scholarly journals Analysis of Symmetric Dual Switch Converter under High Switching Frequency Conditions

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2183
Author(s):  
Yu Tang ◽  
Dekai Kong ◽  
Haisheng Tong
Keyword(s):  
High Frequency ◽  
Low Voltage ◽  
Low Frequency ◽  
High Gain ◽  
Operating Conditions ◽  
Switching Frequency ◽  
Operating Characteristics ◽  
Frequency Condition ◽  
High Switching Frequency ◽  
Parasitic Parameters

Electric vehicle batteries have the problem of low output voltage, so the application of a high-gain converter is a research hotspot. The symmetrical dual-switch high gain converter has the merits of simple structure, low voltage and current stress, and low EMI. Due to the deterioration of circuit performance caused by circuit parasitic parameters under high frequency operating conditions, the former analysis under low frequency condition cannot satisfy the requirements for performance evaluation. To clarify whether the symmetrical dual-switch high-gain converter can maintain its operating characteristics under high-frequency operating conditions, this paper establishes the converter model considering parasitic parameters, and deduces the sneak circuit modes at high frequency. The effects of parasitic parameters at high frequency on voltage gain, switch stress, and symmetrical operating are analyzed, which is beneficial for the selection and optimization of power devices. This paper believes that considering parasitic parameters may reduce the output gain of the symmetrical double-switch high-gain converter considering parasitic parameters under high frequency conditions, increase the switching stress, and affect the symmetry of the circuit operation when the parasitic parameter values are different. Finally, an experimental platform rated on 200 W with 200 kHz switching frequency is established, and experimental verification is given to verify the analysis.

scholarly journals Insulation Life Span of Low-Voltage Electric Motors—A Survey

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1738
Author(s):  
Vanessa Neves Höpner ◽  
Volmir Eugênio Wilhelm
Keyword(s):  
Life Span ◽  
Electric Motor ◽  
Low Voltage ◽  
Frequency Converter ◽  
Rate Of Change ◽  
High Rate ◽  
Switching Frequency ◽  
Electric Motors ◽  
Frequency Converters ◽  
High Switching Frequency

The use of static frequency converters, which have a high switching frequency, generates voltage pulses with a high rate of change over time. In combination with cable and motor impedance, this generates repetitive overvoltage at the motor terminals, influencing the occurrence of partial discharges between conductors, causing degradation of the insulation of electric motors. Understanding the effects resulting from the frequency converter–electric motor interaction is essential for developing and implementing insulation systems with characteristics that support the most diverse applications, have an operating life under economically viable conditions, and promote energy efficiency. With this objective, a search was carried out in three recognized databases. Duplicate articles were eliminated, resulting in 1069 articles, which were systematically categorized and reviewed, resulting in 481 articles discussing the causes of degradation in the insulation of electric motors powered by frequency converters. A bibliographic portfolio was built and evaluated, with 230 articles that present results on the factors that can be used in estimating the life span of electric motor insulation. In this structure, the historical evolution of the collected information, the authors who conducted the most research on the theme, and the relevance of the knowledge presented in the works were considered.

Analysis of Fast-Scale Bifurcation in Peak Current Controlled Buck-Boost Inverter Based on Unified Averaged Model

2016 ◽  
Vol 26 (05) ◽  
pp. 1650074 ◽  
Author(s):  
Hao Zhang ◽  
Shuai Dong ◽  
Weimin Guan ◽  
Ye Liu
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Period Doubling ◽  
Current Control ◽  
High Frequency Oscillation ◽  
Switching Frequency ◽  
Unified Framework ◽  
Frequency Oscillation ◽  
Peak Current ◽  
Averaged Model

In this paper, a unified averaged modeling method is proposed to investigate the fast-scale period-doubling bifurcation of a full-bridge integrated buck-boost inverter with peak current control. In order to increase the resolution of the conventional classic averaged model to half the switching frequency, sample-and-hold effect of inductor current is absorbed into the averaged model, i.e. the proposed unified averaged model can capture the high-frequency dynamical characteristics of the buck-boost inverter, which is both an extension and a modification of conventional averaged model. Based on the unified mode, fast-scale bifurcation is identified, and the corresponding bifurcation point is predicted with the help of the locus movement of all the poles, and their underlying mechanisms are revealed. Detailed analysis shows that the occurrence of high-frequency oscillation means fast-scale bifurcation, while the occurrence of low-frequency oscillation leads to slow-scale bifurcation. Finally, it is demonstrated that the unified averaged model can provide not only a general method to investigate both the slow- and fast-scale bifurcations in a unified framework but also a quite straightforward design-oriented method which can be directly applicable.

