基于TOPSwitch-JX的宽输入范围精密仪表电源设计

为提高仪表电源的性能,保证仪表正常、稳定地工作,设计了一种宽输入电压范围的精密仪表电源。本系统以新型电源转换芯片TOPSwitch-JX为核心,设计反激式电路结构,并采用钳位式的RCD缓冲电路吸收剩磁能量,减小输出纹波和噪声,以提高电源转换效率。同时,设计了5绕组式的高频变压器,实现了3路电压隔离输出。实验结果表明,该电源具有工作稳定、输出纹波小、输入电压范围宽的优点,适合于作为精密仪表电源,可以广泛地推广和应用。     

A wide range delay locked loop for low power and low jitter applications

In this paper, a design of analog delay locked loop is introduced in which new techniques are applied to eventually increase operating frequency range and reduce jitter considerably. In this design, all blocks of a delay locked loop including a voltage controlled delay line, charge pump, and loop filter are accurately designed. A new delay cell is proposed with wide delay range, in which increase of delay range results in using fewer cells, and consequently the power consumption will decrease. Current mirror techniques and feedback in the proposed charge pump also cause higher current matching and better jitter performance. This delay locked loop, which is designed with TSMC 0.18‐μm CMOS technology, has a wide frequency range from 217 to 800 MHz. It consumes maximum 3.4‐mW and minimum 2.6‐mW power dissipation in source voltage of 1.8 V, which is suitable for low power applications. It also has an appropriate lock time that is at least equal to 3 clock cycles at 217 MHz and at most 25 clock cycles at 800 MHz. Jitter performance in this delay locked loop is improved significantly: RMS jitter is 0.65 ps at 800 MHz and 2.54 ps at 217 MHz. Moreover, its maximum peak‐to‐peak jitter is equal to 5.17 ps, and its minimum peak‐to‐peak jitter is equal to 1.39 ps at 217 and 800 MHz, respectively.     

一种宽范围双管反激DC/DC辅助电源设计

宽范围DC/DC辅助电源是高电压大容量电力电子变流系统的重要组成部分,尤其是对于具有标准化、模块化、分布式结构的中高压大容量电力电子变流系统意义更重大。首先,基于双管反激电路,设计制作了一个宽范围高电压80~800 V输入/低电压24 V输出的辅助电源样机,针对常规双管反激电源反馈电路存在的问题,进行了详细分析并提出解决方法;其次,给出了实验波形,对实验波形中的尖峰及震荡现象进行定性分析并给出解决思路;最后,利用闭环系统的开环传递函数对双管反激电路进行了稳定性分析。     

Process variation compensation technique for voltage‐controlled ring oscillator

A voltage‐controlled ring oscillator with process variation compensation circuits is designed using 0.25 µm CMOS technology. The simulation results show that the proposed ring oscillator increases the guaranteed frequency tuning range by 12% compared to a conventional ring oscillator. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

一种新型变频控制的超宽输入辅助电源

在纯电动汽车、光伏发电等特殊系统中,往往需要宽电压输入的开关电源,而采用一般的反激变换拓扑结构很难实现稳定的输出。为此,设计了一种基于新型变频技术的双管反激式开关电源。该变频技术利用输入电压的变化来改变系统振荡频率,从而有效地拓宽了输入电压的变化范围。经过测试,设计的开关电源输入电压范围约为120~850 V,可输出稳定的24 V电压。实测结果表明,所设计的电源具有电压波纹小、调整率低、性能稳定、成本低等特点,可应用于超宽输入电压范围的电源中。     

基于碱性电解槽宽功率适应模型的风光氢热虚拟电厂 容量配置与调度优化

为提高能源利用效率,降低碳排放水平,改善虚拟电厂运行效益,构建了基于碱性电解槽宽功率适应模型的风光氢热虚拟电厂(Virtual Power Plant, VPP)模型。将制氢电解槽、氢燃料电池、储氢罐构成氢能系统,代替传统虚拟电厂中的蓄电池,并提出碱性电解槽宽功率适应模型,提高电解槽在不同输入功率条件下的适应性。利用氢能系统运行时产生热量对系统负荷实行热电联供,并将电解槽产生氧气出售。在此基础上,使用改进多路无网格光线寻优算法对各设备出力调度与设备容量配置进行优化。仿真结果表明,该算法在计算精度和速度上有一定提高。基于碱性电解槽宽功率适应模型的风光氢热VPP,在降低系统运行成本的同时可以有效应对风、光出力波动,提高风、光消纳水平,减少碳排放。     

