In a smart grid, electric loads are supplied by various DC （direct current） power sources, such as solar cells or batteries. On the other hand, traditional AC （alternating current） loads like a directly connected ...In a smart grid, electric loads are supplied by various DC （direct current） power sources, such as solar cells or batteries. On the other hand, traditional AC （alternating current） loads like a directly connected induction motors will also be used. In the circumstances, a smart power conversion unit is one of key components, which can integrate these DC or AC apparatus and trade power among them. Authors have developed an integrated power converter based on a well-known circuit topology of flying capacitor multilevel converter. This paper describes the detail of the circuit topology and its characteristics depending on designed parameters. The achieved power quality is also verified by simulation study.展开更多
In order to provide power quality monitoring activities with metrological certification, a DAS （data acquisition system） has been designed, realized and characterized. The system allows acquisition on tri-phases plu...In order to provide power quality monitoring activities with metrological certification, a DAS （data acquisition system） has been designed, realized and characterized. The system allows acquisition on tri-phases plus neutral lines picking up 499 samples per period of the fundamental at 50 Hz. To ensure certified measurements, the system gets external certified time and voltage references. The system uses a FTDI Virtual Com Port Driver to communicate data over High Speed RS232 virtual interface and it does not need any advanced programming skill. The choice to use a virtual serial communication makes the data acquisition software portable over many platforms, regardless by the development environment and by the programming language. To test the proposed device some custom software have been written in many programming language （C^#, VB6, LabView, MatLab）, moreover in order to characterize the device the most common ADC （analog to digital converter） performing test have been applied.展开更多
High-quality graphene coating was directly grown on stainless steel meshes via chemical vapor deposition process,during which the morphology of the stainless steel was transformed rugged.When the graphene-coated stain...High-quality graphene coating was directly grown on stainless steel meshes via chemical vapor deposition process,during which the morphology of the stainless steel was transformed rugged.When the graphene-coated stainless steel meshes were applied as current collectors of supercapacitors,the changes of the appearance and the graphene coating improved the contact between stainless steel meshes and the active materials,thus benefiting the performance of the supercapacitors.Furthermore,this simple method can be used to prepare the enhanced current collectors for other energy storage devices.展开更多
文摘In a smart grid, electric loads are supplied by various DC （direct current） power sources, such as solar cells or batteries. On the other hand, traditional AC （alternating current） loads like a directly connected induction motors will also be used. In the circumstances, a smart power conversion unit is one of key components, which can integrate these DC or AC apparatus and trade power among them. Authors have developed an integrated power converter based on a well-known circuit topology of flying capacitor multilevel converter. This paper describes the detail of the circuit topology and its characteristics depending on designed parameters. The achieved power quality is also verified by simulation study.
文摘In order to provide power quality monitoring activities with metrological certification, a DAS （data acquisition system） has been designed, realized and characterized. The system allows acquisition on tri-phases plus neutral lines picking up 499 samples per period of the fundamental at 50 Hz. To ensure certified measurements, the system gets external certified time and voltage references. The system uses a FTDI Virtual Com Port Driver to communicate data over High Speed RS232 virtual interface and it does not need any advanced programming skill. The choice to use a virtual serial communication makes the data acquisition software portable over many platforms, regardless by the development environment and by the programming language. To test the proposed device some custom software have been written in many programming language （C^#, VB6, LabView, MatLab）, moreover in order to characterize the device the most common ADC （analog to digital converter） performing test have been applied.
基金supported by the National Natural Science Foundation of China(Grant Nos.20973044,21173057,21103030)the Ministry of Science and Technology of China(Grant Nos.2012CB933400,2012CB-933403)
文摘High-quality graphene coating was directly grown on stainless steel meshes via chemical vapor deposition process,during which the morphology of the stainless steel was transformed rugged.When the graphene-coated stainless steel meshes were applied as current collectors of supercapacitors,the changes of the appearance and the graphene coating improved the contact between stainless steel meshes and the active materials,thus benefiting the performance of the supercapacitors.Furthermore,this simple method can be used to prepare the enhanced current collectors for other energy storage devices.
