Study on High-Performance Switch-Mode Power Converters
| Autor: | Chao-Cheng Wu, 吳朝成 |
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| Rok vydání: | 2002 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 90 In this dissertation, two single-phase zero-voltage-transition-pulsewidth- modulation (ZVT-PWM) soft-switching power converter topologies, a new power-factor-correction (PFC) controller of single-phase AC-DC boost converter and a simplified PFC controller of three-phase three-level PWM boost converter are proposed. Basically, main contributions of the dissertation are summarized as follows: First, two single-phase ZVT-PWM soft-switching power converter topologies are developed in order to improve the problem of the auxiliary switch hard-switching turn-off of the conventional ZVT-PWM power converter and to increase the conversion efficiency. The proposed circuits use inductors and capacitors for the resonant circuit to achieve ZVS for turning on and off the main power switch. Moreover, the auxiliary switch is turning on ZCS and turning off ZCS or ZVS. These converters are very suitable for sing-phase AC/DC PFC applications. Second, to simplify the complexity of the conventional single-phase PFC controller, a new PFC controller, without using input voltage sensor and any multipliers/dividers, is derived for the proposed single-phase AC/DC boost converter to achieve clean sinusoidal input current, adjustable DC voltage, controllable power factor and fixed switching frequency. In addition, the author proposes a general pulsewidth modulator, which can be used to control switch-mode power converters for the duty-cycle control. Finally, the author also proposes a simplified PFC control scheme for the three-phase three-level PWM boost converter with lower switching losses and higher power-factor. The major advantage of this control scheme is that the conduction times of the power switches don’t require complex computation. Based on these control schemes, the three-phase three-level PWM converter is decoupled into a cascade-connect dual-boost converter during each interval of the line cycle. By taking the proposed PFC control method, the multiple-level converter can achieve the goals of controllable power factor and adjustable DC voltage. It shows an effective solution to the applications where high-power and low-cost are concerned. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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