scholarly journals The Conducted Emission Attenuation of Micro-Inverters for Nanogrid Systems

2019 ◽  
Vol 12 (1) ◽  
pp. 151
Author(s):  
Chaiyan Jettanasen ◽  
Atthapol Ngaopitakkul
Keyword(s):  
Electric Power ◽  
Electromagnetic Interference ◽  
Electric Energy ◽  
Low Frequency ◽  
Electrical Equipment ◽  
Solar Panel ◽  
Grid System ◽  
Frequency Range ◽  
Road Lighting ◽  
Conducted Emission

Road lighting systems require a significant amount of electric energy. To compensate for the utilized energy, the concept of a nanogrid road lighting system is presented. A solar panel is installed on the top of a lighting pole to generate electric power. In this research, a photovoltaic simulator (PV simulator), which is used to simulate solar behavior such as current, voltage, and power based on temperature and solar irradiance levels, is employed to replace a solar panel. In the nanogrid system, grid-connected and stand-alone micro-inverters are employed to convert the electric power. The inverters comprise switching devices that can generate electromagnetic interference (EMI) when operating, which is harmful to the grid system and the electrical equipment. In general, EMI has been studied and reduced in electrical appliances, which only receive electric power. However, for the nanogrid system, which supplies electricity to the grid system, there is less study on the EMI topic because the usage is still not widespread. In the future, the nanogrid system will be widely used delivering high power directly into the electrical grid system. Therefore, the study and attenuation of EMI in the nanogrid system are very promising. Conducted emission (CE) is one form of EMI that flows through a cable connecting several appliances in the frequency range of 150 kHz to 30 MHz. CE of grid-connected and stand-alone micro-inverters have high levels in the low-frequency range between 150 kHz–5 MHz and then decreases steadily. CE attenuation is important for this inverter in a solar power system. This research studies the effect of CE mitigation on the nanogrid system. The result is compared with the Comité International Spécial des Perturbations Radio (CISPR) 14-1 standard. Finally, the passive EMI filter can reduce CE and meets the CISPR 14-1 standard.

Noise Test and Countermeasures Research of Locomotive Cab

2011 ◽  
Vol 317-319 ◽  
pp. 1197-1200
Author(s):  
Yan Liu ◽  
Wen Liu ◽  
Bing Yang ◽  
Xiao Pai Zhang ◽  
Ping Zhang ◽  
...  
Keyword(s):  
Low Frequency ◽  
Good Health ◽  
Electrical Equipment ◽  
Intermediate Frequency ◽  
Noise Spectrum ◽  
Channel Noise ◽  
Frequency Noise ◽  
Frequency Range ◽  
Noise Test ◽  
Analysis System

The locomotive cab noise has became an important factor in good health of the drivers through analyzing noise hazards of the locomotive cab, and the noise also can reduce working efficiency, easy to produce hidden trouble on security. Use Multi-channel Noise Test and Analysis System, measure the locomotive cab noise and analyze the results of the noise test, then get the conclusions from the noise spectrum: Locomotive cab noise occurs mainly in the low frequency range and intermediate frequency range; Wheel-rail noise and cooling room noise mainly are low frequency noise; Electrical equipment of the first locomotive cab contribute a major noise. Results of this study provide the basis for the vibration and noise reduction design of the locomotive cab.

scholarly journals Black-Box Modelling of Low-Switching-Frequency Power Inverters for EMC Analyses in Renewable Power Systems

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3413
Author(s):  
Lu Wan ◽  
Abduselam Hamid Beshir ◽  
Xinglong Wu ◽  
Xiaokang Liu ◽  
Flavia Grassi ◽  
...  
Keyword(s):  
Power Systems ◽  
Electromagnetic Interference ◽  
Low Frequency ◽  
Black Box ◽  
Switching Frequency ◽  
Frequency Range ◽  
Negative Sequence ◽  
Renewable Power ◽  
Zero Sequence ◽  
Power Inverters

Electromagnetic interference (EMI) from renewable power systems to the grid attracts more attention especially in the low-frequency range, due to the low switching frequency of high-power inverters. It is significantly important to derive EMI models of power inverters as well as to develop strategies to suppress the related conducted emissions. In this work, black-box modelling is applied to a three-phase inverter system, by implementing an alternative procedure to identify the parameters describing the active part of the model. Besides, two limitations of black-box modelling are investigated. The first regards the need for the system to satisfy the linear and time-invariant (LTI) assumption. The influence of this assumption on prediction accuracy is analysed with reference to the zero, positive and negative sequence decomposition. It is showing that predictions for the positive/negative sequence are highly influenced by this assumption, unlike those for the zero sequence. The second limitation is related to the possible variation of the mains impedance which is not satisfactorily stabilized at a low frequency outside the operating frequency range of standard line impedance stabilization networks.

scholarly journals Switching Power Suppliers Noise Reduction in Ultrasound Doppler Fluid Measurements

