Electrotechnical Systems

125Simulation of Power Electronics Devices

third harmonic) with the triangular carrier waveform having frequency F

c

; at that,

both the single-polar and bipolar carrier waveform can be used. Each block is con-

trolled independently, and triangular carrier waveforms of the blocks are shifted one

after the other by 2π/n, in order to provide the minimal THD value for the inverter

phase-to-phase voltage. The pulse generation for these cases is shown in Figures 4.41

and 4.42, respectively. In the rst case, the phase voltage harmonics are concentrated

around the frequency nF

c

; in the second case—around the frequency 2nF

c

which

makes its ltration easi ...