A high efficiency input/output magnetically coupled interleaved buck–boost converter with low internal oscillation for fuel-cell applications: Small signal modeling and dynamic analysis

Dynamic behavior of DC–DC converters plays a crucial role in stability of renewable energy exploitation systems. This paper presents small signal modeling of an input/output magnetically coupled interleaved buck–boost converter for fuel-cell applications to help the designers with the better understanding of converter dynamics. Aiming to have a continuous converter transfer function for a smooth transition between the operation modes and an improved inner dynamics, a damping network and an input/output coupling have been added to the interleaved structure of well-known cascaded buck–boost converter. Having the same step-up/step-down voltage transfer ratio, smooth transition and improved inner dynamics make this converter quite suitable for renewable energy applications. The paper presents a small signal ac equivalent circuit model of the proposed converter based on state space averaging (SSA) method. Simulation results show remarkable improvements in converter dynamic behavior in both time and frequency domains. Prototype setup of 360 W and 36 V output voltage for a fuel cell with a brand of “FCgen 1020ACS” Ballard Power Systems, Inc. was implemented. Experimental results are presented to verify the theoretical model and its expected merits.     

一种新型非谐振型软开关交错并联Boost电路

提出一种新型非谐振型交错并联Boost零电压转换(ZVT)电路。在传统交错并联Boost拓扑基础上添加了一组由一个电感、两个电容、一个开关管、四个二极管组成的辅助网络,令主开关管实现了零电压开通与关断,辅助开关管实现了零电流开通与部分零电压关断,降低了开关损耗,提升了电路变换效率。软开关可在宽工作范围内有效实现,电路工作在连续电流模式(CCM),控制方式简明易行,辅助网络的引入没有给主开关管带来额外电流应力。通过复用部分辅助元件,提高了辅助网络利用率,减少了体积与费用;降低了开关过程中的dv/dt、di/dt,抑制了开关噪声。详细分析了电路拓扑结构、工作原理,并对主要参数进行了优化选取,最后通过实验验证了理论分析的正确性。     

Improving energy efficiency using a link adaptation algorithm dedicated for 100 Gbps wireless communication

This paper presents a link adaptation algorithm dedicated for 100 Gbps wireless transmission. Interleaved Reed-Solomon codes are selected as forward error correction (FEC) algorithms. The redundancy of the codes is selected according to the channel bit error rate (BER). The uncomplicated FEC scheme allows implementing a complete data link layer processor in an FPGA (field programmable gate array). In our case, we use the Virtex7 FPGA to validate the functionality of our implementation. The proposed FPGA-processor achieves 169 Gbps throughput. Moreover, the implementation is synthesized into 40 nm CMOS technology and the described link adaptation algorithm allows reducing consumed energy per bit to values below 1 pJ/bit at BER <1e−4. With higher BER, the energy increases up to ∼13 pJ/bit.     

Fabrication and characterization of a planar interleaved micro-transformer with magnetic core

This paper presents the design, the fabrication and the characterization of a planar interleaved micro-transformer with an Yttrium Iron Garnet (YIG) core. The design of this micro-transformer and the manufacturing steps are presented. HFSS software is used for the conception and the simulation of the interleaved magnetic micro-transformer. It is composed of two identical windings. A bottom magnetic core is used to improve the integrated transformer performances. To form the windings, we have used a surface micromachining process. We have also used a negative photoresist (SU-8) as an insulating layer and as support for the fabrication of a bridge to connect the central end of the coils to the ground shield. The micro-transformer have been characterized with impedance meter up to 100 MHz, and completed to 1 GHz using vector network analyzer.     

稳健的高效MIMO检测器

无偏最小均方误差迭代树搜索(MMSE-ITS)检测器是目前性能最好的多输入多输出(MIMO)检测器之一。该文通过选择性地扩展部分长度路径和添加一位互补矢量,对无偏MMSE-ITS检测器作了改进。仿真和分析结果表明,和无偏MMSE-ITS检测算法相比,改进算法能以相对较低的处理复杂度获得更好的检测性能。另外,改进的检测器彻底避免了削剪处理,对MIMO信道状况具有较好的适应性,稳健性较强。     

一种交错并联电路的控制部分设计

本文介绍了UC3846的工作原理，设计了一种采用晶振、反相器、脉冲计数器与UC3846一起产生频率的交错并联控制电路。     

Robust optimal output voltage tracking algorithm for interleaved N-phase DC/DC boost converter with performance recovery property

This article suggests a cascade output voltage regulation algorithm for an N-phase interleaved DC/DC boost converter based on reference dynamics. The proposed algorithm has two advantages. The first is to guarantee the performance recovery property using the reference dynamics in the presence of a model-plant mismatch, and the second is to present a systematic procedure determining the stabilising control gains by solving an optimisation problem. The closed-loop performance of the proposed method is evaluated through simulations and experiments using a 3-kW four-phase interleaved DC/DC boost converter where the proposed method is compared with the feedback linearising method.     

Architectural support for inter-stream communication in an MSIMD system

This paper considers hardware support for the exploitation of control parallelism on data parallel architectures. It is well known that data parallel algorithms may also possess control parallel structure. However, the splitting of control leads to data dependency and synchronization issues that were implicitly handled in conventional SIMD architectures. These include synchronization of access to scalar and parallel variables, and synchronization for parallel communication operations. We propose a sharing mechanism for scalar variables and identify a strategy which allows synchronization of scalar variables between multiple streams. The techniques considered are based on a bit-interleaved register file structure which allows fast copy between register sets. Hardware cost estimates and timing analyses are provided, and comparison with an alternate scheme is presented. The register file structure has been designed and simulated for the HP 0.8μm CMOS process, and circuit simulation indicates access times are less than six nanoseconds. In addition, the impact of this structure on system performance is also studied.     

Quantitative T 2 measurement of a single voxel with arbitrary shape using pinwheel excitation and CPMG acquisition

Objective The aim of this study is to present a new approach for making quantitative single-voxel T ₂ measurements from an arbitrarily shaped region of interest (ROI), where the advantage of the signal-to-noise ratio (SNR) per unit time of the single-voxel approach over conventional imaging approach can be achieved. Materials and methods Two-dimensional (2D) spatially selective radiofrequency (RF) pulses are proposed in this work for T ₂ measurements based on using interleaved spiral trajectories in excitation k-space (pinwheel excitation pulses), combined with a summed Carr–Purcell Meiboom–Gill (CPMG) echo acquisition. The technique is described and compared to standard multi-echo imaging methods, on a two-compartment water phantom and an excised brain tissue. Results The studies show good agreement between imaging and our method. The measured improvement factors of SNR per unit time of our single-voxel approach over imaging approach are close to the predicted values. Conclusion Measuring T ₂ relaxation times from a selected ROI of arbitrary shape using a single-voxel rather than an imaging approach can increase the SNR per unit time, which is critical for dynamic T ₂ or multi-component T ₂ measurements.     

交错BCH码在移动窄带图像信道中的性能研究

文章在详述ＢＣＨ码编译码过程的基础上，对交错ＢＣＨ码在移动瞧道压缩图像传输系统中的应用进行了计算机仿真，直观地显示出产错ＢＣＨ码在窄带图像传输系统中的优良性能，并为移动图像传输中码型的选用提供参考。