【作者】 徐孝如；

【导师】 吴晓波； 严晓浪；

【作者基本信息】 浙江大学 ， 电气工程， 2009， 博士

【摘要】 升压变换器是现代电子系统中重要的基本电源转换电路,被广泛应用于固态照明、高压偏置等场合。尤其是由于现代电子系统越来越注重环保和节能理念,对于高转换效率和无污染的要求催生了用固态照明替代传统含汞灯具照明的发展趋势。提高升压变换器的转换效率和集成度对于设计节能环保的电子系统具有重要意义。基于线性化模型,脉冲宽度调制控制的升压变换电路需要设计复杂的补偿环路以实现系统的稳定,这也就意味着较多的补偿元件和更高的成本。此外在低负载下,脉冲宽度调制控制由于开关频率的恒定,其转换效率也较低。相对线性化控制,采用滑模控制的开关变换器无需环路补偿,且具有良好的动态特性和鲁棒性。升压变换电路由于本身拓扑的原因,其电感电流在输出非连续,无法像降压变换器一样方便地实现迟滞滑模控制。因此根据升压电路的特点,提出了自适应开通时间准滑模控制方法。该控制方法能使升压电路在低负载下自动工作于脉冲宽度调制模式,提高了整体转换效率。基于两维相平面分析,推导了自适应开通时间控制的稳定条件。设计的自适应开通时间能依据输入和输出电压自适应改变,使变换器在电感连续导通模式下的开关频率保持恒定以控制输出电压纹波。在改进反馈结构后,功率级表现为电压控制电压源,可用于高调光比的大功率发光二极管驱动电路设计。同时,针对新型低压电池(如燃料电池)低输出电压的特点,在自适应开通时间控制基础上,提出了预测关断-开通时间准滑模控制。该控制方法可以实现更高的最大占空比以提高升压比。采用这种控制方法,对带有功率管集成的通用型片上升压电压调节器进行了实现。与电流模式控制的参考电路相比,提出的电路具有更好的瞬态响应和更高的低载转换效率。为了进一步提高升压电压调节器的集成度,降低外围元件数,还探讨了片上电流检测、过流保护和补偿网络等的电路技术。给出了预测关断-开通时间控制片上升压电压调节器的单片化设计,并进行了仿真验证。更多还原

【Abstract】 Boost converter is a basic power converter in modern electronic systems. It is widely adopted in solid-state lighting and high voltage biasing. The urgent demands of modern electronic systems on energy saving and environmental protection make the solid-state lighting emerge to replace conventional mercury based lamps. Thus, improving the conversion efficiency and increasing the integration of boost converter are important to save energy and drive the solid-state lighting industry.To stabilize traditional PWM controlled boost power converter, complex compensation networks are always required, which means extra external components as well as higher system cost. Besides, the conversion efficiency is degraded during light load condition due to fixed frequency architecture. Sliding mode controlled power converters have the merits of no loop compensation requirement and better dynamic response compared with conventional linear mode controlled ones. However, the output current of the boost converter is discontinuous, and as a result, conventional hysteretic sliding mode control is not suitable. Therefore, adaptive on-time control(AOT), a quasi sliding (QS) mode control, was proposed in this dissertation. With that, the converter runs in efficiency improved pulse frequency modulation (PFM) automatically during light load operation.Based on the two dimensional phase plane analysis, the criterion to stabilize the AOT-QS boost converter was derived; a simple adaptive on-time generator was proposed to make the power converter operate in quasi fixed frequency under inductor continuous conduction mode so as to control the output voltage ripple. After improving its feedback structure, AOT-QS boost converter is designed to be a voltage controlled voltage source. With that, a high dimming ratio high power LED drive controller was designed.Considering the emergence of low voltage batteries like fuel cells, projected off-time on-time quasi sliding mode (PFT-QS) control is proposed. With that, bigger maximum duty cycle can be realized compared with AOT-QS control. Its stability criterion and loop transfer function were derived. A general-purpose boost regulator with on-chip DMOS was implemented using the proposed PFT-QS control method. Test results show the proposed on-chip boost regulator outperforms the conventional current mode controlled one in aspects of conversion efficiency and load transient response.In order to further increase the integration level, circuit techniques like on-chip compensation, current sensing, over current limit were also discussed. Adopting these circuits, the proposed high integration PFT-QS boost regulator was designed, which integrated the components as more as possible on the chip besides the power devices and feedback network. The final boost regulator design was verified by Spice simulation.更多还原