This paper discusses a method for estimating of the level of pulsations at the output of discrete power converters applicable to on-board electric drive systems with high control accuracy. It is proved that the estimation of the level of pulsations at the output of discrete power converters based on the fundamental harmonic of “smooth” trigonometric Fourier series functions is not accurate and presents a new method of pulsation analysis based on the fundamental harmonic is compared with the peak-to-peak analysis of harmonics based on the analysis of the discrete transient process at the output of the converter. On the basis of the discrete Laplace transform, a methodology for estimating peak-to-peak ripples for uncontrolled and controlled power converters has been developed, taking into account the form of their output voltage and the process of pulse-width modulation. The results presented in the paper are of great practical importance and allow for a more accurate estimation of the output pulsation level in order to improve the quality of control in on-board electric drive systems.