CO2激光器高压高频充电电源的应用研究

为改善现有CO2激光器工频充电电源体积、重量大、充电精度低等缺点,开展高频高压充电电源的研究,研制一台采用全桥逆变结构和串联谐振软开关电路、输出电压36 kV、输出平均充电功率为10 kJ／s的高频高压充电电源。该电源系统采用三相380 VAC作为供电系统,大功率智能功率模块（IPM）作为全桥逆变电路,逆变交流信号经串联谐振电路及高频脉冲变压器得到高压脉冲信号,高压脉冲经整流给负载电容充电;同时,电源应用电压、电流双闭环控制系统,输出电压、电流经采样及放大反馈到电源控制芯片SG3525,SG3525通过判断反馈信号的大小控制输出PWM驱动信号的占空比。实验结果表明：电源输出电压36 kV,输出平均功率为10.8 kJ／s,充电效率为0.82,电源纹波系数为1％。电源系统保证了激光器稳定工作在30 Hz条件下。     

36kV/10kW CO2激光器充电电源的研制

为了改善现有CO2激光器工频LC谐振充电时充电电压随激光器工作频率升高而降低、影响激光输出的稳定性和光束质量,不利于装置的小型化和轻量化的问题。采用全桥逆变结构和串联谐振软开关电路,研究了36kV/10kW高频高压充电电源。该电源系统采用三相380V交流电作为供电系统,大功率智能功率模块作为全桥逆变电路。逆变交流信号经串联谐振电路及高频脉冲变压器得到高压脉冲信号,高压脉冲经整流给负载电容充电,电源应用电压电流双闭环控制系统,输出电压、电流经采样及放大后,反馈到电源控制芯片SG3525,芯片SG3525通过判断反馈信号的大小,控制输出脉冲宽度调制驱动信号的占空比。激光器放电频率为25Hz时,电源输出电压为37kV,峰值输出功率为13.05kW,充电效率为0.826。结果表明,该高频高压充电电源适合用作CO2激光器的高压充电电源。     

基于Trans-Z源逆变电路的UPS系统的研究

针对UPS系统中由传统逆变器缺陷引起的升压难、控制复杂、抗干扰差的问题,基于Trans-Z源逆变电路提出一种新的UPS系统拓扑。研究Trans-Z源逆变电路基本结构、工作原理;采用正弦脉冲宽度调制(SPWM)对电路进行总体控制并改变输出电压;在理论分析的基础上给出Saber下的仿真结果;最后,以DSP芯片作为逆变主控芯片,搭建应用于UPS的Trans-Z源逆变电路。实际结果表明,该电路克服了传统逆变器的缺点,移除了死区控制时间,具有更好的升压能力,且提升了UPS带载能力,更适合应用于UPS充放电控制中。     

Z源型光伏并网逆变器研究

介绍并分析Z源型光伏并网逆变器的拓扑结构及其工作原理。基于并网逆变器Z源阻抗网络的特殊性质,为改善输出波形质量,减少并网电流谐波,系统省略传统逆变桥臂的死区设定,通过控制逆变桥臂的直通矢量占空比实现光伏阵列输出电压的升压功能。利用Matlab对逆变器控制系统运行控制模式进行仿真,仿真结果证明理论分析的正确性和有效性。     

UPS电源逆变环节嵌入式重复控制系统的改进

在基于嵌入式重复控制和传统P控制的复合控制方案的基础上,加入积分控制,应用于110V50Hz UPS的逆变环节,加速了调节过程,改善了系统静态特性。文章详细分析了系统的结构、重要控制参数的整定,并在SABER软件环境下建立50Hz UPS电源的逆变闭环控制系统仿真模型。仿真实验结果表明:采用此控制方案在额定负载范围内输出特性良好,能获得稳定的50Hz正弦电压,是一种高性能、低成本的控制系统。     

单相在线式UPS的全数字化控制实现

文章介绍了在线式UPS的基本原理以及逆变器的SPWM调压方法,选用DSP实现UPS的数字化控制和更准确更快速的锁相环控制。对输出电压用数字PID来改善逆变控制的动态性能,得到稳定的输出电压。     

用于UPS的高频链逆变电源

逆变环节是实现UPS的关键技术,为了提高逆变电源的性能,高频链逆变电源以高频化、小型化、无噪声化的优点逐渐代替了传统的逆变电源。文中从电压源型和电流源型高频链逆变器的发展方面分析得出适合用于UPS的一种逆变电源——串联谐振电流源型高频链逆变。     

