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1.
A new quasi current resonant DC link (QCRDCL) topology has been developed in this paper. Although prototype current resonant DC link topologies for AC/AC power conversion have had such problems as irregular high current peaks, uncontrollable pulse width, etc., this new topology enables the AC/AC conversion system to have the properties wherein the current peak is limited and the pulse width is adjustable. The system begins to assume an adjustable-width flat-topped current shape, whereby the system becomes particularly suitable for high power application. With control of the pulse width a very fine load current regulation can be obtained. In this system, an open loop PWM control has been adopted and almost the same quality of output waveforms as the conventional current source inverter has been achieved 相似文献
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文中提出一个新颖实用的交、直流变换器拓扑结构,论述数字式交、直流双向变流器的工作原理,功率变换电路控制策略以及功率变换回路如何选择主要器件及其参数,并通过小批量产品来验证变换器运行的正确性。 相似文献
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Soft-switching techniques are attractive to unity-power-factor AC/DC converter in the view of the size reduction and EMI suppression. A soft-switched boost PFC converter has been studied based on its topology analysis, PSIM simulation and circuit experiment. A special limitation of soft-switching techniques has been found in their AC/DC applications. 相似文献
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A single-stage power-factor-corrected AC/DC converter 总被引:1,自引:0,他引:1
This paper presents a single-stage isolated converter topology designed to achieve a regulated DC output voltage having no low-frequency components and a high-input power factor. The topology is derived from the basic two-switch forward converter, but incorporates an additional transformer winding, inductor and a few diodes. The proposed circuit inherently forces the input current to be discontinuous and AC modulated to achieve high-input power factor. The converter output is operated in discontinuous mode to minimize the bulk capacitor voltage variations when the output load is varied. Analysis of the converter is presented, and performance characteristics are given. Design guidelines to select critical components of the circuit are presented. Experimental results on a 150 W 50 kHz universal input (90-265 V) 54.75 V output AC/DC converter are given which confirm the predicted performance of the proposed topology 相似文献
5.
Ji Yanchao Shan Mingwei 《Power Electronics, IEEE Transactions on》1999,14(2):233-245
This paper proposes a novel three-phase AC/DC converter without a front-end filter. Because an adjustable triangular-wave pulsewidth modulation (PWM) (ATPWM) technique is adopted, not only is a front-end filter located after the three-phase rectifier is omitted, but also the size of the input AC filter and the output DC filter are reduced. In addition, this AC/DC converter has many advantages such as simpler structure, higher reliability, and better output waveform. The principle of operation, harmonics elimination, and feedback control of the novel AC/DC topology are elaborated. A thorough analysis on its performance under an unbalanced system is presented. Finally, the theoretical analysis is proved to be correct by simulations and experiments 相似文献
6.
为了解决常用的逆变器所带来的问题,我们提出一种新型的带升降压功能的三相DC/AC变换器拓扑,并介绍了其工作原理。借助于PSIM仿真软件,对单相和三相电路进行了仿真研究,提出了由单相组成三相电压输出的构成方法。在列出仿真参数的前提下,给出了负载电压,负载电流以及调制给定电压和逆变器输出电压的仿真结果。仿真结果表明三相DC/AC逆变器可以实现50 kHz高频功率变换下宽输入电压范围工频逆变输出,证明了理论分析的正确性。 相似文献
7.
The research on direct AC/AC conversion in the past twenty years has been following two major directions: improving the performance of the original nine-bidirectional-switch matrix converter topology; and using converter topologies composed of unidirectional switches only. In this paper, a direct AC/AC converter topology based on current-source converter modules is proposed. It is shown, through analysis and simulation, that the proposed topology is free of any switching difficulties and gives high-quality sinusoidal waveforms on both sides. Furthermore, with the same number of semiconductor devices as in the original nine-bidirectional-switch matrix converter topology, it is able to perform all aspects of frequency changing, real power flow control, and independent reactive power flow control on both sides. The proposed topology finds applications in electric drive industry, as an AC motor drive, and power system industry, as an asynchronous link. 相似文献
8.
