Variable-step DFT Algorithm to Speed Up Optimization Routines Applied to a Three-Phase Interleaved Vienna Rectifier

Abstract

A variable-step Discrete Fourier Transform with reduced complexity for the electrical quantities of power converters is introduced, as to reduce the time consumption of optimization routines which depend on voltage and current frequency spectrum derived from a complex time domain waveform typically generated by a numeric simulation of a power converter. A variable-step decimation algorithm is also described, reducing the number of points by detecting level transitions and/or derivative discontinuities. The algorithms are validated for a Three-Phase Vienna Interleaved Rectifier voltage and current waveforms employing Discontinuous Pulse Width Modulation.