Electronics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 421 ◽  
Author(s):  
Stefano Ricci
Keyword(s):  
Spread Spectrum ◽  
Electromagnetic Interference ◽  
Low Frequency ◽  
Industrial Applications ◽  
Doppler Spectrum ◽  
Switching Noise ◽  
Frequency Range ◽  
Ultrasound Doppler ◽  
Front End ◽  
Spread Spectrum Modulation

Ultrasound Doppler techniques are widely employed in detecting the velocity of moving fluids both in medical and industrial applications. Echo Doppler electronics systems include a highly sensitive front-end suitable to processing the very low power ultrasound echoes received by the transducer. Moreover, the front-end input bandwidth typically ranges between 100 kHz and 10 MHz, which is the same frequency range where modern switching regulators work. Thus, the front-end is particularly prone to the noise produced by the suppliers that power the board itself. Electromagnetic interference (EMI) filters and spread-spectrum modulation of the switching regulator frequency help, but the results are often not optimal, and unacceptable artifacts are visible in the Doppler spectrum. In this paper a spread-spectrum modulation is proposed that concentrates the switching noise in the low-frequency range of the Doppler spectrum (e.g., 0–100 Hz). This range is removed by the high-pass clutter filter normally used in velocity Doppler investigations, thus switching noise and artifacts are eliminated. The method is verified through mathematical simulations and tested in measurements carried out with a research Doppler system. An example is presented in which the artifacts present during the investigation of a 0.4-m/s flow in a 25.4-mm diameter pipe are effectively removed by the proposed method.

scholarly journals Study of the Static and Microwave Magnetic Properties of Nanostructured BaFe12−xTixO19

Coatings ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 789
Author(s):  
Polina A. Zezyulina ◽  
Dmitry A. Petrov ◽  
Konstantin N. Rozanov ◽  
Denis A. Vinnik ◽  
Sergey S. Maklakov ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Resonance Frequency ◽  
Electromagnetic Interference ◽  
Low Frequency ◽  
Frequency Range ◽  
Functional Coatings ◽  
Nano Structure ◽  
Substitution Level ◽  
Resonance Frequencies ◽  
Ferrite Composites

The effect of Ti substitution on the microwave and magnetostatic properties of nanostructured hexagonal BaFe12−xTixO19 ferrite composites is studied. The microwave permeability is measured in the frequency range of 0.1–22 GHz by a coaxial technique. An analysis of the magnetostatic data is made by the law of approach to saturation. The ferrimagnetic resonance frequencies calculated from the magnetostatic data are consistent with those obtained from the microwave measurements. The natural ferrimagnetic resonance frequencies are located in the frequency range of 15 to 22 GHz, depending on the substitution level x. An increase in the amount of substitution elements results in a low-frequency shift of the ferrimagnetic resonance frequency for samples with x < 1. With x rising from 1 to 2.5, the resonance frequency increases. The results of the study demonstrate that the tailored optimization of the nano-structure of a functional material is a robust tool to fine-tune its microwave magnetic properties. The ferrites under study are promising materials to be applied as functional coatings intended to control electromagnetic interference in microwave devices.

scholarly journals Characteristics and Effects of Conducted Emission from Grid-Connected and Stand-Alone Micro-Inverters in a Nano-Grid Road Lighting System

2019 ◽  
Vol 11 (20) ◽  
pp. 5690 ◽  
Author(s):  
Chaiyan Jettanasen ◽  
Atthapol Ngaopitakkul
Keyword(s):  
Power Transmission ◽  
Grid System ◽  
Lighting System ◽  
Long Distance ◽  
The Road ◽  
Road Lighting ◽  
Conducted Emission ◽  
Power Generation System ◽  
High Level ◽  
Led Luminaire

A road lighting system is important for drivers and uses a lot of energy. The road lighting system must be installed throughout roads which have a long distance and a large volume, which causes power loss in the power transmission line. The concept of combining a power generation system by using a solar power system and a road lighting system is presented to solve this problem; it is called “a nano-grid road lighting system”. The nano-grid system consists of a grid-connected system and a stand-alone system and both systems use micro-inverters to convert the electric power for LED luminaire loads. Both micro-inverters are comprised of switching devices that cause the conducted emission (CE) in the electrical system. The LED luminaire is a very sensitive load because it is less resistant to the CE. Therefore, this research studies the CE in the nano-grid system in each period according to the working pattern of the device to study the CE characteristics for use in the design of CE attenuation methods in the future. The CE of the stand-alone system which is used at nighttime gives a higher level than the grid-connected system and exceeds the Comité International Spécial des Perturbations Radioélectriques (CISPR) 14-1 standard. The CE of the grid-connected system has a high level in the early frequency ranges, whereas the CE of the stand-alone system has a high level throughout the test frequency range.

scholarly journals Polyethylene Composites with Segregated Carbon Nanotubes Network: Low Frequency Plasmons and High Electromagnetic Interference Shielding Efficiency

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1118 ◽  
Author(s):  
Ludmila Vovchenko ◽  
Ludmila Matzui ◽  
Viktor Oliynyk ◽  
Yurii Milovanov ◽  
Yevgen Mamunya ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electromagnetic Interference ◽  
Complex Impedance ◽  
Low Frequency ◽  
Negative Permittivity ◽  
Network Interface ◽  
60 Ghz ◽  
Frequency Range ◽  
Electromagnetic Interference Shielding ◽  
Thick Sample

