Transformer Coils Research Articles

Optimal Design and Analysis of High-Frequency Isolation Transformer for Switched-Mode Power Converters

High-frequency (HF) transformers have gained great interest in recent years due to the advent of powerful soft magnetic materials with low core loss in semiconductor power switches. Also, the optimal design of the HF transformer is a significant issue for high-performance energy conversion systems. In this paper, a 40W 50/12.5/25 V universal input and two output discontinuous-conduction mode (DCM) flyback transformer is designed by using mathematical calculations and analyzed via 3D ANSYS/Maxwell simulation including electromagnetic and loss analysis. It is shown that the simulation results accounting for hysteresis losses, eddy current losses, copper losses, and magnetic flux density determine the accuracy of the mathematical model calculation. Analyzes are performed at 100 kHz frequency levels. Results obtained will include core magnetic flux density, core/copper losses, leakage/magnetizing inductances, windings parasitic capacitances, input/output voltage, current values, and all design parameters. Finally, the proposed HF transformer's overall efficiency is calculated and presented. Significantly, the HF transformer achieves 97.8% efficiency thanks to the transformer's core and coil selection, B-H and B-P characteristics, one-to-one dimension design, and mesh operation. The dynamic and mathematical results of the designed transformer demonstrate the design and efficiency success

Development of an Automatic Phase Selector for Nigerian Power Utility Customers

Power utility customers in a developing country like Nigeria have constituted a habit of changing the electricity supply line from an unavailable or unstable phase to the most available or stable phase. The category of customers involved in this character are those on single phase power supply. However, this act is being carried out manually at the meter point using the cut-out fuses. This attitude results in phase unbalances, overheating electrical equipment including feeder pillars, transformer coils, network faults, and overall system instability. Thus, this paper presents the development of an Automatic Phase Selector for Nigerian Power Utility Customers. The device automatically selects an available phase from the three-phase power supply lines. The research comprises designing an automatic phase selector circuit, simulation of the designed circuit, programming code development in C- Language for the microcontroller, construction of the designed circuit, and carrying out tests on completed work done to ascertain the effectiveness of the developed system. The system operation involved a three-phase supply from the closest distribution network of the power utility company which is connected to a three-in-one gang switch while the switching ON and OFF of their static switches represent phase-off in an ideal situation. The operational results of this system are presented in the form of the truth table which indicates that the affected customer would not have a power supply only when the 3-phases are under voltage or overvoltage or unavailable. This implies that one of the three phases that meet the three criteria would be switched ON. A pure sine wave was used as input into the Optocoupler and the output waveform of the rectified pulsating signal is separately displayed. This output waveform is very clean and noiseless. Finally, the system when practically tested with an unbalanced three-phase supply, worked perfectly enhancing the flexibility of operating an Automatic Phase selector and hence avoiding manual switching of the phase selector which has been attributed to changing of cut-out fuses and associated stress as well as having a user-friendly phase selector.

The Impact of Voltage on Coils with 500 and 1000 Windings on the Performance of a Transformer in the Integrated Physics Laboratory at Campus B of Raden Fatah State Islamic University in Palembang: An Experiment of Physics Education

The premise of this study is the lack of understanding regarding the distinction between utilizing 500 and 100 coils for transformers. This study investigates the influence of altering the number of windings on transformer coils on the generated voltage. The employed research methodology is experimental. The data analysis results indicate that a step-up transformer exhibits a primary voltage that is lower than its secondary voltage. By contrast, a step-down transformer exhibits a primary voltage that is greater than its secondary voltage. This is a result of the disparity in the number of windings between the secondary and primary coils. A step-up transformer is designed with a greater number of windings on the secondary coil, which leads to an increased secondary voltage. In contrast, a step-down transformer is designed with a greater number of windings on the primary coil, resulting in a reduced secondary voltage. This investigation validates the existence of a correlation between the quantity of windings on transformer coils and the voltage generated. Hence, the voltage of a transformer might fluctuate based on alterations in the quantity of windings on the coils.

