Power and energy management of grid/PEMFC/battery/supercapacitor hybrid power sources for UPS applications

This paper presents a hybrid power and energy source supplied by a proton exchange membrane fuel cell (PEMFC) as the main power source in an uninterruptible power supply (UPS) system. To prevent the PEMFC from fuel starvation and degradation and realize their seamless linking in the hybrid UPS system, the power and energy are balanced by the battery and/or supercapacitor (SC) as two alternative auxiliary power sources. Based on the modeling and sizing of hybrid power and energy components, the power and energy management strategies and efficiency measurements of four operating modes in UPS system are proposed. To evaluate the proposed strategies, an experimental setup is implemented by a data acquisition system, a PEMFC generating system, and a UPS system including AC/DC rectifier, DC/AC inverter, DC/DC converter, AC/DC recharger and its intelligent control unit. Experimental results with the characteristics of a 300 W self-humidified air-breathing of PEMFC, 3-cell 12 V/5 Ah of batteries, and two 16-cell 120 F/2.7 V of SCs in parallel corroborate the excellent management strategies in the four operating modes of UPS system, which provides the basis for the optimal design of the UPS system with hybrid PEMFC/battery/SC power sources.     

Switching Power Supplies with Ferrite Inductors in Sustainable Saturation Operation

This paper investigates the Sustainable Saturation Operation (SSO) of Ferrite Core Power Inductors (FCPIs) in Switch Mode Power Supplies (SMPSs). A ferrite inductor is considered in SSO if its current ripple, power losses and temperature rise are acceptable and reliable for both the device and the SMPS, despite the inductance drop determined by the core saturation. An algorithm is discussed, which identifies SSO-compliant FCPIs with minimum size and volume, given the SMPS specifications about the allowed power losses, temperature rise and peak-to-peak current ripple of the inductor. The experimental results relevant to a 465 kHz/3.3 V/1.5 A buck converter show that SSO-compliant inductors allow to increase the SMPS power density, while preserving the overall converter efficiency. Despite the proposed low power application, the findings relevant to the utilization of power inductors in partial saturation have general conceptual valence and similar investigations can be prospectively re-assessed for few kW output power DC/DC converters.     

用于混合动力汽车的三电平双向DC/DC变换器

将三电平技术应用到双向DC／DC装置中,可以提高混合动力汽车驱动系统中双向DC／DC装置的开关频率,为此提出了一种新的三电平双向DC／DC变换器拓扑。通过三电平拓扑和传统两电平拓扑电路的对比分析,得出了相同先决条件下这两种拓扑中开关管电压应力和电感电流可减小的幅度。最后通过仿真试验验证了分析结果。     

高性能升压型DC-DC电源变换器的设计与实现*

利用STM32F103RBT6单片机为主控芯片,采用推挽式拓扑结构及脉冲宽度调制技术,设计制作了一款高性能升压型DC DC电源变换器。该电源变换器的直流输入电压范围为15~25 V,直流输出电压可调范围为30~36 V,最大输出电流为1 A。实验测试结果表明,设计的电源变换器具有较好的负载调整率和电压调整率,输出电压波纹较低,转换效率高,并且具有输出电压的步进调整和测量、显示以及过流、过压保护等功能,在中小型升压型开关电源中具有较好的应用价值和发展前景。     

抑制电流纹波的模块化多电平直流变换器移相调制策略

模块化多电平直流变换器在采用传统载波移相脉宽调制时,如果各模块的输入及输出电压不一致,就会在电感上产生更大的电流纹波,增大电感的损耗,同时也不利于滤波器件的优化设计.针对这种情况,文中通过对电流纹波的频域分析,揭示了传统移相调制技术存在的问题,并确定了电流纹波幅值、各模块输入/输出电压与载波移相角之间的关系.以电流纹波中开关频率次谐波幅值最小为目标计算各模块的载波移相角,根据不同的工况调整移相角的算法,进而实现了一种电流纹波抑制的调制策略.对三模块级联的模块化多电平直流变换器进行了软件仿真和实验测试,仿真和实验结果都表明在各模块输入及输出电压不相等工况下,所提控制策略能够有效地抑制电流纹波,从而验证了所提控制策略的正确性和实用性.     

