9,176 results
Search Results
2. Performance Analysis of Dual Three-Phase Synchronous Reluctance Motor According to Winding Configuration †.
- Author
-
Jeong, Chaelim
- Subjects
ELECTRIC inductance ,ROTORS ,TORQUE ,MACHINERY ,MANUSCRIPTS ,RELUCTANCE motors - Abstract
This manuscript examines the output characteristics of a dual three-phase synchronous reluctance motor (DT-SynRM) according to two winding arrangements under normal and half-control modes. In the case of the DT-SynRM, it can operate by using all of the dual three-phase systems (the normal control) or one of the dual three-phase systems (the half control). In this paper, conventional winding function theory (WFT) is applied, because the output characteristic can be predicted by the inductance behavior. According to the WFT, the inductance value can be affected by the winding function, the turn function, and the inverse air gap function. As a result, the rotor barrier shape as well as the winding configuration are the most important factors that have an effect on the performance of the DT-SynRM. Therefore, the effect of the rotor barrier design on the performance is analyzed when the winding configuration and control mode are different. Finally, the validity of the torque characteristic is substantiated through experimental verification. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Fault-Tolerant Control of PMSM With Inter-Turn Short-Circuit Fault.
- Author
-
Zhang, Jiayuan, Zhan, Wei, and Ehsani, Mehrdad
- Subjects
PERMANENT magnet motors ,TORQUE control ,FAULT diagnosis ,ELECTRIC drives ,SHORT circuits - Abstract
Fault diagnosis and fault tolerant (FT) control of electric drive systems have been extensively studied by many researchers. Naturally, one would like to use fault diagnosis information to improve FT control to achieve good post-fault performance while it is safe to do so. In this paper, a novel FT control method is proposed for permanent magnet synchronous motor with inter-turn short circuit fault. Given fault severity, the proposed FT control can reduce torque ripple while keeping reasonable torque output. The theoretical derivation, simulation, and experimental validation are presented in this paper. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
4. Effect of Loss and Frequency Dispersion on the Performance of Microstrip Directional Couplers and Coupled Line Filters (Short Papers)
- Author
-
B.R. Rao
- Subjects
Radiation ,Materials science ,business.industry ,Attenuation ,Condensed Matter Physics ,Directivity ,Microstrip ,Characteristic impedance ,Inductance ,Optics ,Insertion loss ,Power dividers and directional couplers ,Dielectric loss ,Electrical and Electronic Engineering ,business - Abstract
The effect of ohmic and dielectric losses, conductor thickness, and frequency dispersion on the performance of edge-coupled microstrip directional couplers and interdigital filters have been determined in this short paper. The odd- and even-mode attenuation constants due to ohmic losses in the conductor have been calculated using Wheeler's inductance formula. The theoretical results for the characteristic impedance and propagation constants are in good agreement with the experimental results of Napoli and Hughes. Among the parameters that can be calculated from this theory are the isolation, directivity, and coupling coefficients of lossy directional couplers and the midband insertion loss of interdigital filters.
- Published
- 1974
5. Definition of Nonlinear Reflection Coefficient of a Microwave Device Using Describing Function Formalism (Short Paper)
- Author
-
J. Obregon and F. Farzaneh
- Subjects
Physics ,Radiation ,business.industry ,Mathematical analysis ,Describing function ,Condensed Matter Physics ,Signal reflection ,Inductance ,Nonlinear system ,Optics ,Scattering parameters ,Nonlinear element ,Electrical and Electronic Engineering ,Reflection coefficient ,business ,Voltage - Abstract
At microwaves, it is necessary to define rigorously the large signal reflection coefficient of a nonlinear device. In this paper, the describing function concept is applied to the power waves incident on, and reflected by, a nonlinear element. This method allows us to define the nonlinear reflection coefficient (NLRC) on the power wave basis. This NRLC is then compared with that defined on the current or voltage basis. Numerical calculations applied to nonlinear elements illustrate the theoretical results.
- Published
- 1984
6. Computation of Inductance of Simple Vias Between Two Striplines Above a Ground Plane (Short Papers)
- Author
-
T.K. Sarkar and Antonije R. Djordjevic
- Subjects
Engineering ,Radiation ,business.industry ,Computation ,020208 electrical & electronic engineering ,Electrical engineering ,020206 networking & telecommunications ,02 engineering and technology ,Condensed Matter Physics ,Topology ,Inductance ,Simple (abstract algebra) ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,business ,Ground plane - Abstract
In this paper, an analysis is developed for calculating the lumped inductance of a simple via connecting two infinitely thin striplines, located above a perfectly conducting ground plane. The striplines are oriented in the same direction, and the via is assumed to be in the form of an infinitely thin vertical plate, connecting the two lines. This system is analyzed by a hybrid partial-element and circuit-theory approach. Numerical results are presented to illustrate the application of this technique.
- Published
- 1985
7. Determination of Instantaneous Powers From a Novel Time-Domain Parameter Identification Method of Non-Linear Single-Phase Circuits.
- Author
-
Montoya, Francisco G., de Leon, Francisco, Arrabal-Campos, Francisco, and Alcayde, Alfredo
- Subjects
PARAMETER identification ,DIFFERENTIAL geometry ,MAXWELL equations ,ALGEBRA ,ELECTRIC potential measurement ,REACTIVE power ,IDENTIFICATION ,ELECTRIC circuits - Abstract
This paper proposes a systematic method for the identification of the load circuit parameters (say the $\boldsymbol{R}$ , $\boldsymbol{L}$ , and $\boldsymbol{C}$ elements) based only on the information of the instantaneous voltage and current measured at the point of common coupling (pcc). Geometric Algebra (GA) and concepts of differential geometry are used to produce a rigorous mathematical framework. The identification is formulated as a multidimensional geometrical problem that is solved conveniently by means of GA. Once the passive elements of the load have been identified, the active and reactive powers can be computed from first electromagnetic principles (Maxwell Equations). The theory is general and is verified with linear and nonlinear circuits. The paper shows single-phase circuits but the theory can be extended to three-phase circuits. The method is easy to program and has shown to be very robust for all tested cases. Because of its generality, the method presented will find applications beyond electric circuits. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
8. Moment Method of Calculating Discontinuity Inductance of Microstrip Right-Angled Bends (Short Papers)
- Author
-
B. Easter and Anand Gopinath
- Subjects
Engineering ,Radiation ,business.industry ,Mathematical analysis ,Electrical engineering ,Condensed Matter Physics ,Microstrip ,Inductance ,Moment (mathematics) ,Discontinuity (geotechnical engineering) ,Insertion loss ,Magnetic films ,Electrical and Electronic Engineering ,business - Abstract
A method of estimating quasi-static discontinuity inductances in microstrip lines is outlined. Numerical results for symmetric right-angle bends are presented and compare well with experimental results.
