Frequency Power Transmission Research Articles

Analysis of the Characteristics of Radio Frequency Power Transmission Lines Using a Voltage Current Probe in Low-Pressure Discharge

Analysis of the Characteristics of Radio Frequency Power Transmission Lines Using a Voltage Current Probe in Low-Pressure Discharge

Differential Privacy and IRS Empowered Intelligent Energy Harvesting for 6G Internet of Things

In the era of the sixth generation (6G), the deployment of massive Internet of Things (IoT) generates and processes large amounts of data, resulting in high energy demand and huge challenges to the energy-limited IoT devices. To achieve green and sustainable communication, energy harvesting is a feasible technology to prolong the lifetime of IoT. However, the existing energy harvesting architecture cannot guarantee the privacy of energy users while improving the intelligence and effectiveness of energy transmission. To solve these issues, we propose a differential privacy and intelligent reflecting surface empowered privacy-preserving energy harvesting framework for 6G-enabled IoT. First, a secure and intelligent energy harvesting framework is designed, which includes an intelligent reflecting surface-aided radio frequency power transmission mechanism and a differential privacy-based energy harvesting mechanism. Second, an exponential mechanism-based privacy-preserving energy harvesting scheme is established, where we analyze the adversary mode, propose the differential privacy-enabled location-preserving algorithm, and provide security analysis and proof. Third, we quantify the user satisfaction for energy harvesting and propose a deep reinforcement learning empowered resource allocation scheme to maximize the weighted satisfaction of all system users. Finally, simulation results show the effectiveness of the proposed secure and intelligent energy harvesting architecture for 6G IoT.

Influence of the Electromagnetic Energy Due to Cellular Devices in a Multi-Layer Human Head under Two-Temperature Heat Conduction Model

In this study, a mathematical model of a human head with three layers of skin, bone, and brain for both children and adults was created. The phase-lag time definition was used to evaluate the internal thermal reaction that is created via the human head as a result of chemical processes. In the framework of the two-temperature heat conduction model, the governing equations were developed. The inversions were numerically derived using an approximation approach after applying Laplace transforms. When the human head is exposed to cellular devices that emit an electromagnetic wave, the dynamic and conductive temperature increments distributions have been calculated and discussed with various values of the two-temperature parameter, time, relaxation time, power transmission frequency, and power density. Each layer of the human cranium is affected by all of the characteristics analysed. The impacts of electromagnetic waves emitted by cellular devices were more detrimental to the bones of children’s heads than they are to the bones of adults’ heads.

Wireless Telemetry System With Independent Power and Data Frequency Resonance

Wireless power and data transmission systems are important components in bioelectronics. Achieving resonance at the data transmission frequency without negatively impacting the efficiency at the power transmission frequency may enhance data transmission capability. In this letter, a new system referred to as tuned inductor four capacitor is proposed to achieve resonance at the data transmission frequency of a wireless telemetry system without significantly affecting the efficiency at the power transmit frequency; as a result, this leads to increased voltage and current gains and reduced reflections at the data transmit frequency when compared to an equivalent, traditional, two-coil system. The performance of the proposed design is demonstrated through a system implementation characterized by a transmit coil of 40 mm diameter and receive coil of 15 mm diameter, with a distance between them varied from 17 to 40 mm. This system is experimentally compared with the equivalent two-coil system that has the same transmit and receive coil footprint and layout but conventional transmitter matching circuitry. Results show that, at the data telemetry frequency, there is no reflection, the voltage gain is 60% higher than that of the traditional two-coil system, whereas the current gain is 250% higher.

Investigation of power transmitting coil for wireless power transmission of activity meter for experimental animals

Activity of experimental small animals has been measured as one of animal experiments in the fields of neurophysiology and behavioral psychology. Although an implantable activity meter is useful for this purpose, there are problems to record for a long time because it uses batteries and to stresses animals because of weight and dimensions. A wireless power transmission system, for this reason, is useful. The stable power supply to the activity meter is necessary to generate a uniform magnetic field in the animal cage. This paper describes the design and trial production of the power transmission coil that has the required magnetic field uniformity in the cage for small experimental animal and whose self-resonant frequency is sufficiently higher than the power transmission frequency.