A high efficiency input/output magnetically coupled interleaved buck–boost converter with low internal oscillation for fuel-cell applications: Small signal modeling and dynamic analysis

Dynamic behavior of DC–DC converters plays a crucial role in stability of renewable energy exploitation systems. This paper presents small signal modeling of an input/output magnetically coupled interleaved buck–boost converter for fuel-cell applications to help the designers with the better understanding of converter dynamics. Aiming to have a continuous converter transfer function for a smooth transition between the operation modes and an improved inner dynamics, a damping network and an input/output coupling have been added to the interleaved structure of well-known cascaded buck–boost converter. Having the same step-up/step-down voltage transfer ratio, smooth transition and improved inner dynamics make this converter quite suitable for renewable energy applications. The paper presents a small signal ac equivalent circuit model of the proposed converter based on state space averaging (SSA) method. Simulation results show remarkable improvements in converter dynamic behavior in both time and frequency domains. Prototype setup of 360 W and 36 V output voltage for a fuel cell with a brand of “FCgen 1020ACS” Ballard Power Systems, Inc. was implemented. Experimental results are presented to verify the theoretical model and its expected merits.     

光伏发电系统前级宽输入DC/DC Boost变换器

峰值电流模式DC/DC Boost变换器输入电压范围较宽,适用于两级式光伏发电系统的前级。DC/DC Boost变换器的输入电压较低时,一般采用固定斜坡补偿来保证其稳定运行,低输入电压范围宽时,往往需要过补偿,无法达到设计功率。提出一种动态斜坡补偿的方法,使变换器在较宽输入电压下都能稳定工作且具有较高效率。40 W样机测试结果显示:输入电压在16~24 V的范围内,变换器均能稳定工作。     

适于可再生能源发电储能系统中的双向直流变换器

研究了一种交错式双向直流变换器,该变换器工作在Boost方向时输入端进行交错并联,减小了输入电流纹波,输出端进行交错串联,提高了升压变比;工作在Buck方向时,输入端进行交错串联,输出端进行交错并联,因此该模式下具有较大的降压变比,同时减小了输出电流纹波。另外,在两种工作模式下,功率器件的电压应力都得到了降低。详细地分析了该变换器在两种模式下的工作原理及稳态特性,最后给出了实验结果以验证理论分析的正确性。     

基于飞跨电感的高升压比级联式DC/DC变换器

高升压比DC/DC变换器在微电源并网、不间断电源以及车载电源等场合均有广泛应用。飞跨电感模块,既具有升、降压能力,又可以实现能量双向流动。利用多个飞跨电感模块输入、输出端串、并联组成共正极、共负极和不共地3种不同结构的级联式高升压比DC/DC变换器,其均可在较合适的占空比下维持较低的电流应力,获得高电压增益。模块间采用载波移相调制可以减小模块输入侧电流纹波、变换器输出电压纹波和输出滤波电容容值。详细介绍了飞跨电感模块和DC/DC变换器的结构及工作原理,并以其中不共地变换器拓扑为例通过仿真和实验验证了其正确性。所提变换器具有电压增益便于调节、扩容方便和应用范围广等优点。     

Analysis and implementation of a high‐efficiency zero‐voltage‐zero‐current‐switching DC–DC converter

A high‐efficiency zero‐voltage‐zero‐current‐switching DC–DC converter with ripple‐free input current is presented. In the presented converter, the ripple‐free boost cell provides ripple‐free input current and zero‐voltage switching of power switches. The resonant flyback cell provides zero‐voltage switching of power switches and zero‐current switching of the output diode. Also, it has a simple output stage. The proposed converter achieves high efficiency because of the reduction of the switching losses of the power switches and the output diode. Detailed analysis and design of the proposed converter are carried out. A prototype of the proposed converter is developed and its experimental results are presented for validation. Copyright © 2011 John Wiley & Sons, Ltd.     

