The amplitude of the fundamental voltage drops across the filtering inductances LN are negligible as compared to the amplitude of the mains phase voltages, the voltages across CN therefore are assumed to be impressed and equal to the mains phase voltages.

• 当基本电压从滤波电感降低到LN时，振幅与主电源相线电压相比可以忽略不计，因此我们可以认为通过CN处的电压被输送并且等于主电源相线电压。