The systems which contain coarsely quantized signals are commonly found in applications where the actuators and/or sensors can only output a finite number of levels. This thesis focuses on the problem of synthesizing a finite-level control force for a certain control task, first presenting a systematic design method based on the theory of sliding modes and then applying it to the designs of the class-D audio amplifier and synchronous buck converter.
At the first part, a novel three-level modulation technique for a class-D audio amplifier is designed by the sliding mode control theory. The simulated and experimental results conform to the excellent performance of this three-level modulation scheme. In particular, the proposed modulation scheme improves the poor efficiency of a conventional two-level class-D audio amplifier when the audio input signal is small, also excludes the output LC filter. The experiment shows that the designed three-level class-D amplifier achieves a minimum total harmonic distortion plus noise of 0.039% and an efficiency of 85.18%. At the second part, the controller of a synchronous buck converter is designed. The proposed self-oscillating controller stabilizes the buck converter in sliding mode, without the need of a triangular wave generator like the conventional PWM method. A 12V/1.5V synchronous buck converter with proposed control is built in the laboratory. The experiment shows 0.66% of the static output ripple and 3% of the load regulation error in response to the 15A step change of the load current at a slew rate of 50A/£gs.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0724106-154957 |
| Date | 24 July 2006 |
| Creators | Tseng, Ming-Hung |
| Contributors | Li Lee, Shiang-Hwua Yu, Cheng-Ching Yu, Tzyy-Sheng Horng, Chin-Sien Moo |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0724106-154957 |
| Rights | unrestricted, Copyright information available at source archive |
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