功率理论定义中的参考点选择方法

Reference point selection method in definition of power theory

功率理论定义中的参考点选择问题是一个非常基础而又没有得到统一解决的问题。首先根据多端电路端电流必须满足电路基尔霍夫电流定律(KCL)的要求,得到了参考点选择时受到的约束条件;其次,证明考虑约束条件时参考点选择的唯一性,并从众多可供选择的参考点中找到唯一满足约束条件的参考点;最后,给出了参考点选择的具体方法,并从工程应用角度对参考点选择方法进行简化。以广义瞬时功率理论为例,对所提方法进行进一步解释和兼容性讨论,并对广义瞬时功率理论采用的电流分解方法与功率定义方法进行修正,从而使针对具体电路的功率量成为唯一确定值。

The problem of reference point selection in the definition of power theory is very basic but has not got a uniform solution. Firstly,the constraint condition of reference point selection is determined according to the demand of KCL（Kirchhoff’s Current Law） which must be meet by the terminal currents of a multiterminal circuit. Secondly,the uniqueness of the reference point selection under the constraint condition is proved,and the unique reference point satisfying the constraint condition is selected from many alternative reference points. Finally,the specific method of reference point selection is given,and the reference point selection method is simplified from the perspective of engineering application. Taking the generalized instantaneous power theory as an example,the proposed method is further explained and its compatibility is discussed,and the current decomposition method and the power definition method employed by the generalized instantaneous power theory are modified to make the power of a specific circuit be a unique determined value.