Energy Storage in the Emerging Era of Smart Grids Part 2 pot

5.4 Nanostructured redox materials 5.5 Hybrid systems 6. Conclusions 7. References [...]... focuses on the fundamental operation of the unit in Fig 14 36 Energy Storage in the Emerging Era of Smart Grids Q1 SC1 SC3 Q2 SC5 Q5 SC2 Q4 SC4 SC6 Q3 Fig 14 Reconfigurable series-parallel SC energy storage unit The current flow directions and voltage curves during discharging are shown in Fig 15 At the beginning of discharging, the unit operates as a two series three parallel system in mode A, in which... Universität Hannover 2 Department of Mechanical Engineering, University of Alberta 1 Germany 2 Canada 1 Introduction 1.1 Kinetic energy storage using flywheels Devices employing the concept of kinetic energy storage date back to ancient times Pottery wheels and spinning wheels are early examples of systems employing kinetic energy storage in a rotating mass With the advent of modern machinery, flywheels became... Ayyanar, 20 07; Seeman & Sanders, 20 08) The capacitances (number of capacitors) of each capacitor were determined on the basis of the reported design procedure, as shown in Table 3 Multiple ceramic capacitors were connected in parallel to satisfy the required capacitance Capacitor Capacitance C1 22 μF C2 44 μF (22 μF × 2) C3 44 μF (22 μF × 2) C4 110 μF (22 μF × 5) C5 66 μF (22 μF × 3) C6 22 μF C7 44 μF (22 ... in the bearings and with the air surrounding rotating components, respectively The typical components of advanced FES cells are shown in Figure 1 The energy stored in the rotor is increased by accelerating the rotor to higher speeds, i.e the FES is being charged In electromechanical systems, the rotor is accelerated by the electrical machine operating in motor mode When required the energy stored in. .. 16 SC1 SC2 SC3 SC4 14 12 10 8 6 4 0 (a) 10 20 30 Time [min] 40 50 (b) Fig 5 (a) Photograph of the 40 W prototype of the equalizer using multi-stacked SEPICs, and (b) experimental charge profiles of four series-connected SC modules charged by the prototype from an initially voltage-imbalanced condition 28 Energy Storage in the Emerging Era of Smart Grids The SC module(s) having the lowest voltage was(were)... the housing of the FES unit It is common to connect the rotor via a hub to a rotating shaft that is supported by bearings In these cases the electrical machine is either directly connected to the hub, or it drives the rotor using the common shaft In other designs the electrical machine is integrated into the rotor hub structure During rotor rotation, centrifugal forces generate stresses in the circumferential... employed to minimize energy losses due to friction Only through the use of advanced technology have FES systems become commercially viable for a range of applications, causing FES research and development to be an active and rapidly evolving field  42 2 Energy Storage in the Emerging Era Will-be-set-by -IN- TECH of Smart Grids Fig 1 Example of a commercial flywheel energy storage system (courtesy of POWERTHRU,... progressed, the number of series connections was increased consistently, whereas the number of parallel connections was decreased The cell voltages decreased with discharging, but the system voltage was maintained within a 38 Energy Storage in the Emerging Era of Smart Grids desired voltage range All the cells were uniformly and deeply discharged The experimental results demonstrated that the system... charging progressed Eventually, all the SCs were charged to a uniform voltage of approximately 47 30 Energy Storage in the Emerging Era of Smart Grids V, which is 1 V lower than the peak-to-peak voltage of the ac power source This difference is attributed to diode voltage losses 50 Voltage [V] 45 40 35 30 SC1 SC2 SC3 25 20 0 1 (a) 2 3 4 Time [h] 5 6 (b) Fig 8 (a) Photograph of the prototype of the switchless... further require curing, typically at elevated temperatures, which may occur after or even during the winding process Elevated temperature curing may induce residual thermal stresses, which can affect the radial tensile strength of a composite rotor Hence, thermal effects need to be considered during rotor design Following the filament winding process the rotor rim may require removal of the winding . Energy Storage in the Emerging Era of Smart Grids 26 L1 L2 Lin L3 L4 C1 C2 C3 C4 CinVin Q D1 D2 D4 D3 SC1 SC2 SC3 SC4 V 2 V 2 V 3 V 3 V 4 V 4 V 1 V 1 i Lin i C4 i C3 i C2 i C1 i L1 i L2 i L3 i L4 i D1 i D2 i D3 i D4 . [V] 50403 020 100 Time [ min ] SC1 SC2 SC3 SC4 0 i Lin 0 i L 0 i C 0 i D 0 v DS 0 Time I Lin I Li V in +V i T ON T OFF Energy Storage in the Emerging Era of Smart Grids 28 The SC module(s). (22 μF × 2) C 3 44 μF (22 μF × 2) C 4 110 μF (22 μF × 5) C 5 66 μF (22 μF × 3) C 6 22 μF C 7 44 μF (22 μF × 2) C 8 66 μF (22 μF × 3) Table 3. Capacitance of each capacitor. A photograph of