- Published
- 1974
9. Application of Gratings in a Dielectric Waveguide for Leaky-Wave Antennas and Band-Reject Filters (Short Papers)
- Author
-
Tatsuo Itoh
- Subjects
Physics ,Waveguide filter ,Radiation ,business.industry ,Physics::Optics ,STRIPS ,Integrated circuit ,Dielectric ,Grating ,Condensed Matter Physics ,law.invention ,Inductance ,Optics ,law ,Convergence (routing) ,Electrical and Electronic Engineering ,business ,Electrical conductor - Abstract
Grating structures fabricated in inverted-strip dielectric waveguides have been used for the first time as leaky-wave antennas and band-reject filters. They are potentially useful for millimeter-wave integrated circuits. Experimental results agree reasonably well with theoretical predictions.
- Published
- 1977
10. Power Increase of Pulsed Millimeter-Wave IMPATT Diodes (Short Paper)
- Author
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R. Pierzina and J. Freyer
- Subjects
Engineering ,Radiation ,business.industry ,Electrical engineering ,Impedance matching ,Condensed Matter Physics ,Capacitance ,Inductance ,Resonator ,IMPATT diode ,Parasitic element ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Electrical impedance ,Diode - Abstract
The fabrication and encapsulation of single-drift pulsed IMPATT diodes for 73 GHz is described. The transforming properties of the parasitic inductance and capacitance demonstrate the strong influence of diode-mounting technique. The used reduced-height waveguide resonator is described theoretically, giving an indication of optimum matching between resonator and transformed diode impedance. The diodes deliver more than 10-W output power at 73 GHz with 5-percent efficiency, if they are matched to the resonator by proper parasitic.
- Published
- 1985
11. A Method for Extracting Stray Capacitance and Hysteresis Curves of Potential Transformers Based on Frequency Referring.
- Author
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Shen, Zeliang, Wang, Jingang, Yan, Xiaojun, Zhao, Pengcheng, Cui, Min, Xu, Changjian, and Cao, Xing
- Subjects
ELECTRIC capacity ,IRON ,MAGNETIC hysteresis ,ELECTRIC transformers ,CAPACITANCE measurement ,HYSTERESIS ,HYSTERESIS loop - Abstract
The Potential Transformer (PT) plays an important role in the measurement and monitoring of the power system. The accurate modeling of the PT is very important but not yet perfect. The stray capacitance will have a non-negligible effect on the performance of a PT. However, the influence of stray capacitance is rarely considered in existing models, which makes the broadband simulation performance weak and provides limited references in engineering. In this paper, a calculation method of PT stray capacitance is proposed to analyze the performance of the PT at different frequencies and extract the capacitive current of the PT port. This paper used a non-destructive method to obtain the test data of a PT, calculated the value of the stray capacitance, and drew the hysteresis loops of the iron core. A corresponding simulation model was established to predict the PT performance at different frequencies. The simulation results are in good agreement with the experimental data, which proves the accuracy of the modeling parameters. The data processing logic is clear and is easy to be simplified by programming, which makes it promising in engineering. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
12. Accurate Approximations for a Function Appearing in the Analysis of Microstrip (Short Paper)
- Author
-
E.F. Kuester
- Subjects
Physics ,Radiation ,Admittance ,Mathematical analysis ,Function (mathematics) ,Condensed Matter Physics ,Microstrip ,Inductance ,Simple (abstract algebra) ,Range (statistics) ,Electronic engineering ,Electrical and Electronic Engineering ,Electrical impedance ,Network analysis - Abstract
The function Q(x) defined in the body of the paper is approximated accurately over the entire range -1
- Published
- 1984
13. Effect of Diode Parameters on Reflection-Type Phase Shifters (Short Papers)
- Author
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K.C. Gupta and P. Wahi
- Subjects
Radiation ,Materials science ,business.industry ,Reactance ,Equivalent series inductance ,Electrical engineering ,Phase (waves) ,Condensed Matter Physics ,Capacitance ,Inductance ,Electric power transmission ,Transmission line ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Diode - Abstract
This short paper describes effects of series inductance, shunt capacitance, and resistances associated with p-i-n diodes on the performance of reflection-type digital phase shifters using a shorted transmission line behind a shunt-mounted diode. It is found that the shunt capacitance is the most dominant reactance influencing the phase shift and it increases the phase-shift value. The series inductance reduces the phase-shift value. Expressions for phase shift in various cases are presented.
- Published
- 1976
14. Linear Amplifier-Based Power-Hardware-in-the-Loop Emulation of a Variable Flux Machine.
- Author
-
Amitkumar, K. S., Thike, Rajendra, and Pillay, Pragasen
- Subjects
ELECTRIC inverters ,ELECTRIC controllers ,MACHINING ,POWER amplifiers ,FLUX (Energy) ,ELECTRIC drives - Abstract
Emulation of an electric machine allows the testing of a drive inverter and controller of an electric drive system, prior to the manufacture of a machine prototype. This paper presents the emulation of a variable flux machine (VFM). The VFM emulator system proposed in this paper uses a detailed look-up table-based machine model for the purpose of emulation. This allows the emulator to mimic all machine magnetic and geometric behaviors such as saturation and torque ripple. In addition, the machine emulator proposed in this paper uses high-performance high-bandwidth linear amplifiers as power amplifiers. This enables a high bandwidth; leading to a high accuracy machine emulation. A detailed control description for the proposed machine emulator system and a machine model look-up table data verification against a prototype machine is initially presented. Experimental results are then presented to validate the utility of the proposed VFM emulator system to emulate various machine transient behaviors at different magnetization levels. Experimental results obtained from the emulator are subsequently compared against the experimental results obtained from a prototype VFM drive to verify the emulation accuracy. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
15. Modeling and Signal Integrity Analysis of RRAM-Based Neuromorphic Chip Crossbar Array Using Partial Equivalent Element Circuit (PEEC) Method.
- Author
-
Li, Yan, Fang, Lidan, Tao, Tuomin, Li, Da, Liu, En-Xiao, Jin, Ning, Ahmed, Manareldeen, and Li, Er-Ping
- Subjects
SIGNAL integrity (Electronics) ,CIRCUIT elements ,HIGH performance computing - Abstract
This paper provides a comprehensive study of signal integrity issues in RRAM-based neuromorphic chip crossbar arrays due to interconnect parasitic. First, the parasitic parameters of the crossbar array are calculated by the partial equivalent element circuit (PEEC) method with an efficient unit-cell approach. Numerical experiments show that for a $50\times 50$ array scale, this method consumes only 1.5% of the calculation time of the commercial software based 3D model, which translates to a calculation speed up of 72 times. Moreover, the PEEC circuit simulation results match well with those of the 3D model. Then, we investigate the effects of parasitic parameters such as capacitance and inductance, as well as the feature size of the crossbar array on signal integrity. All of them will lead to corresponding changes in parasitic effects, which in turn result in the most common signal integrity issues such as crosstalk, time delay and mutual capacitive coupling induced sneak path problem. Different from other studies, the excitation used in this paper is the neural spike signal generated by the Izhikevich neuron model, which is both rich in dynamic characteristics and high in computational efficiency. Finally, based on the study we propose a simple but effective design scheme for reduction of signal distortion, which can provide valuable design guidance for neuromorphic systems to achieve high performance and high computational accuracy. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
16. Incremental Frequency Rule for Computing the Q-Factor of a Shielded TE/sub omp/ Dielectic Resonator (Short Papers)
- Author
-
Darko Kajfez
- Subjects
Physics ,Radiation ,business.industry ,Electrical engineering ,Dielectric resonator ,Condensed Matter Physics ,Microstrip ,Conductor ,Computational physics ,Inductance ,Resonator ,Q factor ,Electrical and Electronic Engineering ,business ,Electrical impedance ,Electrical conductor - Abstract
The principle of Wheeler's incremental inductance rule is applied to the TE/sub omp/ cylindrical resonator within a metal enclosure. The procedure permits one to compute the conductor losses solely from the decrease in resonant frequency when the metal walls are receded for one skin depth.