一种新颖的抑制两级式直交逆变器输入电流低频脉动的方法

两级式直交单相逆变器输入电流中含有两倍于逆变器输出频率的低频分量,这些低频分量幅值相对其平均值的比例很高,可达到30%以上,严重时将会影响直流电源系统的稳定性,也会大大影响输入电压源的蓄电池、燃料电池的使用寿命。通过研究该电流低频分量产生的原因,对前级直直变换器提出一种新的控制策略,即在传统的控制策略中引入谐振控制器,可以有效的抑制直直变换器输出滤波电感电流的低频脉动,进而可以有效抑制变换器低压侧输入电源电流低频脉动分量。给出谐振控制器的设计方法,以及引入谐振控制器之后系统各环路的传递函数,分析满足系统稳定性要求的设计准则。最后通过仿真和实验验证该控制策略对于抑制两级式直交逆变器输入电流低频脉动的有效性。     

A DC/DC converter topology for renewable energy systems

This paper presents a DC/DC converter topology for renewable energy systems. The proposed DC/DC converter can be used to obtain a well‐regulated output voltage from low‐voltage power source, such as wind turbine, photovoltaic array, fuel cell, etc. It has the merits of high efficiency, low device stresses, and low current ripple. The operating principle, theoretical analysis, and design criteria are provided in this paper. A laboratory prototype was successfully implemented. The simulation and experimental results are given to verify the feasibility of the proposed scheme. Copyright © 2008 John Wiley & Sons, Ltd.     

交错控制双Boost型DC/DC变换器

提出一种交错控制双Boost型变换器,其包含有2个Boost单元,对应开关管的驱动信号相位差180°。对其在1个开关周期内的6种开关模态的开关通断情况和主要电压、电流的变化情况进行了详细介绍,并对变换器的性能特点进行了深入分析。实验结果表明该变换器具有以下特点:控制简单可靠,有现成的控制芯片可用;有源和无源器件都能实现软开关,不增加开关的电流、电压应力;与传统的Boost型DC/DC变换器相比,在输入、输出条件相同的情况下,输入电感和输出电容都可以减小,这是因为其输入电感电流和输出电压纹波频率都为开关频率的2倍,达到了倍频的效果。     

Analysis and comparison of current control methods on bridgeless converter to improve power quality

In this paper, the performance analysis of power factor correction (PFC) current control methods is presented for a bridgeless converter operating under continuous conduction mode (CCM). The bridgeless converter has been proposed using proportional-integral control (PIC), average sliding control (ASC) and predictive current control (PCC) methods to obtain unity power factor (PF) and lower total harmonic distortion (THD) of input current. Several PFC methods have been developed to satisfy the international standards such as IEC 61000-3-2 and IEEE 519-1992. The detailed steady-state theoretical analysis of the bridgeless converter is presented, which is verified by simulations and experiments carried out on 600 W and 50 kHz. The performance of the current control methods for the bridgeless converter is investigated by a Matlab/Simulink program. The experiments performed in the laboratory under input voltage and load variation ranges verify the theoretical and simulation studies. The control methods are programmed by the TMS320F2812 DSP microprocessor.     

