Abstract-In order to adapt the miniaturization and low EMI of pulsed power supply, a novel Quasi-resonant piezoelectric transformer converter for high voltage pulse capacitor charging was developed. The system has the advantages of simple structure, absorbing the switch capacitive parameters and zero voltage switching (ZVS). Therefore, this converter is suit to operate under high-frequency conditions. The working principle of converter was introduced briefly, the working modes of inverter were analyzed and the formula calculating the resonant inductive and switch frequency was listed. At last, the design instance was described, the result of reality and calculated were well consistent.Keywords-piezoelectric transformer; converter; Quasiresonant; quantum-mode control .
INTRODUCTIONPiezoelectric Transformers (PTs), which transmits electrical energy through mechanical vibration, presents alternative characteristics to magnetic transformer. It is a very attractive device since it has many advantages, such as, potential low cost, small size and weight, no electromagnetic noise and high power density. PTs may become a viable alternative to magnetic transformers in various applications. However, there is little published report on PT applied to high voltage capacitor charging. Most of researches focus on applications to DC/DC converters and LCD backlighting [1][2][3]. And, those circuits given corresponding literature are too complicated to use in low-power PT applications.In this paper, a study of a simple, single-ended quasiresonant amplifier is conducted. The proposed scheme adopts an external inductor which resonates with the PT input capacitance to make PT working high-efficiency. The output voltage is rectified and the resulting DC value is regulated by quantum-mode control strategy. In this way, the simplification of driving circuit and control circuit can be realized to most extent. The working modes of inverter were analyzed and the formula calculating the resonant inductive and switch frequency was listed. Finally, the design instance was described, the result of reality prove the proposed scheme to be available.. CIRCUIT ARCHITECTURE The switch S 1 switches one time completes for one cycle. When S 1 is turned on, the inductor is charged. When S 1 is turned off, the energy stored in the inductor is transferred to the PT input capacitance, thus producing a resonant voltage. Through PT transformation and rectifying by rectifier circuit, a pulsation direct current will be produced to charge the highvoltage capacitor. The control circuit accepts the output voltage feedback signal which the voltage-division resistance gives, compares with the preinstall voltage value, and controls switch S 1 action.Based on the switch state, the converter operation can be broken into two main models of operation discussed as follows:Mode 1 0 1 [ , ] t t t ∈