Seismic effects of the MILROW and CANNIKIN nuclear explosions

1972 ◽  
Vol 62 (6) ◽  
pp. 1411-1423 ◽  
Author(s):  
E. R. Engdahl
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Test Site ◽  
High Gain ◽  
High Yield ◽  
Upper Crust ◽  
Seismic Effects ◽  
Underground Nuclear Explosions ◽  
Low Level ◽  
Nuclear Explosions

abstract Seismic effects of the underground nuclear explosions MILROW (October 1969, about 1 megaton) and CANNIKIN (November 1971, under 5 megatons) were monitored by a network of continuously recording, high-frequency, high-gain seismographs located on Amchitka and nearby islands. Each explosion was immediately followed by hundreds of small, discrete events (mB < 4), of similar focal mechanism and with a characteristic low-frequency signature, which were apparently related to the deterioration of the explosion cavity. This activity intensified, then terminated within minutes of a large, complex multiple event and concurrent formation of a surface subsided area that signaled complete collapse of the explosion cavity (MILROW, 37 hr; CANNIKIN, 38 hr). A number of small explosion-stimulated tectonic events, apparently unrelated to the collapse phenomenon, occurred intermittently for several weeks following each explosion—near the explosion cavity and up to 13 km southeast of CANNIKIN ground zero along the Island. These events were confined to the upper crust of the Island, had characteristic high-frequency signatures, and, near the Rifle Range Fault, had focal mechanisms which could be correlated with pre-existing faulting. The evidence points to a short-term interaction of the explosions with local ambient tectonic stresses. Because these stresses are of relatively low level on Amchitka, the observed seismic effects were significantly less extensive and smaller than similar effects reported from high-yield explosions at the Nevada Test Site. Continuous monitoring of the natural seismicity of the Amchitka region since 1969 has not revealed other evidence for an interaction between either MILROW or CANNIKIN and natural tectonic processes. The structural stability and apparent low level of stress in the upper crust of Amchitka suggest that the Island effectively is seismically decoupled from the active subduction zone below.

Evaluation of Low Cost, High Temperature Die and Substrate Attach Materials for Silicon Carbide (SiC) Power Modules

2018 ◽  
Vol 2018 (1) ◽  
pp. 000317-000325
Author(s):  
Sayan Seal ◽  
Brandon Passmore ◽  
Brice McPherson
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Operating Conditions ◽  
Acoustic Microscopy ◽  
Switching Frequency ◽  
Power Devices ◽  
Formidable Challenge ◽  
Die Attach ◽  
Power Modules ◽  
High Switching Frequency

Abstract The performance of SiC power devices has demonstrated superior characteristics as compared to conventional Silicon (Si) devices. Some of the advantages of SiC power devices over Si include higher voltage blocking capability, low specific on-resistance, high switching frequency, high temperature operation, and high power density. Thus, SiC modules are capable of processing significant levels of power within much smaller volumes compared with its Si counterparts. These high thermal loads present a formidable challenge in integrating SiC devices in power modules. For example, known-good materials and processes for silicon power modules are not rated at the aggressive operating conditions associated with SiC devices. Two of the most critical interfaces in a power electronics module are the die-attach and substrate- attach. A degradation in these interfaces often results in potentially catastrophic electrical and thermal failure. Therefore, it is very important to thoroughly evaluate die-attach materials before implementing them in SiC power modules. This paper presents the methodology for the evaluation of die attach materials for SiC power modules. Preforms of a lead-free high-temperature attach material were used to perform a die and substrate attach process on a conventional power module platform. The initial attach quality was inspected using non- destructive methods consisting of acoustic microscopy and x-ray scanning. Die attach and substrate attach voiding of < 5% was obtained indicating a very good attach quality. Cross-sectioning techniques were used to validate the inspection methods. The initial attach strength was measured using pull tests and shear tests. The measurements were repeated at the rated temperature of the module to ensure that the properties did not degrade excessively at the service temperature. At the rated module temperature of 175 °C, the die bonding strength was found to be ~ 75 kg. This was only 25% lower than the strength at room temperature. In addition, the contact pull strength was measured to be > 90 kg at 175 °C, which was 25% lower than the value measured at room temperature. The effect of power cycling and thermal cycling on the quality and strength of the die and substrate attach layers was also investigated.

scholarly journals A Fractional-Order Element (FOE)-Based Approach to Wireless Power Transmission for Frequency Reduction and Output Power Quality Improvement

