2022 – 2023 · ITEC Asia-Pacific 2023
400-W Circular GaN Power Converter
An 80-mm round GaN inverter board sized to sit inside a small servo motor housing for integrated motor drives.
- 80 mm
- circular board diameter, matched to the motor housing
- 400 W
- target output power
- 10–48 V
- DC-link range, up to 10 A
Problem
Integrated motor drives place the power converter directly on the motor, eliminating long cables, raising power density and reducing high-voltage transients on the windings. For small servo motors the hard part is size: conventional rectangular converter boards don’t fit a cylindrical housing.
Approach
- Chose the axially housing-mounted integration scheme, which keeps the motor diameter unchanged.
- Designed a circular PCB around three TI LMG5200 integrated GaN half-bridge modules, removing discrete gate-drive circuitry and reclaiming board area.
- On-board power conversion: an LM5017 buck converter for the 5 V rail and an LDO for 3.3 V.
- Three-phase current sensing with current-sense amplifiers, plus a comparator-based over-current protection path that signals the controller to shut down.
Results
The prototype was mounted against the end of a 100-W, ~80-mm PMSM and driven by a TMS320F28377D controller with dual-closed-loop control, producing symmetric and stable three-phase stator currents — validating the board for low-power integrated motor drives.
Related publication
Design of a GaN-Based Power Converter for Small-Sized Integrated Motor Drives
IEEE Transportation Electrification Conference and Expo, Asia-Pacific