基于粒子群算法的LCLC谐振变换器优化设计

LCLC谐振变换器广泛应用在空间行波管放大器(TWTA)中,起到升压的作用.在LCLC谐振变换器中,具有多个谐振参数,即变压器漏感、串联谐振电容、励磁电感以及并联谐振电容.多个谐振参数增加了LCLC谐振变换器总损耗优化的难度.该文提出一种基于粒子群优化算法的LCLC谐振变换器优化设计方法,解决LCLC谐振变换器由于多个谐振参数造成的总损耗优化困难的问题.首先,推导了LCLC谐振变换器的总损耗公式;其次,采用粒子群优化算法,对LCLC谐振变换器的总损耗进行了优化,得到了总损耗最小时的谐振变换器参数;最后,基于优化的LCLC谐振变换器参数,搭建了LCLC谐振变换器,并进行了一系列实验.实验结果证明了该优化设计方法的有效性.     

LLC变换器PSPICE仿真的收敛性及参数优化

针对LLC变换器使用PSPICE仿真器进行DC分析和瞬态分析时经常遇到不收敛的问题进行实验,列出了5种有效改进方法。比较了LLC谐振变换器3个参数优化设计的各种方案,提出并验证了运用PSPICE进行多参数优化设计的方法。实验表明,合理运用PSPICE,在谐振开关电源设计中常常会取得比其他方法(软件)更令人满意的效果。     

半桥型LLC变换器稳态建模与参数设计

本文介绍了LLC型谐振变换器的主电路结构和工作原理。通过基波分析法对半桥型LLC谐振变换器进行稳态建模分析,得出了谐振腔的等效电路和直流增益表达式。基于稳态模型的基础上,给出了半桥型LLC谐振电容、谐振电感和励磁电感的设计方法。最后通过saber仿真验证了半桥型LLC谐振变换器稳态模型与参数设计方法的正确性。     

基于改进粒子群优化算法的分布式电源规划

针对目前配电网中存在的分布式电源规划问题,在最大化电压静态稳定性、最小化配电网损耗以及最小化全年综合费用三个方面建立了分布式电源规划的优化模型。在规划模型的基础上,采用拥挤距离排序的多目标量子粒子群优化算法(MOQPSO-CD)以及基于量子行为特性的粒子群优化算法(QPSO),来更新和维护外部存储器中的最优解,通过对全局最优最小粒子的选择引导粒子群能够对分布式电源的配置容量与接入点位置的真实Pareto最优解集进行查找,获得对多个目标参数进行合理优化。最后采用IEEE33节点的配电系统,在模拟仿真实验过程中获得了分布式电源容量配置以及介入位置的合理方案,验证了优化算法的可行性。     

微带天线谐振频率的小波粒子群小波神经网络建模

谐振频率是微带天线设计过程中最重要的一个参数,直接决定设计的成败。本文基于改进的小波变异粒子群优化算法该算法的小波神经网络对矩形微带天线的谐振频率进行建模,可以有效地提高神经网络的建模精度。仿真试验表明,改进的小波变异粒子群优化算法是一种有效的方法,可以有效提高小波神经网络的泛化能力,基于该算法所建立的微带天线的谐振频率模型好于此问题的已有结论。     

基于自适应粒子群优化算法的限速标志识别

针对经典的粒子群优化算法收敛性能不足的问题,提出了一种自适应粒子群优化算法。该算法对进化过程中的收敛方向进行动态调整,通过学习因子对参数选取过程进行调节,使收敛的初期趋向全局最优,后期趋向局部最优。采用自适应粒子群优化算法对支持向量机模型参数进行优化,并应用于限速标志的识别,实验结果表明,文中基于自适应粒子群优化算法的方法拥有较高的识别率,同时算法收敛性显著高于经典的粒子群优化算法。     

一类零电流谐振开关电容变换器的特性分析

具有零电流开关特性的谐振开关电容变换器是开关电容变换器的一种新拓扑形式.本文着重分析电路寄生参数和变换器运行条件对该类谐振开关电容变换器稳态特性的影响,推出变换器输出电压和效率的数学表达式,为研究负载或输入电压变化时变换器的输出性能提供了分析和设计依据.基于输出电压表达式,还提出谐振开关电容变换器的频率控制方案.全文以一个降压式谐振开关电容变换器为例详细说明公式的推导过程,并将此稳态特性分析推广到其它类型的谐振开关电容变换器.最后,文中设计了一台12V/5V/2.5A降压式谐振开关电容变换器样机,实验结果验证了本文的理论分析结果.     

