基于模型预测变开关频率PWM的EMI主动抑制技术

脉宽调制(PWM)是电力电子技术的重要基础领域,是当前电力电子变换器实现交直流电能变换与控制的主要方式。模型预测变开关频率PWM技术是经典脉宽调制技术理论在电力电子变换器领域的重要发展,也是扩频调制技术的一个新兴分支,融合了微秒级时间尺度的开关纹波时域预测模型,可主动控制PWM开关频率自由度,在实现电磁干扰主动抑制的同时,综合权衡了电力电子变换器开关纹波、开关损耗等重要因素。文章综述了基于模型预测变开关频率PWM的传导电磁干扰主动抑制技术的研究进展,回顾了基于不同预测模型的变开关频率PWM技术的实现方法,探讨了模型预测变开关频率PWM技术应用过程中的关键共性问题,进而展望了此技术在电力电子变换器领域的发展方向与机遇。     

开关磁阻电机变角度电压斩波控制实现方法研究

电压斩波、变角度控制,是开关磁阻电机两种基本的控制方式。变角度电压斩波控制结合了两种控制方式的优点,可优化开关磁阻电机调速系统的效率。角度位置传感器的安装是实现角度位置控制及电机四象限运行的关键,并提出了角度细分软件设计方法。提出了变角度与模糊电压斩波控制相结合的原理及实现方法,最终在dsPIC单片机上实现,验证了该方法的有效性。     

基于滑模变结构控制的数字化软开关电源

基于滑模变结构控制技术,采用FLEX10KAFPGA（EPF10K30AQC208）数字控制芯片研制开发了容量为180W的有源箝位正激软开关电源;并且详细分析了该电源的控制时序及滑模变结构的数字化控制方案,最后给出了系统的实验结果。从实验结果可以看出滑模变结构控制鲁棒性强,系统的稳定性能好,动态响应速度快,而且主回路的开关管实现了零电压软开关。     

晶体管音控放大器

在一般近代的短波无线电话终端机上,都装有话音控制增益的放大器,以便对不同的用户话音进行自动的电平调整,供给发射机一个足够高而动态变化很小的调制信号,以保证发射机提供足够的输出功率.这种音控放大器,在利用电子管电路设计时,有用变跨导电子管来自动调整增益;也有将放大器的增益固定,而在放大器之前或放大器级际之间插入变阻电路,用话音来控制变阻电路中流过的电流,以达到输出电平     

ARCP软开关逆变器控制方式比较

随着逆变器开关频率和效率的提高,软开关逆变器会比传统硬开关拓扑显得更具优势。辅助谐振极（ARCP）就是一种典型的ZVT型软开关逆变器拓扑,其辅助开关的控制方式会影响逆变器的可靠性和效率。本文比较了变时间和定时间两种控制方式的特点,给出了ARCP逆变器不同控制下的软开关区域和损耗分析,并在一台2 kW实验样机上进行了验证。     

双馈风力发电系统滑模变结构的设计与实现

与矢量控制相比,直接功率控制(DPC)应用于双馈风力发电系统能简化控制结构,提高系统动态性能。本文提出将一种变指数趋近律滑模变结构控制策略用于双馈风力发电机直接功率控制中,并通过引入空间矢量调制技术使DPC的开关频率保持恒定。该策略采用滑模控制直接计算所需的转子控制电压以消除瞬时有功、无功功率误差。仿真结果表明,与传统矢量控制,开关频率恒定直接功率控制相比,滑模直接功率控制对系统参数不确定、外部扰动具有强鲁棒性,系统的动、静态性能优良。     

新型单相全桥无源软开关逆变器

为改善单相全桥逆变器的运行效率,设计出了一种新型单相全桥无源软开关逆变器,在每个开关周期的换流过程中,利用逆变器的低损耗辅助谐振电路,使开关器件实现软切换以节约电能.辅助谐振电路只含有电感、电容和二极管等无源器件,不会使逆变器的控制变复杂.此外,在逆变器处于死区状态下,负载电流可通过辅助电路进行续流,减小了死区状态对逆变器输出电流波形的不利影响.文中分析了电路的工作过程,在功率为3kW的单相样机上的实验结果表明开关器件能实现软开关,逆变器输出电流波形的畸变率得到了改善.因此,该拓扑结构对于研发高性能单相全桥逆变器具有重要参考价值.     