- Published
- 1984
17. Equivalent Circuit Parameters of Microstrip Step Change in Width and Cross Junctions (Short Papers)
- Author
-
A.F. Thomson, Anand Gopinath, and I.M. Stephenson
- Subjects
Engineering ,Radiation ,business.industry ,Equivalent series inductance ,Mathematical analysis ,STRIPS ,Condensed Matter Physics ,Capacitance ,Resonance (particle physics) ,Microstrip ,law.invention ,Inductance ,Set (abstract data type) ,law ,Electronic engineering ,Equivalent circuit ,Electrical and Electronic Engineering ,business - Abstract
The inductive component of the equivalent circuit of microstrip step change in width and cross junctions has been evaluated theoretically and a comprehensive set of results is presented. Experimental results for one set of step changes in width obtained using the resonant method compare well with theory.
- Published
- 1976
18. Inductance of Nonstraight Conductors Close to Ground Return Plane (Short Papers)
- Author
-
A.E. Ruehli, N. Kulasza, and J. Pivnichny
- Subjects
Physics ,Radiation ,Plane (geometry) ,business.industry ,Equivalent series inductance ,Electrical engineering ,Mechanics ,Derivation of self inductance ,Condensed Matter Physics ,Microstrip ,Kinetic inductance ,Conductor ,Inductance ,Equivalent circuit ,Electrical and Electronic Engineering ,business - Abstract
Measurement and calculation of the inductance of a nonstraight conductor close to ground return plane are considered. An equivalent circuit model solution is given, and the results are compared to measurements for a corner-type geometry. Much larger changes in inductance as a function of frequency have been observed for the corner-type geometry than for the equivalent straight-conductor geometry. The circuit model can be used to predict the inductance for other configurations.
- Published
- 1975
19. Analyzing Lossy Radial-Line Stubs (Short Papers)
- Author
-
S.L. March
- Subjects
Engineering ,Radiation ,business.industry ,Acoustics ,Input impedance ,STRIPS ,Radial line ,Condensed Matter Physics ,Microstrip ,law.invention ,Conductor ,Inductance ,law ,Electronic engineering ,Electrical and Electronic Engineering ,business ,Electrical conductor ,Stripline - Abstract
Equations for the design and analysis of Iossless radial-line stubs are available in the literature. However, when actually fabricated in microstrip or stripline, these stubs possess finite conductor loss. This attenuation must be included if these components are to be properly integrated with other lossy transmission-line elements as part of a microwave computer-aided design program, such as Super-Compact®. New equations for open-circuited radial-line stubs, which include the effects of conductor loss are presented.
- Published
- 1985
20. Discontinuity Capacitance of a Coaxial Line Terminated in a Circular Waveguide: Part II - Lower Bound Solution (Short Papers)
- Author
-
E.W. Risley
- Subjects
Physics ,Radiation ,business.industry ,Electrical engineering ,Condensed Matter Physics ,Capacitance ,Upper and lower bounds ,Microstrip ,Conductor ,Inductance ,Transmission line ,Electrical and Electronic Engineering ,Coaxial ,Atomic physics ,business ,Electrical impedance - Abstract
This calculation provides a lower bound (complementing the upper bound solution given earlier) to the discontinuity capacitance of a coaxial line terminated in a circular waveguide. A 50-/spl Omega/ 0.9525-cm (3/4-in) open-circuited coaxial termination with a solid center conductor was fabricated with center- and outer-conductor diameters of 0.82723 /spl plusmn/ 0.00005 and 1.90487 /spl plusmn/ 0.00005 cm (1 cm=0.393703 in), respectively. The measured value of capacitance of this termination at 1000 Hz was 216.4 /spl plusmn/1.0 fF, as compared with the calculated lower bound of 215.0 fF. (The upper bound for this case was 217.7 fF.)
- Published
- 1973
21. Design Validation of a Single Semiconductor-Based Marx-Generator Stage for Fast Step-Wise Arbitrary Output Waveforms.
- Author
-
Hochberg, Martin, Sack, Martin, Herzog, Dennis, Weisenburger, Alfons, and Mueller, Georg
- Subjects
PULSED power systems ,MICROPROCESSORS ,ELECTROMAGNETIC interference ,SEMICONDUCTORS ,ELECTRIC potential - Abstract
A new modular pulsed-power source with fast rise time and step-wise arbitrary output waveform generation is currently under development to drive the Gepulste Elektronenstrahlanlage device investigated at the Institute for Pulsed Power and Microwave Technology (IHM). Acknowledging the complex design procedures necessary to set up a modular pulsed-power source for voltages of up to 120 kV, this paper focuses on the circuit design for a single stage and its validation prior to the generator assembly. Using a semiconductor-based Marx generator topology, the stages are designed to have an output voltage of 1 kV with a pulse current of up to 600 A. When connected to an ohmic load, the measured current rise times are in the order of 46 ns resulting in the current rise rates of up to 10 kA/ $\mu \text{s}$ using the commercial devices. The step-wise arbitrary output waveform is created by generating the switching commands on the stage using a microprocessor and a fast optical synchronization unit. Effective stage shielding is verified by operating the stage in a 100-kV, 2.5-kA electromagnetic interference test bed. This paper presents the design considerations and the corresponding measurements. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
22. Improved Grid Impedance Compensation for Phase-Locked Loop to Stabilize the Very-Weak-Grid Connection of VSIs.
- Author
-
Li, Chuanyue, Liu, Wei, Liang, Jun, Ding, Xiaolin, and Cipcigan, Liana M.
- Subjects
PHASE-locked loops ,IDEAL sources (Electric circuits) ,SHORT circuits ,FREQUENCY synthesizers ,ELECTRON tube grids ,VECTOR control - Abstract
Voltage source inverters (VSIs) with vector control based on phase-locked loop (PLL) suffer instability when connecting to a very weak AC grid (short circuit ratio (SCR) $ < $ 1.3). The conventional inductive grid impedance compensation for the PLL by virtually reducing the grid impedance can stabilize this connection. However, the analysis in this paper indicates that its stabilization effectiveness is sensitive to grid impedance variance and, indeed, overcompensation causes the PLL instability. Therefore, in this paper, an improved grid impedance compensation for the PLL is proposed to achieve the same stabilization for very-weak-grid connection and possess a good tolerance of grid impedance variance and overcompensation. A comprehensive small-signal model of the VSI using the proposed PLL’s grid impedance compensation is derived for stability analysis and parameter design. The time-domain simulation for this VSI is built to validate the stability analysis. Comparison studies for both proposed and conventional PLL’s grid impedance compensation are conducted including the stability effectiveness, VSI performance and grid impedance variance. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
23. An Integral Fault Location Algorithm Based on a Modified T-Source Circuit Breaker for Flexible DC Distribution Networks.