改进粒子群算法的永磁同步电机PID控制器

采用粒子优化算法进行PID模糊控制训练能提高永磁同步电机的控制精度,提出一种基于改进粒子群算法的永磁同步电机PID控制方法,构建永磁同步电机PID模糊控制目标函数,选择电压、转矩、速度和电磁损耗等参数进行控制约束参量分析。采用改进的粒子群算法进行PID控制的加权训练,实现控制目标函数最优化求解,进行永磁同步电机PID控制律优化。实验结果表明,采用该控制方法进行永磁同步电机控制的调制性能较好,具有较好的输出增益,振荡较小,抗干扰能力较强。     

基于神经网络集成的微带天线谐振频率建模

谐振频率是微带天线设计过程中最重要的一个参数,直接决定设计的成败.提出基于十进制粒子群优化(DePSO)算法和二进制粒子群优化(BiPSO)算法的选择性神经网络集成方法,通过粒子群优化(PSO)算法合理选择组成神经网络集成的各个神经网络,使个体间保持较大的差异度,减小"多维共线性"和样本噪声的影响.为有效保证PSO算法的粒子多样性,在迭代过程中加入混沌变异策略.仿真试验表明:混沌PSO算法可以有效提高神经网络集成的泛化能力,基于混沌PSO算法的选择性神经网络集成所建立的微带天线的谐振频率模型好于此问题的已有结论.     

基于高频谐振拓扑的变压器优化设计

针对谐振变换器在高频工作条件下的高效率挑战问题,将聚焦于磁元件的优化设计,提出了高频变压器的优化设计模型。首先,在满足小尺寸高密度的前提下,分析了电源模块的效率问题,即模块的损耗发热问题;然后,通过变压器的损耗模型建立损耗和变压器尺寸之间的数学关系;最后,通过变压器的优化设计来平衡频率增加和电流增加带来的损耗剧增的问题,得到最优化的变压器设计模型。文章搭建了一台LLC谐振变换器样机。实验结果表明,高频变压器优化设计方法可有效减小电源模块的发热损耗,可有效提高电源模块的功率密度和效率。     

A contactless power transfer system using a series–series–parallel resonant converter

In this article, a contactless power transfer system using a series–series–parallel resonant converter (SSPRC) is proposed. The proposed converter can improve on or eliminate the disadvantages of the contactless system based on conventional resonant converters, since it independently compensates for a primary side leakage inductance, a secondary side leakage inductance and a magnetising inductance. The proposed converter also reduces the circulating currents and the reactive power by controlling the phase angle difference between the inverter output voltage and the current. In addition, the system design can be simplified, since the voltage gain is determined only by the transformer turns ratio for the overall load range without being affected by the other transformer parameters. The proposed converter is analysed with respect to the gain and current margin. The system design procedure is then described for the proposed circuit based on the circuit analysis. Finally, the experimental results are presented in order to verify the proposed contactless power supply.     

An isolated bridgeless AC-DC PFC converter using a LC resonant voltage doubler rectifier

This paper proposed an isolated bridgeless AC–DC power factor correction (PFC) converter using a LC resonant voltage doubler rectifier. The proposed converter is based on isolated conventional single-ended primary inductance converter (SEPIC) PFC converter. The conduction loss of rectification is reduced than a conventional one because the proposed converter is designed to eliminate a full-bridge rectifier at an input stage. Moreover, for zero-current switching (ZCS) operation and low voltage stresses of output diodes, the secondary of the proposed converter is designed as voltage doubler with a LC resonant tank. Additionally, an input–output electrical isolation is provided for safety standard. In conclusion, high power factor is achieved and efficiency is improved. The operational principles, steady-state analysis and design equations of the proposed converter are described in detail. Experimental results from a 60 W prototype at a constant switching frequency 100 kHz are presented to verify the performance of the proposed converter.     

Series resonant converter with auxiliary winding turns: analysis,design and implementation

Conventional series resonant converters have researched and applied for high-efficiency power units due to the benefit of its low switching losses. The main problems of series resonant converters are wide frequency variation and high circulating current. Thus, resonant converter is limited at narrow input voltage range and large input capacitor is normally adopted in commercial power units to provide the minimum hold-up time requirement when AC power is off. To overcome these problems, the resonant converter with auxiliary secondary windings are presented in this paper to achieve high voltage gain at low input voltage case such as hold-up time duration when utility power is off. Since the high voltage gain is used at low input voltage cased, the frequency variation of the proposed converter compared to the conventional resonant converter is reduced. Compared to conventional resonant converter, the hold-up time in the proposed converter is more than 40ms. The larger magnetising inductance of transformer is used to reduce the circulating current losses. Finally, a laboratory prototype is constructed and experiments are provided to verify the converter performance.     

