A Study on Calculation and Mitigation of Minor Hysteresis Loss of Magnetic Materials on Inductors, and High-Efficiency Utility Interactive Inverters utilizing Low Loss Inductors

本研究研究了PWM逆变器高频开关作用对电感磁芯产生的小磁滞损耗，并提出了一种新的损耗计算方法。本研究的主要成果有：1)电感磁芯小磁滞损耗精确测量方法的研制：在功率变换器的设计过程中，准确的损耗预测与计算是最重要的问题之一。对功率半导体损耗的计算方法进行了研究，并提出了许多有用的方法。而对于直流斩波电路和交流逆变电路中使用的电感的精确有效的损耗计算，目前还没有得到很好的研究。造成这种情况的主要原因是难以掌握磁性材料的非线性现象。本文的研究重点是精确测量随功率变换器工作条件变化而动态变化的磁性材料的磁滞损耗。研究了斩波电感上动态微滞回线的测量方法。并成功开发了基于B-H分析仪的精确测量方法。在测量结果的基础上，提出了一种新的损耗表示方法，即损耗图，可以计算斩波电路任意条件下的电感铁芯损耗。该结果与实验结果吻合较好。2) PWM逆变器上交流滤波电感铁损计算的研究进展。研究了在PWM逆变电路中工作的交流滤波电感的铁损。与直流斩波电路相比，PWM逆变器上交流滤波电感的动态迟滞轨迹具有不同的特性。B-H平面上轨迹最关键的特点是调制信号引起的轨迹不形成闭合形状，因此很难计算每个开关周期的铁损耗。在这项研究中，研究人员开发了一个准闭环概念，可以预测每个开关周期的铁损失。利用这种方法，研究人员发现，不同的PWM调制方式，铁损耗的损耗分布差异是完全不同的。这个结果清楚地证实了为什么电感上的损耗随调制方法的不同而不同。少

In this research, minor-hysteresis-loss on the inductor magnetic core which is caused by the high-frequency switching action of the PWM inverters has been studied and also a novel loss calculation method is invented. Also, effective design method in which accurate loss estimation taking in to account is proposed by utilizing the novel calculation method Major achievements on this research are as follows,1) Development of Precise Measuring Method of Minor-Hysteresis Loss on the Inductor Core :On the design process of power converters, accurate loss prediction and calculation are one of the most important issues. The loss calculation method on the power semiconductors has been studied and many useful methods have already been proposed. On the centrally, precise and effective loss calculations of the inductors used on the dc chopper circuit and ac inverter circuit did not have been studied well. The main reason for that is difficulty of grasping the nonlinear phenomenon of the magnetic ma … More terials on the inductor. This study focused on the accurate measurement of magnetic hysteresis loss on the magnetic materials which dynamically changes according to the operation condition on the power converters. The researchers have been studied the measuring method of dynamic minor-hysteresis loop on the chopper inductor. And, accurate measuring method based on the B-H analyzer is successfully developed. Based on the measured results, a novel loss expression method, which we call it "Loss map", is also proposed which enables to calculate the inductor core loss at arbitrary condition of the chopper circuit is invented. This result confirms the experimental results very well.2) Development of Iron Loss calculation of ac Filter Inductor on the PWM Inverter.Iron loss of ac filter inductor of which operates in the PWM inverter circuit is developed. The dynamic hysteresis locus of the ac filter inductor on the PWM inverter has different characteristics compared to that on the dc chopper circuit. The most crucial feature of the locus on the B-H plane is that the locus caused by the modulation signal does not form a closed shape, and hence it is difficult to calculate the iron loss in each switching period. In this study, the researchers have developed a quasi closed loop concept which enables to predict the iron loss on each switching periods. By using this method, researchers have showed that the difference of loss distribution of the iron loss is completely different depending upon the PWM modulation method. This result clearly confirms why the loss on the inductor is different depending on the modulation methods. Less