共查询到20条相似文献,搜索用时 203 毫秒
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LLC谐振变换器由于谐振特性,能够较容易实现软开关和增大变换器功率密度,在中大功率场合得到广泛应用。为了增大功率密度提高输出容量,设计了一种非对称半桥交错并联输出式LLC谐振DC-DC变换器,对变换器的工作过程进行了分析。分析了不同k值对变换器的影响,对谐振网络进行了等效分析。不同谐振频率下变换器分布在不同的工作区域,不同的工作区域中开关MOS管实现软开关过程的难易程度不等。通过仿真和样机测试验证了设计的变换器开关管能够实现零电压开关(ZVS),能够有效减小变换器的开关损耗。 相似文献
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以非对称半桥LLC结构为主体,提出了一种自动磁复位半桥式正反激谐振变换器,变压器励磁电流能够双向流动,具有自动磁复位的复用功能。对变换器的工作原理和谐振网络等效电路进行分析,对谐振电流和谐振电压进行计算。对新型变换器的增益特性和实现软开关的条件进行了研究。通过60 W样机测试验证了开关管能够实现零电压开通(ZVS),变压器能够自动实现磁复位,变压器具有复用功能,对比传统非对称半桥式LLC谐振变换器,该变换器具有效率高、体积小的优点。 相似文献
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针对半桥 LLC谐振变换器谐振参数设计较困难的问题,采用基波分析法(FHA,FirstHarmonicApproximation)建立等效模型,然后分析 LLC变换器实现零电压开通的约束条件,得到 LLC谐振参数优化设计的方法.最后通过Saber搭建仿真平台,验证该参数设计的正确性。 相似文献
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宽输出的半桥型LLC谐振变换器的增益变化较大,会导致变换器在较宽的频率范围内工作,这不利于变压器和控制环路的设计。为提升变换器的效率,对宽输出变换器的增益特点进行了分析,并结合工作频率范围和增益要求,提出了一种针对谐振参数计算的方法。最后制作了一台功率为120W,输出电压在10.8~13.2V可调的样机,验证了该方法的正确性。 相似文献
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磁集成LLC谐振变换器的设计 总被引:1,自引:0,他引:1
LLC谐振变换器优于常规硬开关脉冲宽度调制(PWM)变换器:效率高、重量轻、体积小等,且全负载范围内切换可实现零电压开关(ZVS)。重点并详细介绍了磁集成LLC型谐振变换器的主电路结构和设计方法,用基波分量法求得其电压增益,并用MATLAB仿真,进行谐振网络参数设计和优化,其中还包括了其它元器件的选择。利用所介绍的设计方法,制作了一台工作频率在68.9kHz~106kHz、功率为96W的样机,成功实现了开关管的零电压开关(ZVS)和次级整流管的零电流开关(ZCS),峰值效率达到了92.3%,实验结果验证了设计方法的可行性和有效性。 相似文献
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Bor‐Ren Lin Yu‐Bin Nian 《International Journal of Circuit Theory and Applications》2016,44(2):328-341
In this paper, a new hybrid dc–dc converter with low circulating current within the freewheeling interval, wide range of zero‐voltage switching and reduced output current ripple is presented. The proposed hybrid circuit includes two three‐level pulse‐width modulation converters and a series resonant converter with the shard lagging‐leg switches. Series resonant converter is operated at fixed switching frequency (close to series resonant frequency) to extend the zero‐voltage switching range of lagging‐leg switches. The output of series resonant converter is connected to the secondary sides of three‐level converters to produce a positive rectified voltage instead of zero voltage. Hence, the output inductances can be reduced. The reflected positive voltage is used to decrease the circulating current to zero during the freewheeling interval. Therefore, the circulating current losses in three‐level converters are improved. Finally, experiments are presented for a 1.44 kW prototype circuit converting 800 V input to an output voltage 24 V/60A. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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一种简单的ZVZCS全桥PWM变换器的分析与设计 总被引:10,自引:0,他引:10
讨论了一种零电压零电流开关的全桥DC-DC PWM变换器。通过适当的控制方式及合适的参数选择,这种变换器可以在很宽的负载变化范围内以软开关方式高效率的工作,同时保持了简单的拓扑结构。文中对这种变换器的基本工作原理进行了较详细的理论分析,并根据分析过程中的数学描述对电路的有关参数设计给予了说明。最后通过仿真与一6kW样机实验验证了本文所讨论的变换器工作原理的正确性及实用上的可行性。 相似文献
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Bor‐Ren Lin Chung‐Wei Chu 《International Journal of Circuit Theory and Applications》2016,44(4):874-892
