空间行波管放大器高压电源设计研究

针对空间行波管放大器对高压电源的性能、效率、体积、重量等的特殊要求,提出了一种新型的高效率零电压零电流全谐振高压变换器,给出了高压变换器的拓扑结构,深入分析了变换器的工作原理和零电压零电流软开关的工作模式。利用PSPICE软件对变换器进行了原理性仿真,样机测试结果和理论分析表明由于采用软开关技术使行波管放大器的性能大大提高,该高压电源具有高效率、高可靠性和低纹波等优点,满足空间行波管放大器的要求。     

软开关技术在开关电源中的应用

软开关PWM技术集谐振变换器与PWM控制的优点于一体,既能实现功率管的零电压开关,又能实现功率管的恒定频率控制,是电力电子技术的发展方向之一。与传统PWM硬开关变换器相比,元器件的电压、电流应力小,仅仅增加了一个谐振电感,成本和电路的复杂程度没有增加。移相控制零电压开关PWM变换器就是软开关PWM技术中的一种拓扑,它适用于中、大功率直流一直流变换场合。     

一种改进的无源钳位的全桥移相ZVZCS PWM DC-DC变换器

提出一种改进的无源钳位的全桥移相ZVZCS PWM DC-DC变换器,并对此变换器的工作原理和软开关实现条件进行详细的分析。该电路具有软开关负载范围大、辅助谐振元件的附加损耗小、电压电流应力小等优点。     

全桥ZCS-Boost倍压变换器软开关条件和增益特性研究

为了探讨ZCS-Boost倍压变换器应用于行波管电源的可行性,文章分析了全桥ZCS-Boost倍压变换器的零电流实现条件和增益特性。这一变换器结构简单,具有高增益的特点,适合应用于高压高功率的场合。四个开关管都能实现零电流开关。为了推导的顺利进行,本文简要叙述了这一变换器的工作原理,推导出了实现零电流开关的约束条件;由于工作过程复杂,且工作模式较多,所以这一变换器的增益特性还没有被系统地研究过。本文通过引入变量,初步推导了这一变换器的电压增益公式;最后,对这两个结果,运用PSPICE仿真来验证这一变换器在某新型行波管电源28V直流输入的条件下的可行性,结论显示仿真结果和推导公式相互吻合。     

软开关变换器的设计与仿真研究

针对开关电源开关损耗和电磁辐射的问题，建立了一种采用软开关技术的零电压开关（ZVS）PWM变换器的电路，利用PSpice软件对这种变换器进行仿真研究，分析其暂态和稳态时的性能。仿真表明，合理选择器件参数，当软开关变换器电路中L1=0.3mH，L2=3μH，C1=500p时，开关损耗小，造成的电磁干扰小。仿真发现暂态时开关器件承受了较高的电压应力，实际应用时应考虑开关器件安全性。     

一个高效的升压变换器设计

本文提出了一种新型的DC/DC升压变换器的电路。该电路有一个缓冲电路吸收的电感能量,实现开关管的零电压导通,减少开关管的开关损耗。同时减小二极管关断时反向恢复电流,减小二极管反向恢复的影响。通过Saber仿真和实验验证了所提出电路的可行性。结果表明,本文所提出的电路比传统的DC/DC升压变换器效率高。     

浅谈3KW充电机设计

本文主要介绍3KW充电机设计的软开关设计部分。将移相全桥零电压零电流的软开关电路应用到充电机的设计中，减小了电路中元件的应力，提高了充电机的整机效率。本文分析了使用副边能量缓冲电路的移相全桥软开关电路的工作过程。     

零电流零电压开关的Matlab仿真

运用Matlab软件对一种新型的零电流零电压软转换开关进行了计算机仿真。通过仿真,讨论了参数对这种新型开关特性的影响。     

高频高压低温等离子体发生研究

针对传统气体放电式等离子体发生器电源效率不高、使用寿命有限等问题,提出了一种零电压软开关高频高压低温等离子体发生方法,并设计了一个高效率低损耗的高频高压低温等离子体发生系统。该系统通过移相全桥软开关控制电路提供控制信号,光耦隔离电路降低强电干扰,在零电压软开关驱动下,经高频谐振升压电路对输入信号升压,实现低温等离子体的稳定发生。实验结果表明,系统工作频率稳定在262kHz,系统能够稳定发生低温等离子体,等离子体束长可达13.1cm,系统工作稳定后,零电压软开关系统的效率为87.4%,与传统直流等离子体发生炬最高77%效率相比,提高了10.4%,实现了驱动管耗的降低和输入电源效率的提升。     

