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The effect of sampling frequency on digital sinusoidal pulse width modulated (SPWM) output of phase-shifted carrier-based multilevel voltage source inverter (VSI) and the characteristics of output voltage and load current has been discussed here. The generalised equation of digitally controlled phase-shifted carrier-based multilevel VSI output voltage is derived using double Fourier integral solution. The Jacobi–Anger expansion has been used to obtain the integral solution. Time-domain analysis has been used to establish the relation between sampling frequency, carrier frequency, and fundamental frequency, at different modulation indices for n-level VSI. The load current of VSI is stepped in nature due to stepped variation in the output of the digital SPWM. Therefore, the low-frequency harmonic components closer to the fundamental frequency appear in the frequency spectrum. The variation of total harmonic distortion with respect to multisampling factor (sampling to carrier frequency ratio) has been discussed at different modulation indices for multicarrier-based multilevel inverter. The analytical results are verified through simulation and laboratory experimental results. [ABSTRACT FROM AUTHOR]

This paper characterizes the sampling effect in digital sinusoidal pulse width modulation (SPWM) of voltage source inverter (VSI). The time-domain analysis presented in this paper establishes the relation between the fundamental frequency, carrier frequency, and the sampling frequency at different modulation indices of the SPWM. The analysis investigates the effect of sampling frequency of the digital controller on the output of the VSI. It is shown that the low-frequency harmonic components appear in the frequency spectrum of the VSI output voltage due to sampling. As a result, the output current of digitally controlled VSI is stepped in nature. The double Fourier integral solution of the switched waveform for inner and outer integral limits has been used to derive the expression. The integral solution is obtained using Jacobi-Anger expansions. The generalized results developed in this paper are useful to investigate the sampling effect in high switching frequency DSPWM. The proposed sampling effect has been analyzed for SPWM of single-phase H-bridge inverter. The analytical results are verified using simulation and experimental results. The experimental results have been obtained with the use of field-programmable gate array (FPGA) as a digital controller. [ABSTRACT FROM PUBLISHER]

This paper investigates time-domain analysis of sampling effect in digital pulsewidth modulation (DPWM) of dc–dc converters. The relation between the sampling delay, duty ratio, and multisampling factor (sampling to carrier frequency ratio) has been characterized. The sampling delay of the digital controller used for DPWM of the dc–dc converter has close relation with the actual pulsewidth-modulation output. An increase in the multisampling factor can reduce the delay effect of the DPWM. The output voltage varies as a stepped function of the duty ratio instead of the linear function as observed in ideal modulation. It is shown in this paper that this delay is a periodic function of the duty ratio. The effect of variations in the sampling frequency, switching frequency, and modulation index has been analyzed. The proposed sampling effect has been verified analytically for the buck, boost, and buck–boost dc–dc converters. The experimental results for the buck and boost converters have been obtained with the control circuit realized through a field-programmable gate array-based digital controller. [ABSTRACT FROM PUBLISHER]