Figure 4: Harmonic content for single pulse width modulation

Single Pulse Width Modulation

The harmonic content in the voltage v_o can be reduced by using several pulses in each half cycle. The generation of the gating signal is done by comparing a reference signal with a triangular carrier waveform ( Figure 5 ). The generated gate signals are shown in Figure 5 . The frequency of the reference signal f_r and the carrier signal f_c determine the number of pulses per half cycle ( n_p) as

                                                                                (8)

The instantaneous output voltage (v_o) and the current for resistive and inductive loads are shown in Figure 5 . The output voltage in terms of Fourier series is given by

                                    (9)