Electronics ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 1029 ◽  
Author(s):  
Guidong Zhang ◽  
Zuhong Ou ◽  
Lili Qu
Keyword(s):  
Fractional Order ◽  
High Frequency ◽  
Power Efficiency ◽  
Power Transmission ◽  
Switching Frequency ◽  
Wireless Power ◽  
Wireless Power Transmission ◽  
High Switching Frequency ◽  
Power Quality Improvement ◽  
Power Inductors

A wireless power transmission (WPT) requires high switching frequency to achieve energy transmission; however, existing switching devices cannot satisfy the requirements of high-frequency switching, and the efficiency of current WPT is too low. Compared with the traditional power inductors and capacitors, fractional-order elements (FOEs) in WPT can realize necessary functions though requiring a lower switching frequency, which leads to a more favorable high-frequency switching performance with a higher efficiency. In this study, a generalized fractional-order WPT (FO-WPT) is established, followed by a comprehensive analysis on its WPT performance and power efficiency. Through extensive simulations of typical FO wireless power domino-resonators (FO-WPDRS), the functionality of the proposed FO-WPT for medium and long-range WPT is demonstrated. The numerical results show that the proposed FOE-based WPT solution has a higher power efficiency and lower switching frequency than conventional methods.

Designing of Improved Series Resonant Inverter with FPGA Controller for Heating Applications

2020 ◽  
pp. 2150088
Author(s):  
S. Dhayanandh ◽  
S. Manoharan
Keyword(s):  
High Frequency ◽  
Switching Frequency ◽  
Zero Voltage Switching ◽  
Resonant Inverter ◽  
Series Resonance ◽  
High Switching Frequency ◽  
Series Resonant ◽  
Higher Power ◽  
Series Resonant Inverter ◽  
And Control

Intensive utilization of Induction Heating (IH) innovations can be seen in numerous areas such as manufacturing industries, domestic or house hold and medicinal applications. The development of high switching frequency switches has encouraged the structure of high frequency inverters which are the key component of IH technology. Controlling the power output in a high frequency inverter for IH application is relatively complicated. This paper focuses on designing and developing a typical series resonance inverter and control it by FPGA-based controller. A MOSFET switch-based DC to AC converter is designed and Zero Voltage Switching (ZVS)-based switching strategy is accomplished to acquire less stress on switching devices and greater conversion efficiency. In this technique, secondary switched capacitor cell was proposed for resonant inverter of high frequency. To optimize the performance of the proposed inverter, the FPGA-based control system is implemented. Higher power density is the greatest advantage of this topology. The experimental and simulation model of the proposed series resonant inverter (SRI) for heating applications is developed and simulated using MATLAB/Simulink software.

Partial Impedance Spectroscopy Tests of a 6 kW Proton Exchange Membrane Water Electrolyzer Stack

2010 ◽  
Author(s):  
Taehee Han ◽  
Hossein Salehfar ◽  
Nilesh V. Dale ◽  
Mike D. Mann ◽  
Jivan N. Thakare
Keyword(s):  
High Frequency ◽  
Proton Exchange Membrane ◽  
Low Frequency ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Frequency Range ◽  
Impedance Characteristics ◽  
Pem Electrolyzer ◽  
Exchange Membrane ◽  
Partial Current

Impedance characteristics of a 6 kW proton exchange membrane (PEM) electrolyzer stack are presented under various operating conditions. An electrolyzer stack was operated under room temperature and partial current range (0 to 80 A). The whole stack impedance spectrums were measured by three different power supply configurations. The total sweeping frequency range (0.5 Hz to 20 kHz) is divided into low frequency (0.5 to 20 Hz), middle frequency (20 Hz to 1 kHz), and high frequency (1 to 20 kHz). Each frequency range required a different measurement setup to measure the whole stack impedance data. In this study, the partial impedance spectrums at low and high frequency ranges are successfully measured and analyzed. The measured data is verified with Kramers-Kronig relations. Measurement issues at the middle frequency region are discussed.

scholarly journals Solar PV fed non-isolated DC-DC converter for BLDC motor drive with speed control

2019 ◽  
Vol 13 (1) ◽  
pp. 313
Author(s):  
G. G RajaSekhar ◽  
Basavaraja Banakar
Keyword(s):  
Control Method ◽  
Speed Control ◽  
Current Control ◽  
Operating Conditions ◽  
Switching Frequency ◽  
Bldc Motor ◽  
Solar Pv ◽  
Pv System ◽  
High Switching Frequency ◽  
Interleaved Boost Converter

