Determination of Core Losses in Open-Core Power Voltage Transformers

Žiger, Igor; Trkulja, Bojan; Štih, Željko

doi:10.1109/access.2018.2838446

Cited by 11 publications

(12 citation statements)

References 18 publications

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“…This can be verified by comparing the calculation results of the 3-D EMCN for the Lorentz force with those of 3-D FEA under the same load conditions. Grain-oriented steel is commonly used to enhance transformer performance [14], [15]. Thus, the relative permeabilities in each direction (i.e., the x, y, and z directions) are different.…”

Section: B Calculation and Verification Of Lorentz Force Using 3-d Emcnmentioning

confidence: 99%

Load Noise Prediction of High-Voltage Transformers by Equation Applying 3-D EMCN

et al. 2020

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This paper proposes a method for predicting the load noise of high-voltage (HV) transformers. When the transformer is loaded, the electromagnetic force is generated by the interaction between electric and magnetic fields. This force, the so-called Lorentz force, induces the vibration of the winding structure causing the load noise of transformer. Therefore, calculating the Lorentz force plays a crucial role in predicting the load noise. Herein, a 3-dimensional equivalent magnetic circuit network (3-D EMCN) is applied to calculate the Lorentz force, instead of 3-dimensional finite element analysis (3-D FEA) to shorten the computation time. Subsequently, considering the relationship between the sound pressure and the Lorentz force, the calculated force can be applied in the equation for the sound pressure level (SPL), which represents the relative sound pressure on a logarithmic scale. The formula for the sound pressure varies depending on the sound source model. The source model of load noise can be represented as a dipole source because the structure of the transformer windings is considered as an unbaffled speaker. The transformer parameters identified to affect the load noise are additionally considered for more accurate prediction of load noise. The parameters identified to increase the load noise are simply multiplied to the equation, whereas those with the opposite effect are multiplied inversely. Finally, after this compensation process, the accuracy of the load noise prediction equation is calculated as the standard deviation of the differences between the experimental and calculated results.

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Section: B Calculation and Verification Of Lorentz Force Using 3-d Emcnmentioning

confidence: 99%

Load Noise Prediction of High-Voltage Transformers by Equation Applying 3-D EMCN

et al. 2020

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“…The core losses of HFT mainly include hysteresis losses and eddy current losses [30]. The traditional transformer passes through sinusoidal voltage while HFT in Dual Active Bridge (DAB) passes through square wave voltage.…”

Section: Core Losses Of Hftmentioning

confidence: 99%

A discrete state event driven simulation based losses analysis for multi-terminal megawatt power electronic transformer

Zheng

Zhao

Shi

et al. 2020

Trans. Electr. Mach. Syst.

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“…Heat sources include iron [18] and winding losses, which are calculated within the consideration of high-order harmonics. The magnetic flux density can be calculated on the basis of Maxwell equations, and the magnetic vector potential vector can be described as follows:…”

Section: B Electromagnetic-flow-thermal Couplingmentioning

confidence: 99%

“…If the shape function N m (m = i, j, k) is less than 1, then the temperature data of the sub-model can be described: (18) where T D i , T D j , and T D k are node data of the temperature field. Fig.…”

Section: Temperature In Sub-modelmentioning

confidence: 99%

Research on the Thermal-Electric Coupling Behavior Under Compound AC-DC Voltage Within Saddle-Like Electric-Stress Dependence

et al. 2020

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This paper proposes a nonlinear electromagnetic-thermal-velocity coupling model to study the insulation performance of converter transformer, in which the saddle-like electric-stress dependence is considered under compound alternating current-direct current (AC-DC) voltage situation. Firstly, the conductance of transformer oil and oil-immersed pressboard have been measured through constructed threeelectrode experimental system. An interesting electric-stress characteristic, which is saddle-like electricstress dependence is obtained and counted in the thermal-insulation analysis in the proposed model. Then, the high-order harmonics of compound AC-DC voltage have been considered in the built electromagneticthermal-velocity coupling model. Additionally, the impact of non-uniform temperature result has been mapped to the electric field domain through interpolation method, due to different meshes between the flowthermal and electric fields in accordance with distinct computational characteristics. Finally, the performance of nonlinear thermal-electric coupling properties, including saddle-like electric-stress dependence, have been considered in the proposed coupling model. Results determine that saddle-like thermal-electric dependent properties would considerably change insulation capability, compared with results from the traditional method. Even intensity field of some sampling points could jump more than 1.6 kV/mm. Therefore, it is essential to evaluate the insulation design by practical saddle-like electric-dependent properties. INDEX TERMS Compound ac-dc voltage, converter transformer, electric-stress dependence, finite element sub-model, electromagnetic-thermal-velocity coupling.

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Determination of Core Losses in Open-Core Power Voltage Transformers

Cited by 11 publications

References 18 publications

Load Noise Prediction of High-Voltage Transformers by Equation Applying 3-D EMCN

Load Noise Prediction of High-Voltage Transformers by Equation Applying 3-D EMCN

A discrete state event driven simulation based losses analysis for multi-terminal megawatt power electronic transformer

Research on the Thermal-Electric Coupling Behavior Under Compound AC-DC Voltage Within Saddle-Like Electric-Stress Dependence

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