Question

Q1- The three-phase converter circuit of Fig. 1, Vd 300 V, is applied with PWM switching (mo 0.5, m 39), and the fundamental frequency is 50 Hz. Calculate the rms values of the fundamental-frequency voltage and some of the dominant harmonics in the line voltage (line-to-line). The generalized harmonic lookup table is given below the diagram. S1 S5 dc Fig. 1 Table 8-2 Generalized Harmonics of vL for a Large and Odd m/ That Is a Multiple of 3 0.2 0.4 0.6 0.8 0.1220.245 0.367 0.4900.612 m,±2 0.0100.037 0.080 0.135 0.195 me t 4 2m, + 1 0.0050.011 0.1160.2000.227 0.192 0.111 0.0080.020 3m± 2 0.027 0.085 0.124 0.108 0.038 0.007 0.029 0.064 0.096 0.1000.096 0.005 0.064 0.042 0.0210.051 0.073 0.010 0.030 Note: (Vu)Vd are tabulated as a function of ma where (Vu)h are the rms values of the harmonic voltages

Answer 1

Note the standard formulae used for PWM inverter.

ma- 1 and ma 0-max -f 6 O.2135 2