GaN-Based Power Converters for High-Frequency Industrial Drives

Abstract

Due to the increasing need of high-efficiency, fast-response, and compact motor drive systems in the current industrial sector, a search into the wide bandgap semiconductors has been made and has particularly focused on those kinds of power devices based on Gallium Nitride (GaN). Transistors based on GaN have a better material quality in terms of power parameters than silicon based transistors (higher breakdown voltage, faster switching speeds, lower on-resistance, and superior thermal conductivity) which allow to design high frequency power converters with, at least, an order of magnitude higher frequency. This work is a full scale design, modeling, and performance analysis of a three phase GaN based inverter optimized to high frequency industrial drive applications. The converter also has state of the art GaN HEMTs and runs at 200 kHz switching frequency, significantly saving the sizes of passive components and enhancing dynamic control response and totally harmonic distortion (THD). There is a Space Vector Pulse Width Modulation (SVPWM) scheme to work in the system and perform accurate torque control and a PI-based current controller working in the synchronous d-q reference frame. The simulation model under composition was a detailed one, developed in MATLAB/Simulink with the assessment of both thermal and electric properties of GaN devices with the use of PLECS blocks. The converter was tested in different load line activities and the converter was tested concerning abrupt torque transition and dip voltage. Also, Hardware-in-the-Loop (HIL) testing was performed aboard an OPAL-RT simulator and dSPACE controller board to evaluate real-time behavior of operations. A 10 kW PMSM drive prototype under experimental tests showed that the GaN based system has a high efficiency of 97.5%, a decreased electromagnetic interference (EMI) noise, and a reduced switching loss, and better thermal characteristics when compared with a silicon-based prototype. The article has also verified that GaN-powered converters not only meet the demanding operation requirements of the high-frequency industrial drives, but also advance to the next generation of small-size and energy efficient motor drive products in automation, robotics, and process control systems.