Magnetic and Thermal Behavior of a Planar Toroidal Transformer

This paper presents a study on the magnetic and thermal behaviors of a planar toroidal transformer, comprising two planar toroidal coils. In our configuration, the primary coil consists of twenty turns, while the secondary coil consists of ten turns. This design combines the advantages of both toroidal and planar transformers: it employs flat coils, akin to those utilized in planar transformers, while retaining a toroidal shape for its magnetic core. This combination enables leveraging the distinctive characteristics of both transformer types. This study delves into electromagnetic and thermal behaviors. Electromagnetic behavior is elucidated through Maxwell’s equations, offering insights into the distribution of magnetic fields, potentials, and electric current densities. Fluid flow is modeled via the Navier–Stokes equations. By coupling these equation sets, a more comprehensive and accurate portrayal of the thermal phenomena surrounding electrical equipment is attained. Such research is invaluable in the design and optimization of electrical systems, empowering engineers to forecast and manage thermal effects more efficiently. Consequently, this aids in enhancing the reliability, durability, and performance optimization of electrical equipment. The mathematical model was solved using the finite element method integrated into the COMSOL Multiphysics software v. 6.0. The COMSOL Multiphysics simulation showed correct behavior of potential, electric field, current density, and uniformly distributed temperature. In addition, this planar toroidal coil transformer model offers many advantages, such as small dimensions, high resonance frequency, and high operating reliability. This study made it possible to identify the range of its optimal functioning.

Improving Efficiency of a Wireless Power Transfer (WPT) System by Increasing Coil-Width

Abstract: Efficiency of a wireless power transfer (WPT) system depends on the resonance components and mutual inductance between primary and secondary coils of the transformer. Therefore, design of coils of a transformer is very crucial in WPT system as primary and secondary coils of the WPT transformer are separated by a large air gap. Due to large air gap between primary and secondary coils, coupling coefficient in a WPT system is very low compared to conventional transformer. Therefore, efficiency of the system is very low. In this paper, it is discussed that efficiency of a wireless power transfer (WPT) system can be enhanced by increasing its coil-width.

Analysing and Computing the Impact of Geometric Asymmetric Coils on Transformer Stray Losses

Designing and manufacturing transformers often involves variations in heights and thicknesses of windings. However, such geometric asymmetry introduces a significant impact on the magnitude of stray transformer losses. This study examines the effects of asymmetric coils on the generation of stray losses within core clamps and transformer tank walls. A model has been introduced to ascertain the dispersion magnetic field’s value at a specific distance from the coil. The analysis extends to characterising the dispersion magnetic field reaching the tank walls by using electromagnetic simulation by a finite element method. It explores strategies to diminish stray losses, including the placement of magnetic shunts as protective shields for the tank walls. It delves into the efficacy of employing a transformer shell-type configuration to mitigate the magnetic dispersion field. The findings revealed that achieving greater symmetry in transformer coils can minimise stray losses. Specifically, the incorporation of magnetic shunts has the potential to reduce additional losses by 40%, while the adoption of a shell-type configuration alone can lead to a 14% reduction. This work provides valuable insights into optimising transformer designs, contributes a user-friendly tool for estimating additional tank losses, thereby enhancing the knowledge base for transformer manufacturers.

