Influence of the Inverter´s Modulation Technique on the Audible Noise of Electric Motors

Noise emissions of inverter-driven electric motors are highly influenced by additional electromagnetic noise generated by the current harmonics from inverter operation. The amplitude and the frequency of these harmonics depend on the modulation technique applied in the power electronic converter. The purpose of this paper is to highlight the important role that modulation techniques play in noise generation in variable-speed drives and to analyze the different characteristics of current harmonics and generated noise. A good understanding of the available choices and their characteristics, advantages, and limitations is necessary in order to optimize the acoustic design of the “motor-converter” system.