高频高压低温等离子体发生研究北大核心CSCD

针对传统气体放电式等离子体发生器电源效率不高、使用寿命有限等问题,提出了一种零电压软开关高频高压低温等离子体发生方法,并设计了一个高效率低损耗的高频高压低温等离子体发生系统。该系统通过移相全桥软开关控制电路提供控制信号,光耦隔离电路降低强电干扰,在零电压软开关驱动下,经高频谐振升压电路对输入信号升压,实现低温等离子体的稳定发生。实验结果表明,系统工作频率稳定在262kHz,系统能够稳定发生低温等离子体,等离子体束长可达13.1cm,系统工作稳定后,零电压软开关系统的效率为87.4%,与传统直流等离子体发生炬最高77%效率相比,提高了10.4%,实现了驱动管耗的降低和输入电源效率的提升。     

Novel zero voltage switching dual-switch forward converter with ripple current cancellation

A zero voltage switching (ZVS) dual-switch forward converter with ripple current cancellation is presented. In the proposed converter, active clamp circuit is used to clamp the voltage stresses and to realise ZVS of all switching devices. Active clamp boost converter with power factor correction is used in the front stage of the proposed converter to draw a sinusoidal line current from the AC source and to maintain a constant voltage at the DC bus. The second stage of the proposed converter is a dual-switch forward converter with current doubler rectifier to obtain the isolated low output voltage. Active clamp circuit used in the DC/DC converter can recycle the energy stored in the leakage inductor and magnetising inductor so that the voltage stresses on the switches are limited and the ZVS feature is realised. The current doubler rectifier offers the ripple current cancellation at the output capacitor and reduces the current stress of the transformer secondary winding. The circuit configuration and principle of operation are analysed and discussed in detail. Experimental results with a laboratory prototype based on a 90-260 V_rms input and 12 V/30 A output were provided to verify the effectiveness of the proposed converter.     

Thermal Instrument for Measurement of Voltage, Current, Power, and Energy at Power Frequencies

The design of an instrument for precision measurement of ac voltage, current, power, and energy is described. It has been developed as a standard for evaluating the performance of instrumentation used in the power frequency range (45-65 Hz). Its accuracy relies on a continuous ac/dc transfer which is achieved by automatically balancing the alternating current derived from the quantity to be measured against the equivalent direct current, both passing alternately through the heater of a thermal converter. Since the instrument can be calibrated with direct voltage and current, its total systematic error is limited by the ac/dc transfer to ±0.0005 percent of full scale for voltage and current, and ±0.001 percent of full scale for power and energy measurements.     

Analysis and implementation of an active snubber dc/dc converter with series?parallel connection in primary and secondary sides

An active snubber dc/dc converter to achieve zero voltage switching (ZVS) on power switch is presented. In the proposed converter, the primary windings of two transformers are connected in series so that the primary currents of the two transformers are equal. The secondary sides of the isolated zeta converters are connected in the parallel to share the load current and reduce the current stresses on the secondary windings of the two transformers. A boost type of active snubber is connected in parallel with the main switch to recycle the energy stored in transformer leakage and magnetizing inductors and to limit voltage stress of the main switch. During the transition interval between the active switch and the auxiliary switch, the resonance based on the resonant inductor and the output capacitor of the power switch will allow the switch to turn on at ZVS. The principle of operation, steady-state analysis and design consideration of the proposed converter are provided. Finally, experimental results for a 360 W (12 V/30 A) prototype circuit with 150 kHz switching frequency were given to demonstrate the circuit performance and verify the feasibility of the proposed converter.     

