# Combination of LiCs and EDLCs with Batteries:
## 2 Proposed Hybrid Energy Storage System
### The Multiple Input Converter Implementation
The odd numbered Switches S\({}_{1}\), S\({}_{3}\), S\({}_{5}\), and S\({}_{7}\) for Figure 4a and S\({}_{1}\), S\({}_{3}\), and S\({}_{5}\), while the even numbered Switches S\({}_{2}\), S\({}_{4}\), S\({}_{6}\), and S\({}_{8}\) for Figure 4a and S\({}_{2}\), S\({}_{4}\), and S\({}_{6}\) for Figure 4b are the low side switches. The switches were implemented using N-channel MOSFETs, both for the high side and the low sides. P-channel MOSFETs are sometimes used for high side switching since the driving circuits are less complex than that of the N-channel MOSFETs used in high side switching. However, P-channel MOSFETs usually have a much higher ON state resistance than the complementary N-channel MOSFETs. Therefore, the N-channel MOSFET was the switch of choice in this case, since it has a lower ON-state resistance, which meant higher efficiency could be achieved than if a P-channel MOSFET were to be used. In Figure 4c, the schematic implementation of the high side (Q\({}_{\text{H}}\)) and the low side (Q\({}_{\text{L}}\)) is presented alongside the MOSFET driver implementation circuit. The MOSFETs were switched using an IR2113 MOSFET driver from Infineon technologies. The IR2113 is a half-bridge MOSFET driver with 14-pin dual in-line packaging that allows for driving one half (that is the high side and the associated low side) of the H-bridge switch topology from one chip. This is a very big benefiting feature, since it would eliminate the need to drive every single switch independently, which would have increased the number of chips required; hence, board space is saved. Using a half bridge driver meant that only four drivers were required for the three-input converter and only three driver chips for the two-input converter presented in Figure 4a,b, respectively; therefore, only one driver chip is required for each additional input port to the converter system. In Figure 4c, the 1-k\(\Omega\) resistor placed between the gate and source of the MOSFETs is a gate protection resistor to ensure that the switches turn OFF properly. The 10 \(\Omega\) resistor delays the turn ON, while the diode (\(D_{1}\) and \(D_{2}\)) placed in reverse bias to the resistor both discharges the capacitance of the MOSFET quickly to avoid a delayed turn OFF in order to prevent cross conduction across the adjacent high side and low side switches, respectively. \(L_{1}\), \(L_{2}\), and \(L_{3}\) are the inductors of each of the input sources, and \(Co\) is the output capacitor of the multiple input converters. An _RCD_ snubber design is implemented, which is a snubber circuit involving the use of a resistor, capacitor, and diode. The snubber circuit was used to protect the switches from accidentally turning ON due to stray signals in the circuit by damping the voltage and current ringing, reducing the switching losses and transfer power dissipation from the switches to avoid heating up the switches. \(Rs\) and \(Cs\) are the snubber resistors and capacitors for the snubber circuits of each of the switches. The values of \(Rs\) and \(Cs\) were calculated using Equations (5) and (7) [43,44], respectively. The resistor, \(Rs\), needed to be low enough to allow the dissipation of power at the maximum switching voltage and current, hence the application of Ohms' law, as described in Equation (5). Since the resistor dissipates its energy by storing it in the snubber capacitor \(Cs\), considering a 2-W resistor such that it is able to dissipate half of its power rating into the capacitor for twice the switching frequency in one second, as described in Equation (6), therefore \(Cs\) was obtained as presented in Equation (7) [43,44], where is the maximum switching voltage, is the maximum switching current, \(f\) is the switching frequency, and \(Cs\) is the capacitance of the snubber capacitor.