Three-level Neutral-Point-Clamped Rectifier under Unbalanced Grid Source

• Main Authors: Chien-Wei Lan, 藍健瑋
• Other Authors: Chung-Ming Young
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/a8v874

碩士 === 國立臺灣科技大學 === 電機工程系 === 105 === This thesis proposed a modified unity power factor controller to improve the line current unbalance factor for a three-level Neutral Point Clamped (NPC) rectifier under unbalanced grid source. The delay signal cancellation phase-sequence separation method is adapted to the unity power factor controller to obtain the desired positive-sequence component from the unbalanced grid source as the reference signals. This thesis also investigate the dc bus voltage ripple and finds that the amplitude, frequency, and phase are significantly affected by the unbalanced grid source. The relationship between the ripple and the unbalanced conditions could be used for compensation and improving the ac line current conditions. A MATLAB-based simulation system was built to evaluate the performance of the proposed converter. An experimental test bench, which employs a digital signal processor (TMS320F28069), with 750VDC/ 2k W rating was established for measurement. Finally, both simulation and experimental results demonstrate the validity of the proposed scheme.