液压伺服系统自适应模糊变结构控制

结合变结构控制、自适应控制和模糊技术等特点,提出一种自适应模糊变结构控制方法.首先,设计一个带积分开关平面函数的变结构控制器,并构造一个二维模糊边界层宽度调节器以削弱抖振.其次,基于Lyapunov稳定性理论,引入一自适应算法,自适应调节变结构控制参数.应用于液压伺服系统的控制实验结果表明,所提出的控制方法能削弱抖振,改善液压伺服系统稳态控制精度,具有较强的鲁棒自适应综合性能.     

移相全桥鲁棒性变增益控制策略的研究

针对传统PID控制的移相全桥变换器难以获得理想的动静态特性,在分析移相全桥模型的基础上,设计以输入电压和负载作为变参数的线性变参数模型。利用变参数极值组合将其变为多胞形模型,并通过对其顶点进行稳定性分析和控制器设计,得到一种建立在软开关移相全桥变换器的多胞形线性变参数模型基础上的鲁棒性变增益调度控制。通过Matlab仿真与传统的PID控制进行比较,表明鲁棒性变增益控制器具有更好的控制效果。     

变系数降频模型预测直接功率控制

模型预测直接功率控制是三相并网逆变器有效的控制策略之一，但是为了维持稳定快速的功率跟踪，通常需要一个较高的采样频率，造成不必要的开关损耗。定系数降频控制策略可以降低有效地开关动作次数，但是不方便确定合适的开关函数系数，且降低了系统性能。变系数降频控制策略可以同时实现稳定的功率跟踪和开关频率降低。仿真和实验结果显示，与定系数降频控制策略相比，变系数策略具有更优越的特性。     

级联型电力电子变压器控制策略研究

电力电子变压器是一种新型的电能转换工具,它可以利用电力电子转变技术来实现传统变压器的功能.基于此,本文对级联型电力电子变压器进行了简单的研究,并根据其自身特点制定对应的控制策略.     

一种级联固态变压器整流级均压控制策略研究

固态变压器作为未来智能电网中的核心设备,是一种基于电力电子变换技术实现传统变压器功能的新型智能变压器。模块级联固态变压器可以使低压器件工作在高压情况下,以提高电压等级,使其应用于电网中。模块式级联固态变压器整流级直流侧电压不均是该拓扑一个重要问题。因此从级联式拓扑直流侧电压不均的实质出发,提出一种调节调制波矢量有功分量的大小,重新构造各模块的调制波,使有功功率的重新分配以实现均压的策略,并给出了控制流程。最后通过仿真和搭建实验平台来验证,经仿真和实验效果来看,该均压策略是可行的。     

Current-source parallel-resonant DC/AC inverter with transformer

This paper gives the theory and experimental results for a current-source parallel-resonant inverter with a transformer used to change voltage levels and provide isolation. The analysis is performed in the frequency domain using Fourier series techniques to predict output power, efficiency, DC-to-AC voltage transfer function, and component voltage and current stresses. The inverter consists of two switches, a large choke inductor, a transformer, and a parallel-resonant circuit. The magnetizing inductance of the transformer is used as the inductance of the parallel-resonant circuit, thereby requiring one less component. Each switch consists of a MOSFET in series with a diode. The MOSFETs have their sources grounded so there is no need for a complicated gate-drive circuit. An inverter was designed and constructed. The DC input voltage was 156 V and the output voltage was a sine wave with a peak value of 224 V at an operating frequency of 50 kHz. The output power at full load was 100 W     

Small-signal modeling of a controlled transformer parallel regulator as a multiple output converter high efficient post-regulator

This paper presents a post-regulator based on the use of a controlled transformer, which adds or subtracts an additional voltage to the output filter of a converter in order to regulate its output voltage. So, their actuation is complementary to that of more known post-regulators, such as the magnetic amplifier (magamp) and synchronous switch post-regulator (SSPR), because the regulation is achieved by controlling the voltage across the filter inductor instead of its charge time. Besides, the post-regulator processes the power in parallel to the one flowing from input to output and only handles a percentage of it. The post-regulation by controlled transformer is suitable of being employed in any isolated PWM power converter and combines a good efficiency and the easiness of design of classical switched power supplies. The work describes the post-regulation strategy for obtaining two outputs independently regulated, and presents a model to obtain the control transfer function and the cross-impedance expressions.     