<p>Brushless DC motors (BLDC) are predominantly used these days due to its meritorious advantages over conventional motors. The paper presents PV fed BLDC speeds control system. A closed-loop interleaved boost converter increases the voltage from PV system to required level. Converter for BLDC operates at fundamental switching frequency which reduces losses due to high switching frequency. Internal current control method is developed and employed for the speed control of PV fed BLDC motor by sensing the actual speed feedback. Internal current controlled PV fed BLDC drive is analyzed with increamental speed with fixed torque and decreamental speed with fixed torque operating conditions. Also the system with speed control is verified for variable torque condition. The system is developed and results are developed using MATLAB/SIMULINK software.</p><p><em> </em></p>

scholarly journals A single D.C. link Multi-level 42-sided polygonal Voltage Space Vector Generation with lower order harmonic suppression using Switched-Capacitive filter

2021 ◽  
Author(s):  
Gopakumar K
Keyword(s):  
Induction Motor ◽  
Lower Order ◽  
Low Voltage ◽  
Dynamic Performance ◽  
Low Frequency ◽  
Switching Frequency ◽  
Harmonic Suppression ◽  
Space Vector ◽  
Power Circuit ◽  
Multi Level

<div>Abstract—In this work, a multi-level 42-sided polygonal space vector structure (SVS) for suppression of lower order harmonics for Open-End Induction Motor(OEIM) drive applications is proposed. The proposed power circuit topology consists of two inverters feeding an Open-End Induction Motor from either side. The main inverter fed with a single DC link providing active power for motor operation is switched at low switching frequency. The secondary</div><div>inverter fed with a capacitive supply is switched at high frequency to suppress lower order harmonics upto 39th order, up to the base speed of operation allowing maximum utilization of the DC link. The advantages of lower order harmonic suppression in motor phase voltage, for polygonal space vector structures are combined with multi-level inverter topology. This results in lower switching losses in low frequency switching main inverter and low voltage secondary inverter. Use of a single DC link facilitates four quadrant operation of the inverter. The proposed scheme is validated for steady state and dynamic performance by experimental results.</div>

Fluctuating Pressure Generating in BWR Main Steam Lines Acoustic Excited by Safety Relief Valve Stub Pipes and Dead Legs

2010 ◽  
Author(s):  
Shiro Takahashi ◽  
Keita Okuyama ◽  
Akinori Tamura ◽  
Masaya Ohtsuka ◽  
Masaaki Tsubaki ◽  
...  
Keyword(s):  
Flow Velocity ◽  
High Frequency ◽  
Acoustic Analysis ◽  
Low Frequency ◽  
Sound Field ◽  
Acoustic Resonance ◽  
Operating Conditions ◽  
Relief Valve ◽  
Fluctuating Pressure ◽  
Main Steam

During operation, the BWR-3 steam dryer in the Quad Cities Unit 2 Nuclear Power Plant was damaged by high cycle fatigue. The dryer failure was attributed to flow-induced acoustic resonance at the stub pipes of safety relief valves (SRVs) in the main steam lines (MSLs). The acoustic resonance was considered to be generated by interaction between the sound field and an unstable shear layer across the closed side branches with SRV stub pipes. We HITACHI and CRIEPI have started a research program on BWR dryers to develop their loading evaluation methods. Moreover, it has become necessary to evaluate the dryer integrity of BWR-5 plants in particular which are the main type of BWR in Japan. In the present study, we used 1/10-scale BWR tests and analyses to investigate the flow-induced acoustic resonance and characteristics of fluctuating pressure in MSLs. The test apparatus consisted of a steam dryer, a steam dome and 4 MSLs with 20 SRV stub pipes. A finite element method (FEM) was applied for the calculation of three-dimensional wave equations in acoustic analysis. We demonstrated that remarkable fluctuating pressures occurred in high and low frequency regions. Intensity of three peaks observed in the spectrum of fluctuating pressure in MSLs was increased with St. High frequency fluctuating pressures were generated by the flow-induced acoustic resonance in the SRV stub pipes. Low frequency fluctuating pressures were excited by the acoustic resonance in the dead leg. Frequency of fluctuating pressure generating in the SRV stub pipe was changed with St. On the other hand, frequency of fluctuating pressure excited by dead leg was almost constant. Fluctuating pressure in low frequency range increased gradually with flow velocity and its intensity was roughly proportional to the square of flow velocity. The flow-induced acoustic resonance did not occur for St larger than 0.6 in the BWR MSLs for both low and high frequency ranges. Operating conditions of the BWR-5 from 100 to 115% were in the range of St larger than 0.6, so intense acoustic resonance would not occur in the BWR MSLs.

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