A New Approach to Harmonics and Interharmonics Generation in General VSI/CSI Converters

Generation of harmonics and interharmonics (which are defined as non-integer multiplies of fundamental or switching frequency) and their several different effects on PCC (point of common connection) for grid-connected VSI/CSI systems e.g. ASD (adjustable speed drives) or VSR systems is an important issue for recent industrial applications. In order to describe the generation of harmonics and interharmonics in generalized power converters, a new approach is proposed based on the frequency-domain model concept and a novel analytical model is derived and discussed for commonly used control scheme of d-q reference frame, which is capable of explaining the generation and compensation of harmonics specifically in some cases that previous models can´t be conveniently applied. Several effects of feedback control and compensation blocks are considered, analyzed and simulated. Moreover, experimental results are also provided to investigate the validity of analysis and simulation