Zhong Ye 《Power Electronics, IEEE Transactions on》1999,14(5):816-822
A new control strategy and topology for VAr compensation is presented and analyzed. It treats a three-phase power system as two energy ports and uses one single-phase bidirectional AC/AC power converter to transfer reactive energy between the two ports to produce three-phase reactive power. The compensated reactive power can be leading or lagging. Hysteresis control is investigated as a means of current modulation. The system has fast transient response capability, and one unit of AC/AC converter power generates 2.412 units of reactive power. The characteristics of the topology and predicted results are verified experimentally 相似文献
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基于DSP的能量回馈型交流电子负载的研究 总被引:2,自引:0,他引:2
交流电子负载是一种可以模拟不同负载特性的电力电子装置,不仅可以模拟阻性负载,还可以模拟任意功率因数的感性和容性负载;同时,被测电源发出的电能将以单位功率因数返回电网。其系统主电路采用AC/DC/AC的结构,由共用直流母线的两级电压型PWM整流器组成。文章提出了一种数模混和型控制方案,该方案具有控制简单,占用DSP系统资源少,工作稳定可靠等优点。可以实现多个模块并联工作,满足大功率电源测试需求。仿真和实验结果验证了该方案的可行性和合理性。 相似文献
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M. N. Gitau J. G. Kettleborough I. R. Smith 《International Journal of Electronics》2013,100(12):1499-1516
One effect of the second-harmonic in the load-side current ripple of a single-phase AC/DC converter is to introduce an unwanted third-harmonic into the supply-side current. Although this can be neither eliminated nor reduced by either conventional selective harmonic or natural sinusoidal PWM strategies, it is shown that the use of a modified switching function in the selective strategy enables a considerable reduction to be achieved. Possible applications for the new strategy include single-phase AC/DC converter-fed DC drives and converters providing a DClink for inverter-fed DC drives. 相似文献
14.
The AC/DC measurements of NMOS and PMOS I dsat shifts are compared following DC stress. The results of the I dsat shifts are found to be the same. The AC I dsat measurements were performed under a variety of different conditions (varying frequency, amplitude, and base level) and showed that hot-carrier-induced interfaced states are shallow and fast (<20 ns). AC versus DC stressing was also examined. In PMOS devices, pulsed drain stress was found to be generally quasi-static, while pulsed gate stress produced enhanced device degradation under certain bias conditions. In NMOS transistors AC drain stress was found to be quasi-static in strong device saturation, while AC gate stress resulted in significantly enhanced degradation. In weak device saturation, both gate and drain pulsing resulted in early catastrophic device failure 相似文献
15.
A study of series-resonant DC/AC inverter 总被引:1,自引:0,他引:1
Guan-Chyun Hsieh Chun-Hung Lin Jyh-Ming Li Yu-Chang Hsu 《Power Electronics, IEEE Transactions on》1996,11(4):641-652
A new DC/AC inversion for achieving an AC sinusoidal waveform synthesized by a series of quasi-sinusoidal pulses is described. A modified pulse-width-modulated (PWM) controller is presented for driving the power switch to operate in a forced discontinuous-conduction mode (FDCM) so as to achieve series-resonance in the power stage. The output power results mainly from the energy stored in the resonant capacitor and is independent of the number of the resonant quasisinusoidal pulses. Three dynamic conversion states including charging, resonant, and RC-discharging states are modeled and analyzed. Signal analysis for the composite AC sinusoidal waveform is conducted. A small-signal model for system performance investigation is described. A prototype of a 1 kW DC/AC inverter is examined by simulation and experimentation in order to assess the system performance 相似文献
16.
Cheasty P. Flannery J. Meinhardt M. Alderman A. O'Mathuna S.C. 《Power Electronics, IEEE Transactions on》2002,17(1):141-150
This paper presents the first reported final results of a benchmarking project "StatPEP" which investigated the Status of Power Electronic Packaging used in commercial DC/DC and AC/DC switch mode power supplies. The methodology of the project is first described. Some of the salient results of a comprehensive benchmarking of DC/DC converters (rated power of 100 W) and AC/DC converters (rated power up to 576 W) are presented. Examples for figures-of-merit are presented. The results of the investigation are presented in a generic form, which does not identify individual products. A comparison of the performance of the units shows that the measured power density of the AC/DC units is approximately 10% that of the DC/DC while the thermal density based on footprint is 50%. Also the switching frequency of the AC/DC is 50% that of the DC/DC. Some of the reasons for these differences are discussed 相似文献
17.
Diaz J. Nuno F. Lopera J.M. Martin-Ramos J.A. 《Industrial Electronics, IEEE Transactions on》2004,51(4):850-856
Piezoelectric transformers (PTs) are an attractive solution to reduce size and weight in ac/dc converters. In this paper, a PT-based topology is presented together with a control method. As an application, an 8-W ac/dc adapter (110 V/sub AC/ input, 12 V/sub DC/ output) is presented operating at frequencies around 500 kHz. 相似文献
18.
Eui-Cheol Nho 《Electronics letters》2001,37(4):205-206
A new method that protects against a load short-circuit in a multilevel PWM AC/DC converter is described. The output DC voltage of the proposed scheme can he quickly disconnected from the short-circuit load. In addition, the DC voltage is applied to the load immediately after the fault has been cleared without causing any voltage overshoot. The proposed scheme has the advantages of a simple structure, low cost and low volume. Experimental results are presented to verify the usefulness of the proposed scheme 相似文献
19.
This paper presents a novel AC/DC noise measurement system. This system simultaneously uses a high DC current to generate 1/f2 noise (electromigration noise) in thin films and a low AC current to detect that noise. This new system allows us to separate the noise components of metal thin films and is more stable and sensitive than its predecessors 相似文献