DC-DC开关变换器开关工作频率设计

根据DC-DC型开关变换器的工作原理,以Buck型开关变换器为例,讨论了储能电感、滤波电容、输出纹波电压、变换器转换效率与全控型开关器件的工作频率之间的关系,为开关频率的选择提供了理论依据,并进行仿真验证,仿真结果与理论分析一致,表明了参数计算和选择的合理性.分析的方法和结论为其它类型的DC-DC开关变换器的开关管工作频率的分析和设计提供了有效的分析手段和方法,也为实际DC-DC开关变换器的设计和调试提供了新的思路.     

BUCK型开关变换器最优PID控制器设计

针对开关电源的复杂性和时变性,传统PID控制器整定方法无法很好满足其控制性能要求的问题,提出一种面向性能指标的最优PID控制器参数整定方法。基于DP算法,计算保证闭环系统稳定的PID控制器参数范围;利用具有全局寻优能力的遗传算法,按照ITAE性能指标在该范围内进行参数寻优。以BUCK变换器为利的仿真研究表明,该方法在指定的性能指标上取得了满意的控制效果,在负载发生摄动时,较传统PID控制器,具有较好的鲁棒性,且计算相对简单、实用性强,可推广到非线性PID控制器的参数整定和相关工程实践中。     

Design of practical sliding-mode controllers with constant switching frequency for power converters

A novel experimentally motivated method in order to design a family of easy-to-implement sliding-mode controllers for power converters is proposed. Two main results are presented. First, the relation between sliding-mode control and average control is reinterpreted so that the limitation of the switching frequency for the closed-loop system is achieved in a more direct way than other methods so far reported in the literature. For this purpose, a class of sliding surfaces which makes the associated equivalent control be the system average control is proposed. Second, the achievement of a constant switching frequency in the controlled system is assured without requiring the sliding-mode-based controller to be modified, unlike most previous works. As a result, the proposed sliding surfaces-type can be directly implemented via a pulse-width modulator. The control methodology is implemented for the voltage control in a boost converter prototype in which the load is considered unknown. Experimental results confirm high performance and robustness under parameters variation. Furthermore, the solution proposed is easy to implement and well-suited for other power converters.     

反激式开关电源的电磁干扰建模及抑制方法分析

开关电源在众多领域已被广泛应用,开关电源的高频特性导致了严重的干扰问题.若在设计时能够明确单一元件和EMI的关系,在此基础上经参数控制达到开关电源的EMI控制,将对开关电源的开发设计起到巨大的作用.本文将以反激式开关电源的EMI建模及抑制方法分析作为切入点,对变压器的等效模型进行分析,得出变压器寄生电容对骚扰电压的影响...     

EMI滤波器阻抗失配与EMI信号的有效抑制

为了使EMI滤波器的传导EMI信号在其内部得到最大衰减,依据EMI滤波器应具有双向抑制性的基础上,分析了阻抗失配对插入损耗和反射损耗的影响,给出了理想EMI滤波器的确定原则,以及为减小阻抗失配给插入损耗带来的影响,提出了实际设计和选用EMI滤波器时应遵循的最大失配原则。试验结果表明,这一原则对减小阻抗失配给插入损耗带来的影响非常有效。     

一种适用于两级DC/DC变换器的磁集成结构

针对48 V输入低压大电流输出的两级DC/DC变换器,提出了一种包含两个电感和一个变压器的磁集成结构。该结构的主要特点是实现了磁芯窗口面积利用率的最大化,可降低集成磁元件的铜损和改善其散热条件。以Buck级联半桥两级DC/DC变换器为应用实例,集成了磁元件并制成90 W的样机。实验结果表明,按提出的结构对磁元件进行集成,原有变换器电路的工作特性可得到保持。依据实验结果,对其中的集成磁元件进行损耗分析,并进一步提出了若干集成磁元件的优化措施。     

Power line filter design considerations for DC-DC converters

This article presents an overview of switching regulated DC-DC power convertor electromagnetic interference problems and possible solutions, with special emphasis on power line conducted emissions and power line input filters. Potential stability and performance problems that can be caused by the interaction between the power line input filter and the switching regulator are discussed in detail. Candidate damped input filter structures are presented, along with a general input filter design strategy and a detailed design procedure for one of the candidate configurations     

A practice-oriented course in switching converters

The development of a practice-oriented course in switching power converters at the University of Arkansas, USA, is presented. Students learn, verify, and reinforce lecture concepts by performing switching power converter experiments in the laboratory sessions. PSpice simulations are used extensively to verify concepts and to enhance students' comprehension. A design project is used to integrate the materials taught in the lectures with experience gained in the laboratory sessions. In general, students feel they learn more effectively in a practice-oriented course. The switching power converters course is very time intensive for both students and the instructor. However, it is very well received by students     

开关变换器双频率控制技术

提出并研究一种开关变换器非线性控制策略,双频率控制技术.研究电压型和电流型双频率控制开关变换器的实现方式及特点,对比分析电压型和电流型双频率控制开关变换器的工作特性和控制规律.理论分析、仿真及实验结果表明:电压型和电流型双频率控制具有相同的稳态工作特性;而在动态响应方面,电流型双频率控制具有比电压型双频率控制更为优越的性能.此外,与电压型双频率控制相比,电流型双频率控制具有自动限流功能和更为平稳的启动特性.     

数字化DC-DC变换器的控制器结构优化

针对现有的数字化DC-DC变换器的控制器结构,基于FPGA从DPWM控制策略、采样控制策略和计算控制策略方面对系统进行优化.控制器运算单元采用浮点乘累加器实现,保证了运算精度,同时提出实时运算控制策略和基于查表法的整型转浮点和浮点转整型转换器,从而减少了开关管导通时间的计算时间;提出优化的采样和PWM策略,能够消除采样保持和计算过程所带来的控制器输出延迟;采用基于二阶Σ-Δ的DPWM和双模式补偿算法,消除极限环的同时保证了控制器的快速的动态响应能力.实验证明:利用上述方法能够得到具有快速动态响应而又无极限环现象的稳定输出.     