- Author
-
Diao, Xiaoguang, Liu, Fei, Song, Yuan, Xu, Mengyue, Zhuang, Yizhan, and Zha, Xiaoming
- Subjects
FAULT location (Engineering) ,FLEXIBLE printed circuits ,RADIAL distribution function ,ALGORITHMS ,ELECTRIC lines ,INTEGRALS ,FAULT currents - Abstract
Flexible DC distribution networks have been widely developed because of their advantages of high efficiency, low cost, and easy access to renewable energy. However, as distribution networks have more ends than the two-terminal transmission line, it is more challenging to protect them and locate their faults. Therefore, this paper proposes a modified T-source circuit breaker to protect against DC faults. Based on the proposed circuit breaker, an integral fault location method using double-terminal asynchronous data is proposed. The accuracy of the algorithm is not affected by the fault resistance. There are no differential terms in the algorithm, which greatly reduces the sensitivity to noise. The integral algorithm can remain steady when the voltage and current are zero in oscillation and attenuation periods. This constitutes the main contribution of this paper. Finally, it is verified by simulation and experiment that the proposed circuit breaker can isolate the power source within a short time in the typical DC distribution network. Under a noise of 30 dB for simulation, the location error of the proposed algorithm is <0.4% when the fault resistance is 0.5 Ω–500 Ω. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
24. Communicated after Adjournment in Discussion of Paper M. Leblanc
- Author
-
B. A. Behrend
- Subjects
Engineering ,Differential equation ,business.industry ,Electrical engineering ,Probability density function ,Industrial and Manufacturing Engineering ,Inductance ,Electric power transmission ,Control and Systems Engineering ,Electronic engineering ,Remuneration ,Electrical and Electronic Engineering ,business ,Natural language - Abstract
n/a
- Published
- 1902
25. Analytical modelling of high‐frequency losses in toroidal inductors.
- Author
-
Zhao, Yuhu, Ming, Zhengfeng, and Han, Binbin
- Subjects
ELECTRIC impedance measurement ,FINITE element method ,EDDY current losses ,ELECTRONIC systems - Abstract
Toroidal inductors are widely used in power electronic systems. With the increasing switching frequency of power devices, the AC losses of high‐frequency inductor windings have become an issue that cannot be ignored in design. A method with low computational time cost and high accuracy is urgently needed by designers. This paper proposes a modified analytical method for winding loss calculation of toroidal inductors based on the one‐dimensional Dowell method and the two‐dimensional Ferreira method, and proposes a compensated analytical model considering the proximity effect of inter‐turn conductors of toroidal windings. The analytical method calculates the non‐linear porosity of toroidal windings, and can accurately solve the AC losses of toroidal inductors with arbitrary porosity winding encapsulation. The analytical results are in good agreement with the finite element method (FEM) and experimental data. The experimental measurement data verifies the validity of the proposed model within 1‐MHz frequency, the calculation error of the modified analytical method is less than 25%, and the calculation error of the compensated analytical model is reduced to 10%. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
26. Study on the Simulation of the EMU Body Operating Main Breaker Overvoltage and High-Voltage Side Suppression Method Based on the 3D Structure.
- Author
-
Liu, Lei, Zhang, Jianqiong, Wang, Qingfeng, Li, Xiangqiang, Tang, Xianfeng, and Qin, Qi
- Subjects
OVERVOLTAGE ,ELECTRIC multiple units ,FREQUENCIES of oscillating systems ,DISTRIBUTION (Probability theory) - Abstract
Current circuit simulation research on EMU (Electric Multiple Unit) overvoltage has focused on overvoltage amplitude distribution and the oscillation frequency of the operating main circuit breaker overvoltage. However, when studying the suppression method, the overvoltage amplitude and frequency characteristics must be considered simultaneously, and few studies have reported on the overvoltage frequency distribution. In this paper, a new simulation model of train-operational main breaker overvoltage based on the 3D structure of the EMU body was proposed, which provided guidance for the study of overvoltage suppression in operational main circuit breakers. This model simulated the transient overvoltage characteristics and distribution of the vehicle body when the train operated the main circuit breaker. The simulated results showed that the first vehicle had the highest operating overvoltage amplitude, and the fourth vehicle had the lowest. The overvoltage amplitudes of vehicles 1–4 were all above 1 kV, and the main overvoltage oscillation frequencies of each vehicle were at 0.70 MHz and 1.30 MHz. The accuracy of the distribution characteristics and spectral characteristics of the operating main breaker overvoltage was verified by static tests on trains, and the simulation was considered to be in agreement with the test. Aiming at the problem that there was no universal suppression method for the operating main breaker overvoltage, a general suppression method for the overvoltage on the high-voltage side of the EMU was studied, and an overvoltage suppression device based on a grounding inductor was proposed. The inductance parameter requirements of the suppressor were theoretically analyzed, and the validity of the design of the inductance suppressor was experimentally verified. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
27. Sensorless Position Estimation for Slotless Surface Mounted Permanent Magnet Synchronous Motors in Full Speed Range.
- Author
-
Zhao, Chen, Tanaskovic, Marko, Percacci, Federico, Mariethoz, Sebastien, and Gnos, Patrik
- Subjects
PERMANENT magnet motors ,ELECTRIC potential ,BRUSHLESS direct current electric motors ,SYNCHRONOUS electric motors - Abstract
This paper presents a scheme for rotor position estimation from standstill to nominal speed. The proposed scheme is particularly suited for surface mounted permanent magnet synchronous motors and for slotless permanent magnet synchronous motors with completely smooth cylindrical rotor, which cannot be operated with state-of-the-art sensorless methods seamlessly from standstill. At standstill and very low speed, the position is estimated by using signal injection. A systematic distortion in the position estimation that is due to asymmetries in the motor parameters is identified and compensated. The rotor polarity is identified by a special process based on the estimation of the back electromotive force (back EMF) induced by a minimal rotor motion. At high speed, the position is estimated by using a linear back EMF observer. Different observer gains are used at different speed ranges, so that the position estimate is reliable even at low speed. The combination of these two approaches enables sensorless motor control in the full speed range including standstill. Experiments demonstrate the accuracy of the proposed estimation scheme and its robustness under different thermal conditions. This paper is accompanied by two videos demonstrating sensorless operation. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
28. Resonant Switching Cell Model for High-Frequency Single-Ended Resonant Converters.
- Author
-
Lee, Kyung-Hwan and Ha, Jung-Ik
- Subjects
ZERO voltage switching ,ELECTRIC inductance ,CELLS ,DC-to-DC converters - Abstract
This paper proposes a resonant switching cell model to analyze and design the single-ended resonant dc–dc converters. The single-ended zero-voltage switching (ZVS) converters such as the Class E converter are efficient for megahertz switching because they feature low turn-on and turn-off switching losses. Also, they use only a ground-referenced switch, allowing a simple gate drive circuit. In this paper, we investigate the single-ended resonant converter with the small input inductance, whereas the conventional Class E converter has a large input inductance. The main contribution of this paper is to propose the resonant switching cell as an analytic model that simplifies the analysis and the design of the resonant dc–dc converters. Furthermore, this paper presents the design method of the resonant switching cell model for minimizing the resonant current magnitude and conduction loss while the converter maintains ZVS property. The experimental results from a 10-MHz GaN-based prototype demonstrate the feasibility and effectiveness of the analysis and design based on the proposed resonant switching cell model. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
29. Control of a Three-Phase Grid-Connected Inverter Under Non-Ideal Grid Conditions With Online Parameter Update.
- Author
-
Chowdhury, Vikram Roy and Kimball, Jonathan W.
