双向全桥DC-DC变换器的优化控制研究与实现

双向全桥DC-DC变换器是固态变压器的重要组成部分,双向全桥DC-DC变换器采用移相的控制方式,但简单的单移相控制方式下存在较大的回流功率,根据相关文献里提到的双重移相控制原理分析内移相占空比与传输功率和回流功率的关系。针对减小甚至消除回流功率这一目标,对内移相占空比进行优化计算。最后搭建实验样机,将单移相控制和优化控制进行实验对比,实验结果证实该优化方法正确性和可行性,具有一定应用价值。     

基于模糊PI的复合电源双向DC-DC变换器研究

针对电动汽车复合电源中基于传统PI的双重移相控制双有源桥DC-DC变换器在负载和输入电压出现扰动时存在动态响应速度慢和超调量大的缺陷,通过有机结合传统PI和模糊逻辑控制,提出基于模糊PI的双重移相控制策略。首先分析双重移相控制下变换器的具体工作过程和功率特性,然后阐述基于模糊PI的双重移相控制实现方式,并详细说明模糊PI控制器的设计方法。最后通过实验论证所提出的控制策略可以有效提高变换器的动态响应速度和鲁棒性,减小输出电压波动。     

双有源桥双向DC-DC变换器的多模式控制

双有源桥(Dual Active Bridge,DAB)双向DC-DC变换器能够双向传输功率,实现零电压开关(ZVS),且功率密度高,能够很好地应用到电力自动化设备中。文中详细介绍了DAB变换器的三种常见的控制方式,分别是移相控制、单PWM和双PWM控制。针对变换器存在低载运行时环路电流大、零电压开关范围受限制的缺点,提出一种多模式控制,拓宽了零电压开关的范围,降低了电流的有效值和峰值,使变换器效率提高。最后用MATLAB软件进行仿真,验证了方案的可行性。     

一种新型双向直流变换器拓扑与控制策略研究

随着农用可再生能源发电、分布式发电、微电网与智能电网技术的不断发展,对储能变流系统的要求也越来越高,其中大变压比高压双向直流变换器已成为储能变流的研究热点。针对传统的双向Buck/Boost DC-DC等非隔离型变换器变压比小、开关管电压应力大等缺点,提出了一种新型半桥三电平推挽式(half bridge TL push-pull)双向DC-DC变换器,它具有电气隔离,充放电均可实现两级变压来形成大变压比,开关器件少,且开关管电压应力仅为高压侧输入电压的一半并可实现软开关的优点。并对新型双向DC-DC变换器提出通过对蓄电池荷电状态(SOC)的检测与上位机的指令信号来控制实现双向DC-DC变换器工作模式的切换。并通过仿真实验验证新型双向变流器的可行性与优越性。     

一种固态变压器隔离级DAB变换器控制策略研究

固态变压器是一种将电力电子技术运用到电力变压器中的新型电气设备,固态变压器隔离级采用DAB变换器?适 用于大功率场合,易于实现零电压关联ZVS(Zero Voltage Switching),基于移相控制,通过改变移相占空比来调节传输功率和能量的流动方向,通过在闭环控制中引入补偿环节,消除了系统的静态误差,提高了动态响应速度,搭建仿真模型,验证了移相控制下DAB变换器的工作状态,通过基于 TMS320F28335的实验平台验证了DAB变换器能够实现直流变压功能,并且输出电压能够稳定在设定值,最终经逆变级产生了工频交流电压,验证了控制策略的有效性。     

基于STM32的Buck-Boost双向DC-DC变换器的研究

针对当前汽车电源系统中双向DC-DC（直流电转换为直流电）变换器存在的开关技术复杂、设计和制造成本大、测试和调整难度大、充放电效率低等问题，设计了一种基于SMT32双闭环控制的Buck-Boost（降压/升压）型的低成本直流变换器。首先，详细分析了Buck-Boost直流变换器的电路结构和充放电工作模式。其次，设计了双向DC-DC变换器总体电路图，并进行了比例-积分（PI）调节器参数选择。最后，通过MATLAB搭建了仿真模型。仿真结果表明，所采用的控制方法能很好地实现DC-DC变换器的功率变换，具有稳定性好、抗干扰能力强、响应速度快和效率高的特点，有望进一步降低汽车电源系统的成本。     

双向功率流电压型准Z源DC-DC变换器研究

为克服传统双向DC-DC变换器的不足,对一种新型的双向功率流电压型准Z源DC-DC变换器进行研究。该变换器是基于准Z源变换器的思想,其中双向功率开关由两个面对面连接的IGBT模块构成,通过PWM波形控制双向功率开关导通占空比,实现在单一拓扑结构下双向功率流传输的目的。该拓扑结构的优点是可以实现双向的升/降压输出,并且具有较宽的调压范围。首先应用saber软件对电路进行了仿真验证,然后进行实验验证,其结果证实了该电路拓扑的合理性和优越性。     

移相全桥软开关变换器的研究和设计

DC/DC变换器主要向着高效率、高功率密度、高质量输出和高可靠性方向发展.移相全桥软开关变换器的研究在这方面也显得较为突出.本文主要针对变换器的性能进行研究,设计一种能够实现升压的高效隔离DC-DC变换器,并使之广泛应用.     

