变频器模拟控制方式在矿用绞车系统上的应用

本文介绍了一种基于韩国SOHO变频器的模拟量控制方式在矿用无极绳绞车系统上的应用。设计了一种电压-电流变换电路,利用变频器的模拟量给定功能,将用户给出的电压模拟量转换成电流控制量调节变频器的输出频率或转速,实现精确控制负载三相异步电机的目的。     

工程型变频器机械制动控制功能应用研究

本文简要介绍了通用变频器和工程型变频器的机械制动控制思想方法以及在负载启动停止时两种机械制动的工作过程,分析了工程型变频器机械制动功能的优点,并结合西门子6SE70变频器机械制动功能在济钢副枪起升机构中的应用,给出一个典型的工程型变频器机械制动控制的实例,可为国内位能型负载机械制动控制功能的设计、应用提供参考。     

多电机拖动皮带输送机恒压频比控制变频器

在变频器驱动多机拖动皮带机系统中,一个重要的问题是如何解决系统中各个电动机的功率输出平衡。本文介绍了一种基于恒压频比控制型的多机拖动皮带机变频器。变频器采用主从控制模式,通过对各自有功电流做闭环控制来实现对其输出频率的调整。变频器的输出电压按照恒压频比控制方式,保证了电机气隙磁通的恒定,最终能够达到各个电动机输出功率一致的目的。通过现场的成功应用,证明了恒压频比控制型多机拖动皮带机变频器的有效陛和实用性。     

变频器在变压器绕线机系统中的应用

本文介绍了如何使用普传PI7100变频器的主板端子功能、制动功能及保护功能实现变压器绕线机系统的自动调速控制的工艺要求。着重介绍控制系统如何设计及其工作过程，变频器常见故障及排除措施。     

易驱ED3100变频器

该产品具有无感电流矢量控制,电机变量完全解耦,实现了转矩快速响应和准确控制,低频转矩大,高精度、宽范围调速：0．5Hz,150％额定转矩输出,1：1000;宽电网电压设计．电网输入电压在-15％～15％时变频器可安全运行;具备自动稳压功能和过调制功能,对电网有较强的适应能力;独立风道、无触点软启动开关、低电感直流母线排高可靠性设计;     

基于电网电压补偿的多电平变频器控制方法研究

提出了一种基于电网电压补偿的多电平变频器控制方法，从主回路拓扑结构出发，以低压变频器规则采样法为基本理论，详细介绍了适合于多电平变频器控制的理论分析和算法推导过程。并给出了适合数字信号处理的采样原理和采样时序。直接根据电网电压的变化，实时调节输出电压，能获得与闭环系统相媲美的理想机械特性和运行效果。该方法不仅具有计算步骤简单、输出SPWM对称性好、精度高和控制方便的特点，而且适用于任何电平数目及拓扑结构。试验结果表明，和其他多电平控制方法相比，使用效果好，有很高的利用价值。     

ABB变频器在高炉卷扬上料的应用

本文详细介绍了山东石横特钢集团炼铁厂ABB变频器在高炉上料卷扬机中的应用,该应用方案中ABB变频器根据外部控制信号的要求和实际的运行速度,控制输出频率的大小,实现了高炉上料卷扬机加减速段的平稳制动和稳定爬行,具有较大的实用和推广价值。     

低压CMOS带隙电压源

介绍了CMOS带隙电压源的基本原理,并根据目前CMOS集成电路工艺发展对低电源电压的要求,详细地分析了几种能产生低输出电压且能兼容标准CMOS工艺的CMOS带隙电压源电路.这些电路所需的电源电压只有1V左右,并且都能够输出1V以下具有零温度系数的参考电压,其中有些电路的输出电压可以由电阻的比值来调节,因而可以增加电路设计的灵活性.本文还对低压CMOS带隙电压源电路的低频和高频噪声特性进行了深入分析,提出了改善输出参考电压噪声特性的途径.     

