A New Space Vector Modulation Technique for a Hybrid 2/3-Level Inverter with Minimized Switching Losses

This paper proposes a new space vector modulation (SVM) method for the hybrid 2/3 level. The classical SVM subdivides each sector of the space vector diagram into three regions. In regions two and three, only the configuration of two large vectors and one short vector is used to estimate the reference voltage (V-ref). The configuration of two short vectors and one large vector is omitted, which cannot guarantee a perfect approximation of the reference vector for all the modulation indices. In the proposed SVM, each sector is subdivided into seven different regions, and all possible configurations of vectors will be used to ensure a better approximation of V-ref. Besides, a new switching strategy is suggested to ensure minimum switching losses and to regulate the neutral point voltage with high precision. The new SVM algorithm is compared through a simulation and experimental validation to two methods, namely the conventional SVM algorithm and sine pulse width modulation (SPWM) method. The results showed the superiority of the proposed SVM algorithm over the SPWM method and the prior SVM method. With the proposed SVM algorithm, the total harmonic distortion has been effectively reduced for all modulation indices. Besides, the DC-link voltage is fairly shared between the inverter capacitors. On the other hand, a co-simulation between MATLAB/Simulink and PLECS software is performed for thermal modeling and power loss analysis using the three compared methods. It turns out that the proposed switching strategy reduces the switching losses effectively for low and high modulation indices.