A New Modular Multilevel AC/AC Converter Using HF Transformer

This paper proposes a new modular multilevel AC/AC converter using high-frequency (HF) transformer, which has the advantages of modular design, easy expansion, high power density, no circulation current, good output voltage waveform quality and low cost. This converter has broad application prospects in the fields of high-voltage and high-power wind power generation, fractional frequency power transmission (FFTS) and power electronic transformer. The proposed converter topology can connect two three-phase AC systems with different frequencies and amplitudes directly. By introducing HF transformer, the direct series connection of input and output modules can be realized simultaneously, and the expensive industrial frequency transformer with large volume and weight can be removed. In order to achieve HF electrical isolation, the HF inversion of the output pulse is carried out at the inverter side to realize the HF output of the fundamental wave. After passing the HF transformer, the pulse is restored to the low-frequency output wave by the cycloconverter. Aiming at the problem of freewheeling of HF link, the method of common state conduction is introduced, which can effectively reduce the switching loss. The modulation scheme, control strategy and typical parameter design are developed. Furthermore, the feasibility of the proposed converter is verified by simulation results.

Multi‐frequency power system for renewable source integration in smart grid

This study presents a new power system enabled by power-electronic technology for renewable source integration in micro-grid. The micro-grid is decoupled into multiple independent power channels. These power channels are used for any source to any load-independent power transfer over the common power transmission line. This system works on the principle of frequency-selective orthogonal power transfer and superposition theorem. To demonstrate the proposed power system, a laboratory-scale prototype of an interconnected two-source two-load system is developed. The two sources independently transfer power to their respective loads at power transmission frequencies of 500 and 0 Hz (DC is also a valid frequency for power transmission), respectively, over the common power transmission path. Thus, a two-source two-load system is decoupled into two independent power channels. The proposed system is modular and scalable in structure and can be extended for any number of sources and loads. Finally, the effectiveness of the proposed system is verified through simulations and experimental results which demonstrates independent transmission of 100 W power in each of the two power channels of the two source-two load interconnected system.

Stretchable multichannel antennas in soft wireless optoelectronic implants for optogenetics

Optogenetic methods to modulate cells and signaling pathways via targeted expression and activation of light-sensitive proteins have greatly accelerated the process of mapping complex neural circuits and defining their roles in physiological and pathological contexts. Recently demonstrated technologies based on injectable, microscale inorganic light-emitting diodes (μ-ILEDs) with wireless control and power delivery strategies offer important functionality in such experiments, by eliminating the external tethers associated with traditional fiber optic approaches. Existing wireless μ-ILED embodiments allow, however, illumination only at a single targeted region of the brain with a single optical wavelength and over spatial ranges of operation that are constrained by the radio frequency power transmission hardware. Here we report stretchable, multiresonance antennas and battery-free schemes for multichannel wireless operation of independently addressable, multicolor μ-ILEDs with fully implantable, miniaturized platforms. This advance, as demonstrated through in vitro and in vivo studies using thin, mechanically soft systems that separately control as many as three different μ-ILEDs, relies on specially designed stretchable antennas in which parallel capacitive coupling circuits yield several independent, well-separated operating frequencies, as verified through experimental and modeling results. When used in combination with active motion-tracking antenna arrays, these devices enable multichannel optogenetic research on complex behavioral responses in groups of animals over large areas at low levels of radio frequency power (<1 W). Studies of the regions of the brain that are involved in sleep arousal (locus coeruleus) and preference/aversion (nucleus accumbens) demonstrate the unique capabilities of these technologies.