Comparative the effect of distribution transformer coil shape on electromagnetic forces and their distribution using the FEM

Abstract During the normal life of the transformers, they are subjected to different electromagnetic stresses. One of these stresses is the electromagnetic forces resulting from the passage of short-circuit current in the transformer coils due to internal or external faults and may lead to the failure of the transformer when this electromagnetic force exceeds the threshold level. This work deals with the computation and analysis of leakage magnetic flux and electromagnetic forces when the worst-case fault (symmetrical short-circuit current) occurs in distribution transformer (DT) coils using the finite element method (FEM). The three types of DTs that were adopted in this work are similar in capacity and voltage transformation ratio (250 kVA and 11,000/416 V), but they are different in the shape of coils (oval, cylindrical, and rectangular coils). ANSYS software was used to build two-dimensional models of the three transformers, which were different in coil shapes and in the type of iron core. The objective of this work is to compare the effect of coil shape on the distribution of electromagnetic forces and their value, in order to find out which coil shape is the best to withstand electromagnetic forces when short-circuit current is passed in the coils. The results of the simulation of the finite element models were approximately equivalent to the results of the design calculations that depend on the classical method (the analytical method), but the FEM is more accurate, due to the accuracy of calculating the magnetic flux and its distribution, which cannot be calculated using the classical method. One of the most important contributions of this research is the analysis and calculation of electromagnetic forces for three types of DTs with different coils by applying the same design parameters to all the transformers. The research also contributed to determining the best coil shape by comparing simulation results, and it was found that transformers with cylindrical coils are the best to withstand electromagnetic forces due to the homogeneity of the cylindrical coil structure from all sides.

Fuzzy PID based temperature control method for power transformer coils

Fuzzy PID based temperature control method for power transformer coils

Fuzzy PID-based temperature control method for power transformer coils

Fuzzy PID-based temperature control method for power transformer coils

Magnetic field simulations of the GOLEM tokamak via the NICE code

In this paper, the direct and inverse equilibrium computation mode of the NICE code is put into operation for the case of the GOLEM tokamak. This enables, for the first time, simulations of GOLEM's magnetic field. The computation mode put into operation simulates the magnetohydrodynamic equilibrium of a tokamak plasma based on a given plasma position or given currents in poloidal magnetic field coils. In order to set up NICE, a virtual model of GOLEM is introduced that includes axially symmetrical approximations of GOLEM's iron core and primary transformer coils. The results of NICE simulations are compared with experimental measurements, and it is shown that NICE simulations produce plasma equilibrium configurations typical for GOLEM. Nevertheless, a more detailed validation of GOLEM's virtual model and of the results of NICE simulations is to be performed in the future.

Improving and warning the static stability limit of complex power grid tie-line based on WAMS

In order to solve the technical problems of traditional power system classic formulas that are difficult to explain the static stability limit changes of power grid interconnection lines, as well as the difficulties in improving and warning the static stability limit power of interconnection lines, this paper provides a method for improving and warning the static stability limit of power grid interconnection lines. Firstly, based on the electrical quantities measured by the wide-area measurement system (WAMS) of the power grid, the equivalent reactance of the power grid interconnection lines, and the equivalent impedance from the high voltage side and medium voltage side of the three coil transformers on both sides of the interconnection line are determined. Secondly, under pre-set operation mode and constraint conditions, the configuration quantity and capacity of the dynamic reactive power sources on the medium voltage side of the three coil transformers on both sides of the interconnection line are determined. Finally, based on the determined configuration and pre-set operation mode of the dynamic reactive power sources on the medium voltage side of the three coil transformers on both sides of the interconnection line, the historical electrical quantities measured by WAMS. The static stability limit and static stability margin of the interconnection line are calculated, and warnings are provided.

A reconfigurable dual‐band low noise amplifier for 5G in 65‐nm CMOS

AbstractIn this paper, a reconfigurable low noise amplifier (LNA) is proposed for 5G dual‐bands in a 65‐nm CMOS process. The reconfigurable function of LNA is realized by designing reconfigurable matching networks composed of transformers and MOS transistor switches. The pole characteristics of the resonant network composed of the reconfigurable network and the equivalent circuit of the amplifying device are deduced and analyzed in detail. By establishing the relationship between two reconfigurable frequencies and the ratio of transformer coil inductance under two switching states, the position of the switch and the specific parameters of the reconfigurable matching network are determined. Measurement results show small‐signal gain of 25.5 to 33.9 dB and noise figure of 3.3 to 4.3 dB at 24 to 29.5 GHz bands, and small‐signal gain of 23.5 to 27.8 dB and noise figure of 4.3 to 4.5 dB at 37 to 40 GHz bands, respectively. The chip area occupied 0.34 mm2 including pads.