- Subjects
ELECTRIC inverters ,PHYSICAL constants ,SYSTEM dynamics ,ELECTRIC inductance ,MICROCONTROLLERS ,COMPUTER architecture ,ARCHITECTURE - Abstract
Three-phase grid-connected inverter modeling depends on the equivalent resistance and inductance between the inverter and the grid. However, these parameters are not fixed during the operation of the inverter and vary with the operating conditions. In this paper, a new globally stable adaptive controller is proposed to estimate these values online and update the controller during its operation. A model reference adaptive system (MRAS) based on two fictitious quantities with no physical significance is utilized, namely $M = v \cdot i^*$ and $N = v^* \times i$ , where $v$ and $i$ are the steady-state values of voltage and current in synchronously rotating frame of reference. Detailed stability analysis of the proposed estimation technique has been presented using a Lyapunov energy function-based approach proving the global stability of the technique. Small-signal modeling and analysis of the proposed scheme has also been presented so as to understand the local dynamics of the system. The guidelines to select the parameter of the proposed MRAS system along with updating the controller are elaborated in this paper. Detailed simulation based on MATLAB/Simulink and PLECS, along with experimental studies through a Texas Instruments TMS320F28377S microcontroller, validates the feasibility of the proposed control architecture. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
30. Optimized Toroidal Inductors Versus Planar Spiral Inductors in Multilayered Technologies.
- Author
-
Lopez-Villegas, J. M., Vidal, N., and del Alamo, Jesus A.
- Subjects
ELECTRIC inductors ,ELECTROMAGNETIC testing ,ELECTRIC transformers ,TOROIDAL magnetic circuits ,PLANAR transistors - Abstract
This paper is aimed to compare the performance of toroidal inductors and planar spiral inductors in multilayered technologies, in terms of achievable inductance density. The optimization of planar toroidal inductors in multilayered substrates is investigated theoretically, and closed formulae are derived for their inductances as a function of geometrical parameters. The obtained model is validated by experimental results and electromagnetic simulation. From the comparison of the inductance of toroidal inductors and compact spiral inductors, a selection rule is proposed to choose the most suitable topology that leads to the most compact design. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
31. A Novel Strategy of Control Performance Improvement for Six-Phase Permanent Magnet Synchronous Hub Motor Drives of EVs Under New European Driving Cycle.
- Author
-
Chen, Long, Xu, Hao, and Sun, Xiaodong
- Subjects
SYNCHRONOUS electric motors ,PERMANENT magnets ,PERMANENT magnet motors ,COST functions ,VEHICLE models - Abstract
This paper proposes a model predictive current control (MPCC) method of six-phase permanent magnet synchronous hub motor (PMSHM) using auxiliary voltage vectors. First of all, 26 voltage vectors can be obtained from the switching states of six inverters, and 24 auxiliary voltage vectors can be generated by combining them. Second, four virtual voltage vectors can be found through the required locations, and the two vectors with the lowest cost will be selected by cost function. Then, additional current error correction module can better track the current. Finally, the proposed method is compared with the conventional MPCC method and another method with virtual voltage vectors. The innovation of this paper is that the recombination of vectors can better track and predict the current. A current error compensation module is added to reduce the error between the actual current and the predicted current. And the experimental results show that the proposed method has better performance such as smaller torque ripple and current THD both in steady and dynamic states. Finally, the strategy proposed in this paper was applied to the vehicle model through HIL test platform. The possibility of applying the strategy proposed in this paper to pure electric vehicles was verified under New European Driving Cycle (NEDC). [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
32. Robust Decoupled Outer-Control Design for Single VSC and HVDC Grid With Controller Weak AC System Interconnection.
- Author
-
Dewangan, Lokesh and Bahirat, Himanshu J.
- Subjects
ELECTRIC inductance ,VECTOR control ,STABILITY criterion - Abstract
With the increase in number of VSC based HVDC systems, it is inevitable that there would be interconnections with weak ac grids. The paper presents the analytical basis for identifying coupling in the power loops which is dependent on grid inductance and operating point by utilizing the impedance based modeling technique. The formulation is used to define an inverse-based decoupling outer-loop controller for VSC-HVDC system. The concept is extended to HVDC grids and it is shown that the gains obtained using simple inverse may lead to instability. Robust controller tuning with pole-placement and minimization of $H_\infty$ norm is presented for HVDC grids, which form a restricted feedback system. The results show that the proposed method of decoupling results in effective decoupling of the power loops over a large range of grid inductance values as compared to that with traditional vector control. The system stability is also maintained over a large range of grid inductance values and PLL gains when a sudden variation of parameters is considered. The stability margins can be enhanced by pole-placement. The observations from the small-signal models are confirmed using detailed time-domain simulations. The proposal is expected to be useful in controller design for single VSC as well as HVDC grids, especially, during planing stage. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
33. Analysis of the Unsymmetrical Operation of the DC/DC MMC Considering the DC-Link Impedance.
- Author
-
Razani, Ramin and Mohamed, Yasser
- Subjects
VOLTAGE control ,STRAY currents ,COMPARATIVE studies - Abstract
This paper analyzes the unsymmetrical operation of the dc/dc MMC caused by parametric uncertainty. The unsymmetrical operation is referred to as the condition in which parameters involved in ac power generation are not equal in the phase-legs of the converter. Because existing models in the literature cannot exhibit the unsymmetrical operation of the dc/dc MMC, new detailed and simplified steady-state models are developed in this paper. In the developed models, the connection between the operation of different phase-legs shows itself when the dc-link impedance is considered. Using the developed models, the parameters that can force the converter to operate in unsymmetrical conditions are identified, and the maximum variation that the converter can tolerate is found. It is shown that even a small parameter variation leads to the leakage of the ac circulating current into the dc-link, which is not acceptable. By conducting various case studies, the impacts of the dc-link length, the transmitted power, and the conversion ratio on the unsymmetrical operation of the dc/dc MMC are characterized. The results showed that the converter would be more sensitive to the parameter variation as these parameters increase. Comparative analysis and simulation results confirm the validity and effectiveness of the presented models and analysis method. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
