Analysis of N-phase tapped inductor boost DC-DC converters

High boost‐ratio bidirectional converter for interfacing low‐voltage battery energy storage system to a DC bus

“…The terminal voltages of the RES feeding the DC microgrids are, however, much lower than these DC-bus voltages, necessitating the use of high boost-ratio DC-DC converters (HBRCs) to interface these sources to the DC bus [4-8, 10-12, 15]. The HBRCs employed in these applications can be categorised into those with galvanic isolation [8,[14][15][16][17] and those without [4][5][6][7][8][9][10][11][12][13][14][15][18][19][20][21][22][23][24][25][26]. Galvanic isolation can be provided using either transformers or coupled inductors [14][15][16][17].…”

“…However, they suffer from the high switch and diode voltage stress [6]. Interleaved CIBCs have input-side always parallel connected to share input current, thus reducing conduction and switching losses and also increasing power handling capability [4][5][6]15]. In cascade CIBCs, the output-side part of the circuit is also parallel connected [6,13,15] lowering output current and voltage ripple.…”

“…A novel bidirectional passive lossless snubber circuit to clamp the voltage spikes without affecting normal operation is thus proposed. For operation with low input and output ripple allowing significant filter capacitor reduction, input current sharing for higher power ratings and efficiency, low input voltage and hence switch voltage stress the structure for the interface is modular [4][5][6][7]. Through careful selection of the tapped-inductor windings turns-ratio and duty-cycle, the necessary boost-and buck-ratio and further reductions in the size of components can be achieved while keeping the device blocking voltages within acceptable limits.…”

“…Most practical DC microgrids utilise 350–400 V [4–13] and 700–800 V [4, 5, 13, 14] DC busses to supply single‐phase and three‐phase inverters, respectively. The terminal voltages of the RES feeding the DC microgrids are, however, much lower than these DC‐bus voltages, necessitating the use of high boost‐ratio DC–DC converters (HBRCs) to interface these sources to the DC bus [4–8, 10–12, 15]. The HBRCs employed in these applications can be categorised into those with galvanic isolation [8, 14–17] and those without [4–15, 18–26].…”

“…high input voltage) means higher switch stress and vice-versa. From[4,5], a high duty-ratio equates to high ripple operation.BTIBC performance is evaluated based on the above design considerations, by designing and simulating a two-phase converter with the following specifications:Vbat = 60 V (during charging) and 48 V (during discharging); V bus = 380 V, P o = 1 kW, f sw = 100 kHz, output voltage ripple is 2% of the capacitor voltage, coupling coefficient, k = 0.99, turns-ratio, n = 6, duty-cycle, D 1 = 0.53 (in buck-mode operation) and D 2 = 0.5 (in boost-mode operation), L 1N = 2.97 mH, L 2N = 84.8 µH, C o = 2.5 µF, r L1N = 0.75 Ω, r L2N = 0.028 Ω, and r ds,on = 0.032 Ω.…”