AccuSine RMS current switching frequency

[Sebastian_P]

Hello

I have read something about three types of switching frequency called r1, r2 and r3 in Accusine and @Yan_Zhang  reply me this:

r1: the frequency range which lower than IGBT switching frequency.

r2: the frequency range which around IGBT switching frequency(15kHz~21kHz).

r3: the frequency range which higher than IGBT switching frequency.

The values in the table represents the RMS value current or voltage in according frequency range.

But I can´t understand completly the concept. I know that the AccuSine has one switching frecuency privided for their IGBT. So why there is three ranges called r1, r2 y r3? What is the relationship between electronics IGBT switching frecuency and r1, r2, r3? Could be that these ranges are separated by software and represents differents groups of Harmonics to compensate? 

Thanks.