270W移相全桥ZVSZCS变换器的设计

基于文献[1]中变换器的工作原理,设计了一台270W移相控制零电压、零电流软开关电源,给出了主电路的设计过程。实验结果证明该电源的超前臂能在1/5负载以上范围内实现零电压开关,滞后臂能在任意负载下实现零电流开关,最后给出了实验波形。     

一种带辅助电路的ZCS软开关全桥直流变换器

针对零电压零电流开关(ZVZCS)全桥直流变换器在中大功率应用场合效率不高的问题,提出了一种带辅助电路的零电流开关(ZCS)全桥直流变换器。通过为全桥直流变换器的超前臂和滞后臂设计相应的辅助电路,实现了全桥直流变换器两桥臂开关管的零电流关断,即实现了ZCS。根据提出的ZCS软开关全桥直流变换器结构,试制了一台3 k W的样机。实验结果表明,ZCS软开关全桥直流变换器的超桥臂及滞后臂均工作于零电流开关状态。为验证ZCS软开关全桥直流变换器的效率性能,将其与ZVZCS全桥直流变换器进行效率方面的比较。由比较结果可知,ZCS软开关全桥直流变换器在中大功率应用场合中的效率明显优于ZVZCS全桥直流变换器,表现出良好的性能。     

一种新型控制的ZCT-PWM变换器的分析、设计与实现

详细分析并实现了一种新型的ZCT-PWMBuck变换器,该变换器的主管和辅管均可实现零电压/零电流开关,并且电路可工作在较宽的负载范围内。试验结果证实了理论分析和设计的正确性与可行性。     

一种新型零电流零电压PWM变换器

提出了一种新型零电流零电压变换器。在全桥变换器的基础上在副边增加无源无损吸收电路，实现滞后臂的零电流开关，并给出了设计方法和实验结果。     

次级采用箝位网络的移相全桥ZVSZCS变换器

提出了一种次级加箝位网络的移相全桥ZVSZCS变换器,该变换器实现了超前桥臂的零电压开关和滞后桥臂的零电流开关,减少了续流状态时的初级环游。本文分析了变换器的工作原理和参数设计,并给出了实验结果。     

基于UCC29950的LLC谐振半桥电源的设计

LLC谐振半桥变换器可以在宽电压范围内全负载条件下实现软开关,在整个工作过程中,实现初级MOSFET的零电压开关(ZVS)和次级整流二极管零电流开关(ZCS)。因此可以达到较高的效率和功率密度,而且在负载和输入电压范围变化较大的情况下,其开关频率变化较小。文中首先分析了LLC谐振半桥变换器的工作原理,并基于TI公司的UCC29950芯片设计了一种300W电源样机,该芯片集成了PFC和LLC控制器。文章重点介绍了LLC谐振半桥变换器的参数设计,实验结果表明该电源性能优良。     

一种新型无源无损软开关全桥逆变器

提出了一种新型无源无损软开关全桥逆变器拓扑,并分析了该电路的工作原理,得出了其软开关工作条件。理论分析显示,此电路可以用较少元件实现桥臂四个有源开关器件的零电流开通与零电压关断,并且零电压电容上的能量直接回馈给负载、原理简单、效率较高,同时具有无源无损软开关功能、成本低、可靠性高和不用附加控制电路等优点。在理论分析的基础上,对所提出的电路进行了仿真和实验,仿真和实验结果都验证了理论分析的正确性。     

零电压、电流PWM DC/DC全桥变换控制器设计

本文提出了一种利用耦合输出电感的新型次级箝位零电压零电流变换器,简单分析了所提出的利用耦合输出电感的新型次级箝位ZVZCS电路拓扑的工作原理,对其中以UC3875为核心的控制器设计、驱动电路及参数选择做了分析,文中还给出了仿真及样机实验结果,说明了控制器设计及参数选择是合理的。     

一种新型降压型ZVT-PWM变换器的研究

研究软开关技术能够有效改善功率,降低开关损耗,提高变换器的效率.为了减少电路的整体能耗,提出采用降压型ZVT-PWM变换器.把谐振元件从主功率通道中移开,利用并联的辅助开关回路,使主开关管在开通之前两端电压降为0,实现零电压开通.谐振元件不通过负载电流,使负载对谐振过程的影响减到最小,大大降低了开关损耗.同时,辅助开关管实现零电流关断,二极管的反向恢复也受到控制,减少了电路中谐振回路通态损耗.对电路一个周期内的每个工作模态进行了详细的分析,并进行仿真,证明了电路的可行性和分析的正确性.     

