Supraharmonics reduction in NPC inverter with random PWM

The international standardization community is currently reviewing the harmonic distortion limits in the frequency range 2 to 150 kHz, referred to as supraharmonics. Power electronics has emerged as a ubiquitous technology, which also plays a critical role in this subject. Broadly speaking, the reduction of emission in the lower-frequency ranges appears to result in an increase in supraharmonic emission by equipment. The paper presents measurements of waveform distortion from several illustrative facilities and loads. Until now, power electronics converter has been an important source of waveform distortion, even in this frequency range, but, as stated in this paper, can also be the key to mitigate distortion, when technologies like multilevel converter and random pulse with modulation are properly employed.