1.5kW户用光伏高频逆变器研制

分析了一种具有中间储能环节的高频隔离逆变拓扑结构,该电路能实现前后级解耦,适用于光伏发电系统。前级DC/DC高频升压电路基于有限双极性调制,实现升压功能;后级采用双极性SPWM逆变技术,结合电压平均值反馈使输出电压稳定。详细介绍了高频变压器和LC滤波电路的设计方法,最后搭建了1.5k W高频逆变实验平台,实验结果显示,逆变器具有输出电压稳定,波形畸变小等优点。     

基于一种新型电路拓扑的UPS设菅

文中介绍了一种应用于UPS的新型双Boost电路拓扑,可以实现DC／AC单级升压变换。在对主电路拓扑和工作原理进行分析的基础上,采用SPWM调制方法对其进行了软件仿真和硬件实验。实验结果证明,以Boost变换电路可以实现高频功率变换情况下的单级升压逆变输出。     

小型风力发电系统正弦波逆变器设计

为了提高小型风力发电系统输出电能质量,设计了高效、可靠、低成本的正弦波逆变器。主电路由推挽升压变换器和单相逆变桥组成,采用高频变压器实现电压比调整和电气隔离,降低了噪声,提高了效率、减小了输出电压纹波。逆变器功率开关管采用了RCVD缓冲电路,确保逆变桥安全工作。控制部分采用集成脉宽调制芯片SG3524和正弦函数发生芯片ICL8038实现正弦波脉宽调制(SPWM),简单可靠、易于调试。实验样机体积减小到传统逆变器的1/4,效率达到86%。实验结果表明输出电压波形失真度小于5%,在复杂的工况下实现了220 V/50 Hz的市电输出。     

Robust Model-Following Control of Parallel UPS Single-Phase Inverters

This paper presents a robust control technique applied to modular uninterruptible power-supply (UPS) inverters operating in parallel. When compared to conventional proportional–integral (PI) control, the proposed technique improves the response of the output voltage to load steps and to high distorted output currents, reducing the distortion of the output voltage. Furthermore, an excellent distribution of currents between modules is achieved, resulting in fine power equalization between the inverters on stream. The crossover frequency of the different loop gains involved is moderate, so that robustness to variations of the operation point and to modeling uncertainties is achieved. A comparative study with a two-loop conventional PI control scheme is presented. Experimental results on a 1-kVA modular online UPS system confirm the viability of the proposed scheme.      

Output Impedance Design of Parallel-Connected UPS Inverters With Wireless Load-Sharing Control

This paper deals with the design of the output impedance of uninterruptible power system (UPS) inverters with parallel-connection capability. In order to avoid the need for any communication among modules, the power-sharing control loops are based on the$P/Q$droop method. Since in these systems the power-sharing accuracy is highly sensitive to the inverters output impedance, novel control loops to achieve both stable output impedance and proper power balance are proposed. In this sense, a novel wireless controller is designed by using three nested loops: 1) the inner loop is performed by using feedback linearization control techniques, providing a good quality output voltage waveform; 2) the intermediate loop enforces the output impedance of the inverter, achieving good harmonic power sharing while maintaining low output voltage total harmonic distortion; and 3) the outer loop calculates the output active and reactive powers and adjusts the output impedance value and the output voltage frequency during the load transients, obtaining excellent power sharing without deviations in either the frequency or the amplitude of the output voltage. Simulation and experimental results are reported from a parallel-connected UPS system sharing linear and nonlinear loads.     

基于DSP的全数字UPS逆变器锁相控制技术

为有效保证不问断电源逆变器交直流切换过程不对负载产生过大的冲击,UPS逆变输出电压必须与电网电压的频率及相位保持一致。快速可靠的软件锁相跟踪技术可以准确地为逆变器数字化控制提供与电网电压同频同相的标准正弦电压。本文主要讨论基于TMS320LF2407数字化控制平台的全数字不间断电源中的锁相控制技术。     

Deadbeat control of PWM inverter with modified pulse patterns foruninterruptible power supply

A modified algorithm of pulse-width-modulation (PWM) inverter deadbeat control suitable for uninterruptible-power-supply (UPS) systems is presented. Two state variables are measured at each sampling interval, then, using the data, the pulse width is computed in real time in order to force the output voltage equal to the reference at each sampling instant which is called the deadbeat control. Two kinds of PWM pulse patterns are used to increase the fundamental component of the output voltage, considering the microprocessor computation time. Experimentation and simulation has verified that the proposed control scheme increased the output-voltage amplitude, providing an excellent transient response and accurate phase positioning for various load conditions. This algorithm is suitable for applications of high-power UPS systems, in which the switching frequency is in the range of a few kHz and the precise control of power flow is required     