Bifurcation and chaos in multi-parallel-connected current-mode controlled boost DC-DC converters

This paper studied the bifurcation and chaos phenomenon in a multi-parallel-connected current-mode controlled boost DC-DC converter system with the use of nonlinear mapping bifurcation theory of two dimensions, and the changing rules of the bifurcation charts with the increase of the control parallels and control parameters were concluded. The method of discrete mapping modeling was utilized to construct the difference equations of the system operating in continuous conduction mode (CCM). Analyses and computer emulations were made. __________ Translated from Journal of Proceedings of the Chinese Society for Blectrical Engineering, 2005, 25(6): 67–70 (in Chinese)     

构造稳定节点的功率变流器共模干扰抑制技术

本文提出了一种抑制功率变流器的共模电磁干扰(EMI)的技术方法.并以Boost变流器为例.对所提出的方法进行了深入分析.由于电路中高电压变化率(dv/dt)的动态节点是共模传导EMI产生的主要源头,本文通过调整Boost电感的PCB布局与采用共阳极二极管的方法,在电路中构造稳定节点,对共模传导EMI进行了有效的消除.理...     

DC-DC变换器LTI模型的实验验证研究

定量探讨了峰值电流模式下DC-DC变换器LTI（线性时不变）模型的实验验证问题,导出正弦激励下,电流环响应波形的时域表达式,据此采用解析简化与数值仿真相结合的方法进行傅立叶分析。当开关频率能被激励频率整除时,可得响应的基波分量;否则,响应与激励频率不同,但仍可求其平均基波分量（折算到激励频率）。从数学上证明了LTI模型的预测结果与网络分析仪的实验测量有且仅有（平均）基波意义上的一致性,从而给出了在高频段失效的LTI模型却能被实验验证的合理解释。为把握LTI模型频域验证的本质,认识其局限性,明确其适用条件提供了理论指导。     

一种工作频率可变的双向DC-DC变换器

提出脉冲宽度调制PWM的控制方法应用于可变频的双向直流/直流(DC-DC)变换器。采用连续可变斜率积分器的增量调制法,通过改变脉冲序列的周期可以调频,改变脉冲的宽度或占空比实现调压,输出脉冲宽度的变化可以快速地跟随输出电压的反馈值得到相应的脉冲波形。详细的介绍了主电路和控制电路的电路拓扑和工作原理。最后,构建双向DC-DC变换器与控制电路的实验样机,并进行相应的实验。实验结果验证了该方法控制双向变换器的可行性,且具有工作频率可变及快速响应等特性。     

基于双电源开关变换器电路的研究

针对燃料电池输出电压易受负载变化的影响以及光伏电池输出电压随入射光的强弱和温度而变化的特点,提出了燃料电池与太阳电池双能源并联运行的新型拓扑电路.用燃料电池与交错并联Boost开关变换器连接,可以有效减小燃料电池输出电流的纹波;用太阳电池与双向Buck-Boost开关变换器拓扑联接,不仅可以向负载提供电能,还可以对蓄电...     

EMI滤波器与浪涌抑制技术的结合

介绍了电磁干扰(EM I)滤波器的基本类型以及由基本类型组成的EM I电源滤波器,同时也介绍了2种常用的防雷限压器件———压敏电阻(MOV)和瞬态抑制二极管(TVS);主要讨论了将滤波和抑制浪涌电压2种功能结合在一起的复合功能EM I滤波器(具有限压功能的LC滤波器和复合功能的EM I电源滤波器);给出了LC滤波器在雷电浪涌的差模和共模冲击下,随电容值变化的压敏电阻电压波形和电容电压波形(输出电压波形);最后对电路结构进行了简单扩展。     

A saturable reactor-assisted soft switching PWM DC-DC converter

Owing to the demand to increase the power density of switched-mode power converters, resonant topologies have attracted much attention because of their low switching losses and low EMI. However, they require relatively large resonant components and necessitate high current or voltage ratings at semiconductor devices. This paper describes a new soft-switching PWM full-bridge DC-DC converter which can overcome these drawbacks by utilizing a small saturable reactor. The principles of operation and the steady-state characteristics are illustrated and the role of the saturable reactor is discussed. Moreover, the voltage and current stresses for active and passive components are also presented. To verify the results, experiments were performed with a 350 W, 500 kHz prototype converter. They demonstrated that the converter achieves soft switching in a wide load range with no substantial increase in voltage and current stresses on active and passive components.     

Hardware implementation of an adaptive network-based fuzzy controller for DC-DC converters

A novel control topology of adaptive network-based fuzzy inference system (ANFIS) for control of the dc-dc converter is developed and presented in this paper. It essentially consists of combining fuzzy inference system and neural networks and implementing within the framework of adaptive networks. The architecture of the ANFIS along with the learning rule, which is used to give an adaptive and learning structure to a fuzzy controller, is also described. The emphasis here is on fuzzy-neural-network control philosophies in designing an intelligent controller for the dc-dc converter that allows the benefits of neural network structure to be realized without sacrificing the intuitive nature of the fuzzy system. Specifically, it permits this type of setup to simultaneously share the benefits of both fuzzy control and neural network capabilities. An experimental test bed is designed and built. The components are tested individually and in various combinations of hardware and software segments. Two categories of tests, namely, load regulation and line regulation, are carried out to evaluate the performance of the proposed control system. Experimental results demonstrate the advantages and flexibilities of ANFIS for the dc-dc converter.