Analysis of radio frequency power transmission between in/on‐body beam‐reconfigurable antennas in the medradio band

ABSTRACTThis article presents a performance analysis of beam‐reconfigurable in/on‐body antennas. Both antennas operated within the Medical Device Radio Communications Service band (MedRadio band: 401–406 MHz) and were designed to steer the beam directions. To implement the beam‐steering capability, the two antennas used two artificial switches. The in/on‐body antennas were fabricated on FR‐4 and fabric substrate, respectively. A skin‐mimicking model (εr = 46.74, σ = 0.69 S m−1) was adopted for the simulations and measurements of the two antennas. We performed transmission and reception tests between in/on‐body antennas in an antenna chamber. The test was implemented in various cases, with different antenna distance and angle values. In addition, we compared received power between the calculated results (by virtue of the Friis transmission equation) and the actual measured results, and summarize these findings herein. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1163–1169, 2016; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.29750

Effects of neutral point reactors and series capacitors on geomagnetically induced currents in a high‐voltage electric power transmission system

Geomagnetically induced currents (GIC) are DC‐like currents compared to power transmission frequencies. Consequently, it may be possible to reduce the magnitudes of GIC by installing resistive components or series capacitors into a power grid. We simulate the effects of neutral point reactors and series capacitors on GIC in the Finnish 400 kV network. Reactors add an additional resistance to earthing leads of transformers, and series capacitors block the flow of GIC in transmission lines. The geoelectric field impacting the system is considered to be uniform. The use of reactors does not necessarily reduce the GIC risk. Although the installation of reactors tends to decrease GIC on the average, maximum GIC may even increase. Assuming a reactor at all stations results in a 50% reduction of the maximum GIC compared to the situation with no reactors. With up to four series capacitors, the maximum GIC is reduced by 40% when they are optimally located. However, even small changes in the topology of the grid can cause large changes in GIC. A combination of reactors and series capacitors could in principle provide a way to diminish the GIC risk. This study also emphasizes the difficulty of preventing GIC problems by these means.

Stacked Spirals for Biosensor Telemetry

This paper presents an inductive power transmission coil for biosensor-based telemetric implants. Using stacked spirals reduces the consumed space and the self-resonant frequency (SRF) of the spiral and the required power transmission frequency for the implanted device. A four-layer 15 mm × 15 mm spiral coil of seven turns is simulated in CST Microwave Studio (TM), constructed and tested in hardware with comparable results. Measurements also include the receipt of power inductively from an energized array of spirals powered by a Class-E transmitter at 27 MHz, and rectified to 1 V for biosensor applications.

Modeling of Transcutaneous Inductive Power Transmission

The results of this work are discussed in the context of theoretical research into different wireless power and data transmission methods, subject to a specific environment, such as bioimplantable devices. According to this study, the optimal wireless power transmission method is inductive; optimal power transmission frequency range is 0.1–1 MHz. A mathematical model of transcutaneous wireless power transmission system and a tool for its design are suggested.

2.3.1 Systems Engineering for Space Solar Power Architectures

AbstractConcerns about the availability and use of conventional nonrenewable energy sources have led to an increasing interest in renewable energy. Because renewable energy sources tend to be dilute and intermittent, solar power satellites have been proposed as a means of supplying large amounts of power continuously. Space solar power (SSP) will not be competitive for commercial‐scale baseload power without some combination of greatly reduced launch and non‐recurring engineering costs as well as space resource utilization. However, SSP may be competitive in the near term for niche markets where the fully burdened cost of delivery of conventional fuel is much higher than that for commercial markets. A model under development provides a tool to assess masses and costs of solar power satellites at a variety of power levels, orbits, and power transmission frequencies.

