Parallel Driving of Piezoelectric Transformers

Abstract

Parallel driving of piezoelectric transformers has been studied to increase output power, and output characteristics of multiple piezoelectric transformers that are driven in parallel from 2 to 5 have been compared to those of a single transformer. The voltage step-up ratio increased in proportion to the parallel connection number, n, but the rate of increase decreased gradually, so there was little increase with driving over 5 piezoelectric transformers in parallel. The relative efficiency showed a maximum value of 1.06 with n of 2 and a minimum value of 0.75 with n of 5. The output power increased continuously according to the parallel connection number, but the relative output power per transformer gave a value of 1.015 with n of 2 and decreased to below 1.0 with greater n, so n of 5 gave a value of 0.75.

Piezoelectric Transformer-Based High-Voltage Pulse Generator Using Wide-Bandgap Semiconductors for Medical Electroporation Therapy

“…Therefore, since the PT is not operating permanently at excess power levels and it can be controlled using burst-mode control, it is anticipated that the temperature rise within the PT will remain within its limits. Alternatively, to overcome this issue multiple PTs operating in parallel may be used to charge at a faster rate [ 17 ].…”

“…While a low valued capacitor is used to illustrate the performance and characteristics of the capacitor charging in Stage I (based on available PTs and computational resources), the output pulse-generator stage is demonstrated using the 3.8 kV, 500 µF HV capacitor required for a standard electroporation treatment protocol. Based on the simulation results of Stage I with one single PT, the estimated time taken to charge a 500 µF capacitor to 2 kV is around 60 s. However, if five PTs are connected in parallel [ 17 ], the charge time would be approximately 12 s, which is significantly better than 2–3 min required for a recently proposed low-cost portable electroporator [ 34 ]. The SiC MOSFET G2R50MT33K rated at V DS = 3.3 kV and I DS = 44 A has been chosen for the output HV bridge-inverter (S 1 to S 4 ) which supplies HV bipolar pulses to the equivalent electrode load-resistance, chosen as R load = 50 Ω.…”

Piezoelectric Transformers For A High Power Module

“…The efficiency circ alculation for efficiency of piezoelectric transformer uit [2]. In the equation (1) the efficiency is expressed by "Q m " and "k," mechanical quality factor and electromechanical coupling factor, respectively.…”