双馈风电变流器网侧LCL滤波器设计

本文提出了一种风电变流器网侧LCL滤波器设计方法。该方法在电流谐波脉动最大允许的条件下,选择总电感量;同时兼顾开关谐波电流衰减、基波无功约束条件、谐振频率约束条件,将总电感按一定的比例分为两部分,并选择合适的滤波电容。     

A New PWM-Controlled Quasi-Resonant Converter for a High Efficiency PDP Sustaining Power Module

A new pulsewidth modulation (PWM)-controlled quasi-resonant converter for a high-efficiency plasma display panel (PDP) sustaining power module is proposed in this paper. The load regulation of the proposed converter can be achieved by controlling the ripple of the resonant voltage across the primary resonant capacitor with a bidirectional auxiliary circuit, while the main switches are operating at a fixed duty ratio and fixed switching frequency. Hence, the waveforms of the currents can be expected to be optimized from the view-point of conduction loss. Furthermore, the proposed converter has good zero-voltage switching (ZVS) capability, simple control circuits, no hign-voltage ringing problem of rectifier diodes, no dc offset of the magnetizing current and low-voltage stresses of power switches. Thus, the proposed converter shows higher efficiency than that of a half-bridge LLC resonant converter under light load condition. Although it shows the lower efficiency at heavy load, because of the increased power loss in auxiliary circuit, it still shows the high efficiency around 94%. In this paper, operational principles, features of the proposed converter, and analysis and design considerations are presented. Experimental results demonstrate that the output voltage can be controlled well by the auxiliary circuit using the PWM method.      

Analysis and design of an LCL-T resonant converter as a constant-current power supply

An LCL-T resonant converter (LCL-T RC) is shown to behave as a current source when operated at resonant frequency. A detailed analysis of the LCL-T RC for this property is presented. Closed-form expressions for converter gain, component stresses, and the condition for converter design optimized for minimum size of resonant network is derived. A design procedure is illustrated with a prototype 200-W 20-A current-source power supply and experimental results are presented. The LCL-T RC as a current source offers many advantages such as easy parallel operation and low circulating currents at light load. Additionally, with appropriate phase shift in paralleled modules, the peak-peak ripple in output current is reduced and the ripple frequency is increased, reducing filtering requirements. The leakage inductance of a transformer can be advantageously integrated into the resonant network. These merits make the topology applicable in various applications such as magnet power supply, capacitor charging power supply, laser diode drivers, etc.     

一种贴片电感电容测量新方法的研究

为了得到贴片电感电容在微带电路中的精确值,提出一种基于矢量网络分析仪的电感电容自动测量系统.依据LC谐振电路和微带传输线理论设计制作测量夹具,通过Matlab编写田口优化算法计算得到已知电感电容值,并基于GPIB接口对矢量网络分析仪实现程控,采用VC ＋＋6.0工具开发自动测量系统的用户界面.给出了具体的设计思路和测量方法,实测结果表明,该系统实现了对微带电路中电感电容的快速精准测量,具有很高的实用价值.     

电流不连续状态下LLC谐振型DC/DC变换器的分析与最佳设计

分析了LLC谐振型DC/DC变换器整流二极管电流工作在不连续状态的最大谐振电流、电容最大电压、输入输出电压增益与开关频率、谐振电感比和负载之间的关系特性,根据推导出的表达式,应用MATLAB软件绘制了相应的曲线,由此得出了LLC谐振变换器的参数最佳设计的方法。最后根据此方法设计了实验参数,给出了实验结果。     

Improved voltage clamping scheme for ZVS PWM three-level converter

This paper proposes an improved zero-voltage-switching pulsewidth-modulation (ZVS PWM) three-level converter, which is improved from the original ZVS PWM three-level converter by merely exchanging the position of the resonant inductance and the transformer, such that the transformer is connected with the lagging switches. The improved converter has several advantages over the original, e.g., the clamping diodes conduct only once in a switching period, and the resonant inductance current is smaller in zero state, leading to a higher efficiency and reduced duty-cycle loss. A blocking capacitor is usually introduced to the primary side to prevent the transformer from saturating. This paper analyzes the effects of the blocking capacitor in different positions, and a best scheme is determined. A 2.5-kW prototype converter verifies the effectiveness of the improved converter and the best scheme for the blocking capacitor.