A Novel Hybrid Converter Derived from Buck-Boost Circuit For Standalone Applications

This paper proposes a single-switch circuit derived from buck boost converter which converts input DC voltage into desirable AC and DC voltages. The switching strategy used is sinusoidal pulse width modulation with a DC offset-known as augmented sinusoidal pulse width modulation (ASPWM). The ASPWM waveform is obtained by sine triangle comparison method where the modulating signal is the combination of a sinusoidal signal-obtained from the AC output - and a DC offset-obtained from the DC output. The AC output voltage is predominantly controlled by the amplitude of AC component of the modulating signal, while, the DC output is predominantly controlled by the DC component of the modulating signal. The two possibilities of tapping the AC voltage from the converter have been explained and the method of 'tapping the voltage across the switch' is considered for analysis and simulation. The circuit is extensively simulated in MATLAB. The proposed circuit has applications in PV fed nanogrids for domestic stand alone applications.