No-load Core Loss Characteristics of High-frequency Transformers with Different Nanocrystalline Core Structures
To study the core loss distribution characteristics of high-frequency transformers with different nanocrystalline core structures,three types of nanocrystalline cores such as U-shaped,triangular and O-shaped with working frequency of 10 kHz and rated capacity 20 kVA are selected,and the flux density and iron loss distribution at different positions of the core under no-load condition are compared.Furthermore,the influence of the corner radius on the local core loss charac-teristics is also investigated.The results show that the loss density distribution of the O-shaped core is relatively uniform.For U-shaped and triangular cores,the loss density is evenly distributed in the straight region of the magnetic circuit.In the radial direction of the corner region,the rate of decrease in loss density is initially high and then slows down,while in the tangential direction,the loss density increases initially and then decreases.The maximum loss density at the corner of the U-shaped and triangular cores is significantly higher than that in the straight region.By appropriately increasing the inner radius of the corner,the maximum loss density of the core can be significantly reduced.Experimental results show that the no-load losses of the U-shaped,triangular,and O-shaped cores are 37.3 W,50.5 W,and 20.5 W,respectively.Ad-ditionally,the highest local hotspot temperatures recorded are 46.5℃,55.2℃and 35.0℃,respectively,which are significantly higher than the average temperature of the core.
high-frequency transformercore structureno-load iron lossloss densityloss distribution
万方数据
维普
