A 500 W Microcontroller-Based Powertrain Circuit For Ultrasonic Cleaning Machines

A 500 W microcontroller-based power supply circuit for the piezoelectric transducers used in ultrasonic cleaning machines is presented. The powertrain consists of a boost converter, including AC supply power factor correction, followed by a digitally programmable buck converter delivering the DC bus voltage for a half bridge inverter, driven by a suitable signal from the microcontroller oscillator. Detection of the resonance frequency of the piezoelectric transducer is performed at startup by measuring the load current on the DC bus through a hall sensor.