The Novel Control Strategy Research on Resonant Bridge Modular Switched-Capacitor Converter

在提出的一款谐振型桥式模块化多电平开关电容变换器拓扑基础上,提出了移相加PWM的控制策略。该控制策略实现了变换器高频开关(MOSFET)的零电流、零电压开关,并在保证变换器较高效率运行的基础上,实现了变换器输出电压的可调性,解决了回路峰值电流过大或过小的问题。详细分析了开关电容变换器高频开关移相角与输出电压和回路峰值电流之间的关系,并通过仿真软件SABER和硬件平台对所述控制策略下的软开关、输出电压、峰值电流特性进行了验证,仿真结果与实验结果均证实了上述结论。This paper presents a phase shift plus PWM control strategy for the novel resonant bridge modular multilevel switched-capacitor converter. The proposed method ensures that almost all switching devices keep zero current switching or zero voltage switching, which achieves a high system efficiency. Meanwhile, the output voltage is regulated and the loop peak current is limited in a proper range. The impacts of the switching phase of metal-oxide-semiconductor field-effect transistors( MOSFETs) on both the output voltage and the loop peak current are deduced,respectively. By means of simulation software Saber and hardware platform,the proposed characteristics of soft switching,output voltage,and peak current are verified well.国家自然科学基金(61671400);; 中央高校基本科研业务费(20720150088);; 广东省自然科学基金(2016A030313657);; 福建省科技计划项目(2014H6026);; 福建省自然科学基金(2015J201274)资

Multilevel DC-DC power conversion system with multiple bridge modular switched-capacitor converter

Conference Name:28th Annual IEEE Applied Power Electronics Conference and Exposition, APEC 2013. Conference Address: Long Beach, CA, United states. Time:March 17, 2013 - March 21, 2013.Power Sources Manufacturers Association; IEEE Industry Applications Society; IEEE Power Electronics SocietyMultilevel converters have been demonstrated to have many advantages such as low harmonic, low voltage stress, and high power capability. A multilevel DC-DC power conversion system with multiple bridge modular switched-capacitor converters (BMSCC) is proposed in this paper, with this conversion system, the output voltage can be changed almost continuously without any magnetic component, where the very high temperature operation is possible. Compared with other existing switched-capacitor converters, low semiconductor VA rating, low device requirement is available. Compared with other traditional step-up converters based on output impedance analysis method, the proposed converter brings about a higher efficiency advantage. Experimental results are provided to confirm the analysis and control concept. ? 2013 IEEE

High-Performance Bridge Modular Switched-Capacitor Converter With Small Component Requirement Based on Output Impedance Analysis for Low Loss

In this paper, a novel multilevel bridge modular switched-capacitor converter is proposed for the application in high voltage gain. Compared with the conventional switched-capacitor converters, it utilizes fewer components (switching device and capacitor) to obtain the same voltage conversion, as well as some advantages including low total power device rating, output capacitor requirement, and low output voltage ripple. In order to illustrate its superiority, an output impedance analysis method is developed, which can comprehensively evaluate a two-phase switched-capacitor converter's steady-state performance by judging its output impedance. The simple formulation developed not only permits optimization of the capacitor sizes to meet several constraints such as a total capacitance or total energy storage limit, but also permits optimization of the switch sizes subject to constraints on total switch conductance or total switch volt-ampere products. Consequently, the output impedance under the optimizations has contributed to the comparison of the latest switched-capacitor converters. As a result, the performance (based on conduction loss) of the proposed converter is proved to be optimum in fast-switching-limit impedance and does well in slow-switching-limit output impedance as well. Simulation and experimental results have validated the principle and properties of this converter and the analysis method

A novel quasi-resonant bridge modular switched-capacitor converter with enhanced efficiency and reduced output voltage ripple

