Reversible unity power factor step-up/step-down AC-DC converter controlledby sliding mode

A reversible step-up/step-down ac-dc converter is presented in this paper. It is a fifth-order system, capable of managing power transfer from a dc so urce to an ac one, with any ratio between the dc and the ac voltage levels, and producing a sinusoidal output current, using only one power processing stage. By reversing the energy flow, this circuit becomes a high power fac tor rectifier. This reversion can be obtained simply by inverting the refer ence ac current. The system is analyzed as the connection of two independen t lower order subsystems, controlled by sliding mode with decentralised swi tching scheme. Experimental results from a 100 W prototype operating in bot h senses, as inverter and as rectifier, are shown to confirm the mathematic al analyses and simulations.