A CCII‐based wide frequency range square waveform generator

In this paper, we propose a novel current‐mode solution suitable for the square waveform generation. The designed oscillator, which utilizes only two positive second‐generation current conveyors as active blocks, six resistors and a capacitor, is based on a current differentiation, instead of voltage integration, typical of developed solutions both in voltage‐mode and in current‐mode approaches, so avoiding circuit limitations due to the node saturation effects. The proposed circuit has been designed, as an integrated solution at transistor level, in a standard CMOS technology, with low‐voltage (± 1V) and low‐power (430µW) characteristics. Simulation results have confirmed the good circuit behaviour, also for working temperature drifts, showing good linearity in a wide oscillation frequency range, which can be independently adjusted through either capacitive (in the range pF ? µF) or resistive (in the range M Ω–G Ω) external passive components. Waiting for the chip fabrication, preliminary measurements have been performed using a laboratory breadboard employing the CCII with AD844 commercial component and sample capacitors and resistors. The experimental results have shown good agreement with both simulations and theoretical expectations. Copyright © 2011 John Wiley & Sons, Ltd.     

光伏发电系统宽电压开关变换器参数设计

光伏电池输出电压特性较软使得系统中DC-DC开关变换器需要有宽范围的工作电压,而开关变换器参数合理设计是其安全可靠工作的前提条件。本文以独立光伏发电系统中广泛应用的Buck-Boost变换器为例,分析了其工作原理,讨论了电感和电容对变换器工作模式和输出纹波电压的影响。在此基础上给出了宽输入和宽输出电压范围的电感、电容参数设计方法。通过仿真分析,验证了宽电压范围Buck-Boost变换器参数设计的合理性。     

Low‐power quadrature generators for body area network applications

This paper presents different alternatives for the implementation of low‐power monolithic oscillators for wireless body area networks and describes the design of two quadrature generators operating in the 2.4‐GHz frequency range. Both implementations have been designed in a 90‐nm Complementary Metal‐Oxide Semiconductor (CMOS) technology and operate at 1 V of supply voltage. The first architecture uses a voltage‐controlled oscillator (VCO) running at twice the desired output frequency followed by a divider‐by‐2 circuit. It experimentally consumes 335 μW and achieves a phase noise of ?110.2 dBc/Hz at 1 MHz. The second architecture is a quadrature VCO that uses reinforced concrete phase shifters in the coupling path for phase noise improvement. Its power consumption is only 210 μW, and it obtains a phase noise of ?111.9 dBc/Hz at 1 MHz. Copyright © 2011 John Wiley & Sons, Ltd.     

An adaptive limited wide area differential protection for power grid with microsources

The operation mode of power grids with intermittent distributed generations (DGs) changes frequently due to the bidirectional power flow. In comparison with the conventional grids, the protection relays in power grids with micro-sources are more difficult to set. To tackle this problem, this paper proposes an extended bus differential protection (EBDP) strategy based on the limited wide area (LWA). In this method, the micro-grids are divided into several protection areas at the core of the bus. The whole protection areas are protected by the wide area current differential relays, which are also configured to protect each component in this protection area. Moreover, the protection areas can be changed adaptively according to the power flow direction. Finally, a micro-grid model with multiple DGs is developed using the PSCAD/EMTDC platform. The simulation results indicate that the proposed adaptive limited wide area differential protection (LWADP) has better performance than the traditional relaying protection in detecting the faulty area in micro-grids and isolating the fault, and can be widely utilized in larger micro-grids.     

An adaptive limited wide area differential protection for power grid with microsources

The operation mode of power grids with intermittent distributed generations (DGs) changes frequently due to the bidirectional power flow. In comparison with the conventional grids, the protection relays in power grids with micro-sources are more difficult to set. To tackle this problem, this paper proposes an extended bus differential protection (EBDP) strategy based on the limited wide area (LWA). In this method, the micro-grids are divided into several protection areas at the core of the bus. The whole protection areas are protected by the wide area current differential relays, which are also configured to protect each component in this protection area. Moreover, the protection areas can be changed adaptively according to the power flow direction. Finally, a micro-grid model with multiple DGs is developed using the PSCAD/EMTDC platform. The simulation results indicate that the proposed adaptive limited wide area differential protection (LWADP) has better performance than the traditional relaying protection in detecting the faulty area in micro-grids and isolating the fault, and can be widely utilized in larger micro-grids.     