An impact-insensitive fiber optic current transformer based on polarization maintaining photonic crystal fiber delay coil

When the polarization-maintaining fiber (PMF) delay coil of a fiber optic current transformer (FOCT) is impacted, external forces on the optical fibers and change of their birefringence may lead to extra phase errors during the propagation of optical signals in the fibers. These errors increase the error in current measurement. In the paper, the environmental impact mechanisms influencing the PMF delay coil of FOCT were investigated with a mathematical error model. The method of replacing PMF with a polarization-maintaining photonic crystal fiber (PCF) as the delay coil was proposed. Also, the relationship between structural parameters of air holes and linear birefringence of the polarization maintaining PCF subjected to stress was investigated. The structural parameters of optical fibers were also optimized subsequently. Simulated impact experiments of FOCT with polarization-maintaining PCF and PMF as the delay coil, respectively, demonstrated the effective impact resistance of FOCT with polarization-maintaining PCF delay coil after the optimization of its structural parameters. The current measurement errors of the FOCTs with polarization maintaining PCF delay coil reduced by approximately 35% with respect to the FOCT with PMF delay coil.

Energy Flow and Photons from Primary Coil to Secondary Coil of Transformer

The author proposed the mutual energy theorem in 1987 and the mutual energy flow theory since 2017. The theory of mutual energy has an axiom more than Maxwell’s equations, that is, the law of conservation of energy. The conservation of energy law is not Poynting’s theorem, but an extension of the mutual energy theorem. Because of this new axiom, the new axiom conflicts with Poynting’s theorem. In fact, it is also a conflict with Maxwell’s electromagnetic theory. The author believes that the law of conservation of energy should be adhered to, so Poynting’s theorem or Maxwell’s classical electromagnetic theory should be appropriately modified. These works have been completed by the author in other papers. Recently, when studying the magnetic quasi-static electromagnetic field, the author found that the electromagnetic energy conservation law proposed by the author can be strictly proved in the magnetic quasi-static electromagnetic field environment. This is a great inspiration to the author. Based on the theory of magnetic quasi-static electromagnetic field, the author strictly proves the law of conservation of energy (mutual energy theorem) and the mutual energy flow theorem proposed by the author, and applies this theory to calculate the energy flow from the primary coil to the secondary coil of transformer. In order to simplify the problem, the author only calculates the mutual energy flow between two parallel current elements. The calculation results show that the mutual energy flow is generated on the primary coil and annihilated on the secondary coil. The properties of mutual energy flow are completely consistent with those of photons. It is also close to the photon model in Cramer’s transactional interpretation of quantum mechanics. The author believes that the transmitting antenna is consistent with the primary coil of the transformer, and the receiving antenna is consistent with the secondary coil of the transformer. The author believes that for the theoretical generalization from magnetic quasi-static electromagnetic field to radiated electromagnetic field, the law of conservation of energy, the theorem of mutual energy flow should guarantee and the time average value of self energy flow should be kept at zero. In this way, a new electromagnetic field theory which is different from Maxwell’s electromagnetic theory is obtained. Maxwell’s electromagnetic field theory adds displacement current, but it makes formulas such as the energy conservation law problematic in the case of radiation field. Maxwell’s electromagnetic field theory and mutual energy theory provide the same electric field, but the far-field part of the magnetic field (i.e. radiated electromagnetic field) is different. In addition, the electromagnetic mutual energy theory proposed by the author believes that the charge of the receiver produces an advanced wave. Advanced wave violates today’s causality, but it is an objective physical existence.