基于GaN器件的有源箝位双向反激变换器设计

文章针对氮化镓(Gallium Nitride,GaN)功率晶体管在双向DC-DC变换器中的应用进行设计。近年来,第三代宽禁带功率半导体器件GaN凭借其体积小、高频、高效率等优势,在电力电子应用中得到了广泛的关注。为实现双向DC-DC变换器在便携式小功率应用场景下的能量双向高效传输,设计了一种基于GaN器件的有源箝位双向反激变换器并对其性能进行了验证。详细地介绍和分析了变换器的工作原理、开关模态以及软开关实现条件,并对主电路参数进行设计。采用LTspice软件搭建仿真模型,仿真结果验证了该变换器在小功率应用下可实现开关管软开关性能。最后,设计了一个20 W的实验样机验证了所设计拓扑的准确性和有效性,结果表明该变换器较传统Si MOSFET器件具有更高的转换效率。     

最大功率跟踪控制在光伏系统中的应用

对最大功率跟踪控制中DC-DC变换器的原理和控制方法进行了实验研究,利用DC-DC转换电路和单片机控制系统实现最大功率点跟踪,使太阳电池始终保持最大功率输出;和普通的控制器相比增加输出功率5％～15％。     

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。     

Predictive Approach to Increase Efficiency and Reduce Switching Losses on Matrix Converters

The matrix converter stands as an alternative in power conversion. It has no energy storage devices, performing the energy conversion by directly connecting input with output phases through bidirectional switches based on power semiconductors, allowing high-frequency operation. For this reason, it is known as the all-silicon power converter, featuring reduced size and weight. Forced commutations of the high number of semiconductors cause switching losses that reduce the efficiency of the system and imply the use of large heat sinks. This paper presents a novel method to reduce switching losses based on predictive control. The idea is to predict switching losses for every valid switching state of the converter, if applied during the next sampling time, and then, select the optimum state based on an evaluation criterion. The proposed strategy was experimentally tested on an 18-kVA matrix converter driving an 11-kW induction machine, reducing energy losses and increasing efficiency up to 3% compared to the basic strategy. As a consequence, the converter misuses less energy and requires smaller heat sinks.     

A fault-tolerant strategy based on SMC for current-controlled converters

The sliding mode control (SMC) is used to control variable structure systems such as power electronics converters. This paper presents a fault-tolerant strategy based on the SMC for current-controlled AC–DC converters. The proposed SMC is based on three sliding surfaces for the three legs of the AC–DC converter. Two sliding surfaces are assigned to control the phase currents since the input three-phase currents are balanced. Hence, the third sliding surface is considered as an extra degree of freedom which is utilised to control the neutral voltage. This action is utilised to enhance the performance of the converter during open-switch faults. The proposed fault-tolerant strategy is based on allocating the sliding surface of the faulty leg to control the neutral voltage. Consequently, the current waveform is improved. The behaviour of the current-controlled converter during different types of open-switch faults is analysed. Double switch faults include three cases: two upper switch fault; upper and lower switch fault at different legs; and two switches of the same leg. The dynamic performance of the proposed system is evaluated during healthy and open-switch fault operations. Simulation results exhibit the various merits of the proposed SMC-based fault-tolerant strategy.     

风力发电系统变流器的直接功率控制策略

以永磁直驱型风力发电系统为研究对象,针对其变流器结构和控制策略进行了研究。通过选择最优双PWM“背靠背”变流拓扑结构,并采用直接功率控制策略进一步提高了风力发电系统的并网性能。建立了输出功率为10 kW的并网系统仿真模型,验证控制策略的正确性。结果表明,基于直接功率控制策略的“背靠背”变流拓扑具有结构合理、控制策略新颖的优点,在保证直流侧电压稳定的同时,电网电流谐波畸变率低、波形良好,能够实现单位功率因数并网,满足并网要求。     

新颖的含PFC的PWM ZVS AC-DC变换器

提出了一种新的具有功率因数补偿(PFC)功能的零电压开关(ZVS)AC-DC变换器,该变换器基于不连续导电模式(DCM)下的Boost环节实现PFC功能,但其具有ZVS机制,从而解决了DCM下因开关关断大的峰值电流引起的关断损耗高、EMI严重的问题,同时还消除了由于开关的寄生电容引起的开通损耗.该变换器可以采用通用控制芯片并工作在PWM模式.文中分析了提出变换器的工作原理,并给出了基本设计原则.模拟和实验结果证明了提出的电路是可行的.     

