变压器中的电磁能量分布与功率传输

Electromagnetic energy distribution and power transfer in transformer

基于电磁场理论讨论变压器的能量传输机制.借助一个简化的变压器模型,以场路结合并对照的方式,通过理论分析和数值验证,讨论了变压器中磁场与感应电场分布、能量分布的特点及对二次侧负载的依赖性;分析和计算了坡印亭矢量.结果表明:铁心中主磁通并不传输能量.它的作用是在空间建立感应电场;感应电场与空气中的漏磁场一起形成坡印亭矢量,实现功率传输.进一步讨论了有功功率和无功功率的传输,给出了坡印亭矢量的空间分布图像,以期建立一个直观的认识.最后,给出了一次侧与二次侧绕组交错叠绕和同轴叠绕两种更加贴近实际情况的例子.

The energy transmission mechanism in transformer was discussed based on electromagnetic theory.Via a simplified transformer model, the characteristics of magnetic field, induced electric field and energy distribution in transformer, and their dependence on the secondary side load were discussed by theoretical analysis and numerical verification through a field-circuit combination way.The Poynting vector was analyzed and calculated.Results show that the main magnetic flux in the core cannot transmit energy,but only induce electric field in space.The induced electric field and the leakage magnetic field in the air form the Poynting vector to realize the power transmission.The transmission of active power and reactive power was discussed further,and the spatial distribution image of Poynting vector was given to build an intuitive understanding. Finally, two more practical examples were briefly discussed,in which the primary and secondary windings were alternately wound or coaxially wound.