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全桥三电平直流变换器的最佳开关方式 总被引:5,自引:6,他引:5
该文提出了一种新的关于直流变换器三电平拓扑变换的分析方法。应用该方法得到了零电压开关全桥三电平直流变换器,同时提出了加入箝位二极管的改进型变换器。该变换器使用了以能量传输最大、滤波电感电流纹波最小、开关管实现软开关等为条件寻找到的最佳开关方式,克服了传统零电压开关全桥直流变换器中开关管电压应力高、滤波电感电流纹波大、整流二极管存在寄生振荡等缺点,所以其变换效率更高,响应速度更快,进一步拓宽了它的应用范围。最后通过一个开关频率为50kHz、额定输入电压为600V、输出功率为2.8kW的实验样机加以验证分析结果。 相似文献
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本文提出了一种带有源箝位的ZVT-PWM升压PFC变换器。详细分析了该变换器的工作原理,讨论了电路的参数,进行了软件仿真,并在一台功率为3kW、工作频率为100kHz的通信用开关电源装置上进行了实验验证。仿真和实验结果都证明了这种变换器不仅可实现主开关管的零电压转换和辅助开关管的零电流开关,而且开关管的电压电流应力非常小,同时变换器效率可高达94%. 相似文献
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以结合开关理论为基础,提出了一种可以建立软开关PWM变换器的系统方法。应用这种方法,许多种无源和有源软开关PWM变换器家族中所派生出的变换器,如:Buck—Boost变换器、Cuk变换器、Sepic变换器和Zeta变换器都能够通过Buck变换器和Boost变换器这两种最基本的变换器得到,不仅对变换器家族可以进行更加深入的了解,还可以揭示出软开关变换器之间的内在联系。通过对结合开关理论的具体介绍,在对有源PWM软开关变换器中的零电压转换(ZVT)PWMDC/DC变换器的派生变换器电路拓扑的建立原理和得出过程重点阐述的同时。将有源软开关PWM变换器进一步分成了Buck和Boost家族两大类,并证明了所提出的这种建立软开关PWM变换器的方法的正确性和可行性。 相似文献
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对于工作在软开关和硬开关两种模式下的推挽结构的DC/DC变换器作了比较研究,分析了它们各自的优缺点,并从工程应用角度出发,研制了一台300W的DC/DC变换器。 相似文献
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一种新型的零电压零电流转移DC-DC变换器 总被引:2,自引:0,他引:2
林国庆 《中国电机工程学报》2007,27(22):106-109
提出了一种新型的零电压、零电流转移DC-DC变换器,即通过采用两条辅助谐振网络实现了全部主、辅开关管的软开关,主开关管实现了零电压零电流开通、零电压零电流关断,开关管电压电流应力小,辅助开关管实现了零电流通断,特别适用于以IGBT作为开关器件的高电压大功率场合。并以其在Boost变换器的应用为例分析了它的工作原理,软开关实现条件,给出了谐振参数的设计方法,该软开关设计思想可以推广到其它基本的DC-DC变换器中。电路仿真和实验结果验证了所提出的方案是可行的。 相似文献
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B.‐R. Lin C.‐L. Huang M.‐Y. Li 《International Journal of Circuit Theory and Applications》2009,37(3):413-431
This paper presents a zero voltage switching (ZVS) converter with interleaved pulse‐width modulation scheme. An active clamp circuit is adopted in the proposed converter to recycle the energy stored in the leakage inductor of the transformer and reduce the voltage stress of the main power switch in the converter. The ZVS feature of switches can be achieved due to the resonance during the transition interval of two power switches. Two full‐wave rectifiers with ripple current cancellation are connected in parallel at the output side to reduce the current stress of the secondary winding of transformers. Instead of the conventional interleaved forward converter, power switches in the proposed converter can perform the functions of both forward converter and active clamp at the same time. Therefore, the circuit components in the power circuit are less than that of in the conventional interleaved forward converter. The operation principle and system analysis of the proposed converter are provided. Some experimental results for a 240 W (12 V/20 A) prototype are provided to demonstrate the effectiveness of the proposed converter. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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Abstract— This study proposes a multi-level power converter for a battery energy storage system (BESS) with bidirectional power flow. The multi-level power converter includes a DC-DC power converter, a selection switch set and a full-bridge inverter. The DC-DC power converter performs bidirectional power conversion and provides a DC voltage that is greater than the peak voltage of the utility. Integrating the selection switch set and the full-bridge inverter produces a five-level AC voltage that controls the real power flow and the reactive power flow between the battery set, the DC-DC power converter and the grid. Because partial power is directly processed using only the selection switch set and the full-bridge inverter, the DC-DC power converter is operated only when the grid voltage is greater than the voltage of the battery set. Therefore, the power conversion efficiency for the proposed BESS is improved. The proposed BESS uses only eight power electronic switches, so the power circuit is simplified. A hardware prototype with a digital signal processor controller is used to verify the performance of the proposed BESS. The experimental results are as expected. 相似文献
