超宽带大功率合成器设计北大核心CSCD

在80 MHz~1 GHz频段,单个功率管输出功率能达到100 W以上,为研制输出功率400 W的功率放大器,文中设计了四路功率合成器。该合成器需要实现功率容量大、工作频带宽、体积小的设计目标。在功率容量方面,文中采用悬置带状线结构,其功率容量远远大于微带线结构;在工作频带方面,采用切比雪夫九节阻抗变换器,将工作带宽拓宽为80 MHz~1 GHz;在体积方面,文中合成器的功率合成部分采用Y型节级联实现四路功率合成,阻抗变换部分采用切比雪夫阻抗变换器进行阻抗变换,该结构相较于磁环巴伦功率合成器,不但具有损耗小、平坦度高的优点,而且通过将阻抗变换器设计成曲折的形状,进一步缩小了合成器体积。仿真与实测结果显示该合成器在80 MHz~1 GHz范围内还具有较高的平坦度,合成效率可达90%以上。     

An active balancer with rapid bidirectional charge shuttling and adaptive equalization current control for lithium-ion battery strings

This article proposes an active balancer, which features bidirectional charge shuttling and adaptive equalization current control, to fast counterbalance the state of charge (SOC) of cells in a lithium-ion battery (LIB) string. The power circuit consists of certain bidirectional buck-boost converters to transfer energy among the different cells back and forth. Owing to the characterization of the open-circuit voltage (OCV) vs SOC in LIB being relatively smooth near the SOC middle range, the SOC-inspected balance strategy can achieve more precise and efficient equilibrium than the voltage-based control. Accordingly, a compensated OCV-based SOC estimation is put forward to take into account the discrepancy of SOC estimation. Besides, the varied-duty-cycle (VDC) and curve-fitting modulation (CFM) methods are devised herein to tackle the problems of slow equalization rate and low balance efficacy, which arise from the diminution in balancing current as the SOC difference between the cells decreases in the later duration of equalization especially. The proposed strategies have taken the battery nonlinear characteristic and circuit parameter nonideality into account and can adaptively modulate the duty cycle with the SOC difference to keep balancing current constant throughout the balancing cycle. Simulated and experimental results are given to demonstrate the feasibility and effectiveness of the same prototype constructed. Compared with the fixed duty cycle and the VDC methods, the proposed CFM has the best balancing efficiency of 81.4%, and the balance time is shortened by 27.1% and 18.6%, respectively.     

用于电弧检测的电力专用SoC设计

针对传统的电弧电路故障检测结果不准确的问题,设计用于电弧检测的SoC系统,并且在55nm工艺下进行流片验证。采用包含两种结构的模数转换器的片上电压源,设计了锁相环以及复位电路,精度最高可达8.67 bit。验证结果表明,本设计可提高电弧检测的准确性。     

Single-switch boost-buck DC-DC converter for industrial fuel cell and photovoltaics applications

The realization of dc-dc converters performs a vital function in exploiting renewable energy sources such as solar photovoltaic (PV) and fuel cell applications. This paper demonstrates a single-switch unidirectional buck-boost dc-dc converter for continuous power flow control, excluding the hybrid switched-capacitor. The proposed converter utilizes a limited number of passive components, only four diodes and three inductors required, in addition to six capacitors. The converter can operate at a wide input voltage range with continues input current. The converter has experimented under real-time conditions with 660 W PV system. The obtained efficiency ranges from 93% to 98%. Furthermore, the converter has interfaced with 550 W fuel cell operated under different fuel pressure. The realized efficiency ranges from 91% to 97%. The maximum measured inductance current ripple is limited to under 0.70 A in both scenarios, whereas 0.16 V is the maximum output voltage ripple.     

基于平均功率平衡控制的磁悬浮分子泵电力失效补偿方法

高速磁悬浮涡轮分子泵（Turbo Molecular Pump, TMP）因其高能量密度、微振动、无需润滑等优点被广泛应用于工业领域，但外部电源失效时，高速转子跌落后与保护轴承产生剧烈撞击和摩擦，将给系统带来致命损害。针对以上问题，提出一种基于平均功率平衡法的电力失效补偿控制（Power Failure Compensation Control, PFCC）方法。首先，设计电机能量回馈电路；其次，对Buck-Boost变换器进行数学建模，设计一种双环非线性控制器，其中电流内环使用滑模控制，电压外环使用平均功率平衡控制（Average Power Balance Control, APBC），并利用Lyapunov函数推导出系统的稳定性条件；最后，通过搭建磁悬浮分子泵PFCC实验平台，对所提出的方法进行实验验证。结果表明：本文所提出的方法具有快速响应和输出鲁棒性，磁悬浮转子由额定转速21000 r/min降至3900 r/min时跌落，电机能量转化效率为96.6%，提高了磁轴承系统的安全性。     

