超磁致伸缩执行器热损耗模型与实验

针对高频大电流驱动下超磁致伸缩执行器发热严重影响其有效位移输出精度的问题，采用管式冷却结构措施以抑制执行器温升.根据欧姆定律建立交流(DC)与直流(AC)电同时作用下执行器电阻损耗理论模型，基于麦克斯韦方程推导出磁致伸缩棒内部磁场方程及涡流损耗模型，从复数磁导率虚部出发得出磁致伸缩棒磁滞损耗模型.求解上述模型可知:当驱动频率达到50Hz时，磁致伸缩棒损耗占执行器总损耗5%.通过搭建执行器热特性测试实验台，实验测得执行器损耗与理论计算结果吻合良好；管式冷却具有较好的冷却效果，可将磁致伸缩棒温度控制在50℃以内，其实验结果与有限元仿真结果最大误差为3℃以内，进一步验证热损耗计算公式有效性并为精密超磁致伸缩执行器的设计和应用提供了理论支持. 

Theoretical analysis and experiment of power loss in giant magnetostrictive actuator

The performance of giant magnetostrictive actuator (GMA) is seriously affected by temperature rising under high frequency large current.In order to reduce GMA's temperature,pipe cooling was presented and its working principle was introduced.According to Ohm's law,coil loss was obtained under the action of alternating current (AC) and direct current (DC).Based on Maxwell equation and imaginary part of complex permeability,the eddy current loss and hysteresis loss of GMM were deduced,respectively.Then,it was found that GMM power loss accounted for 5 ％ of GMA power loss when the drive frequency reached 50 Hz.Finally,the experiment platform of GMA thermal characteristic was built and the result indicated that the calculation of GMA power loss was in good agreement with that of theory.And the pipe cooling had good cooling effect on GMA temperature.GMM rod temperature could be controlled within 50 ℃.The maximum error of the experiment and simulation was within 3 ℃.The research result further indicates the calculation of GMA power loss is valid and has a significant guidance for the design and application of GMA.