Forward converter regulator using controlled transformer

A new control scheme is proposed for a forward power converter regulator using a controlled transformer. Pulse width modulation (PWM) control is used to reset the control core of the controlled transformer. As a result, a low-cost ferrite core can be used for the controlled transformer to achieve good regulation and high efficiency. Overall efficiency of 82-86% is achieved in a 200 kHz, 500 W, 5 V output regulator. A PWM-controlled transformer regulator is particularly suited for high-output-current and/or high-output-voltage postregulator applications     

主变压器强油风冷信号回路改进

主变压器风冷信号是供变电运行和监控运行人员参考的重要信号,由此来确定变压器冷却器的工况.文章针对电力系统中主变压器冷却器信号不能准确反映各组冷却器工况的问题,提出增加测控装置遥信点和运用视觉效果防止主变压器风冷全停的改进方案.改进方案实现强油风冷主变压器冷却器的工况更加详细,有效地防止主变压器冷却器全停和因此而造成主变压器跳闸事故的发生,增强电力系统供电的可靠性.     

基于功率分配控制的多路输出反激变换器

为了改善多路输出反激变换器交叉调整率,提出了一种基于功率分配的控制策略。利用ARM实时采样各路输出端的实时负载,结合各路期望输出电压计算期望输出功率的总和,进一步计算高频变压器初级所需的实时输入功率,获得主开关和次级整流开关的导通比,使得每一路的输出获得期望的功率和稳定的输出电压。实验结果表明,利用基于功率分配的控制策略所设计的双路输出反激变换器获得了小于1.6%的交叉调整率和小于2.2%的负载调整率以及小于0.7%的输入电压调整率。所设计的变换器不仅有效解决了交叉调整率的问题而且具有较好的负载调整率和输入电压调整率。     

A self-driven active clamp forward converter using the auxiliary winding of the power transformer

This study proposes a new self-driven active clamp forward converter eliminating the extra drive circuit for the active clamp switch. The converter used the auxiliary winding of the power transformer to drive the active clamp switch and a simple RC circuit to get the dead time between the two switches. The operation principle was presented and experimental results were used to verify theoretical predictions. A 100-W (5 V/20 A) prototype converter that only exhibited 1.5-turn winding number in the auxiliary winding was sufficient to drive the active clamp switch on the input of 50 V. Finally, the measured efficiency of the converter was presented and the maximum efficiency of 91% was obtained.     

Voltage-follower control in zero-current-switched quasi-resonantpower factor preregulators

In this paper, we propose to study the use of several zero-current-switched (ZCS) quasi-resonant converters (QRCs) (buck-boost, flyback, SEPIC, Cuk, boost, and buck) with a half-wave switch, working as power factor preregulators (PFPs) with voltage-follower control. The analysis carried out demonstrates that these converters show excellent characteristics to obtain a high power factor (PF) without using any input-current feedback loop, and they also allow high switching frequency to operate because they integrate transformer and rectifier diode parasitics into the power topology     

Decoupled output voltage control of quantum series resonantconverter for improved buck-boost operation

A new output voltage control technique is proposed to obtain the improved buck-boost operation of the quantum series resonant power converter (QSRC). The new nonlinear dynamic model of QSRC is first derived and the cross-coupled nonlinear term existing in the output voltage dynamics is decoupled by using control methods such as the periodic control of the boosting switch (PCBS) and the resonant current control (RCC). By applying the state-space averaging concept to the decoupled dynamics, two linear large signal averaged models are obtained for PCBS and RCC schemes. Using the proposed technique, the flux imbalance problem of the isolation transformer and the robustness of the output voltage response can be easily considered. This technique can also be widely applicable to the cascade buck-boost power converter, which can be implemented by inserting a boosting switch between the output filter inductor and the ripple capacitor of the forward power converter. The validity of the proposed scheme is confirmed by the computer simulations and the experiments