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A current-controlled VSI-PWM rectifier and inverter with capacitor DC link is regarded as one of the most important structures for three-phase to three-phase power conversion. This type of power converter normally requires twelve switches for the rectifier and an inverter composed of self turnoff switch such as a bipolar transistor or an IGBT with an anti-parallel diode. In this paper, a new three-phase to three-phase AC/AC power converter for AC motor drives is proposed. The proposed power converter employs only eight switches and has the capability of delivering sinusoidal input currents with unity power factor and bidirectional power flow. This paper describes the feasibility and the operational limitations of the proposed structure. A mathematical model of the system is derived using the generalized modulation theory and experimental results for steady-state and dynamic behavior are presented to verify the developed model 相似文献
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A switched reluctance motor requires a power converter circuit to control the unipolar phase current in its phase windings. A converter circuit for a four-phase reluctance motor that uses only four switches is described. Unlike previous circuits with one switch per phase, the switches are created at the motor voltage. Each switch is connected to two of the four phase windings. The switching signals must be carefully derived so that independent control of the phase currents is maintained despite the common connections. Analysis is given to predict the ideal switching algorithm for the converter circuit. This produces the optimum torque at all speeds and currents. Experimental results are given for the performance of the proposed converter circuit as compared with that of other circuits with one switch per phase. It can be seen that for a given supply voltage and peak phase current, the novel converter circuit produces superior torque output from the motor. The low number of switches in the coinverter together with the performance of the four-phase reluctance motor will result in an ideal low-cost variable-speed drive 相似文献
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变压器原副边桥臂电压不匹配时,移相控制三电平双有源全桥直流变换器(3L-DAB)的开关管可能会工作在硬开关模式,导致系统损耗增加、效率降低。针对这个问题,该研究对3L-DAB变换器的软开关工作范围展开详细的分析。首先,描述了移相控制下3L-DAB变换器的功率传输特性;在此基础上,基于稳态时域模型,推导了随着移相角和变压比的变化,变压器原副边所有开关器件的软开关工作范围。然后,对比分析了考虑开关管结电容前后变换器的软开关工作范围变化。最后,通过仿真和搭建的实验平台验证了理论分析的正确性。 相似文献
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软开关隔离型Boost变换器研究 总被引:3,自引:1,他引:3
隔离型Boost变换器具有变压器结构简单、输入电流纹波小、效率高等优点,适合于低压大电流输入应用,但该变换器存在着开关管关断电压尖峰很大、两开关管不能同时关断以及启动冲击电流很大等问题.采用附加RCD吸收电路可以减轻上述问题的影响,但不利于变换器整机效率的提高.提出了一种软开关的隔离型Boost变换器,利用LCD电路实现功率管的软关断,并将储能电感设计为反激变压器型式以限制启动冲击电流.分析了电路的工作原理,给出了电路的参数设计原则.28V输入、48V输出、300W实验样机效率达到了92.4%. 相似文献
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《Electric Power Systems Research》2001,58(3):157-167
A single-phase three-level pulsewidth modulation (PWM) AC/DC converter with the function of power factor corrector and active power filter is proposed to reduce harmonic currents flowing into the power system and to draw a nearly sinusoidal current with unity power factor. The circuit topology of the adopted three-level PWM AC/DC converter is based on a conventional two-level full-bridge rectifier and one AC power switch. The control signals of the power switches are derived from the voltage balance compensator, current controller and detected operation region of mains voltage. A three-level PWM voltage pattern on the AC side of the converter in each half cycle of mains frequency is generated. Computer simulations are implemented to confirm the operation of the adopted converter with the function of power factor corrector and active power filter. 相似文献
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为了提高传统Cuk变换器的电压增益和变换器工作效率、同时减小电流纹波和变换器的体积重量。提出一种适用于光伏发电系统的高增益Cuk变换器。利用带有自举电容的开关电感单元替代传统Cuk变换器中的输入电感,并对开关电感单元与输出电感进行了磁集成。分析了变换器的工作模态,推导得到了变换器电压增益表达式;分析了二极管与开关管电压应力的大小,给出了电感耦合度的设计准则。给出了高增益Cuk变换器集成磁件设计方案,并给出了设计方法。与传统Cuk变换器相比,高增益Cuk变换器的电压增益提高了2倍。仿真与样机实验结果验证了理论分析的正确性,表明提出的高增益Cuk变换器具有优良的综合性能。 相似文献
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C-dump变换器是一种用于无刷直流电动机的新型功率变换器,其开关控制方式对电枢电流和变换器储能电容电压脉动有较大的影响。该文对C-dump变换器主开关和斩波开关的开关控制方式及其对电机电流和变换器储能电容电压脉动的影响进行了研究。首先对C-dump变换器主开关的PWM控制和滞环控制两种工作方式进行了比较。然后重点对斩波开关的滞环控制,斩波频率高于主开关频率的PWM控制、斩波频率低于主开关频率的PWM控制、主开关与斩开关同步PWM并结合斩波开关滞环控制等5种开关控制方法进行了详细的理论分析与比较。结果表明:主开关与斩波开关同步PWM并结合斩波开关滞环控制可较好地减小储能电容电压和电机电流脉动,有利于改善系统性能。最后进行了仿真与实验验证。 相似文献