基于B-SIT的半桥谐振DC-DC变换器电路

本文介绍了串联谐振逆变器电路构成的零电流软件开关变换器,并描绘了其在稳态时的工作原理.对带有电压箝位二极管环路的半桥零电流谐振DC-DC变换器的性能进行了评价.实验结果表明,该变换器结构简单,成本低,效率高,容易实现软开关,且产生的开关损耗很小.     

一种新型反激变换器的研究

本文基于NCP1205芯片设计了一种新型准谐振反激变换器。在分析该变换器工作原理的基础上,进行了电路设计和工作频率计算。由实验结果,新型反激变换器具有良好的负载调整率、动态响应快、输出电压纹波小及开关损耗低的特点。     

基于主电流控制的并联DC-DC升压变换器改进

并联DC-DC升压变换器之间的负载电流分配关系到系统可靠性;针对并联DC-DC升压变换器,提出了一种基于主电流控制的改进下垂方法;该方法利用并联DC-DC升压变换器的算法,根据下垂法的负载调节特性自适应地调整每个变换器的参考电压;与传统的下垂法不同,在所有变换器的内环控制器中使用其中一个并联变换器的电流反馈信号,以避免并联变换器控制回路的时延差异;研究结果显示,该算法保证了负载均流与下垂法的负载调节特性一致,在并联变换器参数失配的情况下对该算法进行了测试,通过Matlab/Simulink仿真验证了该算法的有效性。     

Modelling and simulation of matrix converter under distorted input voltage conditions

Matrix converter is an energy conversion device which directly connects a three-phase voltage source to a three-phase load without dc-link components. Therefore, the output of the matrix converter is directly affected by the disturbance or imbalance in the input voltages. Many researchers have made an effort to overcome this problem in recent years. In this paper, the behaviors of the matrix converter controlled with the optimum-amplitude Venturini method are investigated and a novel compensation technique based on fuzzy logic controller is proposed to eliminate the undesirable influences of the input voltage under the distorted input voltage conditions. The proposed technique is based on closed loop control of the three-phase output current to enhance the output performance of the matrix converter. The mathematical model of the proposed system is developed. The simulation of the development model is performed in Matlab&Simulink. Some results demonstrating validity of the proposed compensation technique are presented.     

DC–DC Converter with Pi Controller for BLDC Motor Fuzzy Drive System

The Brushless DC Motor drive systems are used widely with renewable energy resources. The power converter controlling technique increases the performance by novel techniques and algorithms. Conventional approaches are mostly focused on buck converter, Fuzzy logic control with various switching activity. In this proposed research work, the QPSO (Quantum Particle Swarm Optimization algorithm) is used on the switching state of converter from the generation unit of solar module. Through the duty cycle pulse from optimization function, the MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) of the Boost converter gets switched when BLDC (Brushless Direct Current Motor) motor drive system requires power. Voltage Source three phase inverter and Boost converter is controlled by proportional-integral (PI) controller. Based on the BLDC drive, the load utilized from the solar generating module. Experimental results analyzed every module of the proposed grid system, which are solar generation utilizes the irradiance and temperature depends on this the Photovoltaics (PV) power is generated and the QPSO with Duty cycle switching state is determined. The Boost converter module is boost stage based on generation and load is obtained. Single Ended Primary Inductor Converter (SEPIC) and Zeta converter model is compared with the proposed logic; the proposed boost converter achieves the results. Three phase inverter control, PI, and BLDC motor drive results. Thus the proposed grid model is constructed to obtain the better performance results than most recent literatures. Overall design model is done by using MATLAB/Simulink 2020a.     