全桥隔离DC/DC变换器的直接功率控制方法

以无工频变压器电力牵引传动系统为应用背景,对其中的全桥隔离DC/DC变换器开展研究。在电力牵引传动系统中,单相网侧脉冲整流器直流输出电压中含有二倍电网频率的电压脉动,该二倍频脉动可能会引起电机中的拍频现象。因此,为减小该二倍频电压脉动对DC/DC变换器输出电压的影响,研究全桥隔离DC/DC变换器在输入电压动态变化时的高性能控制方法非常必要。为提高全桥隔离DC/DC变换器在输入电压脉动以及突变情况下的动态响应性能,基于单相移控制方法,提出了一种直接功率控制方法,并进行了详细的分析。最后,基于RT-LAB和赛灵思XC3S500E的半实物仿真平台和基于TMS320F28335控制器的实物实验平台对所提出的控制方法进行验证,半实物仿真和实物实验结果表明:在输入电压突变、输入电压含有脉动和波动的情况下,该直接功率控制算法能有效提高输出电压的动态性能,减小输入电压扰动对输出电压的影响。     

An Isolated PFC Zeta-forward Single-stage Single-switch for LED Driver Without Electrolytic Capacitor

Abstract

The high-brightness light-emitting diodes (LEDs) require an AC/DC converter with power factor correction (PFC). The large output electrolytic capacitor, which is used to minimize the low frequency LED current ripple, degrades the operating lifetime of the LED driver. In order to increase the lifetime of an AC–DC LED driver, the electrolytic capacitor should be eliminated without significantly increasing the output current ripple. In this article, an isolated single-stage single-switch AC/DC high power factor LED driver without electrolytic capacitor is proposed in which a zeta power factor (PF) corrector is integrated with a forward converter. The detailed theoretical analysis and design procedure of the proposed single-stage PFC converter is presented. The experimental results of a 110 V_rms, 21?W prototype verify the theoretical analysis. The input PF is 0.99 in the proposed converter that complies with lighting equipment standards such as IEC-1000-3-2 for class C equipment.     

基于VSC的多端直流输电系统的控制策略

在换流器控制器设计中,采用基于输入输出反馈线性化策略的双闭环控制器结构和直流电压前馈补偿环节,既实现有功和无功的解耦控制,又改善了换流器交流侧的输出电压和电流波形.在多端系统稳定控制中,提出了多点直流电压控制策略,它提高了多端系统的功率平衡能力和运行的可靠性与经济性.文章对1个5端的电压源型直流输电( voltages...     

高增益电流型直流升压变换器研究

本变换器作为能馈电子负载的第一级,需要满足低压大电流输入、高增益,同时输入电流纹波小的要求,为此本设计采用高增益电流型直流升压变换器-级联升压Boost变换器。交错并联输入可以有效减小输入电流纹波,两级Boost级联可以方便提高升压比。文中给出了变换器中电感的设计、开关管的选择、输入电流闭环的设计,以及同步整流技术在该变换器中的应用。最后设计制作了一台3.3 V输入、48 V输出、330 W试验样机,试验结果满足能馈电子负载的要求。     

基于离散演化映射的DC/DC变换器混合逻辑动态建模

针对传统DC/DC变换器模型存在计算量大、进行了大量近似、不能反映电流纹波特性等不足,有机结合哈密顿原理和混杂系统理论,提出基于离散演化映射的DC/DC变换器混合逻辑动态建模方法。以Buck变换器为例,首先采用变分积分器对其进行离散化得到离散演化映射模型,然后基于混杂系统理论将CCM和DCM模式进行统一,进而得到混合逻辑动态模型。结果表明,所建立模型计算量小、精确度高,能完整描述系统的各个工作状态且能反映电感电流纹波等动态特性,为DC/DC变换器建模方法提供了新的思路。     

基于倍压单元耦合电感高增益DC/DC变换器

提出一种基于倍压单元的新型DC/DC高增益变换器.在传统Boost变换器的基础上引入倍压单元,提高变换器电压增益,并把2个储能电感进行磁集成,减小变换器体积和电感电流纹波.分析了该变换器的工作原理以及工作模态,推导了输出电压增益公式、各二极管和开关管的电压应力以及电感电流纹波.与传统Boost变换器相比,电压增益提高了...