In the context of increasing demand for flexibility and controllability in distribution networks,this paper proposes a dual-bus parallel supply(DBPS)system based on bipolar direct AC/AC conversion.First,the topology o...In the context of increasing demand for flexibility and controllability in distribution networks,this paper proposes a dual-bus parallel supply(DBPS)system based on bipolar direct AC/AC conversion.First,the topology of the DBPS system,which is composed of both conventional and flexible bus ports,is described.Then,through analyzing the principles of the DBPS sys-tem,the voltage flexible regulation range is obtained,and its superiority over a topological reciprocity system is achieved.Then,a control strategy for the DBPS system is proposed based on the theory of power flow regulation of distribution ring networks and the principles of flexible bus regulation of the DBPS system.Finally,simulation analyses on flexible control scenarios in different net-working modes of the DBPS system verify the correctness and validity of the proposed theory.展开更多
It is already well known that availability of petroleum oil, as a world energy source, is running low. Much work has been done by experts to produce renewable energy, especially using vegetable oil as a raw material. ...It is already well known that availability of petroleum oil, as a world energy source, is running low. Much work has been done by experts to produce renewable energy, especially using vegetable oil as a raw material. Accordingly, this paper presents preparation and activity test of Cu catalyst using coconut shell activated carbon （AC） as a support, for conversion of n-pentanol and n-butanol to their alkenes as the first step of conversion of ethanol to biogasoline. This conversion is interesting due to any agriculture product containing sugar or starch can be converted to ethanol. Activated carbon was used as a catalyst support because this material is inert; hence, it would not yield unexpected side product, and pollution of environment with the used catalyst can be prevented because the used catalytic metal can easily be recovered. Results of the work showed that coconut shell carbon contained some metals, which disturbed in preparation catalyst by cation exchange process. Washing the carbon with ammonium acetate or HCI solution could reduce the metals content more compared to using water, with optimum concentration for ammonium acetate solution was 1.25 M. Application of Cu/AC in converting n-pentanol and n-butanol, based on qualitative analysis to the products using GLC, GC-MS, and FTIR, when n-pentanol and nitrogen gas were flowed into a reactor filled with Cu/AC catalyst, it could be converted to n-pentene with 200 ℃ as the optimal temperature. While when n-butanol and nitrogen gas were flowed into a reactor filled with more Cu/AC catalyst, the product was supposed to contain its aldehyde and butyl vinyl ether.展开更多
Five catalytic processes and their catalysts will be introduced in my talk. Firstly,the demonstration test(3000 ton/a)results using a novel catalyst Co/SiO2 with egg-shell structure and the strategies for this catalys...Five catalytic processes and their catalysts will be introduced in my talk. Firstly,the demonstration test(3000 ton/a)results using a novel catalyst Co/SiO2 with egg-shell structure and the strategies for this catalyst preparation based on the issues from the mass transfer of produced wax from F-T synthesis will be discussed. Recent progresses on C2-oxygenate synthesis from syngas over a Rh/SiO2 catalyst and a 10 thousands ton/a demonstration test facility in China will be built in 2010 will be reported in the second section. A naphtha and diesel distillate which cut off the heavier end of S-F-A distribution direct synthesis with low methane selectivity from syngas over a Co/AC1 catalyst and a 10000 ton/a demonstration test with a bubble column slurry reactor will be talked about in this speech. A high α-alcohols of C2-C18 direct synthesis with more than 50 wt% selectivity and low methane and methanol selectivities from syngas over a Co2C/AC2 catalyst,a 3000 ton/a demonstration test with a bubble column slurry reactor and the primary fundamental understandings will be detailedly discussed in the forth section. In situ formation of homogeneous active sites on the surface of supported Rh heterogeneous catalysts and their application in hydroformylation of olefins will be introduced in fifth section.展开更多
单级式双有源桥(dual active bridge,DAB)DC/AC变换器控制自由度多,变压器匝比、漏感、开关频率等参数相互耦合,导致变换器效率优化面临多重制约。该文分析变压器匝比、漏感与软开关范围、漏感电流有效值、漏感电流峰值之间的约束关系,...单级式双有源桥(dual active bridge,DAB)DC/AC变换器控制自由度多,变压器匝比、漏感、开关频率等参数相互耦合,导致变换器效率优化面临多重制约。该文分析变压器匝比、漏感与软开关范围、漏感电流有效值、漏感电流峰值之间的约束关系,提出直接表征DAB-DC/AC变换器效率的物理量:效率敏感因子。通过研究效率敏感因子对系统损耗的影响机理,实现变换器效率最优的硬件参数设计,为多参数耦合的单级式DAB-DC/AC变换器效率优化提供理论指导。最后通过一台450 W样机验证所提理论的正确性。展开更多
在两级式AC-DC变换器中,前级功率因数校正(power factor correction,PFC)固有的瞬时功率波动特性会造成母线电压存在二倍频纹波,影响后级CLLLC谐振变换器的输出电压质量。针对以上问题,该文提出了基于二阶广义积分(second order general...在两级式AC-DC变换器中,前级功率因数校正(power factor correction,PFC)固有的瞬时功率波动特性会造成母线电压存在二倍频纹波,影响后级CLLLC谐振变换器的输出电压质量。针对以上问题,该文提出了基于二阶广义积分(second order generalized integral,SOGI)的可变增益母线电压纹波前馈控制方法。采用SOGI提取母线电压纹波信息,基于品质因数Q与电压增益的关系和母线电压纹波对归一化频率的影响,解析了母线电压纹波对CLLLC谐振变换器输出电压的影响机理,得到Q值与前馈增益系数Ka的关系,采用仿真寻优加数据拟合的方法得到前馈可变增益系数曲线。仿真和实验结果表明,相比于无前馈控制,所提控制方法对CLLLC谐振变换器的输出电压纹波具有较好的抑制效果,输出电压纹波降低了72%,验证了所提算法的有效性。展开更多
基金supported in part by the National Natural Science Foundation of China(No.52107182).
