I. Introduction
The piezoelectric transformer (PT) is a compact device capable of generating high voltage and is present in many common technologies, such as LCD screens and compact ac/dc converters, typically supplying between 30 and 300 V [1]–[3]. Under certain conditions, researchers have used the PT to achieve much higher output voltages, ranging from 5-kV ozone generators to 120-kV X-ray sources [4], [5]. These high-voltage modes of operation have motivated the investigation of the PT as a driver in compact X-ray sources for medical, industrial, and emergency response applications [6].