交-交变频系统环流建模仿真研究

本文针对相位控制交—交变频工作环流进行了讨论,并应用MATLAB/Simulink建模方法分析了不同控制与调制信号所产生的输出电压波形,研究了输出电压谐波分量对交—交变频器环流大小的影响,总结了交—交变频器环流特征,为进一步深入研究交—交变频器的工作性能奠定了基础。     

一种级联H桥多电平变频器改进型载波移相PWM调制策略

级联Ｈ桥多电平变频器已经广泛应用于光伏发电、电机调速等领域，但由于各单元独立直流电源参数差异，导致各单元直流电压不均衡， 在单元直流电压不均衡时，传统载波移相ＰＷＭ调制策略存在输出电压低频边带谐波无法消除的问题，从而影响输出电能质量，对传统载波移相ＰＷＭ调制策略下变频器输出电压进行了傅里叶分析，研究了一种可变移相角的改进型载波移相ＰＷＭ调制策略，根据不同工况实时改变移相角，从而消除输出电压的低频边带谐波，有效提高输出电能质量，最后，通过样机实验验证了改进型调制策略的有效性。     

Phase control for resonant DC-DC converter with class-DE inverter and class-E rectifier

In this paper, a phase control scheme for Class-DE-E dc-dc converter is proposed and its performance is clarified. The proposed circuit is composed of phase-controlled Class-DE inverter and Class-E rectifier. The proposed circuit achieves the fixed frequency control without frequency harmonics lower than the switching frequency. Moreover, it is possible to achieve the continuous control in a wide range of the line and load variations. The output voltage decreases in proportion to the increase of the phase shift. The proposed converter keeps the advantages of Class-DE-E dc-dc converter, namely, a high power conversion efficiency under a high-frequency operation and low switch-voltage stress. Especially, high power conversion efficiency can be kept for narrow range control. We present numerical calculations for the design and the numerical analyses to clarify the characteristics of the proposed control. By carrying out circuit experiments, we show a quantitative similarity between the numerical predictions and the experimental results. In our experiments, the measured efficiency is over 84% with 2.5 W output power for 1.0-MHz operating frequency at the nominal operation. Moreover, the output voltage is regulated from 100% to 39%, keeping over 57% power conversion efficiency by using the proposed control scheme.     

H∞ control applied to boost power converters

The controller in a pulse-width-modulation (PWM) power converter has to stabilize the system and guarantee an almost constant output voltage in spite of the perturbations in the input voltage and output load over as large a bandwidth as possible. Boost and flyback power converters have a right-half-plane zero (RHPZ) in their transfer function from the duty cycle to the output voltage, which makes it difficult to achieve the aforementioned goals. Here, the authors propose to design a controller using H^∞ control theory, via the solution of two algebraic Riccati equations. The almost optimal H^∞ controller is of the same order as the converter and has a relatively low DC gain. The closed-loop characteristics of a typical low-power boost power converter with four different control schemes were compared by computer simulation. The H^∞ control was found to be superior in a wide frequency range, while being outperformed by the others at extremely low frequencies. Good agreement was found between simulation results and experimental measurements     

一种低噪高输出电压DC—DC变换器设计

针对某航天器设备用的130V高压DC—DC变换器的低噪声要求,采用初级侧隔离的负载端直接反馈控制方式,次级侧采用结合LC低通无源滤波电路和有源滤波电路的两级输出滤波电路设计方法。通过实验,不仅实现了高压DC—DC变换器的低噪声输出,而且通过优化设计,使得两级滤波器的体积较小,可靠性较高,实现了星载应用。     

A Unity Power Factor Correction Preregulator With Fast Dynamic Response Based on a Low-Cost Microcontroller

Low cost passive power factor correction (PFC) and single-stage PFC converters cannot draw a sinusoidal input current and are only suitable solutions to supply low power levels. PFC preregulators based on the use of a multiplier solve such drawbacks, but a second stage dc-dc converter is needed to obtain fast output voltage dynamics. The output voltage response of PFC preregulators can be improved by increasing the corner frequency of the output voltage feedback loop. The main drawback to obtaining a faster converter output response is the distortion of the input current. This paper describes a simple control strategy to obtain a sinusoidal input current. Based on the static analysis of output voltage ripple, a modified sinusoidal reference is created using a low cost microcontroller in order to obtain an input sinusoidal current. This reference replaces the traditional rectified sinusoidal input voltage reference in PFC preregulators with multiplier control. Using this circuitry, PFC preregulator topologies with galvanic isolation are suitable solutions to design a power supply with fast output voltage response (10 or 8.33 ms) and low line current distortion. Finally, theoretical and simulated results are validated using a 500 W prototype.     