基于K60和FPGA的四相交错并联Boost变换器效率优化设计

设计了一种基于K60单片机和FPGA为主控制器的四相交错并联Boost变换器,变换器可以根据输出电流的变化,自动改变工作相数,以提高变换器的效率.采用数字PID控制算法实现输出电压无静差调节,提高负载变化时电压调节的响应速度.设计了电压/电流采样电路、MOSFET驱动电路、存储电路以及软件控制策略,并制作了实验样机,对实验数据进行分析,验证了设计的可行性.     

LCC谐振变换器的优化设计与实现

LCC谐振变换器是电除尘高频高压电源的核心器件,十分适用于高压大功率场合,针对连续模式应用于电除尘高频高压电源的不足,采用LCC谐振变换器断续模式进行优化设计。分析了带RC负载的LCC谐振变换器断续模式(简称DCM)的工作原理及拓扑结构,采用状态空间法推导了其数学模型,研究并建立了新颖的LCC谐振变换器断续模式下的损耗模型。在此基础上提出了一种基于遗传粒子群算法的LCC谐振变换器优化设计方法,该方法直观并且准确,实现了软开关技术,提高了电源的工作效率。并在现场通过一台72KV/85KW的电除尘高频高压电源样机验证了本文的正确性。     

Decentralized adaptive neural network control of cascaded DC–DC converters with high voltage conversion ratio

Decentralized output voltage tracking of cascaded DC–DC converters is an interesting topic to obtain a high voltage conversion ratio. The control purpose is challenging due to the load resistance changes, renewable energy supply voltage variations and interaction of the individual converters. In this paper, four novel decentralized adaptive neural network controllers are designed on the cascaded DC–DC buck and boost converters under load and DC supply voltage uncertainties. In the beginning, individual buck and boost converter average models that can operate in both continuous and discontinuous conduction modes are derived. Then, the interconnected and decentralized state-space models of cascaded buck and boost converters are extracted. These models are highly nonlinear with unknown uncertainties which can be estimated by neural networks. Further, two decentralized adaptive backstepping neural network voltage controllers are proposed on cascaded buck converters to deal with uncertainties and interactions. However, these control strategies are not applicable to a boost converter due to its non-minimum phase nature. Then, two novel decentralized adaptive neural network with a conventional proportional–integral reference current generator are developed on the cascaded boost converters. Practical stability of the overall system is guaranteed for the proposed controllers using Lyapunov stability theorem. Finally, four control strategies provide good quality of output voltage in the presence of uncertainties and interactions. Comparative simulations are carried out on cascaded buck and boost converters to validate the effectiveness and performance of the designed methods.     

A new variable-mode control strategy for LLC resonant converters operating in a wide input voltage range

This paper proposes a new variable-mode control strategy that is applicable for LLC resonant converters operating in a wide input voltage range. This control strategy incorporates advantages from full-bridge LLC resonant converters, half-bridge LLC resonant converters, variable-frequency control mode, and phase-shift control mode. Under this control strategy, different input voltages determine the different operating modes of the circuit. When the input voltage is very low, it works in a full-bridge circuit and variable frequency mode (FB_VF mode). When the input voltage rises to a certain level, it shifts to a full-bridge circuit and phase-shifting control mode (FB_PS mode). When the input voltage further increases, it shifts into a half-bridge circuit and variable frequency mode (HB_VF mode). Such shifts are enabled by the digital signal processor (DSP), which means that no auxiliary circuit is needed, just a modification of the software. From light load to heavy load, the primary MOSFET for the LLC resonant converter can realize zero-voltage switching (ZVS), and the secondary rectifier diode can realize zero-current switching (ZCS). With an LLC resonant converter prototype with a 300 W rated power and a 450 V output voltage, as well as a resonant converter with 20–120 V input voltage, the experiments verified the proposed control strategy. Experimental results showed that under this control strategy, the maximum converter efficiency reaches 95.7% and the range of the input voltage expands threefold.