| Summary: | 碩士 === 國立成功大學 === 工程科學系 === 89 === In this thesis, the small signal mathematical model of a zero-current-zero-voltage-transition (ZCZVT) soft-switching boost power converter is proposed, and two controllers are also designed to achieve output voltage regulation.
The ZCZVT soft-switching converter is composed of a conventional PWM circuit and a resonant circuit to achieve zero voltage/zero current switching (ZVS/ZCS) and constant frequency operation. This converter overcomes the existing problems of high switching losses of the conventional PWM converters and the conduction losses due to high voltage/current stresses of resonant converters. As a result, ZCZVT soft-switching converters are suitable for high power application system.
In the literature, the soft-switching converters were only restricted to DC steady-state analysis. Most of researchers thought that the ac small signal mathematical model should be the same as that of the traditional PWM boost converter. Thus the derivation of the ac model has not been done yet. From the analysis results, the input-to-output voltage conversion ratio of the ZCZVT soft-switching converter depends on load. Moreover, the dynamical behavior will be changed under the variations of load.
In this thesis, the averaging method for the two-time-scale discontinuous system (AM-TTS-DS) is used to derive the small signal model of a ZCZVT soft-switching converter. Based on this model, a classical controller and a modified integral variable structure controller (MIVSC) are then designed. The simulation responses and experimental results show that the MIVSC controller has better regulation capacity under the variations of load and line voltage variations than classical controller.
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