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Ekctrical & Computer Eng ince ring: An International Journal < ECU) Volume4. N untber 3. Septeniber 2015

• Slaircasc waveformquality

• Common-modę (CM) vol lagę

• Switching frequency

• Inpul cuirent

Slaircasc wawform qualitv: Mullilewl comerters generale the oulpul voltages with vcry Iow dislorlion. and also can reducc ihe dv/dt stresses: ihercforc problcms of electromagnetic COmpalibilily (EMC) can also be reduced.

Comnton-modc (CM) valtagc: Mullilevcl converters generale smaller CM vo!lage which results in reduced slress in ihe bearings of a motor connected lo a mullilevel motor drivc. Purlhemiorc. by using the advanced modę lechnology ihe CM vollage can be reduced.

Switching frcqucncy: Mu lii lewi conwrlers can operate at boih fundamenlal switching frequency and high switching frequency Pulse widlh modulation (PWM). Ilshould be noted ihal lower switching frcqucncy usually means lower switching loss and higher efficiency.

Inpul currcnt: Multilevel conwrteis can draw inpul currenl with Iow distortian comparatively [5][20-28].

Mullilevcl converters has few disadvantages likc it require morę devices which inereases system cost comparatively hencc probability of a devicc failure inereases [261 [29-31].

5. Matlab/Simulation And Results

5.1 For Neutral point clamped multilevel converter siniulation results

Simulation results arc shown in this section. for Neutral point clamped mullilewl converter arc displayed front Figurę 5 to Figurę 8. As shown in figurę (I) in NPC topolog)' the total voltagc or inpul voltagc V* divides across the capacitor after tltal the operation of switches decides the oulpul vollage that is the three lcvcl conwrter vollage is divided in Iwo parts actuss the two capacitor Ci and C’i.e. + ^ and for simulation puiprtse the value of inpul vollage isequal to 100V and the output-voltage wavcform is shown in Figurę 5 .similarly lite simulated response lorfivc level .seten lcvcl and nine lewls arc displayed in Fig.6.7.and 8 rcspectivcly.

Figurę 5.Wavcform of output-vohagc withrcspcct to tirne of thrcc lcvcl neutral point clamped multikwel

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