共查询到20条相似文献,搜索用时 203 毫秒
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本文提出一种适用于金卤灯负载特性的新型控制策略,解决了半桥低频方波变换器用作金卤灯电子镇流器时开路电压偏低的问题、实现了灯启动过程的恒流和限流控制、稳态时的恒功率控制。采用零电流检测电路使电感在低频正负半周内均工作在临界电流模式,开关管实现了零电流接通。采用差分平衡电路对灯电压、灯电流进行取样,解决了悬浮的灯电压、电流信号与驱动电路的共地问题。给出了主要参数的计算方法。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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提出了一种两级无声谐振金卤灯电子镇流器的新型控制方法。镇流器包括功率因数校正、一个带降压功能的半桥逆变电路和点火电路。这种新型的控制方法使灯工作于400Hz的低频方波工作状态,保证不出现声谐振的发生。还提出了一种新颖且简单的方法,克服了逆变电路换向瞬间的电流过冲问题,降低了灯工作电流的波峰系数。70W金卤灯电子镇流器的样机验证了这种控制方法的可行性。 相似文献
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该文提出一种低频方波工作的高性能车用金卤灯电子镇流器,该镇流器由带耦合电感的DC/DC升压变换器和低频方波DC/AC逆变器组成,效率高,开关应力小,无声共振。通过选择合理的控制量,探索出了适用于车用金卤灯的控制规律,使得电子镇流器的输出特性与金卤灯的动态特性相匹配:提出一种新型的恒功率控制策略,保证MH灯在不同电源电压和灯电压下输出功率基本不变;巧妙利用主电路整流器件构造高压脉冲触发电路,使车用MH灯能瞬时快速启动;给出了主要电路参数的计算方法。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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一种HID灯用电子镇流器控制方法的研究 总被引:1,自引:0,他引:1
提出了一种基于半桥的两级低频方波HID灯用电子镇流器,详细分析了其工作原理及控制方案。半桥逆变器输出低频方波信号,有效克服了HID灯声谐振现象;电路中电感工作在临界电流模式,降低了开关管损耗,提高了效率。通过对一个35W金卤灯的实验验证了该方案的可行性。 相似文献
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研发一款基于数字控制的全桥逆变的高性能车用金卤灯电子镇流器。该镇流器由带耦合电感的高频DC~DC升压变换器和低频方波DC—AC全桥逆变器组成,主电路利用整流器件构造高压脉冲触发电路,使车用金卤灯能瞬时快速启动;采用数字控制的分段控制方法很好地控制了灯的启动及稳态工作过程。 相似文献
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Vortex water wall high-pressure argon arc lamps are used to generate intense light and are capable of operating at radiative efficiencies greater than 50%. These lamps are being considered for use in a pulsed DC mode of operation in the next generation of rapid thermal processing applications. The results of a series of experiments have shown that the breakdown to arc transition consists of a prethermionic electrode emission phase and a prethermal ionization phase. The large dynamic voltage and current range between the breakdown phase and the arc phase necessitates the use of three different power circuit topologies. A high-voltage ignition circuit is connected in series with an arc-sustaining power source. The series connection ensures that the arc-sustaining power supply is isolated from the high-voltage ignition circuit. The arc-sustaining current source power source consists of a step-down hysteresis-current-controlled DC/DC converter cascaded with a constant off-time output-voltage-controlled step-up DC/DC converter. The current-controlled converter supplies the minimum arc-sustaining current, whereas the step-up converter provides the minimum post-ignition prethermal ionization voltage. The inclusion of a shorting switch allows one to reduce the current ratings of the high-voltage circuit components. Finally, experimental verification of a simplified circuit model of the ignition to arc transition, the circuit operation, a power supply design procedure, and a design example are provided 相似文献
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Haw‐Yun Shin Jui‐Piao Yang 《International Journal of Circuit Theory and Applications》2010,38(4):343-358
