Design of Three-Zone Hybrid Pulse Width Modulation Method For Reduced Current Ripple

This paper presents a Three-Zone Hybrid Pulse Width Modulation (HPWM) algorithm for induction motor drives. This paper brings out a method for designing hybrid PWM techniques inVolving multiple sequences to reduce line current ripple. The three proposed hybrid PWM techniques (three-zone PWM) employ three different sequences, respectively, in every sector. Then, the rms stator flux ripple, which is a measure of ripple in line current characteristics have been plotted for all the HPWM and SVPWM algorithms. From which, it is concluded that the SVPWM algorithm gives superior performance at low modulation indices, whereas the HPWM algorithm gives superior performance at higher modulation indices. The proposed techniques lead to a significant reduction in THD over CSVPWM at high line Voltages. A Novel hybrid PWM technique, employing these two sequences in conjunction with the conventional sequence, is proposed. The proposed PWM technique is designed using the Notion of stator flux ripple. A procedure is presented for designing hybrid PWM techniques inVolving multiple sequences for reduced current ripple. The proposed PWM technique results in reduced current ripple over CSVPWM at higher modulation indices. The three-zone technique results in the lowest THD among real-time techniques with uniform sampling. Hence, to achieve the superior waveform quality at all modulation indices, a three-zone Hybrid PWM (HPWM) algorithm has been presented in this paper. To validate the proposed algorithms, several numerical simulation studies have been carried out and results have been presented and compared.