Reducing the resonant frequency difference of piezoelectric transformers parallel system with mechanical coupling

Abstract The resonant frequency difference of piezoelectric transformers (PTs) with a classical parallel connection could worsen system performance, then the mechanical coupling of PTs was proposed to avoid the disadvantage. Experimental results showed that when the difference was relatively small, the performance of the classical parallel system and proposed mechanical coupling system was similar. However, when the difference increased, the maximum output power of a classical parallel system at a temperature rise of 20 °C reduced by 32.6% and that of mechanical coupling system reduced by 7.7%. This indicated mechanical coupling was better than classical parallel connection in improving the output power of PTs.