DEVELOPMENT OF SWITCHING MODE RECTIFIERS: MODELING, CONTROL AND MULTI-MODULE OPERATIONS

Autor: Sheng-Hua Li, 李聖華
Rok vydání: 2004
Druh dokumentu: 學位論文 ; thesis
Popis: 92
The major purposes of this dissertation are to perform circuit design, dynamic modeling, control and multi-module operations for switch-mode rectifiers (SMRs). First, the analyses and quantitative designs for a single-phase ( ) SMR and a zero voltage transition (ZVT) soft switch-mode rectifier (SSMR) are made. The digital signal processor (DSP) based control environment is established, and the quantitative and robust voltage digital controls are performed to let the designed SMRs possess good line drawn power quality under well-regulated DC output voltage. Secondly, the multi-module operations of the established SMRs are studied. These include the parallel operation of multiple SMR modules and the development of SMR via the connection of SMRs. For the first topic, a DSP-based parallel SMR system is established. A current sharing control scheme based on master/slave concept is designed to yield good current sharing performance between modules. As to the development of SMR, the proposed system consists of three SMRs, two center-tap autotransformers and three changeover switches. As any one module is randomly faulted, the -connected SMR automatically becomes modified T-connected. The three-phase switch mode rectification is normally operated with good power quality in line drawn currents. If two modules are faulted simultaneously, the remaining single module performs the SMR operation to continuously provide DC output voltage. In all cases, the DC output voltages are well regulated by the designed robust controller. Finally, in the performance improvement studies for hysteresis current-controlled (HCC) PWM scheme, a robust fixed-frequency HCC PWM control scheme for SMR is developed. Through robust harmonic spectrum shaping, the constant frequency control performance is insensitive to the changes of system parameters and operating conditions, and the low frequency harmonics possess smaller magnitudes. In addition, the robust HCC PWM schemes with linear and random varying hysteresis bands are also developed to let the harmonic spectra of the SMR be uniformly distributed.
Databáze: Networked Digital Library of Theses & Dissertations
Externí odkaz: