共查询到17条相似文献,搜索用时 625 毫秒
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为克服传统硬开关逆变器存在的缺点,提出了一种新型并联谐振直流环节软开关逆变器,其辅助谐振电路含有耦合谐振电感,结构相对简单,有利于降低硬件成本。通过辅助电路的谐振使直流母线电压下降到零时,逆变器的主开关可以完成零电压开关,同时辅助开关也可以在辅助谐振电路的工作过程中完成软开关,而且直流母线零电压持续时间可以自由选择,与负载电流和谐振参数无关。文中依据不同工作模式下的等效电路图,对其工作原理进行了分析,给出了软开关的实现条件和逆变器的控制方法。制作了一个140W的实验样机,实验结果表明逆变器的主开关和辅助开关器件都实现了软开关,所以该软开关逆变器能有效地降低开关损耗和提高效率。 相似文献
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王强 《中国电机工程学报》2012,(3):36-42,18
为了实现逆变器的高效率和高性能运行,提出一种新型直流母线并联谐振零电压过渡软开关逆变器,通过在传统硬开关逆变器的直流环节添加辅助谐振单元,实现了逆变桥开关器件的软开关动作,同时,辅助谐振单元的开关也为软开关动作。此外,电路中避免了使用大电容,没有中性点电位的变化问题。该电路对谐振元件和辅助开关的功率要求较低,控制简单且不依赖于负载条件。对其工作原理进行分析,给出不同工作模式下的等效电路图和回路的参数设计方法。制作一个10kW的实验样机,通过实验结果验证该软开关逆变器的有效性。 相似文献
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《电机与控制学报》2015,(10)
为提高逆变器的效率,提出了一种新型并联谐振直流软开关逆变器的拓扑结构,在辅助谐振电路中设置了1对反并联的晶闸管来控制谐振电流,使逆变器的直流环节电压周期性下降到零,逆变器的主开关可以在零电压条件下完成切换,同时辅助开关器件在逆变器换流过程中也实现了零电压开关或零电流开关。该逆变器在换流过程中不需要设定和负载有关的电感电流阈值,有利于降低辅助电路损耗和简化控制。对电路在1个开关周期内的各个工作模式进行了理论分析,给出了设计规则,并建立起辅助谐振电路损耗和分压电容的电压偏差量的数学模型。制作了一台5k W的实验样机,实验结果表明逆变器的工作过程符合原理分析,所以该软开关逆变器可以有效地提高效率。 相似文献
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《中国电机工程学报》2019,(1)
为实现一种结构简单、高效、低电压应力的软开关逆变器,该文提出一种新型谐振直流环节三相逆变器和负载自适应换流控制。其换流回路避免了2个大的分裂电解质电容,并且无耦合电感,可简化电路的分析与计算。通过换流开关控制换流电路,使逆变器的主开关管能完成零电压零电流开通和准零电压关断,换流开关能完成准零电流开通和准零电压关断。另外,与定时间控制相比,负载自适应控制可动态调节每个开关周期内换流开关管的开关时间,可以提高效率和直流母线电压利用率。逆变器主开关管和换流开关管具有相同且固定的开关频率,主开关管和换流开关管电压应力均等于逆变器的输入直流电压。对逆变器的负载自适应控制、软开关谐振过程进行研究,分析逆变器谐振参数的设计方法,设计10kW实验样机并完成实验验证。 相似文献
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王强 《中国电机工程学报》2012,(6):33-39
为改善逆变器的效率和性能,提出一种具有谐振直流环节的新型零电压软开关逆变器。通过在传统硬开关逆变器的直流环节添加辅助谐振单元,实现了逆变桥开关器件的零电压软开关动作。其辅助谐振单元中,只有2个辅助开关器件,控制相对简单,零电压持续时间不依赖于负载条件,而且电路中避免了使用大电容,没有中性点电位的变化问题。对其工作原理进行分析,给出不同工作模式下的等效电路图和软开关的实现条件。制作一个10 kW的实验样机,通过实验结果验证了该软开关逆变器的有效性。 相似文献
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本文对IGBT超音频感应加热电源设计的有关问题进行了讨论,基于串联谐振电路和晶闸管调压调功方式,采用锁相环和GAL器件进行设计,开发了一种IGBT超音频感应加热电源的控制电路,并介绍了控制电路的主要组成部分和设计特点。 相似文献
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A digital computer program written by Westinghouse engineers aids the design of new static logic systems for metal mills. The computer program accepts logic equations specifying the functions to be performed. The program generates circuit drawings of logic circuitry plus paper tape for controlling an automatic wiring machine. The automatic wiring machine wires the back panel receptacles for plug-in cards which contain the integrated-circuit AND/NAND logic elements. The design engineer determines functional requirements to be performed by the logic circuits. He expresses these requirements in convenient logic statement form and adds comments on circuit functioning. Logic and comment statements are keypunched for input to the computer. The computer analyzes the equations, converts the functions to AND/ NAND logic circuits and generates the punched-paper tape required by the automatic wiring machine. In addition, the computer generates the circuit diagrams showing the actual AND/NAND circuits with complete (JIC) cross references and comments on circuit functioning. During computer processing diagnostic messages are generated to aid in finding design errors. Only one type of logic board is used in the new static logic system to perform all logic functions. This reduces maintenance to mere board replacement and greatly reduces spare board inventory. Triac outputs are featured in addition to normal contact closure outputs. Traic is a static ac switch which can operate pilot-operated solenoid valves, contactors, indicating lights, and other common ac loads. The logic system combines the advantages of fully wired integrated-circuit logic with the convenience and accuracy of computer aided design. 相似文献
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Junichi Kunisaki Azusa Takano Tsutomu Yamada Yasushi Takemura 《IEEJ Transactions on Electrical and Electronic Engineering》2008,3(3):334-337
Hyperthermia is a therapeutic procedure for raising the body temperature in cancer patients. A resonant circuit is expected to be used as the heating source for hyperthermia, because the circuit can be heated by an applied AC magnetic field. In order to miniaturize the resonant circuit, optimal design of the circuit parameters is essential. In this paper, the characteristics of resonant circuits consisting of various combinations of the inductor and the capacitor are studied. The measurements of temperature rise and the impedance of the circuits determine the optimum circuit parameters. Copyright © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
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This paper considers the effects that preventive maintenance on circuits breakers and protection systems inside substations can have on the reliability of electricity supply. By performing preventive maintenance, the probability of a failure to operate of the circuit breaker (unrevealed fault) can be reduced, provided that the preventive maintenance process is carefully carried out. On the other hand, the probability and frequency of an overlapping failure event increases when the frequency of performing preventive maintenance on circuit breakers and protection systems increases. This article shows that an optimal preventive maintenance frequency can be deduced dependent on the substation topology, provided that the maintenance process is carefully carried out. The paper demonstrates also that carelessly performed preventive maintenance can even lead to a decrease in reliability of electricity supply. 相似文献