A novel quasi-resonant bridge modular switchedcapacitor converter (BMSCC) is proposed in the paper. The main merit is that its resonant circuit has high stability and simplicity, resulting from the employment of the stray inductance distributed in the circuit as a collective resonant inductor. Accordingly, the current spike during switching operation is removed due to zerocurrent- switching (ZCS) realization. Another distinct merit is that the proposed converter features symmetric construction.With this kind of construction, the voltage ripple of charge/pump capacitors can be cancelled out with each other and then output voltage ripple will be largely reduced. Thus, it is unnecessary to use a bulky capacitor to reduce output voltage ripple. Compared with conventional SCCs, at the same conversion ratio, the BMSCC with symmetric construction requires fewer switches and capacitors with lower voltage stress, so as to cut the size and cost and promote the power destiny further. It is also noteworthy that the symmetric construction character assures that the two symmetric parts can work independently under a simplified control strategy. In addition, the modular configuration contributes to convenient voltage extension conveniently. The simulation and experimental results of a 100Wprototype with a voltage conversion ratio of eight validate the principle and features of this topology. ? 1986-2012 IEEE

Novel Quasi-Resonant Bridge Modular Switched-Capacitor Converter With Enhanced Efficiency and Reduced Output Voltage Ripple

A novel quasi-resonant bridge modular switched-capacitor converter (BMSCC) is proposed in the paper. The main merit is that its resonant circuit has high stability and simplicity, resulting from the employment of the stray inductance distributed in the circuit as a collective resonant inductor. Accordingly, the current spike during switching operation is removed due to zero-current- switching (ZCS) realization. Another distinct merit is that the proposed converter features symmetric construction. With this kind of construction, the voltage ripple of charge/pump capacitors can be cancelled out with each other and then output voltage ripple will be largely reduced. Thus, it is unnecessary to use a bulky capacitor to reduce output voltage ripple. Compared with conventional SCCs, at the same conversion ratio, the BMSCC with symmetric construction requires fewer switches and capacitors with lower voltage stress, so as to cut the size and cost and promote the power destiny further. It is also noteworthy that the symmetric construction character assures that the two symmetric parts can work independently under a simplified control strategy. In addition, the modular configuration contributes to convenient voltage extension conveniently. The simulation and experimental results of a 100 W prototype with a voltage conversion ratio of eight validate the principle and features of this topology

High step-up converter with passive lossless clamp circuit and switched-capacitor: Analysis, design, and experimentation

Conference Name:28th Annual IEEE Applied Power Electronics Conference and Exposition, APEC 2013. Conference Address: Long Beach, CA, United states. Time:March 17, 2013 - March 21, 2013.Power Sources Manufacturers Association; IEEE Industry Applications Society; IEEE Power Electronics SocietyIn the paper, a novel high step-up dc-dc converter with coupled-inductor and switched-capacitor is proposed for sustainable energy system. The converter utilizes two-stage switched-capacitors as voltage sources to extend the voltage gain and auto-balance two branches current. Besides, the voltage stress on the main switches is reduced further due to the voltage distributed on the switched-capacitors. The Winding-coupled inductors work in fly-back or forward mode at different operation stages, which extends the voltage gain and make use of the magnetic as possible to improve the power density. The main switches are turned off under zero voltage switching(ZVS) condition because of a passive clamp circuit and turned on under zero current switching (ZCS) condition due to the coupled inductor inherent leakage. Additionally, the diode reverse-recovery problem is alleviated because its current falling rate is controlled by the leakage inductance. Thus, the efficiency can be further improved. Then, the operating principle and performance of the converter are discussed in detail. Finally, a prototype circuit with 20-V input voltage, 200-V output voltage and 300-W output power is implemented to verify the performance of the proposed converter. ? 2013 IEEE

Safe-Commutation Strategy for the Novel Family of Quasi-Z-Source AC-AC Converter

A novel quasi-Z-source ac-ac converter for voltage sag/swell compensation in smart grids is proposed in this paper. Derived from the basic ac-ac safe-commutation mechanism, a new voltage-based commutation strategy is developed, which is achieved without snub circuit and only by sampling the output voltage. Therefore, the control circuit is simplified greatly. Two switches in a one-phase loop are always turned on for current freewheel path in dead time, and current spike and voltage spike are solved well. Compared with conventional ac-ac converters, fewer switches conduct with soft switching during operation, resulting in high efficiency. Then, the proposed converter is analyzed, including the operating modes and voltage ration based on a state-space average. The experimental results validate the theoretical predication well. The safe-commutation strategy can also be easily applied to other converters of the proposed family

Effects of Elongated Needle Therapy on the Expressions of Fas and Caspase-3 in Rabbits With Acute Spinal Cord Injury