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.     

Sliding mode based powertrain control for efficiency improvement in series hybrid-electric vehicles

This study involves the improvement of overall efficiency in series hybrid-electric vehicles (SHEVs) by restricting the operation of the engine to the optimal efficiency region, using a control strategy based on two chattering-free sliding mode controllers (SMCs). One of the designed SMCs performs engine speed control, while the other controls the engine/generator torque, together achieving the engine operation in the optimal efficiency region of the torque-speed curve. The control strategy is designed for application on a SHEV converted from a standard high mobility multipurpose wheeled vehicle (HMMWV) and simulated by using the Matlab-based PNGV Systems Analysis Toolkit (PSAT). The performance of the control strategy is compared with that of the original PSAT model, which utilizes PI controllers, a feedforward term for the engine torque, and comprehensive maps for the engine, generator and power converter (static only), which constitute the auxiliary power unit (APU). In this study, in spite of the simple modeling approach taken to model the APU and the optimal efficiency region, an improved performance has been achieved with the new SMC based strategy in terms of overall efficiency, engine efficiency, fuel economy, and emissions. The control strategy developed in this work is the first known application of SMC to SHEVs, and offers a simple, effective and modular approach to problems related to SHEVs.     

电动汽车电机驱动系统效率优化控制

针对电动汽车专用PMSM控制系统的动态损耗问题,提出了一种改进的效率优化策略。分析了PMSM损耗模型,推导出系统损耗和定子磁链的关系,得到最优磁链与定子电阻相关。基于小波神经网络的动态定子电阻补偿方法,进而解决了由于最优磁链受动态定子电阻影响使得最优磁链难以准确计算的问题,以使电机驱动系统效率最佳。利用Matlab/Simulink仿真软件建立了系统模型,仿真结果证明,该策略能有效提高电动汽车驱动系统的效率。     

Transformer‐Reuse Reconfigurable Synchronous Boost Converter with 20 mV MPPT‐Input, 88% Efficiency,and 37 mW Maximum Output Power

This paper presents a transformer‐based reconfigurable synchronous boost converter. The lowest maximum power point tracking (MPPT)‐input voltage and peak efficiency of the proposed boost converter, 20 mV and 88%, respectively, were achieved using a reconfigurable synchronous structure, static power loss minimization design, and efficiency boost mode change (EBMC) method. The proposed reconfigurable synchronous structure for high efficiency enables both a transformer‐based self‐startup mode (TSM) and an inductor‐based MPPT mode (IMM) with a power PMOS switch instead of a diode. In addition, a static power loss minimization design, which was developed to reduce the leakage current of the native switch and quiescent current of the control blocks, enables a low input operation voltage. Furthermore, the proposed EBMC method is able to change the TSM into IMM with no additional time or energy loss. A prototype chip was implemented using a 0.18‐μm CMOS process, and operates within an input voltage range of 9 mV to 1 V, and an output voltage range of 1 V to 3.3 V, and provides a maximum output power of 37 mW.     

Spectral and energy efficient cognitive radio‐aided heterogeneous cellular network with uplink power adaptation

In future heterogeneous cellular networks, cognitive radio compatible with device to device communication technique can be an aid to further enhance system spectral and energy efficiency. The unlicensed smart devices (SDs) are allowed to detect the available licensed spectrum and utilise the spectrum resource which is detected as not being used by the licensed users. In this work, we propose such a system and provide comprehensive analysis of the effect of selection of SDs' frame structure on the energy efficiency, throughput and interference. Moreover, uplink power control strategy is also considered where the licensed users and SDs adapt the transmit power based on the distance from their reference receivers. The optimal frame structure with power control is investigated under high‐signal‐to‐noise ratio (SNR) and low‐SNR network environments. The impact of power control and optimal sensing time and frame length, on the achievable energy efficiency, throughput and interference are illustrated and analysed by simulation results. It has been also shown that the optimal sensing time and frame length which maximizes the energy efficiency of SDs strictly depends on the power control factor employed in the underlying network such that the considered power control strategy may decrease the energy efficiency of SDs under very low‐SNR regime. Copyright © 2016 John Wiley & Sons, Ltd.