PVMD Delft University of Technology Learning objectives DC-DC - PowerPoint PPT Presentation

Buck-Boost Converter and its Efficiency Olindo Isabella PVMD Delft University of Technology

Learning objectives DC-DC converter 1. Introduction to electrical conversion 2. Electrical components 3. Topologies 4. Efficiency of a buck-boost converter DC-AC inverter

Buck-Boost converter + - + V in V out R L V L I L Load C - + - L I out

Buck-Boost converter: on I in + ON - + V in V out R L V L I L Load C - + - L I out

Buck-Boost converter: off + OFF V d ~ 0 - + V in V out R L V L I L Load C - + - L I out

Continuous mode V out V out V out V in D 0 0,25 0,5 0,75 1 See Solar Energy book, Appendix F

Comparison ! & )* ! "#$ = & + ! ! "#$ = ! "#$ = 1 − & ! )* )* 1 − & Buck Boost Buck-Boost V out = 0 D = 0 V out = 0 V out = V in D = 1 V out = V in V out = ∞ V out = ∞ )* = ! )* = 1 − & "#$ ! ! ! ! )* = ! "#$ (1 − &) "#$ & & Buck Boost Buck-Boost D = 0 V in = ∞ V in = V out V in = ∞ D = 1 V in = V out V in = 0 V in = 0

Efficiency of the converter P out = output power P D = dissipated power P switch = switch losses P L = coil losses

Example MOSFET , metal-oxide semiconductor field-effect Controller transistor - + MOSFET MOSFET Inductor Capacitor V output V input (L) (C) - +

Recap