34. Coreless AFPM Pulsed Alternator With Low Internal Inductance.
- Author
-
Sezenoglu, Ceyhun and Balikci, Abdulkadir
- Subjects
LINEAR induction motors ,CAPACITORS ,ELECTRIC inductance measurement ,ALTERNATING current generators ,STATORS - Abstract
The linear induction launcher consists of two parts: the barrel section and the projectile section. The barrel contains of a long coaxial sectionalized group of coils that are energized by a capacitor bank or generator sets. This paper deals with the design, implementation, and experimental test of a coreless axial-flux permanent magnet (AFPM) pulsed alternator with a flywheel system as an energy source for linear induction coil launchers. The proposed coreless AFPM generator has a low internal inductance and resistance of stator windings without compensation windings when compared with the conventional iron core machines. This paper describes the coreless AFPM generator configuration and shows the simulation findings. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
35. A Study on the Synchronous Reluctance Motor Design for High Torque by Using RSM.
- Author
-
Lee, Jae-Kwang, Jung, Dong-Hoon, Lim, Jongsuk, Lee, Ki-Doek, and Lee, Ju
- Subjects
RELUCTANCE motors -- Design & construction ,TORQUE ,ELECTRIC power consumption ,ENERGY development ,SYNCHRONOUS electric motors - Abstract
Recently, electric power consumption has increased rapidly owing to the development of electric devices, and thus environmental problems such as global warming have come to the fore. Therefore, developed and developing countries are preparing various measures to prevent global warming. Minimum energy performance standards (MEPS) are one of the representative measures. MEPS is an efficiency regulation for induction motors that limits the minimum efficiency with regard to the power of the induction motors, in order to save energy. Studies have been conducted on induction motors to improve the efficiency and to satisfy MEPS. However, It is very difficult to satisfy the efficiency of induction motor for MEPS. Therefore, synchronous reluctance motors (SynRMs) are actively being studied to replace induction motors. In this paper, a SynRM is designed using a Kw-map. Moreover, to improve the output characteristics, the rib thickness of the SynRM is optimized using the response surface method. Finally, the validity of the design method, proposed in this paper is verified with a real test using the prototype. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
36. Resolution of the Paradox Concerning Energy Flow on Nonlinear Transmission Lines (Short Papers)
- Author
-
R.H. Freeman and A.E. Karbowiak
- Subjects
Physics ,Inductance ,Work (thermodynamics) ,Nonlinear system ,Radiation ,Electric power transmission ,Classical mechanics ,Mathematical model ,Transmission medium ,Electrical and Electronic Engineering ,Dissipation ,Condensed Matter Physics ,Realization (systems) - Abstract
The energy relations and the constitutive relations pertaining to a nonlinear transmission line are examined in detail. It is concluded that mathematical models which have been used in certain studies and which lead to the paradox concerning energy dissipation in the shock front are inadmissible. Correct models are free from such paradoxes. The work leads to the formulation of the hypothesis of realization: it is impossible to realize a continuous loss-free transmission medium which would be characterized by nonlinear distributed inductance L(I) and capacitance C(V), unless the medium is dispersive.
- Published
- 1973
37. Comment on 'Varactor Q Measurement' [Short Papers]
- Author
-
J.M. Roe and E.W. Sard
- Subjects
Physics ,Inductance ,Radiation ,business.industry ,Bandwidth (signal processing) ,Electrical engineering ,Electronic engineering ,Electrical and Electronic Engineering ,Condensed Matter Physics ,business ,Capacitance ,Varicap ,Electronic circuit - Published
- 1972
38. A new hybrid analytical model based on winding function theory for analysis of unbalanced two-phase induction motors.
- Author
-
Rezaee-Alam, F., Hamidi, A., and Hosseini, M.
- Subjects
INDUCTION motors ,CONFORMAL mapping ,COMPUTATIONAL electromagnetics ,FINITE element method ,MAGNETIC fields ,MAGNETIC circuits - Abstract
The purpose of this paper is to present a new Hybrid Analytical Model (HAM) based on Winding Function Theory (WFT) for electromagnetic analysis of the performance of one typical Unbalanced Two-Phase Induction Motor (UTPIM). Difierent indexes of electromagnetic modeling, such as winding distribution, slotting efiect, and magnetic saturation, can be accurately considered by using the proposed HAM. To obtain this new hybrid technique, WFT is reformulated to consider magnetic saturation in addition to the inuence of slotting and winding distribution. The Conformal Mappings (CMs) are used to calculate the slotted air-gap length accurately. The Magnetic Equivalent Circuit (MEC) model is used to consider the Magneto-Motive Force (MMF) drop in stator and rotor cores due to the excitation of one phase-winding. The results obtained from CMs and MEC are then utilized in reformulated WFT to calculate the inductances of the respective phase-winding. Transient analysis is then done to calculate the indexes of performance, such as air-gap magnetic field, phase currents, electromagnetic torque, and rotor speed, by using the lookup table of inductances while considering difierent capacitors in the auxiliary phase. In each step, the accuracy of analytical results is confirmed by comparing with corresponding results obtained from the Finite Element Method (FEM). [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
39. Simulations and Experiments of EMFY-1 Electromagnetic Launcher.
- Author
-
Ceylan, Doga, Karagoz, Mustafa, Cevik, Yasin, Yildirim, Baran, Polat, Hakan, and Keysan, Ozan
- Subjects
ELECTROMAGNETIC launchers ,CURRENT distribution ,DENSITY currents ,MAGNETIC fields ,CONSTRUCTION materials ,BREECH delivery - Abstract
ASELSAN Inc. has been conducting experimental research on electromagnetic launch technologies since 2014. The first prototype, EMFY-1, has 25 $\text {mm} \times 25$ mm square bore and 3-m-length rails. In addition, two capacitor-based pulsed-power supplies (PPSs) with 1- and 4-MJ stored energy are built to supply launcher. During the design process of EMFY-1, a 3-D finite element (FE) model has been developed to simulate the electromagnetic and mechanical aspects of the railgun. This paper presents the simulation and experimental results of EMFY-1 with C-type aluminum armature. FE model, developed using COMSOL Multiphysics, includes both launcher and the PPS system. In addition to the velocity and position of the armature with respect to time, it is possible to observe the magnetic field, current density distributions and breech voltage using the FE model. In the experiments, pulse currents of the PPS modules, breech, and muzzle voltages are measured. The velocity of the projectile is measured using the B-dot probes. In this paper, two experiments of EMFY-1 will be presented. In the first experiment, the launch package with 42-g total mass is accelerated to 2778 m/s, and in the second experiment, the launch package with 130-g total mass is accelerated to 1560 m/s. The simulation results of the proposed FE model are compared with the experiments. It is observed that there is a good agreement between experimental and simulation results. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
40. Investigation on Contribution of Inductance Harmonics to Torque Production in Multiphase Doubly Salient Synchronous Reluctance Machines.
- Author
-
Zhang, K., Li, G. J., Zhu, Z. Q., and Jewell, G. W.
