Generation of noncharacteristics harmonics generated by adjustable speed drives

The generation of the noncharacteristics harmonics in AC supply feeding adjustable speed drives is experimentally investigated, taking into account the effect of the modulation index, the DC filter cutoff frequency and the output frequency of the inverter. Test performed included a single ASD connected to the mains, two inverters connected to the DC link and two ASDs connected to the grid, all under balanced supply and load. The behavior with an unbalanced supply and balanced load is also reported.