共查询到17条相似文献,搜索用时 156 毫秒
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为了提高LLC谐振变换器的输入电压适应范围,提出了一种新颖的双模态LLC谐振变换器。所提出变换器的隔离变压器原边绕组中设计有一个辅助抽头,使得变压器具有两种工作变比,对应两种工作模态:低输入电压区模态和高输入电压区模态。通过检测输入电压控制高频开关,使得变换器自动选择适应当前输入电压的工作模态。文中给出了所提出变换器的详细工作原理和换流过程分析。为了避免变换器在设定的输入电压切换点附近因模态连续切换而产生的震荡,提出了一种基于电压滞环和模态保持的模态切换策略。最后,研制了一台300W的实验样机,样机输入电压为25V~60V,控制芯片为TMS320F28335,样机实验结果验证了所提出的双模态LLC谐振变换器及其模态切换策略的可行性。 相似文献
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半桥LLC谐振变换器稳态建模及分析 总被引:1,自引:0,他引:1
介绍了半桥LLC谐振变换器的工作原理,研究了半桥LLC谐振变换器的稳态建模,利用MATLAB软件绘出其直流增益曲线,在此基础上分析了变换器主要参数对其工作性能的影响。样机实验验证了理论分析的正确性。 相似文献
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针对全桥LLC谐振变换器在脉冲频率调制(Pulse Frequency Modulation, PFM)下存在电压增益范围较窄和动态响应较差的问题,提出一种定频移相-变频时移混合控制策略。该方法在结合PFM和移相调制的基础上,当电压增益大于1时,采用变频时移控制;当电压增益小于1时,采用定频移相控制,同时改善了变换器的电压增益范围和响应速度。详细分析了混合控制策略在LLC谐振变换器上的工作原理及增益范围,并搭建了一台240W的实验样机,实验结果验证了该策略的可行性和优越性。 相似文献
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张乐 《信息技术与信息化》2023,(3):177-181
针对LLC谐振变换器传统零电压软开关(zero voltage switch, ZVS)在MHz频率条件下不再适用的问题,提出了精确的MHz的ZVS边界模型。首先对LLC谐振变换器在死区时间内的工作模态进行详细分析;然后通过详细模态的数学建模得出ZVS实现的边界模型;最后在该边界模型的基础上,发现LLC工作在兆赫兹时采用调频控制方式存在软开关范围受限的问题,搭建了一套1 MHz工作频率的半桥LLC样机。实验结果表明,所提方法重新定义了LLC谐振变换器MHz工作时的ZVS边界,并验证了理论分析的准确性。 相似文献
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董招辉阳璞琼胡波陈文光 《真空电子技术》2017,(3):23-26
本文设计了一个以LLC谐振变换器为主电路,输出端采用倍压整流,L6599芯片为控制核心的功率可调高压变频微波炉电源。运用基波分析法推导出变换器的直流增益,利用MATLAB软件绘出了直流增益曲线,以此讨论了各参数对LLC谐振变换器的影响,优化各参数的设计。最后利用PSPICE软件对设计的微波炉电源主电路进行了仿真,设计并制作了一台电源样机,验证了设计的正确性和可行性。 相似文献
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本文针对LLC串联谐振变换器提出了一种新颖的基于时域分析的精确分析方法,给出了设计。的准则和流程。LLC串联谐振变换器具有拓扑结构简单,高效率和易高频化的特点,目前得到了广泛的应用。为了优化设计并澄清其设计准则,充分理解该拓扑的直流增益特性以及各参数对效率的影响显得尤为重要。而基于基波近似的传统频域分析方法难于给出准确的结果。本文依照所提出的精确分析设计方法,搭建并测试了一个MHz的LLC串联谐振变换器,其效率达96%。试验结果证实了所提出的时域分析方法和设计准则的有效性。 相似文献
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通过分析对比大功率LED驱动电路的拓扑结构,采用LLC谐振拓扑,提出了一种适用于宽范围恒流输出的设计方法,并进行了效率优化。LLC半桥谐振变换器可在全负载范围内实现功率开关管的零电压开通(ZVS)和整流二极管的零电流关断(ZCS),以此减小开关损耗。并且采用基波近似方法分析LLC谐振变换器,通过交流等效电路,导出了归一化直流增益曲线,讨论了半桥LLC的三种主要工作方式,以及对应的三个工作区间,分析了每个工作区间的特点和应用场合。 相似文献
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分析LLC谐振变换器的工作原理,提出了一种利用计算机仿真软件SABER辅助设计LLC谐振变换器的方法,并用该方法设计了一款为电力机车上的仪器仪表供电的LLC变换器,通过实验验证了该方法的准确性。 相似文献
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This article analyses and presents an LLC resonant converter with a high power factor for LCD-TV applications. It integrates the advantages of power factor correction and the LLC resonant converter. It can improve not only power quality but also circuit efficiency. Since the power factor corrector is used in the first stage of the LLC resonant converter, it is suitable for wide input voltage range application. On the basis of the resonant behaviour, zero voltage switching is achieved for the power switches and ZCS is achieved for the rectifier diodes. An experimental prototype of 90–260V rms input and 12V/10A and ?12V/10A outputs with 92.6% efficiency for 32″ LCD-TV application is built in the laboratory to verify the operation principle of the adopted converter. 相似文献
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针对模拟电源效率较低的现状,提出一种基于DSP的数字电源方案。在对LLC谐振全桥变换器工作原理简单分析的基础上,采用DSP TMS320F28335设计了一款输入为DC300-400V,输出为DC48V/12A的原理样机,利用Saber仿真软件对其进行仿真与调试,仿真结果与实验数据表明,本文设计的LLC全桥谐振变换器能够在全负载范围内实现初级零电压开通(ZCS)以及次级零电流关断(ZVS),输出电压纹波小于±0.5%,效率达到95%以上,满足设计要求。结论表明,LLC谐振变换器符合电源高功率密度、高效率的发展要求。 相似文献
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Three-level LLC series resonant DC/DC converter 总被引:5,自引:0,他引:5
Yilei Gu Zhengyu Lu Lijun Hang Zhaoming Qian Guisong Huang 《Power Electronics, IEEE Transactions on》2005,20(4):781-789
Paper presents a three-level soft switching LLC series resonant dc/dc converter. Zero-voltage switching (ZVS) is achieved for each main switch without any auxiliary circuit. Voltage stress of each main switch is half of input voltage. Zero-current-switching (ZCS) is achieved for rectifier diodes. Wide input/output range can be achieved under low frequency range because of two-stage resonance. Only one magnetic component is required in this converter. Efficiency is higher in high line input, so this converter is a preferable candidate for power products with the requirement of hold up time. For design convenience, relationship between dc gain and switching frequency, load resistance is deduced. Its open load characteristic and short load characteristic are exposed to provide theory basis for no load operation and over current protection. Design consideration of four dead times is presented to assure that voltage stress for main switches is within half of input voltage and ZVS for each main switch is achieved. Finally the principle of operation and the characteristics of the presented converter are verified on a 500V-700V input 54V/10A output experimental prototype, whose efficiency reaches 94.7% under rating condition. 相似文献