- Subjects
RELUCTANCE motors ,TORQUE ,ELECTRIC inductance ,NATURAL numbers ,FOURIER series ,FOURIER analysis - Abstract
This paper investigates the contribution of each order inductance harmonic to the torque (both average torque and torque ripple) of multiphase doubly salient synchronous reluctance machines (DS-SRMs). Such machines are similar to switched reluctance machines but supplied with sine wave currents. The investigations in this paper are as follows. First, a general analytical torque model based on Fourier series analysis of inductances has been built for machines with different phase numbers, slot/pole number combinations, and also winding configurations. The instantaneous torque for DS-SRMs with any given phase number can then be accurately predicted. Using such model, contribution of each order inductance harmonic to torque can be investigated separately. It is found that the torque ripple frequency of the DS-SRM only depends on phase number. For example, for an m-phase machine, there will be m $\times $ kth-order torque ripple if mod(mk, 2) = 0, where m is the phase number and k is a natural number. This paper also explains why certain phase numbers inherently produce lower torque ripple than others. The findings in this paper provide a future direction for potential torque ripple reduction methods either from machine design or advanced control. The simulations have been validated by experiments using a six-phase DS-SRMs. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
41. Single and Power-Combined Linear E-Band Power Amplifiers in 0.12- $\mu$ m SiGe With 19-dBm Average Power 1-GBaud 64-QAM Modulated Waveforms.
- Author
-
Wagner, Eric and Rebeiz, Gabriel M.
- Subjects
ELECTRONIC amplifiers ,SILICON ,GERMANIUM ,WAVE analysis ,MODULATION theory - Abstract
This paper presents a set of wideband, fully integrated E-band power amplifiers (PAs) designed in 0.12- $\mu \text{m}$ silicon-germanium (SiGe) BiCMOS and working in the range of 60–75 GHz. The single PA is based on common-emitter (CE) driver stages followed by a CE output stage. A three-stage and four-stage versions of the single-PA as well as four- and eight-way combined variants of the four-stage PA are measured and compared. The single, four-way, and eight-way combined PAs achieve saturated output powers of 16, 19.5, and 24 dBm with peak power-added efficiencies (PAEs) of 18%, 11%, and 12%, respectively. Modulated waveforms are passed through each amplifier and data rates as high as 32 Gb/s are demonstrated for all amplifiers when driven in the linear mode. Measurements of how error-vector magnitude (EVM) and PAE degrade versus output power are presented and it is demonstrated that the eight-way combined PA can deliver 17–20 dBm of average power in a 64-quadratic-amplitude modulation, 1-Gbaud waveform (6 Gb/s), with an EVM of −32 to −24 dB and a PAE of 3%–5% without predistortion. To the author’s knowledge, this is the first paper reporting detailed measurements of PA EVM and PAE versus output power at these frequencies. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
42. Comments on “A Single-Inductor Multiple-Output Switcher With Simultaneous Buck, Boost, and Inverted Outputs”.
- Author
-
Abbasi, Majid, Afifi, Ahmad, and Pahlavani, Mohamad Reza Alizadeh
- Subjects
ELECTRIC current converters ,PULSE width modulation transformers ,ELECTRIC leakage ,ELECTRIC controllers ,RESONANT inverters - Abstract
In the paper by Patra et al., a single-inductor multiple-output switcher was presented to produce buck, boost, and inverted outputs simultaneously. Unfortunately, this study showed some unexpected mistakes, especially in state-space equations and in the calculation of output voltages. The objective of this note was to provide correct analysis and rectify the errors in this paper. Some tables and equations have been modified that were present in the initial draft of this paper. The obtained parameters in this work could be an effective supplement and extension for the original work in the paper by Patra et al. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
43. A High-Power Factor Vernier Machine With Coil Pitch of Two Slot Pitches.
- Author
-
Liu, Yue, Li, H. Y., and Zhu, Z. Q.
- Subjects
VERNIERS ,COILS (Magnetism) ,PERMANENT magnet motors ,MAGNETIC flux ,PHASE transitions - Abstract
In this paper, an 18-slot/26-pole vernier permanent magnet synchronous machine (VPMSM) with coil pitch of two slot pitches is proposed based on a nine-slot/18-flux-modulation-pole/26-pole VPMSM with concentrated tooth-coil windings. Compared with the original VPMSM, the number of slots is doubled and the phase winding connection is adjusted to reduce the space harmonic content, the phase inductance, and hence, improve the power factor. This paper shows that the proposed VPMSM increases power factor from 0.73 to 0.95 with better torque and flux-weakening capability. Moreover, a series of VPMSMs with high-power factor is proposed from the same design principle and given design guidelines. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
44. Semi-Analytical Methods for Calculation of Leakage Inductance and Frequency-Dependent Resistance of Windings in Transformers.
- Author
-
Fouineau, Alexis, Raulet, Marie-Ange, Lefebvre, Bruno, Burais, Noel, and Sixdenier, Fabien
- Subjects
ELECTRIC transformers ,LEAKAGE inductance ,ELECTRIC resistance ,WINDING machines ,MAGNETIC devices - Abstract
Leakage inductance and frequency-dependent resistance of windings are the key parameters for the design of magnetic devices. This paper focuses on analytical or semi-analytical calculation techniques to be integrated into a medium frequency transformer optimization process. To this extend, a review of the currently most used method to calculate the inductance and resistance of windings transformer is established. Based on this review, new calculation methods are developed. Magnetic field cartography is evaluated on the basis of 2-D structures thanks to a combination of Ampère’s law and the image method. From this magnetic field map, leakage inductance can be calculated. The obtained accuracy with this method is equivalent to 3-D finite-element modeling (FEM). For frequency-dependent resistance evaluation, new methods based on 2-D or 1-D approach are compared to FEM and reviewed models. An analysis of the behavior of each model is done, showing that newly developed models are more suitable in the case of a medium frequency transformer design in terms of accuracy, robustness, and calculation time. This paper could be useful to the designers of magnetic devices because newly developed models could easily be adapted to various geometries, such as toroidal structures or even inductors. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
45. Modeling and Experimental Study on Multibrick Parallel Discharge Driver Based on PEEC Method.
- Author
-
Yan, Jiaqi, Wang, Guiji, Chen, Xuemiao, Gou, Yang, Zhang, Siyu, Wang, Yanan, Shen, Saikang, Cheng, Le, Mei, Kaisheng, and Ding, Weidong
- Subjects
ISENTROPIC compression ,STRAIN rate ,ELECTRIC capacity ,MAGNETICS ,SIMULATION methods & models - Abstract
Isentropic compression experiments (ICEs) are an important method to study the dynamic characteristics of materials at pressures, temperatures, and stress or strain rate not attainable in conventional shock experiments. Yet it makes high demands toward the precise current pulse tailoring capability of the source. The China Academy of Engineering Physics is now developing a 20-brick parallel discharge driver and a 256-brick parallel discharge driver (CQ-7) to improve the performance and flexibility of compact magnetic compression devices. The load current of ICEs is tailored by optimizing the switch trigger sequence and the brick charging voltage. This paper establishes the equivalent circuit model of the 20-brick parallel discharge driver, taking the distributed inductance, resistance, and capacitance of transmission plates into account based on the partial-element equivalent circuit method. Besides, the equivalent circuit model of discharge brick based on the switch arc resistance model is also established to study the influence of key structural parameters on the output current. Furthermore, by comparing the simulation and experimental results of simultaneous discharge of 20-brick driver, the accuracy of simulation model is confirmed. This paper is of great significance to the design and optimization of multibrick parallel discharge drivers. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
46. Stability Improvement of Current Control by Voltage Feedforward Considering a Large Synchronous Inductance of a Diesel Generator.
