Effects of disc-shaped piezoelectric size reduction on resonant inductorless DC-DC converter

This paper studies the impact of disc-shaped piezoelectric resonator dimensions on a non-isolated inductorless piezoelectric DC-DC converter. An analytical model, linking geometrical parameters to output power and efficiency is introduced. This later reveals the benefits of reducing the thickness and diameter of the piezoelectric disk. Five piezoelectric discs with different dimensions are tested and compared in experimental works, giving very high efficiency up to 98% and output power up to 1.7 W. An exceptional power density of 366 W.cm-3 was measured at 450 kHz for a 25-30 Volt conversion with an efficiency of 81%.