基于风险的电力系统低电压安全预警

分析了电力市场环境下传统的电力系统电压安全评估方法的缺点,提出了基于风险的电力系统低电压安全预警。该方法充分考虑了事故发生的可能性和事故发生对系统电压造成的后果,综合得出了系统的低电压风险值,根据该风险值对系统的电压安全情况进行了分级预警。IEEE30节点的仿真算例说明了该方法的有效性。     

一种风电机组在低风速区间的功率控制方法

由于在低风速区间风速变化较快、风能密度较低,因此对风电机组的功率转换效率造成了较大影响。针对风电机组在低风速区域的运行特点,从功率控制角度出发,以提高风电机组功率输出效率为目的,采用最大功率点跟踪控制策略(MPPT)实现对风能最大限度的捕获,提出了大范围快速对焦最优转速的控制策略。与传统爬山法相比,该方法具有寻优速度快、精确度高、简单易行的优点。在Power Simulation(PSIM)环境中仿真分析,研究结果表明:该控制策略对提高机组稳定性和功率转换效率具有一定的价值。     

低压电力线通信技术的发展及应用

简要分析了低压电力线的传输特性,并针对当前国内、外电力线通信技术的研究及发展状况,提出了电力线扩频通信技术的一些应用。     

A large dynamic range voltage controlled attenuator with improved linearity-in-dB for ultrasound applications

A large dynamic range (DR) and high linearity-in-dB voltage controlled attenuator (VCAT) for ultrasound applications was presented. Continuous tunable VCAT implemented with Metal-Oxide-Semiconductor (MOS) transistors used as shunt devices was proposed in this work, and the linearity-in-dB performance was analyzed in detail. Nonlinearity of the shunt transistors operated in different regions resulted in poor linearity-in-dB attenuation of the VCAT, which was undesirable in an ultrasonic receiver system. An effective linearity-in-dB improvement scheme was then proposed. The full scale range of the input control voltage was divided into N intervals with a same equal-length by uniformly distributed voltage values. At these division voltages, the attenuation gains were corrected to be the ideal ones by the tracing and comparing circuits. In this way, the non-linearity-in-dB was limited to the intervals between the two adjacent corrected attenuation gains, and the overall linearity of the VCAT was improved greatly. Measurement results showed that the dynamic range of the proposed attenuator was 36-dB, and the gain errors were in a range from − 1.22 to − 0.55 dB. The noise figures (NF) at the commonly used ultrasonic frequencies was below 6-dB, and the S11 was better than − 10 dB over the input range of the control voltage.     

采用广域测量信号的PSS参数优化设计

为了解决传统的电力系统稳定器PSS(Power System Stabilizer)因局限于反馈本地信号而不能很好地抑制区域模式的问题,针对区域模式装设引入广域测量信号的PSS,针对地区模式装设引入本地信号的PSS。根据参与因子确定PSS装设地点,然后应用遗传算法对其参数进行协调。由于PSS反馈远方信号,设计时考虑了通信延迟的影响。算例表明,提出的方案能够较好地抑制低频振荡。     

一种多层Hybrid Ring结构功分器/合路器的设计

针对传统的高功率功分器易烧毁和相位差较大等性能的缺点,提出了一种能够承受高功率和更好性能的多层Hybrid Ring结构四路功分器的设计。避免了传统威尔金森功分器在输入功率不平衡时,烧毁隔离电阻,从而导致整个发射系统崩溃的现象发生,同时还显示较好的相位一致性。从而提高了整个功放系统的稳定性和技术指标。通过实际测试得到在1~3 GHz的频率范围,四路功分/合路器插入损耗低于6.3 dB,相移精度小于+/?0.3o,驻波比小于1.3的较好实验结果,它能够广泛应用到无线通讯和相控阵雷达组件中,具有很高的应用价值。     

低压电力线通信组网性能优化方法

低压电力线载波通信介质访问控制(MAC)接入协议是影响组网性能的重要因素之一。针对低压电力线通信信道非对称性导致组网性能相对较低的问题,提出面向低压电力线通信改进人工蛛网荷载受限的改进型自适应p-坚持载波侦听多路访问(CSMA)优化方法。详叙了低压配电网物理拓扑映射为改进人工蛛网逻辑拓扑的组网过程;运用所提方法对改进人工蛛网的吞吐量、分组传输时延进行优化,即根据已知参与信道竞争的活跃节点数,动态调整接入概率,控制节点发送数据分组行为,使信道处于最佳传输状态,保证了组网性能。仿真结果验证了所提方法的有效性。     

中低压电网过电压的产生及限制方法

电力系统过电压危害性较大，一旦发生，往往造成电气设备损坏和大面积的停电事故。本文针对电网中中低压侧中性点接地方式的运行状况，分析了系统产生过电压的各种原因，并提出了电网中过电压的限制方法。     

基于进化策略并考虑宽频段补偿的PSS参数优化

将进化策略结合PSS宽频段补偿特性的方法应用到多机电力系统稳定器(PSS)参数优化。考虑到一种运行方式配置的PSS可能在其他运行方式下失效或恶化,以PSS在低频振荡范围内(0.1～2Hz)产生的附加阻尼转矩△Te与△ω尽可能同相位为目标优化超前-滞后环节参数;再以多机PSS在整个系统内产生的最小阻尼比尽量大为目标进行全局优化。New England 10机系统仿真结果表明,这是一种有效的PSS参数优化方法,所得到的参数优化结果对系统运行方式变化有很好的鲁棒性。