Reduced‐order method for mathematical modeling of multiphase dc‐dc converter

A multiphase dc‐dc converter is effective for miniaturization and achieving high‐power density in a switching power supply. However, its mathematical modeling becomes complex as the phase number of the circuit increases. This study proposes a new modeling method to derive a reduced‐order method in a simple manner. The frequency characteristics of the reduced‐order model are fit to those of the original mathematical model of the multiphase dc‐dc converter. Therefore, the efficacy of the proposed method is validated.     

双发单收谐振型电磁波测井线圈系刻度方法研究

增大源距是提高随钻电磁波电阻率测井仪器探测深度的有效方法，但是接收信号随源距增大严重衰减。本文将谐振原理引入随钻电磁波电阻率测井，采用双发单收谐振型线圈系结构，提高接收线圈的电压幅度。实验室通常采用刻度环模拟地层电导率，开展仪器响应特性研究。双发单收谐振型线圈系的刻度方法与传统的开路线圈系结构完全不同。本文基于DOLL几何因子理论，对双发单收谐振型线圈系刻度环参数选择方法进行研究，发现参数选择应该兼顾相对平稳度与刻度环电阻分辨度，以减小测量误差。实验比较了均匀地层中接收线圈开路和谐振响应特性，表明谐振方法只增大了接收响应的幅值而没有改变幅度比，验证了刻度环参数选择方法的正确性以及谐振方法的正确性。     

共轴非平行非对称线圈结构对MCR-WPT效率的影响

磁耦合谐振式无线电能传输是一种全新的电能传输方式,为工业、生活及医疗等领域带来了极大便利。但传统的对称线圈结构已制约了无线输电技术在矿井、医疗等具有特殊需求领域的应用。综合前人提出的共轴非平行结构及非对称线圈结构的无线输电系统,分析了两共轴非平行线圈传输距离半径比、线圈半径比与偏移角对无线电能传输效率的影响,并分析了各因素对效率的相互影响。仿真结果显示传输距离半径比越大效率保持基本不变的偏移角度范围越小,偏移角对传输效率的影响越平缓。随传输距离半径比的增加效率先增加后逐渐降低,偏移角度在80°附近时,传输距离半径比对效率的影响最大。线圈半径比对传输效率的影响与偏移角度、传输距离等有关。试验验证了该理论分析的正确性,为研究复杂环境下的无线电能传输提供了理论基础,也为进一步开发无线电能传输系统提供了参考。     

计及RSC控制的DFIG短路电流直流分量解析表达

现有文献针对计及转子变流器(RSC)控制的双馈感应风电机组(DFIG)定子短路电流解析表达,将定子磁链当作一阶直流衰减分量或忽略功率外环控制。基于DFIG电压、磁链和RSC控制方程,得到定子电流关于定子电压和定子功率的传递函数,提出定子电流的精确解析表达式。基于RSC内、外环PI参数关系,推导直流分量衰减时间常数和角频率关于PI参数的表达式。分析了RSC内外环PI参数对定子电流直流衰减分量的影响。仿真结果验证了解析表达式的准确性,为PI参数选取和保护装置测量、整定提供依据。     

Performance enhancement of energy extraction capability for fuel cell implementations with improved Cuckoo search algorithm

This paper addresses an improved optimization method to enhance the energy extraction capability of fuel cell implementations. In this study, the proposed method called Dynamic Cuckoo Search Algorithm (DCSA) is tested in a stand-alone fuel cell in order to control the system power under dynamic temperature response. In the operational process, a fuel cell is connected to a load through a dc-dc boost converter, and DCSA is utilized to adjust the switching duration in dc-dc converter by using voltage, current and temperature parameters. In this way, it controls the output voltage to maximize power delivery capability at the demand-side and eliminates the drawback of conventional cuckoo search algorithm (CSA) which cannot change duty cycle under operating temperature variations. In this regard, DCSA shows a significant improvement in terms of system response and achieves a more efficient power extraction than the conventional CSA method. In order to demonstrate the system performance, the stand-alone fuel cell system is constructed in Simulink environment via a processor-in the-loop (PIL) based digital implementation and analyzed by using different optimization methods. In the analysis section, the results of the proposed method are compared with conventional methods (perturb&observe mppt, incremental conductance mppt, and particle swarm optimization). In this context, convergence speed and efficiency analysis for both methods verify that the DCSA gives original results compared to conventional methods.