A new direct current (DC)/DC converter with parallel circuits is presented for medium voltage and power applications. There are five pulse‐width modulation circuits in the proposed converter to reduce current stress at low voltage side for high output current applications. These five circuits share the same power switches in order to reduce switch counts. To reduce the converter size, conduction loss, and voltage stress of power semiconductors, the series connections of power metal‐oxide‐semiconductor field‐effect transistor (MOSFET) with high switching frequency instead of insulated gate bipolar transistor (IGBT) with low switching frequency are adopted. Thus, the voltage stress of MOSFETs is clamped at half of input voltage. The switched capacitor circuit is adopted to balance input split capacitor voltages. Asymmetric pulse‐width modulation scheme is adopted to generate the necessary switching signals of MOSFETs and regulate output voltage. Based on the resonant behavior at the transition interval of power switches, all MOSFETs are turned on under zero voltage switching from 50% load to 100% load. The circuit configuration, operation principle, converter performance, and design example are discussed in detail. Finally, experimental verifications with a 1.92 kW prototype are provided to verify the performance of the proposed converter. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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提出一种LCC谐振变换器的非对称移相控制方法。该方法采用PWM移相混合调制方式,有两个控制变量,实现了更高的控制自由度。分析LCC谐振变换器的稳态特性,包括输出功率特性、软开关特性以及谐振电流特性。分析结果表明,不同的控制变量组合能够实现同一输出功率,但会导致软开关及谐振电流特性发生变化。在此基础上提出一种效率优化策略,使谐振变换器在输出功率不变的情况下谐振电流降至最低,同时保证了软开关的实现。所提出的方法能够进一步提升LCC谐振变换器的效率。通过仿真及1.9k W样机验证了理论分析及所提控制方法的可行性和有效性。 相似文献
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Bor‐Ren Lin Chung‐Wei Chu 《International Journal of Circuit Theory and Applications》2016,44(5):996-1011
In this paper, a new soft switching direct current (DC)–DC converter with low circulating current, wide zero voltage switching range, and reduced output inductor is presented for electric vehicle or plug‐in hybrid electric vehicle battery charger application. The proposed high‐frequency link DC–DC converter includes two resonant circuits and one full‐bridge phase‐shift pulse‐width modulation circuit with shared power switches in leading and lagging legs. Series resonant converters are operated at fixed switching frequency to extend the zero voltage switching range of power switches. Passive snubber circuit using one clamp capacitor and two rectifier diodes at the secondary side is adopted to reduce the primary current of full‐bridge converter to zero during the freewheeling interval. Hence, the circulating current on the primary side is eliminated in the proposed converter. In the same time, the voltage across the output inductor is also decreased so that the output inductance can be reduced compared with the output inductance in conventional full‐bridge converter. Finally, experiments are presented for a 1.33‐kW prototype circuit converting 380 V input to an output voltage of 300–420 V/3.5 A for battery charger applications. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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传统LLC谐振变换器采用变频控制,在输入电压变化范围较宽时开关频率变化范围宽,其磁性元件难以优化设计。将LLC谐振变换器中的谐振电感设计为柔性电感,通过改变柔性电感的电感而改变变换器的谐振频率,改变LLC变换器的输出特性,实现宽输入电压、宽负载范围内的恒频调压,进而可以实现变压器、电感、滤波电容等元件的优化设计。首先介绍了柔性电感的原理,分析了采用柔性电感的全桥LLC谐振变换器的工作特性,并给出了闭环恒频控制的实现方案。最后通过一台输入电压23~35 V、输出电压100 V、功率200 W的原理样机,验证了基于柔性电感的恒频控制LLC谐振变换器的可行性。 相似文献