The aim of the thesis is to answer one of the problems that still suffers the Three-Level Neutral-Point-Clamped Converter. This drawback is the decrease in the reliability of the converter due to the increase in the number of semiconductors that is necessary to use, which adversely affects the costs of maintenance and repair of the converter.

In order to minimize this problem, various solutions are posed aimed at increasing the reliability of the converter by analyzing in detail its principle of operation and their advantages and disadvantages.

Additionally, some of the topologies presented can improve the performance of the converter during normal operation periods in the absence of faults, allowing completely eliminate low-frequency oscillations in the neutral point voltage. This enables that the modulation strategy was focused on issues such as the improvement of the quality of voltage and current waves or the minimization of switching losses. In this sense, a modulation technique that minimizes the switching losses of some of the fault-tolerant topologies presented in the thesis is also introduced, achieving higher efficieny than the standard three-level Neutral-Point-Clamped converter under modulation SPWM (Sinusoidal Pulse Width Modulation) and optimum performance from the point of view of neutral point voltage.