energy ◽  
Energy Conversion ◽  
Reactive Power ◽  
Operating Conditions ◽  
Velocity Variation ◽  
Induction Generator ◽  
Synchronous Generators ◽  
Wind Energy Conversion ◽  
Wide Range ◽  
Doubly Fed

Wind energy conversion systems (WECSs) seem certain to play a major part in the world’s energy future due to their known high power capacity. The maximum power tracking is unavoidable due to the wind velocity variation and the non-linear relation with the turbine mechanical power. Commercial wind turbines are commonly coupled to either doubly-fed induction generators (DFIGs), wound rotor synchronous generators (WRSG) or permanent magnet synchronous generators (PMSGs). The DFIG-based WECS has several advantages over others. One of which is the power converter in such systems only deals with rotor power, hence the converter rating can run at reduced power rating. However, DFIG has the famous disadvantage of the presence of slip rings which leads to increased maintenance costs and outage times. Hence, brushless doublyfed induction machines (BDFIMs) can be considered as a viable alternative at the penalty of complicated controller requirement and limited decoupling control capability due to the machine’s non-linearity. In this paper, an enhanced performance indirect vector controller is proposed for WECS based on brushless doubly-fed twin-stator induction generator (BDFTSIG). The presented controller offers (i) simplified implementation, (ii) decoupled active-reactive power control, and (iii) a wide range of operation. The proposed controller performance is investigated under various loading conditions showing enhanced transient and minimal steady-state oscillations in addition to complete active/reactive power decoupling. The rigorous simulation and experimental results verify the claimed controller effectiveness under all possible operating conditions for sub- and super-synchronous speed range.

scholarly journals Inter-strand Circulating Current Analysis of End-region Transposed Coil of Power Generator using 3D Multi-layer FEM

2017 ◽  
Vol 6 (6) ◽  
pp. 449-455
Author(s):  
Masafumi Fujita ◽  
Takaaki Hirose ◽  
Takashi Ueda ◽  
Hiroyuki Ishizuka ◽  
Masashi Okubo ◽  
...  
Keyword(s):  
Current Analysis ◽  
Power Generator ◽  
Circulating Current

A Solution to CT Saturation by Gregory Newton's Backward Interpolation

2011 ◽  
Vol 12 (6) ◽  
Author(s):  
Sukanta Das ◽  
Gautam Bandyopadhyay ◽  
Prasid Syam
Keyword(s):  
Operating Conditions ◽  
Discrete Wavelet ◽  
Mother Wavelet ◽  
Secondary Current ◽  
Steel Core ◽  
Protection Systems ◽  
Controller Board ◽  
Abnormal Operating Conditions ◽  
Secondary Side ◽  
Primary Current

Saturation problem in steel core Current Transformers (CTs) causes dreadful effects in protection systems as true replica of the primary current is not always reflected in CT secondary side under abnormal operating conditions. This is why detection and production of exact replica of primary current in the CT secondary side is very crucial. This paper presents a discrete wavelet transform based application using 'Daubechies3’ as mother wavelet for the detection of saturation. The compensation of saturated signal is done by Gregory Newton's Backward Interpolation (GNBI). The whole scheme of detection of CT saturation and compensation of saturated CT secondary current has been successfully tested on various saturated signals simulated in MATLAB/SIMULINK with various case studies. Finally, the scheme is validated in real time using DS1104 controller board of dSPACE. The results obtained are very encouraging.

Considerations for Training Simulations of Liquid Pipelines

2006 ◽  
Author(s):  
Brett Christie ◽  
David Norris
Keyword(s):  
Capital Cost ◽  
Operating Conditions ◽  
Pipeline System ◽  
Training Environment ◽  
Control Center ◽  
Scada System ◽  
Flow Charts ◽  
Set Up ◽  
Abnormal Operating Conditions

The use of integrated offline training simulators within the liquids pipeline community has not been widespread. Some companies opt to use a stand-alone generic pipeline simulation, which has advantages of ease of set up and offer relatively lower capital cost. They can also be effective in training on basic hydraulics under both normal and abnormal operating conditions. However, since they do not train on the actual pipeline system of the company, trainees do not learn any of the specifics of their company’s pipeline. Also, if the system is not interfaced to the pipeline SCADA system, trainees may have difficulty transferring what they have learned into their day to day control of the pipeline. This paper outlines the major considerations for ensuring that the offline training environment is as a realistic depiction of the actual pipeline control center as possible. Techniques and guidelines, such as Gap analyses, cause & effect diagrams, and flow charts are presented.

An Efficient Sensorless Slip Dependent Thermal Motor Protection Schemes Applied to Submersible Pumps

2015 ◽  
Vol 14 ◽  
pp. 75-86 ◽  
Author(s):  
Mohamed I. Abdelwanis ◽  
Fatallah Selim ◽  
Ragab Abdel-Aziz El-Sehiemy
Keyword(s):  
Induction Motor ◽  
Motor Performance ◽  
Estimation Algorithm ◽  
Operating Conditions ◽  
Motor Speed ◽  
Rotor Resistance ◽  
Three Phase ◽  
Submersible Motor ◽  
Abnormal Operating Conditions ◽  
Motor Protection

This paper proposes a sensorless procedure to estimate the induction motor speed and the dependable heat contents of the stator and rotor sides. The proposed procedure is based on the electrical models of a three phase Induction Motor (IM). The motor electrical models for normal and abnormal will be discussed and a technique is introduced for accommodating frequency dependent skin effect of the rotor resistance using a simple proposed speed estimation algorithm. The electrical models are customized from the positive and negative sequence networks. The speed detection is based on the rotor parameters slip dependent. The models are then used to analyze different operating conditions of the motor. Two thermal motor protection schemes are suggested. The first scheme is dependent on the stator side while the other scheme is developed for rotor side. The Matlab software is used for this purpose to emulate efficiently the proposed estimation procedures through a complete motor modeling which is fed from the power grid. Finally, the results provide the motor performance characteristics which involve current, torque, speed and stator/rotor temperature versus time for numerous operating conditions. It is concluded that the proposed sensorless procedure is efficient to protect the induction motors against abnormal starting as well as the overheating on either stator or rotor sides. Also, the proposed sensorless estimation for speed and temperature is reliable for submersible motor applications. The proposed schemes can be considered as costless preventive maintenance procedure.Index Terms: induction motor, slip dependent, sensorless, thermal model, abnormal operating conditions.

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