Analisa Kinerja Operasional dan Temperature Terhadap Life Time Transformator 370 MVA

Transformers are very important electrical equipment in the electricity system. Transformers function to increase and decrease the voltage of the electrical assembly system and distribution system. With the temperature conditions in Indonesia, the average temperature in the power plant uses transformer insulation oil cooling. The loading on the power plant transformer always changes depending on the load management center. At the time of loading, there will be current flowing into the transformer coil resulting in increased transformer temperature. Too hot temperatures will cause damage to the transformer insulation and will result in a reduction in the useful life of the transformer itself. This research is carried out observation and analysis by knowing the performance of the transformer in the duration of 24 hours of normal operation by comparing the effect of operating temperature when the load changes, environmental temperature and hotspot temperature. The change in temperature increase that occurs in the transformer is influenced by several factors, including the individual transformer and the temperature of the environment where the transformer is operated. The individual temperature of the transformer is caused by the amount of loading borne by the transformer so that the current flowing in the transformer winding will be higher, the current that continues to increase will cause the transformer winding. A very high temperature in the winding will cause damage to the insulation and the temperature rise can change the insulating properties of the transformer oil which results in the value of the insulating oil decreasing and the decrease in the ability of the insulation level affects the useful life of the transformer. Another factor of increasing transformer temperature is from ambient temperature. With the conditions under which the transformer is operated and the tropical climate conditions in Indonesia which are quite high, this can cause an increase in transformer temperature.

Modular Electromagnetic Transducer for Optimized Energy Transfer via Electric and/or Magnetic Fields.

In this paper, a modular electromagnetic transducer that achieves the optimal transfer of energy from the electric and/or magnetic fields is proposed. Both the magnetic field resonance coupling and the influence of the electric field near the copper transducers of the printed circuit board and inside the FR4-type epoxy material are considered. In our printed arrays of flat transducers, we consider face-to-face capacitances for the study of resonance coupling. Because the space between coil turns is almost double the plate thickness, the coplanar capacitance can be ignored for frequencies under 2 MHz. A radio frequency (RF) transmitter and transducer were built to demonstrate the increased energy transfer efficiency when using both electric and magnetic fields in the near-field region. The transversal leakage flux coupling of a long RF coil was more efficient than a simple axial magnetic field coupling when using pancake transceiver coils. The optimal configuration having one long coil at the base and two or more flat coils as capacitor plates near coil ends generated the highest tandem of magnetic and electrical fields. A power regression tool was used to convert and simplify the transducer current and voltage variation with distance. In this regard, the current change corresponded to magnetic field variation and the voltage change to the electric field variation. New formulas for estimating the near-field region and the self-capacitance of the RF transformer coil are proposed; the optimal function in the frequency domain for a given transducer distance was defined by simulation.

Evaluation of the Smoking Factor in the Blood of Workers in Diyala State Company and its Relationship to Heavy Metals (Lead, Nickel and Copper)

Environmental pollution of heavy metals is becoming an increasing problem and has become a major concern due to the adverse effects it causes worldwide. Heavy metals are naturally occurring elements that have a high atomic weight and a density at least five times greater than water. It’s a multiple industrial, domestic, agricultural, medical and technological applications have led to its widespread use in the environment; Raising concerns about their potential effects on human health and the environment. The aim of the current study is Evaluation the relationship between the smoking factor in the blood of workers in Diyala State Company and to the percentage of the heavy metals such as lead (Pb), nickel (Ni) and copper (Cu) . This study was conducted for the period from 1/10/2021 to 1/3/2022, Eighty two blood samples were collected (58 blood samples from workers working in the Diyala State Company affiliated to the Ministry of Industry and Minerals, while, 24 control samples were from control samples for employees who don’t working with industrial emissions).The workers were divided into three groups based on the location work inside the station, sector (A) represented painter workers, sector (B) characterized the workers specialized in the copper coil of the electrical transformer, while sector (C) represented the iron core section of the electrical transformer. Five ml. of venous blood was taken for each sample. The concentration of Pb, Ni and Cu in the blood samples were determined by using the Flameless Atomic Absorption Spectrometer (FLAAS). The results of the intensive study showed the presence of high levels of lead, nickel and copper in smokers and non-smokers workers within the profession compared to control samples during the service period, with significant differences (P < 0.05). The results showed increasing levels of lead, nickel and copper with the progression of the service life, and the elements (lead, nickel and copper) recorded the highest average during the service period of 21-34, The painting worker showed high level of Ni while, Cu level peaked in wires worker . Based on age periods, elements levels (Pb, Ni, and Cu) were increased with age period progression, where it is found the levels of Pb, Ni, and Cu scored highest mean within >50 age period, while the least mean value of Pb, and Cu at 3-40 years age period, and least mean value of Ni was at <30 age. Finally, the results discovered there is positive correlations among metals and worker’s age.

