直流电－直流电开关变流器的统一建模方法

提出一种能通用于脉宽调制（ＰＷＭ）型，准谐振型，桥式串（并）联谐振型等各类开关变流器的统一建模方法，脉冲波形积分法。本法能充分反映各类变流器的自身特点，为变流器动态性能指标的分析与设计提供统一衡量标准，文中以两种类型变流器为例阐明建模原理，并将建模结果与有关文献进行比较，计算机仿真结果证明所建模型是正确的。     

Improved Discrete-Time Approach for Modeling a Class of Switching Converters

An improved discrete-time approach is proposed for modeling a class of switching converters which have non-invertible coefficient matrixes in state equations. In the form of block matrix, the proposed approach is generally derived by using the linear relation between the derivatives of two blocks in state equations. A filter- converter example is provided to illustrate the effectiveness of the proposed approach. Our work perfects the discretetime approach in modeling and analyzing of switching converters, so engineers can deal with more practical system.     

工作于断续电感电流模式的PWM开关变换器的统一建模方法

基于通用的“高频网络平均法”,本文提出了一种新的ＰＷＭ开关变换器的统一建模方法。由此方法,我们得到变换器的低频等效电路模型,所得模型即利于建立电路的微分方程,又适合地ＳＰＩＣＥ的仿真可获得变换器的直流特性及小信号特性。仿真及实验结果证明了该模型的正确性。     

三电平矩阵式电力变换器的开关损耗数学模型

从三电平矩阵式电力变换器的拓扑结构入手,分析在高频下工作时开关损耗带来的负面效应。通过对开关单元单相PWM逆变器的开关损耗进行研究,建立了开关单元平均等效电路模型,并推导了变换效率;通过对开关损耗数学模型的建立,探讨了开关过程损耗与开关频率和开关传导损耗与占空比的关系,仿真结果验证了数学模型的正确性。     

Current Injected Equivalent Circuit Approach to Modeling of Switching DC-DC Converters in Discontinuous Inductor Conduction Mode

A new current injected equivalent circuit approach (CIECA) to modeling switching dc-dc converter power stages is developed, which starts with current injected approach, and results in a set of equations which describe completely input and output properties and an equivalent linear circuit model valid at small signal low frequency levels.     

Interleaved Buck Converters Based on Winner-Take-All Switching

This paper studies basic interleaved buck converters using a switching rule based on a winner-take-all principle. As the parameters are selected suitably, the system can realize multiphase synchronization automatically which is convenient for the ripple reduction of the output current. As the parameters vary, the system exhibits a variety of synchronous phenomena. Using the piecewise-constant model, we give the parameter condition theoretically for existence and stability of the synchronous phenomena. The simple test circuit is presented and typical synchronous phenomena are confirmed experimentally.     

一种基于时间序列的CCM Buck变换器瞬态精确解析分析方法

本文提出了一种新的Buck开关变换器(连续导电模式)建模与分析方法.此方法对开关变换器的零状态响应和零输入响应分别建模,并针对开关电路响应延时性的规律,提出了时间序列表示形式,获得了变换器输出的瞬态精确解析解.这种解析解实现了变换器电容电压与电感电流的解耦表示;建立了变换器的输出电压与占空比的函数关系;可表示变换器的瞬...     

New Physical Insights on Power MOSFET Switching Losses

Realistic estimation of power MOSFET switching losses is critical for predicting the maximum junction temperature and efficiency of power electronics circuits. The purpose of this paper is to investigate the internal physics of MOSFET switching processes using a physically based semiconductor device modeling approach, and subsequently examine the commonly used power loss calculation method in light of the new physical insights. The widely accepted output capacitance loss term is found to be redundant and erroneous based on the new modeling and measurement results. In addition, the existing method of approximating switching times with the power MOSFET gate charge parameters grossly overestimates the switching power loss. This paper recommends a new MOSFET gate charge parameter specification and an effective switching time estimation method to compensate for the power loss calculation error introduced by the two-slope voltage transition waveform of the power MOSFET.      

