基于损耗分析的大容量高频变压器铁芯材料选型方法

铁芯材料的选择对大容量高频变压器的磁拓扑性能具有决定性影响,而损耗特性最为关键。为此,针对高频方波激励,采用改进的Steinmetz公式分析了变压器3种常用磁性材料即铁氧体、纳米晶和非晶材料的损耗特性与频率、磁通密度的关系,并给出了磁性材料损耗密度的三维表征图。在对损耗密度进行分析的基础上,将铁芯总损耗与高频变压器视在功率的比值定义为损耗因子,并依据损耗因子的三维表征图与实例分析,结合工作频率和体积等因素比较了3种典型磁性材料所制成的铁芯的损耗特性。分析指出,损耗因子是衡量高频变压器损耗特性优劣的重要指标,以最低损耗因子水平结合体积与成本因素进行分析,可作为铁芯材料的具体选择准则。

Material Selection Based on Loss Characterization for High-power High-frequency Transformer Cores

Magnetic material has a decisive effect on the performance of high-power high-frequency transformer,especially on the loss characteristics.Regarding to high frequency square-wave excitation,the modified Steinmetz equation was adopted to analyze the relationship between the transformer loss characteristics and frequency as well as magnetic flux density,and three-dimensional expression of the magnetic material loss density was given.The concept of loss coefficient was proposed and the loss characteristics of three typical magnetic materials were analyzed and compared by taking into account of the factors such as working frequency and volume,on the basis of three-dimensional expressions.Analyses suggest that loss coefficient is an important indicator to evaluate the core loss of high-frequency transformers,and the lowest loss coefficient together with volume and cost analysis can be the selection criteria for core materials in high-power high-frequency transformer.