This study designs and develops a digital control integrated circuit (IC) for driving circuits operating multiple cold cathode fluorescent lamps (CCFLs). The control IC adopts an external crystal oscillator for the IC's external frequency to provide the driving circuits a fixed frequency. Inside the IC, two control loops are designed, under synchronized operation frequencies, for a boost regulator and an inverter. The main function of the boost regulator control loop is to supply a steady DC voltage for the inverter. In designing the inverter's control circuit, an adjustable‐frequency adjustable‐voltage soft‐start technique is used to start the lamps. We also use burst mode digital dimming technique to achieve synchronized dimming for the parallel‐connected lamp‐ignition circuits. The feedback voltage from the CCFLs can determine if any lamp is abnormal via a proposed lamp abnormality detection circuit. To deal with the equivalent‐circuit's component parameter differences among various manufacturers' and brands' piezoelectric transformers (PTs), the inverter's operation frequency is designed fine‐tunable in this study. Finally, the proposed design concept was implemented with an actual control IC and a driving circuit for CCFLs. The measured data and waveforms from our test circuitry are presented, which verifies the validity of the miniaturized controller proposed in this study. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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联接云南电网与南方电网主网的鲁西背靠背直流异步联网工程异步联网工程投产初期,广西侧送出交流线路受故障影响仅剩一回,随后广西侧母线电压和输出电流中出现了频率为1 270 Hz的谐波分量,引起柔性直流单元换流变压器分接开关频繁动作,最终导致柔性直流单元跳闸。首先,从鲁西背靠背直流异步联网工程高频谐振事件入手,分析大容量模块化多电平换流器(modular multilevel converter,MMC)与交流系统的谐振机理;接着,给出了MMC谐波阻抗的计算方法,利用阻抗分析法分析了高频谐振的条件,并提出MMC的控制结构改进方法,有效抑制了其输出电流的高频谐波分量;最后,通过PSCAD/EMTDC仿真对谐振事故现象进行了复现,证明了所提抑制策略可以实现对高频谐波谐振的有效抑制。 相似文献
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大功率LED高频驱动电路设计 总被引:3,自引:0,他引:3
由于白光LED具有低成本、长寿命和小体积的特性,被迅速应用到了照明和背光等领域,其驱动电路也层出不穷,但大多数驱动源都没有解决效率不高,LED发光亮度不一致,发热量大等问题。该文提出了一种基于恒流二极管的大功率LED高频驱动方案,以带可控端的2THL系列恒流二极管为驱动元件,通过在控制端输入高频脉冲小信号控制恒流二极管通断,从而实现高频恒流驱动大功率LED这一目的。调节脉冲信号占空比即可实现LED调光。该文设计的驱动电路不仅能够保证LED持续、稳定、高效地工作,在一定程度上减小了LED芯片发热量,提高了LED灯具使用寿命,并且对输入电源要求不高,整体可以节能40%左右。 相似文献
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Willkens C.A. Axelson S.R. Bateman L.S. Croucher D.D. 《Industry Applications, IEEE Transactions on》1996,32(5):1027-1030
In 1988, Norton introduced its line of low-voltage 12 and 24 V miniature igniters made from a patented ceramic/intermetallic material. These igniters demonstrated superior strength and speed in a compact low-wattage assembly for gas-fired ignition. High-voltage igniters are being developed to complete the family of igniters for gas-fired ignition. These igniters have extremely low power requirements in the range of 50-100 W, are designed to operate at line voltages of 120 V and are leading to designs for operation up to 230 V. These were developed using compositional and dimensional changes to the low voltage igniters. The 120 V igniter has exceeded 200,000 cycles in life testing and has been submitted for agency approval. These igniters are also undergoing field testing in various demanding gas-fired appliances. The evolution of the low-voltage igniter into the high-voltage model, as well as performance and material development issues are discussed 相似文献
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为了修复因硫化而报废的铅酸蓄电池,设计了一台输出直流电压与间歇高频谐振电压脉冲叠加式铅酸蓄电池修复仪。给出了修复仪的系统电路结构,介绍了其工作原理;详述了间歇式高频脉冲修复电路的原理,列写了修复电路的状态方程并进行了分析;设计了以PIC16F887单片机为核心的控制系统,介绍了控制器的特点;设计了以线性光耦HCNR201为核心的电压检测电路和电流检测电路及其PWM驱动电路;针对不同体积的硫酸铅晶体所需的能量不同,提出了一种变占空比的控制策略。实验结果表明,所设计的铅酸蓄电池修复仪能够较好地修复因硫化而报废的铅酸蓄电池,满足设计要求。 相似文献