文摘In the context of increasing demand for flexibility and controllability in distribution networks,this paper proposes a dual-bus parallel supply(DBPS)system based on bipolar direct AC/AC conversion.First,the topology of the DBPS system,which is composed of both conventional and flexible bus ports,is described.Then,through analyzing the principles of the DBPS sys-tem,the voltage flexible regulation range is obtained,and its superiority over a topological reciprocity system is achieved.Then,a control strategy for the DBPS system is proposed based on the theory of power flow regulation of distribution ring networks and the principles of flexible bus regulation of the DBPS system.Finally,simulation analyses on flexible control scenarios in different net-working modes of the DBPS system verify the correctness and validity of the proposed theory.
文摘It is already well known that availability of petroleum oil, as a world energy source, is running low. Much work has been done by experts to produce renewable energy, especially using vegetable oil as a raw material. Accordingly, this paper presents preparation and activity test of Cu catalyst using coconut shell activated carbon （AC） as a support, for conversion of n-pentanol and n-butanol to their alkenes as the first step of conversion of ethanol to biogasoline. This conversion is interesting due to any agriculture product containing sugar or starch can be converted to ethanol. Activated carbon was used as a catalyst support because this material is inert; hence, it would not yield unexpected side product, and pollution of environment with the used catalyst can be prevented because the used catalytic metal can easily be recovered. Results of the work showed that coconut shell carbon contained some metals, which disturbed in preparation catalyst by cation exchange process. Washing the carbon with ammonium acetate or HCI solution could reduce the metals content more compared to using water, with optimum concentration for ammonium acetate solution was 1.25 M. Application of Cu/AC in converting n-pentanol and n-butanol, based on qualitative analysis to the products using GLC, GC-MS, and FTIR, when n-pentanol and nitrogen gas were flowed into a reactor filled with Cu/AC catalyst, it could be converted to n-pentene with 200 ℃ as the optimal temperature. While when n-butanol and nitrogen gas were flowed into a reactor filled with more Cu/AC catalyst, the product was supposed to contain its aldehyde and butyl vinyl ether.
文摘Five catalytic processes and their catalysts will be introduced in my talk. Firstly,the demonstration test(3000 ton/a)results using a novel catalyst Co/SiO2 with egg-shell structure and the strategies for this catalyst preparation based on the issues from the mass transfer of produced wax from F-T synthesis will be discussed. Recent progresses on C2-oxygenate synthesis from syngas over a Rh/SiO2 catalyst and a 10 thousands ton/a demonstration test facility in China will be built in 2010 will be reported in the second section. A naphtha and diesel distillate which cut off the heavier end of S-F-A distribution direct synthesis with low methane selectivity from syngas over a Co/AC1 catalyst and a 10000 ton/a demonstration test with a bubble column slurry reactor will be talked about in this speech. A high α-alcohols of C2-C18 direct synthesis with more than 50 wt% selectivity and low methane and methanol selectivities from syngas over a Co2C/AC2 catalyst,a 3000 ton/a demonstration test with a bubble column slurry reactor and the primary fundamental understandings will be detailedly discussed in the forth section. In situ formation of homogeneous active sites on the surface of supported Rh heterogeneous catalysts and their application in hydroformylation of olefins will be introduced in fifth section.
文摘单级式双有源桥(dual active bridge,DAB)DC/AC变换器控制自由度多,变压器匝比、漏感、开关频率等参数相互耦合,导致变换器效率优化面临多重制约。该文分析变压器匝比、漏感与软开关范围、漏感电流有效值、漏感电流峰值之间的约束关系,提出直接表征DAB-DC/AC变换器效率的物理量:效率敏感因子。通过研究效率敏感因子对系统损耗的影响机理,实现变换器效率最优的硬件参数设计,为多参数耦合的单级式DAB-DC/AC变换器效率优化提供理论指导。最后通过一台450 W样机验证所提理论的正确性。
