Transient response analysis of a Rosen-type piezoelectric transformer and its applications

This paper investigates the characteristics of voltage transient response, such as the maximum voltage, direct current (DC) time constant, alternating current (AC) time constant and oscillation frequency, and their applications for a Rosen-type piezoelectric transformer (PT). The transient response is induced immediately after an AC voltage connected to the PT is switched off. For the applications, the maximum voltage is used to elucidate how to cause an electrical shock for users of the PT under open-circuit operation. The DC time constant and the AC time constant are used to estimate the equivalent resistance of the mechanical loss and the dielectric resistance of the dielectric loss, respectively. Also, the AC time constant is used to estimate the quality factor of the PT. Additionally, the oscillation frequency is used as an antiresonant frequency of the PT. In order to verify the above characteristics and applications, both an equivalent circuit with initial conditions and a drive system with a control switch interposed between the PT and its AC voltage source are adopted to derive the transient response and measure its characteristics. Effects of the load resistance of the PT and the switching-off time of the voltage source on the transient response are measured and discussed.