共查询到18条相似文献,搜索用时 78 毫秒
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提出一种全桥双谐振CLL谐振DC-DC变换器拓扑。该变换器有两个谐振网络,共用一个变压器。该谐振变换器能在全负载范围内,实现开关管的零电压导通ZVS(zero voltage switching)和副边整流二极管的零电流关断ZCS(zero current switching),变换器开关管的开关损耗低,同时消除了二极管的反向恢复损耗,实现较高效率,适用于分布式电源系统中的直直变换模块。采用基波分析FHA(fundamental harmonic approximation)方法对该谐振变换器进行分析,得到了该变换器的直流增益特性。最后,制作了一台200 W的实验样机,验证了理论分析的正确性。 相似文献
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离线式半桥零电压开关多谐振变换器的参数最优化 总被引:1,自引:0,他引:1
本文在对HBZVS-MRC工作模式分析及功耗分析基础上,提出了一种新的设计方法,建立以变压器原边峰值电流最小为优化目标、以谐振参数为设计变量的优化设计模型,利用HBZVS-MRC仿真程序及离散非线性优化算法进行寻优计算,通过实验验证,得到较满意的结果。 相似文献
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LLC变换器具有实现原边零电压开通和副边零电流关断的软开关特性,其功率密度高,在车载电源、LED等领域被广泛应用。但LLC谐振变换器由于工作的复杂性,导致谐振参数缺乏一种有效且明确的设计方法。论文基于基波近似法(first harmonic approximation, FHA)对传统的增益公式进一步化简,提出了一种简单明确的谐振参数设计方法。为了验证此方法设计的参数最优性,制作了一台7.5 kW的实验样机。输出电压范围为100 V~375 V,而且可在200 V~375 V的电压范围内实现7.5 kW的恒功率输出,整机平均效率达到95%以上,峰值效率可达到96.7%。实验结果表明,提出的参数设计方法可最大化地提高变换器效率。 相似文献
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近年来,氮化镓(GaN)器件凭借其开关速度快、导通电阻小等优点被广泛应用于电力电子变换器中,与此同时,谐振栅极驱动电路也受到广泛的关注,特别是在高开关频率、小功率的应用场合中,用以降低驱动电路的损耗.然而,与硅器件不同的是,GaN器件的开通阈值电压相对较低,且没有体二极管,反向导通压降较大,因此传统的谐振栅极驱动电路不适使用GaN器件.该文针对高频应用场合中寄生参数易引起驱动信号振荡的问题,结合GaN器件特点,提出一种非对称电压的谐振栅极驱动电路.此外,对于需要两个同步开关的应用场合,如开关电感变换器等,采用具有两个二次侧的变压器实现两路隔离同相驱动信号的输出.该文介绍了谐振栅极驱动电路的工作原理,并以效率最优的原则设计电路参数,设计一台开关频率为1MHz的驱动电路样机,并进行实验验证,实验结果与理论分析结果吻合较好. 相似文献
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谐振开关电容变换器中潜电路现象的研究 总被引:6,自引:0,他引:6
潜电路是潜伏在系统中的一种通路或状态,它在一定条件下出现并导致系统产生非预想到的特性.该文在降压式谐振开关电容变换器中发现潜电路现象,其特点是在控制策略完全不变的情况下,仅由电路扰动就会导致潜电路现象发生.文中从理论上分析了产生该潜电路现象的原因,证明了它是一种在过去研究中未曾观察到的新现象,推导得出了潜电路的发生条件及相应的变换器运行特性,并基于潜电路的回路特征,提出消除潜电路的相关措施,并将这一结果推广到其它类型的谐振开关电容变换器.实验结果证实了这一发现和理论分析结果. 相似文献
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本文介绍了一种多元件级联式谐振变换器,该变换器结合了串联谐振变换器和并联谐振变换器的特点,并且在运行性能上有所提高。文章利用经典交流分析法,推导了电压传输增益,同时分析了非连续导通模式下的各种开关状态,得出相应的等效电路,并且运用数值解法求得谐振电压电流的波形和临界负载电流。 相似文献
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Kasi Ramakrishnareddy Ch Shunmugam Porpandiselvi Neti Vishwanathan 《International Journal of Circuit Theory and Applications》2019,47(7):1173-1187
A three-leg resonant converter is proposed to drive two light emitting diode (LED) lamps of different power ratings. This may be required when both main and local lighting are essential. The proposed converter is operated simultaneously at two different frequencies. Two series resonant circuits are used to allow two different frequency currents. Each lamp is powered through a series resonant circuit and is controlled independently. LED lamp currents are regulated at the desired operating current by using phase-modulation control and asymmetrical duty ratio control. In addition, pulse-width modulation (PWM) dimming control is implemented for two LED lamps independently. The proposed topology has advantages of zero-voltage switching (ZVS), regulation of lamp currents, independent illumination control, and high efficiency. A 126-W prototype has been developed experimentally to confirm its working principle, performance, and validity. 相似文献
