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为提高转换效率并降低电源开关的电流应力,提出一种基于新型有源缓冲电路的PWM DC-DC升压变换器。该有源缓冲电路使用ZVT—ZCT软开关技术,分别提供了总开关ZVT开启及ZCT闭合、辅助开关ZCS开启及ZCT闭合。消除了总开关额外的电流及电压应力,消除了辅助开关电压应力,且有源缓冲电路的耦合电感降低了电流应力。另外,通过连续将二极管添加到辅助开关电路,防止来自共振电路的输入电流应力进入总开关。实验结果表明,相比传统的PWM变换器,新的DC-DC PWM升压变换器在满负荷时电流应力降低且总体效率能达到98.7%。 相似文献
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一种ZCT PWM全软开关变换器的仿真研究 总被引:1,自引:0,他引:1
在零电流过渡(ZCT)功率变换电路中,主开关管的开通和辅助开关管的关断是工作在硬开关条件下的,其开关损耗大。文中通过对传统主电路拓扑结构及控制方法改进后,详细分析该变换器的工作原理并进行仿真验证。结果表明主开关管和辅助开关管不仅实现了软开关通断的工作方式,同时还能消除升压二极管的反向恢复问题。 相似文献
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介绍了典型的零电流转换ZCT(Zero Current Transition)PWM直流变换器的基本工作原理,分析了其存在的主开关电流应力大和辅开关硬关断的问题,提出了一种改进型开关电路。对其拓扑结构和工作原理进行了详细分析,设计了电路参数,并对其进行了Pspice仿真。结果证明此改进能够使辅助开关近似零电流关断,提高了变换器的性能。 相似文献
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提出一种新型的零电压零电流转换(ZCZVT)的正激拓扑。拓扑工作频率为300kHz,能实现主开关管的零电压开通(ZVS)和零电流关断(ZCS),同时辅助开关管也能实现零电流关断(ZCS),且变压器的磁通复位不需要辅助绕组。文章进行了拓扑的稳态分析,并且讨论了谐振电路的参数设计。最后,在研制一台48V输入、12V/100W输出样机的基础上,实验验证这种新型正激ZCZVT PWM DC-DC变换器的软开关特性。 相似文献
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为了降低开关损耗,提高变换器的效率,提出了一种改进的零电流转化软开关无桥功率因数校正电路,实现了变换器主开关管和辅助开关管的零电流导通和零电流关断,有效地减小了导通损耗,提高了电路的效率。详细分析了电路的工作模态、工作条件和主开关管的导通损耗。仿真和实验结果表明,该功率因数校正电路实现了输入电流对输入电压的良好跟踪,功率因数高,谐波含量少,效率较传统的全桥功率因数校正电路有明显的提高。
关键词:全桥;零电流转换;无桥;功率因数校正 相似文献
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Jong-Woo Choi Seung-Ki Sul 《Power Electronics, IEEE Transactions on》1995,10(4):479-484
This paper proposes a novel resonant circuit capable of PWM operation with zero switching losses. The resonant circuit is aimed at providing zero voltage intervals in the DC link of the PWM converter during the required converter device switching periods, and it gives minimum DC bus voltage stresses and minimum peak resonant current. It requires only two additional switches compared to a conventional PWM converter. It is observed that the resonant circuit guarantees the soft switching of all the switching power devices of converters including the switches for resonant operation. Simulation results and experimental results are presented to verify the operating principles 相似文献
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This paper presents the analysis and design of a new low-loss auxiliary circuit for three-level pulsewidth-modulation single-phase full-bridge inverters which achieve soft switching at all semiconductor devices. The active auxiliary commutation circuit (AACC) is composed of an LC circuit and two bidirectional switches, where one auxiliary switch commutates under zero-voltage switching condition and the other under zero-current switching condition. The AACC dispenses with the use of auxiliary voltage sources. Low reactive energy is added to the converter, resulting in low RMS current stresses at the main switches and, consequently, higher efficiency is achieved. Auxiliary circuit design procedures and experimental results are presented to prove the operation principle 相似文献
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This paper proposes a new soft-transition control strategy for a three-phase zero-current-transition (ZCT) inverter circuit. Each phase leg of the inverter circuit consists of an LC resonant tank, two main switches, and two auxiliary switches. The proposed strategy is realized by planning the switching patterns and timings of these four switches based on the load current information. It enables all the main switches and auxiliary switches to be turned on and turned off under zero-current conditions, and achieves a near zero-voltage turn-on for the main switches. Compared with existing ZCT strategies, the diode reverse recovery current and switching turn-on loss are substantially reduced, the current and thermal stresses in the auxiliary devices are evenly distributed over every switching cycle, and the resonant capacitor voltage stress is reduced from twice the DC bus voltage to 1.3-1.4 times the DC bus voltage. The proposed strategy is also suitable for three-phase power-factor-correction (PFC) rectifier applications. The operation principles, including a detailed analyst based on the state-plane technique, and a design rule are described in this paper. The circuit operation is first verified by a computer simulation, and is then tested with a 50-kW three-phase inverter to the full power level together with a three-phase induction motor in a closed-loop speed/torque control. Significant reductions in switching losses and voltage/current stresses over existing techniques have been experimentally demonstrated 相似文献
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提出了一种基于DSP TMS320F2812数字控制的平均电流型交错并联升压型功率因数校正(Boost PFC)变换器。重点提出了150 kHz/Phase开关频率下的控制算法与改进的采样算法,并对电压、电流双环数字控制回路进行分析与PI补偿设计。基于Matlab/Simulink对并联交错Boost PFC数字控制系统进行建模仿真,并制作300 W输出功率的样机,成功对Boost PFC控制系统进行了验证与实现。 相似文献
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提出了一种基于CMOS工艺的新颖软启动电路,该电路利用限流和数字软启技术,实现了输出电压快速、稳定软启,有效抑制了DC-DC开关电源启动过程中所产生的浪涌电流和输出电压过冲.该电路可方便地集成于DC-DC开关电源内部,无需软启动引脚和外接软启动电容,有利于减小封装尺寸和应用电路板空间及降低成本.该软启动电路已经集成到一款Buck型PWM开关控制器当中.试验结果显示,在输出电容等于300μF,空载或带载的情况下,启动过程都非常平稳,电感电流稳定,输出电压上升平滑无过冲,启动时间小于300μs. 相似文献
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在谐振极软开关逆变器辅助电路的换流过程中,为避免剩磁通的累积导致变压器铁心饱和,提出了一种变压器辅助换流的三相节能型谐振极逆变器的拓扑结构,在二极管反向阻断的作用下,变压器的磁化电流无法形成稳态环流,从而使变压器中的能量全部向负载转移,磁化电流最终变化到零,实现了变压器的去磁复位.此外,逆变器的主开关和辅助开关可以分别完成零电压软切换和零电流软切换.分析了电路的换流过程.实验结果表明逆变器的开关器件完成了软切换,变压器磁化电流能减小到零.该拓扑结构对于研发高性能谐振极逆变器具有一定的参考价值. 相似文献