The Implementation and Performance Evaluation of $3\phi$ VS Wavelet Modulated AC–DC Converters

Abstract

This paper presents the implementation and performance testing of the wavelet modulation technique for operating three phase, voltage source (VS), six-pulse ac-dc converters. The wavelet modulation technique is realized by a nondyadic-type multiresolution analysis (MRA), which is constructed using sets of dilated and translated scale-based linearly combined wavelet basis functions. A dc reference signal is processed using this MRA, where three sets of groups of nonuniform recurrent samples are created by the analysis stage. The synthesis stage of the nondyadic MRA reconstructs the dc reference signal using three sets of dilated and translated scale-based linearly combined synthesis wavelet basis functions, which are used to activate the switching elements of the ac-dc converter. Simulation and experimental performances of the 3φ ac-dc converter, that is, operated by the wavelet modulation technique, are investigated for supplying static and dynamic load types. Performances of the 3φ wavelet modulated ac-dc converter are also investigated for unbalanced input 3φ voltages. Simulation and experimental results show that high magnitude of output dc components, and significant reductions of input and output harmonic components of the 3φ VS ac-dc converter can be accomplished using the wavelet modulation technique. These improvements in the performances of 3φ ac-dc converters are further demonstrated through comparisons with the pulse-width and space-vector modulation techniques under similar conditions of loading and 3φ input voltages.