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Analysis and Optimization of LLC Resonant Converter With a Novel Over-Current Protection Circuit 总被引:2,自引:0,他引:2
Xiaogao Xie Junming Zhang Chen Zhao Zhuo Zhao Zhaoming Qian 《Power Electronics, IEEE Transactions on》2007,22(2):435-443
A novel over-current protection (OCP) method for a LLC resonant converter has been proposed in this paper. This method is very attractive for its inherent current limit ability, especially under short-circuit condition. Combined with the frequency increasing method, good current limit features can be achieved. Compared to the conventional LLC resonant converter with frequency increasing method, LLC with the proposed OCP method can reduce the maximum frequency to an acceptable value. Detailed theoretical analysis and optimization design considerations have been presented. An experimental prototype converter based on the proposed method has been built up to verify the theoretical analysis. Experimental results meet the theoretical analysis very well 相似文献
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Bor-Ren Lin 《International Journal of Electronics》2018,105(5):836-847
Conventional series resonant converters have researched and applied for high-efficiency power units due to the benefit of its low switching losses. The main problems of series resonant converters are wide frequency variation and high circulating current. Thus, resonant converter is limited at narrow input voltage range and large input capacitor is normally adopted in commercial power units to provide the minimum hold-up time requirement when AC power is off. To overcome these problems, the resonant converter with auxiliary secondary windings are presented in this paper to achieve high voltage gain at low input voltage case such as hold-up time duration when utility power is off. Since the high voltage gain is used at low input voltage cased, the frequency variation of the proposed converter compared to the conventional resonant converter is reduced. Compared to conventional resonant converter, the hold-up time in the proposed converter is more than 40ms. The larger magnetising inductance of transformer is used to reduce the circulating current losses. Finally, a laboratory prototype is constructed and experiments are provided to verify the converter performance. 相似文献
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de Groot H. Janssen E. Pagano R. Schetters K. 《Power Electronics, IEEE Transactions on》2007,22(6):2307-2320
In this paper, the design of a 1-MHz LLC resonant converter prototype is presented. Aiming to provide an integrated solution of the resonant converter, a half-bridge (HB) power metal oxide semiconductor (MOS) module employing silicon-on-insulator technology has been designed. Such a technology, which is suitable for high-voltage and high-frequency applications, allows enabling HB power MOSFET modules operating up to 3MHz with a rated voltage of 400V. The power device integrates the driving stages of the high-side and low-side switch along with a latch circuit used to implement over-voltage/over-current protection. The module has been designed to be driven by a digital signal processor device, which has been adopted to perform frequency modulation of the resonant converter. By this way, output voltage regulation against variations from light- to full-loaded conditions has been achieved. The issues related to the transformer design of the LLC resonant converter are discussed, too. Owing to the high switching frequency experienced by the converter, 3F4 ferrite cores have been selected for their low magnetic power losses between 0.5 and 3 MHz and core temperatures up to 120degC. The resonant converter has been designed to operate in an input voltage range of 300-400V with an output voltage of 12V and a maximum output power of 120W. Within these design specifications, a performance analysis of the LLC converter has been conducted, comparing the results obtained at the switching frequencies of 500kHz and 1MHz. A suitable model of the LLC resonant converter has been developed to aid the prototype design. 相似文献