Design Space of Sub-Resonant Frequency- Controlled Series–Series-Compensated Inductive Wireless Power Transfer Links Operating With Constant Output Current Under Frequency Constraints

Output current of inductive wireless power transfer links (IWPTLs) with battery loads is influenced by coupling coefficient and input–output voltage. To regulate the output current while keeping the operational frequency near resonance, dc–dc converters are often added at IWPTL input and/or output, increasing system complexity and dimensions while reducing lifetime and reliability. On the other hand, a sub-resonant frequency control method was shown to eliminate the need for dc–dc converters addition as well as preventing IWPTL overrating. The technique is based on imposing bifurcation (or frequency splitting) and varying the operational frequency within certain region below resonance to regulate IWPTL output current. Due to the fact that some applications restrict the operational frequency band, methodology for deriving the design space of sub-resonant frequency-controlled series–series (SS)-compensated IWPTL (SS-IWPTL) operating under frequency constraints with constant current (CC) output is proposed in this work. The algorithm identifies all feasible combinations of loosely coupled transformer (LCT) coils self-inductances and coupling coefficients for expected ranges of input–output voltages and prescribed operational frequency band, allowing to maintain CC output. Simulations and experiments are carried out to verify the proposed methodology.

Improved auxiliary inductive coil connectors in DC boost converters with high voltage gain for renewable energy source applications

&lt;span lang="EN-US"&gt;This study investigates an auxiliary technique for the integration of inductive coil connectors (AIIC) within a single switched DC converter with high voltage gain for renewable energy source applications. The aim is to develop and improve the rate of voltage gain for both coils by using inductive coil connectors (coupling inductance) on the input side that goes through the ratio operator of both inductive coils of the high frequency transformer by having the prototype power circuit operate at a switching frequency 80 kHz. Experimental results show that the output power is at 125 W, output voltage is at 325 V, and input voltage is at 36 V. Furthermore, the duration of change of critical waves of the duty condition was analyzed to confirm that the results were consistent with the proposed technique.&lt;/span&gt;

TROUBLESHOOTING TEMPERATURE GAUGE ON CONTROL PANEL OF ENGINE 3066 AT ALAT BERAT WORKSHOP OF POLITEKNIK NEGERI JAKARTA

Troubleshooting on the temperature gauge on the engine control panel 3066 with the serial number is 7JKa method used to find the cause of the problem with the temperature gauge. The temperature gaugecontained in the 3066 control panel engine does not work while running. Therefore, this research aims todetermine the cause of the temperature gauge on the 3066 control panel engine not functioning. The formof this research is to take data on the method of problem solving and repair of temperature gauges that areexperiencing problems by buying new components that do not use transformer step-ups. Instrumentationdata in literature research, data, visual inspection and making changes to temperature gauges. The resultsof conducting literature studies, studying data, visual inspection, and replacing the temperature gauge witha new one on the 3066 control panel engine, get the root of the problem of damage to the coil of the stepup transformer because the input voltage is too large. Keywords : Troubleshooting, Control Panel, Heavy Equipment, Temperature Gauge