Rotor-Shape Optimization of Interior-Permanent-Magnet Motors to Reduce Harmonic Iron Losses

In this paper, we develop novel rotor designs of interior-permanent-magnet motors in order to reduce harmonic iron losses at high rotational speeds under field-weakening control. First, an optimization method, combined with an adaptive finite-element method, is applied to automatically determine the shapes of the magnets and rotor core. The optimized motor is manufactured to confirm the validity of the calculation. It is clarified that the iron loss of the optimized motor is reduced to nearly half of that of the conventional motor, without a significant decrease in maximum torque. Next, the contribution of each part of the rotor to the iron-loss reduction is analyzed by the experimental design method. Finally, several designs of the rotors are proposed from the viewpoints of manufacturing cost and performance.     

基于HPR-SA算法的开关电源优化设计

最优设计技术已在开关电源的设计中有了一些成功的应用,大多以重量和损耗为优化的目标,但还存在很多需要解决的问题,其中之一就是没有一个效率和可靠度高的工程优化算法。文章就是在这种背景下,分析了BUCK变换器的工作状态,从体积和性能的角度,建立了BUCK电路的优化模型,将拉格朗日乘子法和模拟退化算法相结合,提出HPR-SA算法,并将其应用于BUCK变换器的优化设计之中,优化后体积有一定的减小,输出电压仿真波形,完全符合性能指标的要求,从而证明该算法的可行性和有效性。     

Robust High Bandwidth Discrete-Time Predictive Current Control with Predictive Internal Model—A Unified Approach for Voltage-Source PWM Converters

This paper presents a robust high bandwidth discrete-time predictive current control scheme for voltage-source pulsewidth-modulated (VS-PWM) converters. First, to achieve high bandwidth current control characteristics, a digital predictive current controller with delay compensation is adopted. The compensation method utilizes a current observer with an adaptive internal model for system uncertainties. The predictive nature of both the current observer and the internal model forces the delays elements to be equivalently placed outside the closed loop system. Second, to ensure perfect tracking of the output current in the presence of uncertainties and providing means for attenuating low- and high- frequency system disturbances, the frequency modes of the disturbances to be eliminated should be included in the stable closed loop system. Toward this, an adaptive internal model for the estimated uncertainty dynamics is proposed. To cope with the high bandwidth property of the lump of uncertainties in VS-PWM converter applications, the disturbance slowly varying assumption is relaxed in the proposed controller. The relaxation is achieved by adopting a curbing sliding-mode-based feedback gain vector within the internal model observation system. Comparative evaluation tests were carried out on a grid-connected VS-PWM converter and a direct drive permanent magnet synchronous motor (DD-PMSM) drive system to demonstrate the validity and effectiveness of the proposed control scheme at different operating conditions.     

Symbolic Analysis of Switching Systems: Application to Bifurcation Analysis of DC/DC Switching Converters

A symbolic method is proposed in this paper for analyzing the bifurcation behavior of switching nonsmooth systems. The proposed method focuses on the symbolic sequence describing the topological change of the system which characterizes its bifurcation behavior. The concept of block sequence is first introduced. Based on the block sequence, the smoothness of the PoincarÉ map is described. Moreover, two main theorems are given to detect border collision and standard bifurcations. Finally, a specific example of the buck switching converter is presented to illustrate the application of the proposed symbolic analysis method. Using the proposed method, two-dimensional (2-D) bifurcation diagrams, which can assist engineers in identifying regions of preferred or undesired operations in the select parameter space, can be easily obtained.     

开关功率变换器中的间歇现象 ——仿真与实验

 文章从电路耦合滤波的角度考虑,分析了一类间歇分谐波与间歇混沌现象产生的原理,确定耦合电路传导和辐射干扰是产生该现象的根源,并构造了一个开关变换器模型作为研究对象,仿真与实验均得到了相似的非线性现象,同时对不同的电路参数集,讨论并分析了其对间歇现象产生所起的不同影响,为变换器的稳定设计提供信息.该研究方法也可推广到其他非线性电路系统的类似研究中.     