Polyethylene (PE) based composites with segregated carbon nanotubes (CNTs) network was successfully prepared by hot compressing of a mechanical mixture of PE and CNT powders. Through comparison with a composite comprising randomly distributed carbon nanotubes of the same concentration, we prove that namely the segregated CNT network is responsible for the excellent electrical properties, i.e., 10−1 S/m at 0.5–1% and 10 S/m at 6–12% of CNT. The investigation of the complex impedance in the frequency range 1 kHz–2 MHz shows that the sign of real part of the dielectric permittivity ε r ′ changes from positive to negative in electrically percolated composites indicating metal-like behavior of CNT segregated network. The obtained negative permittivity and AC conductivity behavior versus frequency for high CNT content (3–12%) are described by the Drude model. At the same time, in contrast to reflective metals, high electromagnetic shielding efficiency of fabricated PE composites in the frequency range 40–60 GHz, i.e., close to 100% at 1 mm thick sample, was due to absorption coursed by multiple reflection on every PE-CNT segregated network interface followed by electromagnetic radiation absorbed in each isolated PE granule surrounded by conductive CNT shells.

scholarly journals Power quality improvement recommendations for shipboard power systems

2020 ◽  
pp. 55-61
Author(s):  
В.Ф. Белей ◽  
М.С. Харитонов ◽  
Р.О. Брижак
Keyword(s):  
Power Systems ◽  
Power System ◽  
Energy Saving ◽  
Electric Power ◽  
Power Quality ◽  
Electromagnetic Interference ◽  
Electrical Equipment ◽  
Electric Power System ◽  
Maritime Industry

В настоящее время на судах и объектах морской индустрии широко внедряется энергосберегающее электрооборудование, что позволяет добиться резкого снижения расхода электроэнергии и массогабаритных показателей оборудования, существенно расширяет функциональные возможности электротехнических комплексов и систем, приводит к улучшению эксплуатационных характеристик. Однако использование новейших энергосберегающих технологий, основанных на нелинейных элементах, и коммутация электрооборудования приводит к ухудшению качества электрической энергии в судовой электроэнергетической системе. В то же время, растет число потребителей, предъявляющих к качеству электроэнергии повышенные требования. В итоге, работа судовых энергокомплексов может отличаться от расчетной, а в ряде случаев становится аварийной. В работе приведены результаты экспериментальных исследований показателей качества электрической энергии в судовой электроэнергетической системе учебного парусного судна «Крузенштерн». Представлены результаты лабораторных исследований на физической модели судовой электростанции с источниками электромагнитных помех, обоснованы организационные и технические решения по снижению уровня электромагнитных помех в судовых электроэнергетических системах. Nowadays, energy-saving electrical equipment is widely introduced on ships and maritime industry facilities. It leads to a decrease in power consumption, weight and dimensions of equipment, significantly expands the functionality of electrical complexes and systems, and provides improvement of operational characteristics. However, the use of the latest energy-saving technologies based on non-linear elements and the switching of electrical equipment leads to a deterioration in the quality of electrical energy in the ship's electric power system. At the same time, the number of consumers with increased requirements for the quality of electricity is growing. As a result, the operation of ship power complexes may differ from the normal one, and in some cases it becomes emergency. The paper presents the results of experimental studies of electric power quality indicators in the ship's electric power system of the sail training ship "Kruzenshtern". The results of laboratory studies on a physical model of a ship power plant with sources of electromagnetic interference are presented, organizational and technical solutions to reduce the level of electromagnetic interference in ship power systems are substantiated.

scholarly journals Extremely Low Frequency Signal Acquisition, Recording and Analysis

2016 ◽  
Vol 67 (3) ◽  
pp. 185-191
Author(s):  
Franz P. Zantis ◽  
Ján Hribik ◽  
Daniela Ďuračková
Keyword(s):  
Electromagnetic Interference ◽  
Low Frequency ◽  
Signal Acquisition ◽  
Electronic Systems ◽  
Frequency Range ◽  
Low Frequencies ◽  
The Public ◽  
Precise Knowledge ◽  
The Time Domain ◽  
Oscillations And Waves

Abstract Our environment is permeated by electrical and magnetic alternating waves in the frequency range above the AC voltage of 50 Hz and also in the radio frequency range. Much attention from the public is given to these waves. Through numerous studies and publications about this type of oscillations and waves it is largely known from which sources they occur and which impact they have. However, very little information could be found about electrical and magnetic alternating waves in the frequency range below 50 Hz. The aim of this research is to demonstrate that these signals exist and also to show how the signals look like and where and when they occur. This article gives an overview of the occurrence of these ELF (Extremely Low Frequencies) signals, their specific properties in view of the time domain and in view of the frequency domain and of the possible sources of these waves. Precise knowledge of the structures of the ELF signals allows conclusions about their potential to cause electromagnetic interference in electronic systems. Also other effects in our environment, eg on flora and fauna could be explained.

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