Design of High Performance Single-phase Three-level Bidirectional Power Converters

• Main Authors: Ling-Wei Kung, 孔令煒
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/87duu5

碩士 === 國立臺灣科技大學 === 電機工程系 === 104 === This thesis is concerned with the design of low total harmonic distortion (THD), high efficiency, single-phase bidirectional power converters. Under stand-alone inverter operation mode, voltage and current as well as phase-compensated peak-voltage closed-loop controls are proposed. The computer simulation confirmed phase-compensated peak-voltage closed-loop control strategy can provide a single-phase source with fast response, stable and low harmonic distortion power to load. In addition, the dc-link voltage closed-loop control, incorporating with a digital all-pass filter, can create a voltage with angular position lagging 90 degrees behind single-phase input voltage to calculate the peak input voltage for the generation of unit sine reference waveform for current command. The proposed dc-link voltage closed-loop control strategy can reduce the current harmonics of ac side and improve power factor. In this thesis, the 32 bit digital signal processor,“TMS320F28335”, is used as the core of the controller. Digital all-pass filter, dc link voltage and phase-compensated voltage peak closed-loop control software are programmed and executed by C language, thereby effectively reducing circuit components and enhancing system reliability. The experimental results for 1kW system under stand-alone inverter mode with phase-compensated peak-voltage closed-loop control show that the THD of output voltage is 2.76% and the efficiency is 95.2% for three-level inverter. Comparing with the corresponding values of 4.06% and 96%, respectively, of two-level inverter, an improvement of 1.3% in THD with reduction of 0.8% in efficiency for three-level inverter is observed. Besides, the measured results for 1kW system under ac to dc power converter operation mode indicate that the THD of input current is 5.72%, and the efficiency is 88.89%. In short, both computer simulation and experiments verify the high performance of low harmonics and high efficiency of the proposed system.