基于LTC3789的DC/DC变换器设计

为将宽输入范围直流电压变换成稳定直流电压输出,以控制器LTC3789为核心,高速、高频、低损耗MOSFET器件为控制开关,采用恒定频率的电流控制模式,设计了一款能够实现宽范围输入电压同步、无缝、高效的升压-降压DC/DC变换电路,并进行了物理实验验证。实验结果表明,所设计的以LTC3789为控制核心的电路能够实现6-30V直流输入,12.8V稳定直流输出的DC/DC变换,并且电路工作稳定、可靠。     

The uni-polarity phase-shifted controlled voltage mode AC-AC converters with high frequency AC link

A circuit configuration and circuit topological family of voltage mode ac-ac converters with high frequency ac links, which are based on forward converters, and a uni-polarity phase-shifted control strategy are proposed and deeply investigated. These kinds of converters consist of a input cycloconverter, a high frequency transformer, an output cycloconverter, input and output filters, and can transfer an unsteady ac voltage with a high harmonic into steady same-frequency ac sinusoidal voltage with a low harmonic. By using uni-polarity phase-shifted control strategy, output filtering inductance current is naturally commutated, and zero voltage switching of the output cycloconverter is realized. The converters' averaging model, the output characteristic curve, and design criteria for the key circuit parameters are given. The theoretical analysis and test result of 1kVA 220V /spl plusmn/ 10% 50Hzac/110V 50Hz ac prototype have shown that the converters have such advantages as high frequency electrical isolation, simple topology, two-stage power conversion (LFAC/HFAC/LFAC), bidirectional power flow, uni-polarity synchronized pulsewidth modulation waveform, high efficiency, high power density, high steady precision, low total harmonic distortion of the output voltage, strong adaptability to various loads, high line power factor, and low audio noise etc.     

基于FPGA的光弹调制器用高压驱动电路设计

为满足光弹调制器对高电压、高稳定和精确易控制的驱动电压需求,设计了一种基于FPGA控制、全桥结构LC谐振升压的高压驱动电路。该电路与传统的光弹调制器驱动控制电路相比,大幅降低了直流电源的电压输入要求,通过DDS调节方波频率来控制光弹调制器工作频率,调节方波占空比来控制输出电压。该电路应用于光弹调制器实验,结果表明在光弹调制器的谐振频率下,外部直流电压为5 V时,方波占空比范围为0~50%,对应电压峰-峰值可调节范围为0~840 V。电路具有稳定可靠、操控方便、带负载能力较强等优点,能够实现光弹调制器驱动电压实时精确的控制。     

High-performance online UPS using three-leg-type converter

A high-performance single-phase online uninterruptible power supply (UPS) is proposed. The UPS is composed of a three-leg-type converter which operates as a battery charger and an inverter. The first leg is controlled to charge the battery, and the third leg is controlled to make the output voltage. The common leg is controlled in line frequency. The charger and the inverter are controlled independently. The charger has the capability of power-factor correction while charging a battery. The inverter regulates output voltage and limits output current under an impulsive load. The three-leg-type converter reduces the number of switching devices. As a result, the system has less power loss and a low-cost structure. In the determination of the charger voltage, the nominal voltage is derived using the feedback linearization concept and then a perturbed voltage is determined for the reactive power control. The disturbance of input voltage is detected using a fast sensing technique of the input voltage. Experimental results obtained with a 3-VA prototype show a normal efficiency of over 87% and an input power factor of over 99%.     

A new UPS topology employing a PFC boost rectifier cascadedhigh-frequency tri-port converter

A new uninterruptible power supply (UPS) topology using the high-frequency tri-port UPS technique is proposed which presents the advantages of no-break power, low cost, input unity power factor, high power density, and high power conversion efficiency. Through the proposed circuit configuration, charging concept, and control strategy, the battery management is easily obtained by controlling the output voltage of the power-factor-correction (PFC) converter, which results in no additional power device being required for charging. The implementing circuit of the charging method is submitted to perform the two-stage charging, constant current charging, and constant voltage charging. The proposed technologies can be applied to the switching power supply with built-in UPS function featuring a low-cost solution for computer equipment, Finally, an experimental AC online UPS is built to verify the proposed concept, analysis, and control strategy     

逆变器无差拍性能控制方案的分析与设计

分析了两种单电压环的无差拍控制方案。通过分析,比较了两者的异同,指出单纯保证输出电压无差拍控制方案的劣势。并详细分析了能够同时实现两个状态无差拍控制的单电压环控制方案。该方案利用输出电压反馈进行极点配置,实现系统对给定无差拍跟踪;利用负载电流进行前馈控制,实现系统对扰动的抑制。并针对控制策略进行了仿真,验证了方案的可行性。