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提出了LLC谐振变换器采用频率调制(FM)和脉冲宽度调制(PWM)的变模式控制策略。输入额定电压时变换器采用FM控制以获得最大性能效率;输入电压降低时,采用非对称占空比PWM控制使变换器处于反激变换模式,获得最大电压增益;在输入电压较高或负载较轻时,采用对称占空比PWM控制,实现全负载范围内开关管零电压开关(ZVS)和整流二极管零电流开关(ZCS),降低开关损耗。对变模式控制策略工作模式以及特性进行了分析,给出了控制方案电路框图。实验结果验证了变模式控制策略的可行性,变换器获得了更高性能效率和更高功率密度。 相似文献
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Yu‐Kang Lo Jing‐Yuan Lin Chung‐Yi Lin 《International Journal of Circuit Theory and Applications》2012,40(10):985-998
This paper presents a two‐transformer LLC series resonant converter (SRC), which is derived from incorporating two identical converters. The proposed converter allows a low‐profile power supply design for liquid crystal display (LCD) TVs and servers. The presented converter can equally share the total load current between two transformers and the output rectifier modules. Therefore, the heat problem can be effectively relieved. The steady‐state analysis and design of this new two‐transformer LLC SRC are described. The experimental results are recorded for a prototype converter with an output voltage of 12thinspaceV, an output power of 300 W, and a resonant frequency of 74 kHz. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Kasi Ramakrishnareddy Ch Shunmugam Porpandiselvi Neti Vishwanathan 《International Journal of Circuit Theory and Applications》2019,47(12):2019-2031
New power control is introduced in the full-bridge dc-dc converter to drive an LED lamp in this paper. LEDs are semiconductor devices that behave like a constant voltage load with low equivalent series resistance (ESR). Hence, they require precise control for current regulation. In the proposed driver, the LED lamp is driven by two voltage sources connected in series through a series resonant circuit. It processes the majority of lamp power through the full-bridge diode rectifier and supplies small power through a center-tapped rectifier. The LED lamp current is controlled at the selected operating current by using center-tapped rectifier output voltage. In addition, pulse-width modulation (PWM) dimming is implemented. The proposed topology features zero-voltage switching (ZVS), regulation of lamp current, dimming operation, and high efficiency. The working principle, performance, and prototype validation are given for the proposed LED driver. 相似文献
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开关管关断损耗是三电平LLC谐振变换器高频工况下的主要损耗,是一个与谐振电感L_r、谐振电容C_r、励磁电感L_m以及电压增益Gv密切关联的变量。首先用时域分析法,建立了开关管关断电流I_(off)与电感比k、归一化频率f_n和品质因数Q之间的解析函数;并结合开关管关断过程特点,建立了关断损耗P_(sw-off)与[k,f_n,Q]之间的解析函数。然后构建出[I_(off),k,f_n,Q]和[P_(sw-off),k,f_n,Q]2个四维图形,分析参数之间的规律。在此基础上,推导了在电压增益的需求和开关管零电压导通的实现2个约束条件下来优化P_(sw-off)的[k,f_n,Q]参数取值空间,进而采用粒子群优化算法求解关断损耗优化下的[k,f_n,Q]值。最后设计了一个200 V输入、130 V输出、负载电阻48.4Ω、额定功率350 W的实验样机,并对比分析了所提方法与降低谐振电流有效值来减少导通损耗的传统优化方法分别在满载与半载条件下的关断损耗,证明了所提优化方法在降低开关管关断损耗、提高变换器效率方面效果明显。 相似文献