Estratégia de modulação space vector otimizada aplicada ao conversor multinível modular

Abstract

The MMC has been standing out due to its several advantages, such as modularity, the ability to synthesize output voltages with multiple levels, and low THD. The converter also presents a lower voltage on semiconductor devices and eliminates the need for transformers with multiple windings. Thus, the converter presents itself as a good candidate for both medium and high voltage applications. Modulation strategies allied to the control of internal currents and the voltage on the capacitors of the submodules present themselves as one of the main challenges for the topology. This master’s dissertation proposes an optimized SVM strategy applied to the MMC, in which the switching sequences are generated through the minimization of a cost function. The choice of the four switching vectors closest to the reference provides low output voltage harmonic distortion. In addition, the other objectives of the strategy are to ensure the balance of the capacitor voltages of the SM s and also to control the internal currents of the converter arms. Simulation results are presented to demonstrate the good performance of the proposed modulation strategy, as well as to establish a comparison with the phase-disposition and phase-shifted carrier-based modulation strategies. Keywords: Cost Function, Energy Balance, Internal Currents, Internal Current Control, Modular Multilevel Converter, Space Vector Modulation, Switching Sequence.