Identifying power line harmonic radiation from an electrical network

Abstract. It has been suggested that the space environment is being polluted by power line harmonic radiation (PLHR), generated from harmonics of the electrical power transmission frequency (50 or 60 Hz) and radiated into the ionosphere and magnetosphere by long power lines. While some in-situ satellite measurements of PLHR have been reported, it has proved difficult to confirm the source and overall significance. The electricity network of the city of Dunedin, New Zealand, is tiny compared to the many large industrial zones found outside New Zealand. However, the 1050Hz ripple control signal injected into the local electrical grid at regular intervals as a load-control mechanism provides an opportunity for identifying PLHR strengths radiated from a spatially well defined electrical network. In-situ observations by satellites should allow a greater understanding of PLHR and its significance as man-made pollution to near-Earth space. Calculations have been undertaken to estimate the strength of the radiation fields expected from the ripple control signal which is injected into the Dunedin city electrical network. We find that ground-based measurements will not be sensitive enough for detection of the ripple control radiation fields, even during the quietest winter night. While significant power penetrates the lower ionosphere, this is well below the reported threshold required for nonlinear triggering in the Van Allen radiation belts. Some radiated fields at satellite altitudes should be detectable, allowing in-situ measurements. At the altitude of the DEMETER mission, the radiated electric fields will not be detectable under any ionospheric conditions. However, we find that the radiated magnetic fields may be detectable by the DEMETER satellite at certain times, although this will be very difficult. Nonetheless, there is the possibility for future experimental campaigns. Keywords. Magnetospheric physics (Magnetosphereionosphere interactions; Plasma waves and instabilities) – Ionosphere (Active experiments)

Magnetospheric line radiation observations at Halley, Antarctica

Magnetospheric line Radiation (MLR) events are relatively narrowband VLF signals that sometimes drift in frequency, and have been observed in both ground based and satellite data sets. Line radiation has been attributed by some authors to be power line harmonic radiation (PLHR), generated from harmonics of the power transmission frequency (50 or 60 Hz) and radiated into the ionosphere and magnetosphere by long power lines. We present the result of a survey undertaken on the basis of measurements made of MLR events observed at Halley station, Antarctica (75°30′S, 26°54′W, L ≈ 4.3) in part of June 1995. Particular attention is given to the frequency spacing, drift rates, and amplitude of the MLR lines. MLR is present in 7.0% of the minute‐long VLF recordings made at Halley. The MLR lines rise in frequency as often as they fall. However, these lines do not necessarily rise or fall monotonically and can oscillate while drifting. The Halley MLR has a wide range of line spacings and does not preferentially show spacings near harmonics of electrical transmission frequencies, either 50 Hz or 60 Hz. There is no correlation between the frequency drifts of the local 50 Hz Halley electrical supply and those of the observed MLR lines. The distribution of MLR line spacings observed in the Halley data has a roughly exponential form, suggesting a different mechanism for MLR than for PLHR.

High Frequency Power Transmission and Selective Division among Loads by Using Distributed Constant Line.

At present, a high frequency induction heating system usually consists of a high frequency power source and a heated load circuit. But some systems are necessary to heat up two or more loads.In such a case, there are many problems. For an example, the same number of the power source or switches, changing loads, are required. In addition, many high frequency power transmissionlines should be laid for the plural load circuits.The authers offer a new system, which can be able to supply the high frequency power slectively and effectively to two induction heating circuits, the system is composed of a high frequency voltage type inverter, a parallel resonant load circuit and a series resonant load circuit, and they are connected in series by the distributed constant lines, having the specific length.This paper describes the operating principle of the system and the optimum operating conditions. And also through the analyses of the operating characteristics of the system, the paper explaines the facts that the effective and selective transmissions of the high frequency power to the loads are available and the minimum interference between the loads for the supplied power divisions is accomplished.Finally, the theoretical simulation waveforms are compared with the actual waveforms obtained from the test equipment, having the output ratings of 1 to 2MHz and 1kW, and they correspond with each other. So it is clarified that the theory described in the paper is reasonable.

