Tham khảo tài liệu 'sliding mode control part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 94 Sliding Mode Control The variables Vscmax and Csc are indeed related by the number of cells n. The assumption is that the capacitors will never be charged above the combined maximum voltage rating of all the cells. Thus we can introduce this relationship with the following equations VSCMAX - nVSCcell C . -SCcell CSC - n 11 Generally Vscmin is chosen as Vscmax 2 from 6 resulting in 75 of the energy being utilized from the full-of-charge SOC1 100 . In applications where high currents are drawn the effect of the RESR has to be taken into account. The energy dissipated Wloss in the Resr as well as in the cabling and connectors could result in an under-sizing of the number of capacitors required. For this reason knowing SC current from 6 one can theoretically calculate these losses as W di2 t R dT- P R C. ln Vscnom I 12 vvloss J XC V- ESRU-T 1 SC ESR MIN inl ỵr I 12 0 V VSCMIN J To calculate the required capacitance Csc one can rewrite 6 as jCscMIN vSCmAX - VSCmIN - Psct W . 13 From 6 and 13 one obtains CSC - CSCMIN 1 x x- . PSCt 14 where X is the energy ratio. From the equations above an iterative method is needed in order to get the desired optimum value. The differential capacitance can be represented by two capacitors a constant capacitor Co and a linear voltage dependent capacitor kV0. k is a constant corresponding to the slope voltage. The SC is then modelled by fd -_ 1 dế C 0 kV0 SC 15 Vsc - RrsrÌsc Vo Where C 0 kV0 0 C. State of the art and potential application Developed at the end of the seventies for signal applications for memory back-up for example SCs had at that time a capacitance of some farads and a specific energy of about . 1 State Of Charge 95 Sliding Mode Control of Fuel Cell Supercapacitors and Batteries Hybrid Sources for Vehicle Applications High power SCs appear during the nineties and bring high power applications components with capacitance of thousand of farads and specific energy and power of several and . .
