共查询到19条相似文献,搜索用时 296 毫秒
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有源箝位正激变换器有很多优点,现在正得到广泛应用。本文介绍了有源箝位技术的工作原理与主要参数的设计方法,以及应用于正激变换器中的优势。 相似文献
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本文研究一种具有非线性电压转换的正激变换器,通过在有源箝位正激变换器的变压器二次侧增加一个续流二极管和一个输出滤波电感得到。该变换器保留了有源箝位正激变换器的优点,同时,具有更高的占空比利用率,使得其具有宽输入电压适应范围,软开关的实现和二极管电压电流应力的减小,使其功率转换效率进一步提高。研制了一台50~100V输入, 12V输出的原理样机,实验结果验证了理论分析的正确性以及该技术的可行性。 相似文献
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提出一种同步整流有源箝位正激变换器。该变换器是在传统的同步整流有源箝位正激变换器的原边增加一个由箝位电容和电感构成的辅助网络得到。该辅助网络可以使变换器在全负载范围内更容易实现主开关管和辅助开关管的ZVS(Zero-Voltage Switching),副边采用自激式同步整流技术,能进一步提升变换器效率,适用于低压、大电流输出场合。详细分析了变换器的工作原理,搭建了一台8 V/100 W试验样机证明了理论分析的正确性。 相似文献
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The authors point out the major differences between symmetrical topology magamps and the forward converter magamp. In a forward converter, a small portion of the magnetizing current of the power transformer is diverted to the secondary for reset of the magamp's saturable reactor. In symmetrical topologies, the transformer's magnetizing current is not used for reset of the saturable reactor(s). The magnetizing current shifts to the secondary where it causes a series of problems. The authors examine these problems, identify solutions, and explain why a half-bridge magamp supply is inherently less versatile than is the forward converter 相似文献
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龚春英 《电气电子教学学报》2006,28(5):18-22
在电力电子技术课程中,推挽式、半桥式和全桥式隔离型变换器电路属一类变压器磁芯双向磁化的基本电路,在实际中得到广泛的应用。如何给学生解释清楚铁心双向对称磁化的原理是一个教学难点。本文以推挽电路为例分析了铁心双向对称磁化工作机理。从带磁复位绕组的单端正激变换器的变压器铁心磁化工作原理出发,将推挽变换器看成是两个带磁复位绕组的单端正激变换器的组合。并从空载时占空比小于四分之一情况出发,循序渐进地全面细致地分析了各种负载情况下的工作原理,这种讲解思路严谨且易于被学生理解和接受。 相似文献
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The forward converter with the active-clamp reset offers many advantages over the forward converters with other transformer-reset methods. However, during the line and load transients, the maximum magnetizing current of the transformer and the peak voltage of the primary switch are strongly affected by the active-clamp circuit dynamics. As a result, the design of a forward converter with the active-clamp reset cannot be optimized based only on its DC characteristics. Due to the nonlinearity of the circuit, it is very difficult to derive the closed-form equations for the transient response of the active-clamp circuit. In this paper, an average-state-trajectory approach is proposed to analyze the transient behavior so that the trends of the maximum magnetizing current of the transformer and the peak voltage of the primary switch can be easily predicted under worst-case conditions and parameter variations 相似文献
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McNeill N. Gupta N.K. Burrow S.G. Holliday D. Mellor P.H. 《Power Electronics, IEEE Transactions on》2008,23(2):591-599
This paper investigates the application of reset voltage feedback for reducing errors due to droop in the signal derived from a current transformer sensing unidirectional current pulses in switched-mode power converter applications. Droop is minimised by applying a correcting voltage in series with the transformer's output terminals during the current pulse. The magnitude of the correcting voltage is based on the transformer's reset voltage sensed during the power converter's previous switching cycles. A model of the scheme is presented and a circuit is implemented. Reductions in both peak and average current droop are demonstrated. 相似文献
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A self core reset and zero voltage switching (ZVS) forward converter topology is presented in this paper. By employing a simple auxiliary circuit, the proposed topology is able to achieve self reset of the power transformer without the use of the conventional tertiary reset winding, and its main switch can be turned on and turned off under ZVS independent of line and load conditions. This simplifies the power transformer, and the switching losses are substantially removed to improve the overall efficiency. Steady state analysis of the circuit is performed. Based on the analysis, a design procedure is presented, and the effects of the circuit parameters on the flux excursion of the power transformer are investigated to make sure self reset can be achieved without increasing the core losses. Simulation and experiment on a 5 V, 100 W prototype circuit operated at 200 kHz are carried out to verify the design, about 5% higher overall efficiency is obtained in the prototype converter than in its conventional counterpart 相似文献
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This paper presents a forward converter topology that employs a small resonant auxiliary circuit. The advantages of the proposed topology include soft switching in both the main and auxiliary switches, recovery of the leakage inductance energy, simplified power transformer achieving self-reset without using the conventional reset winding, simple gate drive and control circuit, etc. Steady-state analysis is performed herein, and a design procedure is presented for general applications. A 35-75-Vdc to 5 Vdc 100-W prototype converter switched at a frequency of 200 kHz is built to verify the design, and 90% overall efficiency has been obtained experimentally at full load. 相似文献
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This paper presents a new topology named zero-voltage switching (ZVS) resonant reset dual switch forward dc-dc converter, which, compared with resonant reset single switch forward dc-dc converter, maintains the advantage that duty cycle can be more than 50%, at the same time disadvantages of high voltage stress for main switches and low efficiency are overcome. In addition, ZVS is achieved for all switches of the presented topology. Therefore, this proposed topology is very attractive for high voltage input, wide range, and high efficiency applications. In this paper, the operation principle and characteristic of this topology are analyzed in detail. Next, the design consideration is presented. Finally, the advantages mentioned above are verified by experimental results 相似文献