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.     

考虑流量演进过程的丰水期梯级水电风险调度

丰水期梯级水电流域来水充沛,上下游水电站之间的流量演进过程对于水电站的优化调度具有重要影响。为了细致描述上下游出入库流量传播过程,结合槽蓄方程和水量平衡方程,运用马斯京根法建立了上下游流量的耦合关系,同时针对丰水期天然来水和市场电价的双重不确定性,综合考虑发电商的风险喜恶行为对调度决策的影响,构建了梯级水电风险调度模型,并利用混合整数线性规划法予以求解。算例结果表明,丰水期考虑河道流量演进过程的梯级水电优化调度模型精确性更高,在不同风险偏好下,可有效地平衡风险和发电效益之间的矛盾。     

A fuel cell powered autonomous surface vehicle: The Eco-SWAMP project

Autonomous surface vehicles are becoming consolidated robotic tools for marine, coastal and inland surveys. Autonomous surface vehicles are usually equipped with electronic instruments to perform remotely controlled or autonomous geo-morphological, biological, chemical, physical analyses and data collection. Actually, well-established solutions provide battery power but the research focuses on introducing a fuel cell to decrease the environmental impact meanwhile increasing the cruising range. In this paper, the design of the Eco-SWAMP, a fuel cell powered autonomous surface vehicle, is presented starting from its battery-powered version, the SWAMP prototype. The experimental power consumption profile of the SWAMP during four missions is analysed to define the primary energy sources ratings of the Eco-SWAMP. After a commercial choice of primary sources, power management algorithms are designed and compared in MATLAB/Simulink environment by simulation results. The proposed procedure can be easily applied to any autonomous marine vehicle.     

Review on non-isolated multi-input step-up converters for grid-independent hybrid electric vehicles

The increase in temperature, regulations of CO2 emissions, and the cost of conventional fuels forced the transportation industry to move towards the electrical energy sector. The increasing nature of electrification of transportation will increase the stress on the existing power system because of the charging of battery-based electric vehicles (EV). This paper briefly reviews the effect of electrification of transportation on the existing power system. The Lion's share of the EVs is battery-based, and these EVs extensively depend on Lithium. The Lithium is a non-renewable energy source just like fossil fuels, and reserves may last one day. The availability of Lithium reserves across the world and alternate for the grid-dependent EVs are illustrated in this paper. This paper also briefly discusses the fuel cell-based EVs, solar PV based EVs along with battery-based EVs and compare the battery with fuel cell.There is a significant need for research and development on grid-independent hybrid electric vehicles (GIHEV). From the last few years, the extensive part of the hybrid electric vehicles is making use of multi-input DC-DC converters to interface multiple sources to enhance the performance and reliability of the vehicle. Among different types of multi-input DC-DC converters, non-isolated multi-input DC-DC converters are best suited for low and medium power electric vehicle applications. This paper displays the synthesizing process of multi-input converters. Some of the existing efficient non-isolated multi-input high step-up DC-DC converter topologies are immensely discussed and compared. This review is intended to serve as a suitable guideline and reference for future work in the field of non-isolated multi-input high step-up DC-DC converter topologies for GIHEVs.     

A simple and effective design strategy to increase power conversion efficiency of linear charge pumps

This paper introduces a simple design strategy to increase the power efficiency of linear charge pumps. The technique exploits a voltage amplitude of the clock signal lower than the supply voltage to reduce the power conversion losses. The nominal output voltage is maintained unaltered by increasing the number of stages.     

一种射频抗电磁干扰的矿用红外温度传感器

设计了一种适用于复杂条件下实施井下温度探测的射频式红外温度传感器。借助于光学系统、光电探测器实时感应井下温度并提取温度信号,同时在DC-DC电源隔离模块中实施EMI滤波以抗电磁干扰,处理后的信号经过A/D转换、运算器放大后显示在LCD上,实施读取数据并记录在传感器的存储片上,实现了矿井复合灾害条件下的温度测试,测试精度控制在±2%。     

A comparative review on power conversion topologies and energy storage system for electric vehicles

Fossil fuel depletion and its adverse impact on global warming is a major driving force for a recent upsurge in the development of hybrid electric vehicles technologies. This paper is a conglomeration of the recent literature in the usages of an energy storage system and power conversion topologies in electric vehicles (EVs). An EV requires sources that have high power and energy density to decrease the charging time. Commonly used energy storage devices in EVs are fuel cells, batteries, ultracapacitors, flywheel, and photovoltaic arrays. The power output from energy storage sources is conditioned to match load characteristics with the source for maximum power delivery. A DC-DC converter topology performs this task by way of transforming voltage under the condition of power invariance. In addition, power electronics is also required to power DC/AC motors efficiently with precise control as these motors provide tractive efforts and acts as prime movers. This paper therefore brings out a critical review of the literature on EV's power conversion topologies and energy storage systems with challenges, opportunities and future directions by systematic classification of EVs and energy storage.     

Small signal modelling and control of high gain coupled inductor boost inverter for solid oxide fuel cell based power generation system

Small signal model of high gain coupled inductor boost inverter is established in presented work. Developed small signal model is then integrated with the model of planar solid oxide fuel cell and simulation of complete system is realized using MATLAB/Simulink environment and compared with the already developed fuel cell-based power converters. Coupled inductor boost converter was chosen to achieve higher gain in dc link voltage by selecting the appropriate turn ratio. Small signal model for dc-dc and dc-ac stages is derived separately and accordingly control system is designed. Dual loop with feed forward control scheme for coupled inductor boost inverter resulted in good performance like stable dc link, fast transient response, low total harmonic distortion (THD) and input disturbance rejection. Mathematical analysis, simulation and hardware results prove the stability and reliability of the complete system.     

基于TL494 升压型DC-DC 稳压电源的设计

根据开关电源在各种电子产品中的发展趋势,介绍一种12 V转24 V的升压型DC-DC稳压电源。该电源采用TL494作为控制器件,根据其工作原理,合理选择了电源中的开关管、滤波电容、储能电感和续流二极管的参数设计,利用脉冲宽度调制技术进行电路控制,并通过控制开关管的导通时间,保持输出电压的稳定。仿真测试结果表明:该电路输出电压满载时变换效率大于70%,具有较高的安全性和可靠性。