摘要：AbstractMultilevel converters are used for DC/AC power supply conversion, which is often applied in electric vehicle (EV) motor drives. AC conversion is done by a stepped output voltage, which provides a near-sinusoidal voltage with its fundamental frequency, but contains some higher harmonics. The elimination of several harmonics is fully implemented and well described in numerous publications, see Chiasson et al. (2003, 2004, 2005); Li et al. (2010); Tarisciotti et al. (2014), and Majed et al. (2014). In these papers the first set of undesired harmonics was eliminated, which in general was done by solving an equivalent system of equations using different methods such as resultants, Newton-Raphson (Chiasson et al. (2003)) and Optimal Minimization of Total Harmonic Distortion (OMTHD) technique, see Li et al. (2010). Higher harmonics stayed unrecognized to these optimization algorithms and delivered an undesired power spectrum to the total harmonic distortion (THD) of AC conversion.This paper presents a novel approach to the global THD-optimization of three-phase systems taking into account all harmonics up to infinity. This global optimization is implemented using interval arithmetic, see Hansen and Walster (2003), which neither need a convex objective function nor continuous-differentiable function. Interval arithmetic computes guaranteed intervals containing the global minima. The optimum is computed with an algebraic objective function, which is derived from Parseval’s theorem on a 2πperiodic function.
