This chapter introduces a new class of power converters, that is, ac-link universal power converters [1–12]. This category of power converters is described as “universal,” because the inputs and outputs of these converters can be dc, ac, single phase, or multiphase. Therefore, they can be employed in a variety of applications including, but not limited to, photovoltaic (PV) power generation, battery–utility interfaces, battery chargers and wind power generation.
In ac-link universal power converters, the link has high-frequency alternating current and voltage; therefore, there is no need for dc electrolytic capacitors at the link. Considering all the problems associated with bulky electrolytic capacitors, such as temperature dependency, this converter is an excellent alternative to dc-link converters.
In fact, the ac-link universal power converter is an extension of the dc–dc buck–boost converter and by adding complementary switches and modifying the switching scheme, the link inductor, which is the main energy storage element in this converter, can have alternating current instead of direct current. ...