高频多相数字DC-DC控制芯片的设计

介绍应用于低电压大电流DC-DC的高频多相数字控制芯片的设计。该芯片采用电压模式控制、数字比例-积分-微分(PID)控制算法,由可编程电压基准源、窗口ADC、数字PID电路以及数字脉宽调制(DPWM)电路组成。该芯片提供1MHz开关频率、四相PWM信号输出、5bit电压识别(VID)码控制系统的输出电压,实现从1.1V到1.85V可调。芯片在0.35μm工艺下流片。实验结果证实了芯片的性能与设计方法的正确性。     

一种恒压输出的DC-DC升压电路设计

针对DC-DC升压器存在效率低,纹波电压较大,输出电压不稳定等问题,文中开发和设计了一种具有恒定输出电压的DC-DC升压转换器的方法。通过升压电路和电压反馈技术,将波动的输入电压变成恒定的直流电压输出。该设计通过将转换器的输出电压与参考电压相比较,两者的差值会产生一个PWM信号控制升压器的通断时间,从而达到恒定电压输出。仿真结果显示,该实验电路能在频率为20 kHz的连续导通模式中工作,产生24 V的恒定输出电压,输出功率为100 W。     

一种用于COT架构Buck变换器的导通定时器

针对恒定导通时间(COT)控制架构Buck变换器的开关频率随输入与输出电压变化较大的问题,在COT架构的基础上,引入输入电压前馈,使开关管导通时间与输入电压成反比,同时引入输出电压反馈,使开关管导通时间与输出电压成正比,从而使系统开关频率保持恒定,简化了输出滤波器的设计,减小了电磁干扰。Hspice软件仿真结果表明,导通时间随输入与输出电压的变化而变化,开关频率基本保持恒定。采用此结构的Buck变换器具有极佳的瞬态响应性能。     

Ultrafast Tracking Power Supply With Fourth-Order Output Filter and Fixed-Frequency Hysteretic Control

A practical solution is presented for the design of a non-isolated dc/dc power converter with very low output ripple voltage and very fast output voltage step response. The converter is intended for use as an envelope tracking power supply for a radio frequency power amplifier (RFPA) in a TETRA enhanced data service (TEDS) base station. A simple and effective fixed-frequency hysteretic control scheme for the converter (buck with fourth-order output filter) is developed and analyzed. The proposed approach is verified experimentally by a 500 W output prototype, capable of delivering any voltage in the range of 10–30 V within 10 $mu{hbox {s}}$ with 10 mVpp of output ripple and efficiencies in the 88%–95% range.      

TRIAC dimmable ballast with power equalization

A two-stage, two-wire TRIAC dimmable electronic ballast for fluorescent lamps is presented in this paper. It is constructed by using a flyback converter as the input power factor corrector to supply a half-bridge series-resonant parallel-loaded inverter to ballast the lamp. The flyback converter is operated in discontinuous conduction mode so that the filtered input current profile is the same as the TRIAC-controlled voltage waveform. The switches in the inverter are switched at a constant frequency slightly higher than the resonant frequency of the resonant tank. Based on the constant average input current characteristics of the inverter, the dimming operation is simply achieved by pulsewidth modulation control of the magnitude of the flyback converter output voltage. No synchronization network is required between the input and output stages. In addition, a linear power equalization scheme is developed so that the dc-link voltage (and hence the lamp power) is in a linear relationship with the firing angle of the TRIAC. The average output voltage of the dimmer controls the equalized flyback converter output voltage. Modeling, analysis, and design of the ballast will be described. A prototype was implemented to verify the experimental measurements with the theoretical predictions.