Voltage-Sensorless Control and GaN Multilevel Converter for Charging Non-Linear and Lossy Electrocaloric Capacitors

This work represents the control and operaton of highly-efficient GaN multilevel converter for cyclic charging and discharging of lossy and non-linear capacitive loads without additional voltage sensor. A hysteretic inductor current control with efficient zero voltage switching is used to achieve high power conversion efficiency. The transitions between the multiple input voltage levels are triggered by voltage-sensorless timing circuit. The maximum expected switching period during hysteretic current control is calculated based on LC-circuit analysis and detected by a timeout circuit. The control system is implemented on an programmable system on chip (PSoC), and verified with a GaN-based six-level converter and electrocaloric, non-linear and lossy capacitive of around 10 µF by 240 V.