A new design strategy for DC/DC LLC resonant converter: Concept,modeling, and fabrication

In this paper, a new design procedure for LLC converter has been introduced. In fact, this method is a computer-based design algorithm based on a numerical technique. In the process of designing, the value of the resonant element is obtained by solving the LLC converter fundamental equation. This converter will be controlled by using state feedback, such as output voltage variable. As a matter of fact, in a control system, the change of output voltage (because of load variation) will affect the switching frequency, so the output voltage will be tuned. In the designing process, the fundamental equations of LLC converter are obtained, and the value of the resonant elements is calculated. Also, a comparison analysis is carried out between the proposed and typical methods. The simulation is done to investigate the validity of the proposed method. Moreover, a prototype is manufactured, and the experimental test is done to evaluate its applicability.     

A fuel-cell/battery hybrid DC backup power system via a new high step-up three port converter

In this paper, a fuel-cell (FC)/battery hybrid direct-current (DC) backup power system is proposed for high step-up applications. This system is composed of a newly developed non-isolated three-port converter, which achieves a high voltage gain by taking the advantage of a quasi Z-source network and an energy transfer capacitor. After analyzing the converter, a comprehensive comparison study and a design procedure are provided. Moreover, the controllers regulating the source power levels while smoothing the FC power profile according to the proposed energy management strategy (EMS) are designed based on the developed small-signal model of the proposed converter. Both hardware and controller design procedures are validated through the PSIM model of the whole system. As a result, it is shown that the proposed system can effectively couple FC and battery while transferring their energies to a high voltage DC bus according to the offered EMS.     

A new controller for boost dc–dc converters based on a novel sliding surface

ABSTRACT

In this paper, two control schemes for boost converters affected by uncertainties in input voltage and load are proposed. The boost converter dynamics is redefined in terms of new state variables to facilitate the use of a disturbance observer that can estimate matched and unmatched disturbances. A sliding surface, which is new in the context of boost converters, is proposed to enable tracking and regulation of output voltage without requiring measurement of input voltage and load current. The stability of the overall system including the disturbance observer, the sliding variable and the output is proved. The performance of the schemes is assessed for regulation of output voltage and tracking of reference voltage by simulation as well as experimentation in which various types of uncertainties and various types of reference voltages are considered.     

电动汽车的双向DC-DC变换器多模态控制方法

针对当前电动汽车功率控制过程中存在负载跳变抗干扰性能差、响应速度较慢等问题,提出一种应用于电动汽车的双向DC-DC变换器多模态控制方法。文章详细分析了电动汽车双向DC-DC变换器的拓扑结构和升降压控制模式;结合不同工况下的变换器工作状态,分析电压和电流模式控制,得出其电压、电流开闭环函数;利用多模态控制方法,由变换器的功能控制单元下达电压、电流环给定信号来实现功率波动平抑控制;在MATLAB中搭建了仿真模型。仿真结果表明,文章所提出的控制方法能够较好地实现双向DC-DC变换器的功率波动平抑功能,具有稳定性好、对负载跳变抗干扰性能强、响应速度快的特点。     

CaO-SiO2-FeO-Cr2O3-MgO-MnO渣系物相组成的热力学计算

摘要：在含铬铁水转炉冶炼过程中，Cr很容易被氧化成Cr2O3进入渣中，并与渣中其他成分反应生成高熔点含铬尖晶石。采用FactSage热力学软件计算了CaO-SiO2-FeO-Cr2O3-MgO-MnO转炉渣系在冶炼温度1300～1700℃下的物相组成，研究了Cr2O3、FeO和碱度对炉渣中尖晶石相含量的影响规律。研究结果表明，温度和渣系成分都会影响炉渣的物相组成。渣系中含有Cr2O3时，物相中均含有MgCr2O4、FeCr2O4和MgFe2O4尖晶石相，尖晶石相的总含量随着Cr2O3和碱度的增加而增加，随着炉温的升高而减少。温度为1300～1500℃时，炉渣中尖晶石含量随着FeO的增加而增加；温度为1500～1700℃时，尖晶石含量随着FeO的增加而略有减少。在温度小于1500℃的转炉冶炼前中期，炉渣物相组成中尖晶石相所占比例较大，易造成化渣不良或者炉渣粘稠，影响转炉冶炼工艺的顺行。     

A 340-GHz thin film polarisation converter

This paper introduces a 340-GHz polarisation converter. The polarisation converter consists of a bilayer metamaterial, which is processed by the flexible thin film lithography method. Two-dimensional metamaterial offer such advantages over traditional quarter-wave-plates as compactness, low profile and simple fabrication process, but the insertion loss is comparably high. In order to lower the insertion loss, the 10-μm ultrathin polyimide substrate and a bilayer structure separated by a quarter wavelength air impedance match layer are adopted. After the horn antenna’s far-field test by vector network analyser and the Gaussian beam test based on Terahertz time-domain spectroscopy (THz-TDS), the results show that in the band of 325–350 GHz, the transmission loss is less than 2 dB, and the axial ratio is less than 3 dB; besides, simulation and test insertion loss performance difference is less than 1 dB, which indicates that the method we adopt is effective. In addition, based on transmission line theory, we analyse its working principle and the influence from the fabrication error.     

A New Design Methodology for Time-Based Capacitance-to-Digital Converters (T-CDCs)

This paper introduces a 9-bit time-based capacitance-to-digital converter (T-CDC). This T-CDC adopts a new design methodology for parasitic cancellation with a simple calibration technique. In T-CDCs, the input sensor capacitance is first converted into a delay pulse using a capacitance-to-time converter (CTC) circuit; then this delay signal is converted into a digital code through a time-to-digital converter (TDC) circuit. A prototype of the proposed T-CDC is implemented in UMC 0.13 μm CMOS technology. This T-CDC consumes 8.42 μW and achieves a maximum SNR of 45.14 dB with a conversion time of 1 μs that corresponds to a figure of merit (FoM) of 16.4 fJ/Conv.     

庞庞塔煤矿综采工作面恒压供液系统研究

结合庞庞塔煤矿综采工作面的具体应用现状,设计了变频驱动控制的恒压供液系统。在泵出口管道中设置压力传感器、流量计等,同时在每台液压支架乳化液入口处安装一个蓄能器。压力、流量等数值由各种传感器来进行采集,并把监测到的数据反馈给PLC控制器。PLC控制器通过把传感器送来的数据和系统预设好的数值进行比较来判断供液系统是否需要加压或着减压,以此通过变频器来改变电机的转速,以实现供液系统维持恒压状态。     

SC15/182F分体式电驱梭车的研制及应用

梭车是短壁机械化开采技术的重要运输设备。简要介绍了现有梭车的现状及应用局限,详细阐述了分体梭车的主要设计思路,重点介绍了薄壁分体式机架的结构特征,阐述了分体梭车在模块化卷电缆装置、四象限变频驱动等方面的技术升级,并介绍了分体梭车在国内矿区的应用情况。