- Author
-
Jo, Jongmin, An, Hyunsung, and Cha, Hanju
- Subjects
ELECTRIC potential ,DIESEL electric power-plants ,ENERGY storage ,ELECTROSTATICS ,ELECTRIC power plants - Abstract
In this paper, the damping ability of point of common coupling (PCC) voltage feedforward is analyzed in order to improve the stability of current control, in which interference with an LCL filter of a battery energy storage system (BESS) and synchronous inductance of a diesel generator is considered in a stand-alone microgrid. A BESS can be charged by a diesel generator when the state of charge of the battery bank is significantly insufficient and where the BESS operates with constant current constant voltage control and the diesel generator provides constant voltage constant frequency control. In this case, large synchronous when the diesel generator is in a steady state may severely cause the instability of current control. The stability analysis should be required to guarantee the paralleled operation between BESS and diesel generator. An equivalent circuit model of the diesel generator is needed to perform these processes. To bring availability of analysis, this paper considers a simple equivalent circuit model considering synchronous inductance in the steady state, and it has very large inductance corresponding 1 per unit. The resonance issue is attenuated by the damping ability of PCC voltage feedforward where it is possible to improve the stability by appropriately adjusting the gain of the voltage feedforward. The effects of the synchronous inductance and the feedforward loop are analyzed in the s-domain and z-domain. The gain of the voltage feedforward is determined to be 0.2 and 0.4 based on stability analysis. To verify the validity of the damping effect of PCC voltage feedforward, a demonstration site is constructed and the stability is verified through simulation and experiment with a full model, and total harmonic distortion of current is improved to 2.44%. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
47. The Voltage–Current Scaling Relationship and Impedance of DC Electromagnetic Launchers.
- Author
-
Engel, Thomas G. and Veracka, Michael J.
- Subjects
ELECTROMAGNETIC launchers ,PROJECTILES ,LINEAR electric motors ,LINEAR induction motors ,DYNAMICS - Abstract
Electromagnetic launchers (EMLs) including railguns, helical guns, and coilguns have been proposed for numerous applications. However, the scaling characteristics of EMLs are unknown. This paper examines the nonlinear operating characteristics of EMLs and derives the operating voltage and current scaling relationships as determined by the mass and velocity of the projectile and the length of the launcher. The scaling relationship is derived using the kinetic power relationship common to all types of EMLs. The scaling relationship is expressed as a simple function of the projectile velocity, projectile mass, and launcher length. This paper also defines the impedance of an EML. The accuracy of the scaling relationship and the EML impedance are verified in a comparison with the experimental results of practical EMLs. The effects of resistive losses and inductive energy storage on the scaling relationship are included in the analysis. [ABSTRACT FROM PUBLISHER]
- Published
- 2015
- Full Text
- View/download PDF
48. Analysis and Prevention of Commutation Failure Caused by Line Coupling Effect in LCC-HVDC.
- Author
-
Hong, Lerong, Zhou, Xiaoping, Xia, Haitao, Liu, Yifeng, Zhu, Renlong, and Chen, Yandong
- Subjects
ELECTRIC lines ,ELECTROMAGNETIC coupling ,CONSTRUCTION costs ,VOLTAGE ,POLISH people - Abstract
In actual line-commutated converter based high- voltage direct-current (LCC-HVDC) projects, multiple HVDC transmission lines are usually installed on the same tower to save transmission corridors and reduce construction costs. However, electromagnetic coupling effect between adjacent lines can cause commutation failure (CF) in the non-fault poles when a line or pole fails. Hence, this paper deeply investigates the mechanism and the prevention strategy of CFs caused by line coupling effect in single- and double-circuit HVDC systems. The influencing factors of line coupling effect and the coupling characteristics under fault conditions are analyzed first based on the modeling of parallel transmission lines and the traveling wave theory. Then the mechanism of CF caused by line coupling effect is investigated with the consideration of different fault conditions, different line structures, and different system operation modes. Based on the above analyses, prevention strategies for CFs of non-fault poles in single- and double-circuit systems are proposed. Finally, the simulation results verify the correctness of the theoretical analyses and the effectiveness of the proposed control strategies. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
49. Experimental Verification of 2.4 kVAr and 12 kVAr Prototype Variable Inductors Controlled By Virtual Air Gaps With Magnetic Orthogonality.
- Author
-
Zurek, Stan, Hall, Jeremy, Kutrowski, Tomasz, and Cheer, Andy
- Subjects
VIRTUAL prototypes ,AIR gap (Engineering) ,FLEXIBLE AC transmission systems ,MAGNETIC circuits ,MAGNETIC fields ,ELECTROMAGNETIC devices - Abstract
This paper describes experimental verification of single-phase variable inductor prototypes rated at 2.4 kVAr (75 mH, 10 A, 230 V, 24 kg) and 12 kVAr (43 mH, 30 A, 400 V, 78 kg). Results for much smaller devices rated at 1-10 Var are also shown. The variability of inductance of the main AC winding was achieved by adding a DC winding, wound through the apertures placed symmetrically in the core such that both windings were magnetically orthogonal. Local saturation caused by the magnetic field due to DC winding creates virtual air gaps. This method is capable of lowering the main inductance by over 90% if no real air gap is present, but for industrial applications the range of variability is likely to be closer to 20-30% range, depending on the size of the real air gap in the magnetic circuit. The amount of variation/control can be improved by using more than one control winding. Very good repeatability of performance was observed, with relatively small total harmonic distortion introduced due to control. The experimental findings agree with a generalised analytical model. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
50. Transition Study of Current Distribution and Maximum Current Density in Railgun by 3-D FEM–IEM.
- Author
-
Bayati, M. Sajjad, Keshtkar, Asghar, and Keshtkar, Ahmad
- Subjects
ELECTRIC charge ,FINITE element method ,ELECTROMAGNETISM ,ELECTRIC inductance ,NUMERICAL analysis ,SIMULATION methods & models ,ELECTRICAL engineering - Abstract
The intelligent estimation method (IEM) is based on approximations which can be described by the configuration and behavioral characteristic of the problem. This paper used the IEM in time domain (IEM-TD) which can be utilized to predict the current distribution and maximum current density. A detailed IEM technique to compute the current distribution over the surface of a rail, current profile around the rail, and maximum current density ( J\max) formula will be presented in this paper. The current distribution is computed for rectangular and circular rails that are shown in color figures. Finally, this paper considers the effect of the rail dimensions and material on these parameters that are shown in several figures. The results of this paper are compared to other published studies and FEM simulation. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
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