Flicker produced by harmonics modulation

Flicker effect caused by voltage harmonics modulation is discussed. Simple functions are used to show that harmonic components, despite satisfying the specific harmonic limits, may produce flicker due to combined amplitude modulation (AM). Computer simulations, based on the International Electro-technical Commission (IEC) methodology, are numerically validated and then applied to calculate the instantaneous flicker sensation, resulting from different combinations of harmonics modulation. The results are also confirmed in laboratory tests using a flickermeter to measure the flicker levels obtained by synthesizing the same type of signals on a programmable function generator.