An active current-sensing constant-frequency HCC buck converter using phase-frequency-locked techniques

A hysteresis-current-controlled (HCC) buck converter with active current-sensing and phase-frequencylocked techniques is presented in this paper. The proposed active current-sensing technique can not only consume less power than previous techniques, but also fully sense the inductor current. Although the buck converter is HCC, the switching frequency can be constant due to the devised phase-frequency-locked technique. The proposed converter has been designed and implemented with TSMC 0.35 microm DPQM CMOS processes. It is shown in the experimental results that the HCC buck converter features the following characteristics: 1) up to 800 mA of load current, 2) wide input and output voltage range, 3) high power efficiency, and 4) constant-frequency operation.     

High-frequency link symmetrical active edge resonant snubbers-assisted ZCS-PWM DC?DC converter

A novel symmetrical zero current switching (ZCS)-pulse width modulation (PWM) cells-assisted high-frequency transformer link DC-DC converter using insulated gate bipolar transistor (IGBT) modules is presented. The proposed soft switching scheme is based on the switched-capacitor and inductive snubber in the high-voltage side inverter, assisted by active switching of MOSFET synchronous rectifier in the secondary-side low-voltage converter stage. By introducing the ZCS-PWM snubber cells, soft switching commutation which is less sensitive to the current level through the IGBTs can be achieved under the wide output power ranges. The converter circuit topology and the ZCS snubber cell operation are examined and evaluated with simulation results, and the feasibility of the converter topology is verified by experiments using a 1.0 kW-25 kHz prototype system.     

可编程数字控制精密延时电路设计

设计一种基于斜波式发生器原理可编程数字控制精密延时电路,用恒流源电路充放电和18位的DA转换器分别接入高速比较器的两端,DA转换器预先设定一电压基准,恒流源充电电容达到电压基准,高速比较器开始反转,形成一个触发脉冲信号,然后充电电容通过高速二极管快速放电重新计时。设计成18bit数字控制可编程动态范围2ps的采集时间间隔,提高采集信号的精度和频率。     

High power factor operation of resonant converters on the utility line

Operation and characteristics of resonant converters on the utility line are presented. Series-parallel (LCC-type) resonant converter operating with discontinuous current mode and continuous current mode (variable frequency control as well as fixed-frequency) are considered. Design examples are presented. SPICE simulation and experimental results obtained for the designed converters (rated at 150 W) are presented to verify the theory. It is shown that high line power factor (>0.95) and line current total harmonic distortion (THD) of <25% are obtained for the LCC-type converter for a wide load range (from full load to 10% rated load) without any active control, and the switch peak current decreases with the load current. With active line current control, low distortion and zero voltage switching for the entire cycle are realized.     

基于高低压电源切换的双环恒流控制电磁流量计励磁控制系统

为了提高电磁流量计高频方波励磁性能,基于励磁恒流控制仿真分析,采用外环高低压电源切换和内环电流微调的双环励磁恒流控制方式,以保证电磁流量计高频方波励磁时一次仪表输出信号零点稳定、电源利用效率高。设计方波励磁控制系统,以实现高频方波精确励磁。仿真结果表明,高压源电压越高越有利于拓宽励磁频率范围。实验结果表明,系统在高频方波励磁时,励磁电流响应速度快且电磁流量计传感器输出信号零点稳定。     

一种具有高电压传输比的新型Cuk矩阵变换器

对传统矩阵变换器存在电压传输比低的缺陷进行研究,提出一种新型的称为Cuk矩阵变换器的电路拓扑结构。介绍了该拓扑结构的基本构成及其工作原理,推导了其电压传输比与占空比之间函数关系的解析表达式,阐述了所采用的双闭环控制策略的基本设计方法,并通过仿真对其有效性和可行性进行了验证。结果表明：该拓扑结构能实现输出电压和频率的任意调节,其电压传输比可大于1,也可小于1,且直接输出标准的正弦波而无需滤波环节,有效地解决了传统矩阵变换器电压传输比低的难题,具有一定的应用价值。     

A dual translinear-based true RMS-to-DC converter

A new design technique for a true rms-to-dc converter is implemented around a dual translinear-based squarer circuit. A dual translinear loop and current mirrors are the basic building blocks in this realization scheme, and the computation is carried in current-mode. The conversion circuit consists of a squarer, a low-pass filter and a square-root circuit. Since no rectifier function is required, this converter configuration enables us to obtain a wideband frequency response. The input signal can he voltage or current. In addition, the modification of the converter to construct a vector summation computing circuit is also discussed