基于能量守恒平均模型的开关变换器建模

文中介绍了一种常用的开关变换器建模方法——能量守恒平均法,依据能量守恒平均原理,建立连续模式下Buck变换器的直流和小信号模型,并给出开环传递函数。仿真分析表明,该模型能够准确描述变换器的频域特性,验证了理论推导的有效性。     

DC—DC 开关功率变换器分析方法的述评

本文对ＤＣ－ＤＣ开关功率变换器分析方法作了一个较全面的述评，着重介绍了拓扑不变的等效电路模型，寄生效应的处理方法，状态空间平均在准谐变换器的应用以及渐近法在变换器中的应用等四个方面，另外，介绍了不稳定分析一些结果。     

矩阵式变换器四步换流的仿真研究

利用SIMULINK对矩阵变换器的四步换流进行了仿真，验证了理论的正确性。     

数字峰值电压控制开关变换器瞬态特性的研究

数字控制技术的应用是开关变换器发展的一个重要方向,但是数字控制环路的延时对瞬态响应的影响是重要的制约因素。基于数字峰值电压算法和所提出的克服延时算法,提出了改进型数字峰值电压算法。对改进型数字峰值电压控制开关变换器的瞬态性能进行了研究,并与数字峰值电压控制开关变换器的瞬态性能进行了对比。通过实验对分析及仿真结果进行了更进一步的验证。     

电流模式控制的DC-DC变换器中电流环的设计

电流反馈环路是开关变换器中重要的模块之一,主要分析了常用的SENSEFET技术的不足,提出了一种优于SENSEFET技术的电流检测电路.该电路通过检测功率管上的压降反应电感电流的变化,利用工作在线性区的PM06管代替电阻,采用体偏置跨导增大环路增益,提高检测精度,使输出检测电流与电感电流的比率几乎不受温度,工艺,电源电压等因素的影响.同时设计了一种自适应斜坡补偿电路,可根据输入,输出电压自动调节补偿斜率,有效解决了传统固定斜率斜坡补偿所产生的带载能力降低的问题.电路的输入电压范围为2.5～5.5V,工作频率为1MHz,可精确检测0～3.5A的电感电流,适用于大电流的开关变换器.     

利用端口扩展器提高设计灵活性并降低成本

在嵌入式设计中,即便进行了周密的计划,完全按照最严格的程序进行工作,项目也可能会遭遇理查三世一样的失败:比方说,您所选用的处理器可能不具备足够的引脚,导致目标难以实现.在选择芯片、驱动LED时,总难做到全面,人们总是事后才失望地发现,本应选择引脚更多的另一款处理器.即便进行了前期计划,为设计上的问题预留了空间,但还是不能确保得到你想要的引脚(还要考虑到安全性),因为市场或公司的市场营销策略总是要求尽可能降低成本.即便您全力以赴,总算得到批准采用具有10个额外引脚的处理器,能够按时完成设计工作,但这样做只能造成公司下一步肯定采取降低成本的措施.     

Digital Carrier Modulation and Sampling Issues of Matrix Converters

Although the modulation of ac–ac matrix converters using space vector theory has long been established, their carrier-based modulation principles have only recently attracted some attention. Reasons commonly stated for evaluating the carrier-based alternative include simpler converter control because of its inherent autosequencing process, and easier implementation using fast on-chip timers embedded in most modern digital signal processors. Motivated by these likely merits, which have previously been proven for dc–ac inverters, an investigation is now pursued here to develop appropriate digital carrier modulation schemes for controlling conventional (direct) and indirect matrix converters with minimized semiconductor commutation count and smooth sextant transitions with no erroneous states produced. For guaranteeing the latter two features, correct digital sampling instants and state sequence reversal must be chosen appropriately, as demonstrated in the paper for the two different topological options, which, to date, have not yet been discussed in the existing literature. To validate the concepts discussed, experimental testing on the implemented conventional and indirect matrix laboratory prototypes was performed with their respective results captured and presented in the paper for visual confirmation.