Dead time and semiconductor voltage drops are an inevitable feature with pulse width modulated power converters. Both influence the power converters output voltage spectrum: semiconductor voltage drops can cause a DC voltage component, whereas dead time causes the fundamental harmonic amplitude to decrease, as well as enhances output voltage THD. Semiconductor voltage drops, if evenly distributed among semiconductor switches, cause only a degradation of the output voltage fundamental harmonic amplitude. If unevenly distributed, they can cause a DC voltage component, which can, in return, cause a large DC current component, in case of a low ohmic impedance load. Dead time is more influential for low amplitude modulation ratios and high frequency modulation ratios. Dead time and semiconductor voltage drops influence on output voltage spectrum must be calculated, in order to compensate their influence. A novel output voltage spectrum analysis method was proposed, based on the fact that a Fourier series of a periodic function is the best possible approximation on it's fundamental period. The proposed method enables determining the Fourier coefficients' integration limits in time domain, which enables incorporating dead time influence. The proposed method is valid for an arbirtary modulation signal and an arbirtary carrier signal waveform, so dead time influence change depending on the load current direction can also be accounted for. The influence different semiconductor voltage drops have on the output current DC component was shown via simulation, for different voltage drop values and distribution combinations. Dead time influence on the output voltage fundamental harmonic amplitude and phase shift was shown via simulation for several amplitude and frequency modulation ratios. The proposed spectrum calculation method was used to show the influence dead time and semiconductor voltage drops have on the output voltage spectrum. The method was tested against a well-known example, the naturally sampled two-level converter sine wave modulation. Dead time influence on the three level neutral point clamped inverter was shown for a modified modulation signal. The modulation signal was modified by injecting a zero-sequence signal, which eliminates the neutral point voltage ripple. An open-loop compensation method for the fundamental output voltage harmonic, based on the analysis results, was proposed. The proposed compensation method was verified via a simulation experiment. This experiment featured three switching frequencies and five dead time durations. All simulations were conducted for a low amplitude modulation ratio, and for both modulation signal waveforms. The proposed method was further tested on a laboratory model with 1200~V/300~A IGBT modules, for two modulation signal waveforms, three switching frequencies and five dead time durations. The proposed compensation method was implemented using fixed point arithmetics. Both simulation and experimental results show that the proposed compensation method successfully compensates the dead time and semiconductor voltage drops influences on the output voltage fundamental harmonic. The proposed compensation method is straightforward, easy to implement and resource inexpensive. The compensation method was tested for multiple modulation signal waveforms, and for multiple dead time durations. It was shown that the proposed compensation method successfully compensates dead time and semiconductor voltage drops for a variety of modulation signal waveforms, switching frequencies and dead time durations.