This paper presents a variety of single phase ac line conditioning approaches. The topologies use a minimal number of devices and feature buck-boost voltage regulation capability without a transformer, while preserving a neutral connection which is common with the input ac line. The simplest form of the converter is seen to be a ac voltage regulator with output voltage range of 0-2 p.u. with reasonable line current waveforms. Modifications allow the circuit to operate with fully controlled input current. The circuit can be further extended to provide significant ride-through capability without using a battery. Finally, a full function single phase UPS can also be realized if required. The paper contains analytical, simulation and experimental results.