目的探讨芒针透刺治疗急性脊髓损伤的可能作用机制。方法 135只日本大耳兔随机均分为假手术组、模型组和芒针透刺组,每组45只。模型组和芒针透刺组建立兔T13-l1急性脊髓损伤模型;假手术组、模型组不给任何刺激,芒针透刺组芒针透刺双侧秩边、水道穴,辅以针刺气海、中极,得气后同侧秩边、水道连接于针灸治疗仪上,刺激时间15MIn,频率20~40次/MIn,强度1.5~3.0V,每日1次,共5天。分别于术后1、3、5天取伤段脊髓观察形态学变化,检测脊髓细胞凋亡受体fAS、CASPASE-3蛋白及其MrnA表达。结果假手术组各取材点脊髓界限清晰,神经元细胞结构完整;模型组脊髓组织正常结构紊乱,局部区域内神经元细胞可见细胞核消失;芒针透刺组脊髓组织结构及神经元细胞破坏较模型组轻微。与假手术组比较,模型组大鼠术后1、3、5天脊髓fAS、CASPASE-3蛋白及MrnA表达明显升高(P<0.05或P<0.01);芒针透刺组术后第3、5天CASPASE-3蛋白及MrnA表达明显降低,术后第3天fAS蛋白及MrnA亦降低(P<0.05或P<0.01)。结论芒针透刺对急性脊髓损伤有明显的保护作用,抑制脊髓fAS、CASPASE-3水平可能是其作用机制之一。Objective To study the possible mechanism of elongated needle therapy for acute spinal cord injury.Methods Totally 135 Japanese rabbits were randomized into the sham operation group,model group and elongated needle therapy group,with 45 in each.The T13-L1 acute spinal cord injury models were established in the model group and elongated needle therapy group.The sham operation group and model group were not given any stimulation.The elongated needle therapy group was given elongated needling on bilateral points Zhibian( BL54) and Shuidao( ST28),and common acupuncture needling on Qihai( CV6) and Zhongji( CV3).The morphological changes of spinal cord were observed.The expressions of Fas,Caspase-3,Fas mRNA and Caspase-3 mRNA were detected.Results The spinal boundary was clear and neuronal cell structure was intact in the sham operation group.The spinal structure was disordered and the nucleus of neuronal cells was disappeared in the model group.The damage of spinal structure and neuronal cells was slight in the elongated needle therapy group.Comparing with the sham operation group,the expressions of Fas,Caspase-3,Fas mRNA and Caspase-3 mRNA were significantly increased in the model group on the 1st,3rd,and 5th days after operation( P < 0.05 or P < 0.01).The expressions of Caspase-3 and Caspase-3 mRNA were significantly decreased in the elongated needle therapy group on the 3rd,and 5th days after operation,and the expressions of Fas and Fas mRNA were significantly decreased in the elongated needle therapy group on the 3rd day after operation( P < 0.05 or P < 0.01).Conclusion The elongated needle therapy has an obvious protective effect on acute spinal cord injury,which may be relevant to inhibiting the expressions of Fas and Caspase-3.浙江省中医药科研基金资助项目(2008CB067

铈助催铁系乙苯脱氢催化剂的XPS、TPR研究

通过XPS、TPr-gC和Xrd发现，铁系乙苯脱氢催化剂中的CEO＿2在反应条件下会被部分还原，而且，氧化钵和氧化铁之间有一定程度的相互作用，其结果是使负电荷由铁向铈迁移并增加了氧化铁的抗还原能力。基于上述事实，讨论了铈助催化作用的本质。中国石油化工总公司资助项

联锁啮合型聚合物地砖

[申请号]201030203469.8{申请日]2010.06.10 [名称] 联锁啮合型聚合物地砖[公开（公告）号]CN301381529S 　 [公开（公告）日] 2010.11.10 　 [主分类号]25-01 [分类号]25-01 [申请（专利权）人]厦门大学 [地址]361005 福建省厦门市思明南路422号 [发明（设计）人]戴李宗;郭一宾;何凯斌;陈光剑;许一婷;谢晋良;罗伟昂 　 [专利代理机构] 厦门南强之路专利事务所 35200 　 [代理人]陈永秀;马应森 　1.外观设计产品名称为联锁啮合型聚合物地砖。2.本产品的用途为地砖。3.本产品的设计要点在于产品形状，边缘呈波浪形。4.立体图最能表明本产品的设计要点