| Summary: | 博士 === 國立中山大學 === 電機工程學系研究所 === 102 === Quantized control utilizes only a finite set of levels to control a dynamic system. The simplest way for doing this is to design a linear feedback system and then quantize the control signal to a set of prescribed levels. However, inserting a quantizer in a linear control system may seriously affect the stability and performance of the system. In this dissertation, a feedback modulation scheme called the sliding mode modulation is used to linearize a quantizer. The outstanding feature of the sliding mode modulation is its capacity to eliminate in-band modulation error while decorrelating the modulation error from the continuous control force, enabling a quantizer to be effectively and reasonably linearized. Subsequently, an optimal noise-shaping design, which minimizes the frequency-weighted tracking error and the continuous control force simultaneously, is considered, yielding the double-loop control scheme for a linearized quantized control system. The sliding-mode modulation and the double-loop control scheme are applied to a three-level filterless class-D audio power amplifier and a three-phase synchronous buck converter, respectively, to verify theirs effectiveness. Finally, the proposed quantized control strategy, the sliding-mode modulation combined with the optimal noise-shaping design, is used in designing a nine-level class-D audio amplifier. Experimental results indicate that the designed class-D audio amplifier exhibits high robustness and high-quality audio performance, which achieves a minimum total harmonic distortion plus noise (THD+N) of 0.0135% and delivers a maximum output power of 8.3W with 80% peak efficiency into a commercial loudspeaker.
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