Effects of a satellite power system on ground‐based radio and radar astronomy

Intensive studies of the feasibility of a satellite power system (SPS) are currently being carried out under a program initiated by the U.S. Department of Energy and the National Aeronautics and Space Administration. In such a system, satellites in the geostationary orbit convert solar radiation to microwaves, which are beamed to collecting stations on earth in order to provide electric power. An envisioned reference system for such studies is composed of 60 satellites spaced at 1° intervals, each radiating 6.7 GW at 2.45 GHz. Such a system can interact with radio and radar astronomy systems in a number of ways. The power signal and its harmonics, which fall close to radio astronomy bands, can cause overloading of input stages, and mitigation will require development of cryogenically cooled filters. Radiation within radio astronomy bands can result from transmitter‐generated noise, thermal noise from the large solar cell arrays, and possibly from intermodulation, component failures, and turn‐on transients. Noise and harmonics can also be generated by the power‐collecting rectennas. There may be propagation effects resulting from ionospheric heating. For those effects for which the magnitude can be estimated from present data, comparison is made with the interference thresholds for various types of radio telescopes. It is concluded that for any radio telescope, a zone of sky will be centered on the arc of satellites, in which observations with high sensitivity are precluded. The width of this zone, as determined by thermal radiation, is estimated to vary from about 30° for single‐antenna telescopes to a few degrees for high‐resolution arrays and interferometers. There will be some degradation in performance in bands close to the power signal and its second harmonic, and it will be necessary to insure that adequate shielding by terrain exists between radio observatories and the power receiving sites. The interference thresholds are higher for radar astronomy than for radio astronomy, but one of the main frequencies, 2.38 GHz, is very close to the power transmission frequency, and targets are usually close to the ecliptic and therefore at declinations close to the arc of satellites. Coexistence of radio and radar astronomy with the SPS will be crucially dependent upon the quality of engineering and maintenance of the satellites.

Low temperature dielectric loss due to antioxidants in polyethylene

Certain antioxidants added to polyethylene are known to cause increased dielectric loss in the audio-frequency range at liquid helium temperature. Although the peak loss factor occurs at several kilohertz, the increase at power transmission frequency is sufficient to affect the performance of an ac superconducting cable insulated with polyethylene tape. Contrary to recent reports, we now have reason to believe that the effect is an exclusive feature of antioxidant molecules which are 3, 5-ditert-butyl-4-hydroxy-phenyl compounds. It is attributable to tunnelling of the hydroxy hydrogen atom. Other substituted phenols and non-phenol antioxidants can all effectively protect the polyethylene without increasing the dielectric loss. 4.2 K dielectric loss measurement may be used as a rapid, sensitive and specific test for the presence of 3, 5-ditert-butyl-4-hydroxy-phenyl compounds in polyethylene.

Human thresholds of electric shock at power transmission frequencies.

Reliable quantitative data about electric shock to humans at power transmission frequencies are available for three physiological responses to electrical stimulation: perception, uncontrollable muscular contraction, and death. Some humans can perceive less than 0.5 rna of 50 to 60 Hertz current, depending upon the type of hand contact made with an electrically energized circuit. Most adult male workers should be able to release 9 rna of 50 to 60 Hz current. A safety threshold of 5 ma, recommended for the general population including children, is based upon the conclusion that current in excess of release threshold should be regarded as hazardous and potentially lethal. Relevant threshold conditions inctude body size, current pathway, contact duration, and total resistance. Voltages calculated from reliable experimental data on effective currents and expected resistances are lower than voltages generally recommended to be safe.

Power Transmission at High Frequency

This paper presents data for power transmission up to a frequency of 5000 cycles per second and enables calculation of the resistance and inductance of a transmission line delivering high frequency power. Classical expressions are involved. Graphs and data are presented from which values can be selected and the transmission line parameters easily determined. A knowledge of these parameters enables the design of an efficient and acceptable high frequency power transmission system.