Design of an optimized PCB motor with a GaN switched integrated motor drive

Printed circuit board (PCB) machines are gaining popularity because of their ease of manufacturing. However, it is harder to drive these machines with conventional drivers since they have relatively low phase inductances. The capabilities of gallium nitride (GaN) at higher switching frequencies make it possible to drive the machine with a small driver footprint which is suitable for integrated motor drive systems. In this paper, an integrated motor drive with GaN switches is constructed. The electromagnetic design starts with the analytical calculation of air-gap flux density and later on an analytical model is used in the non-dominated sorting genetic algorithm (NSGA-II) algorithm multi-objective optimization of the axial-flux permanent magnet synchronous machine with PCB stator. The model is validated on finite element analysis. The design of the control and power stage of driver circuitry is given in detail with all the necessary sensors and control circuitry. A mechanical and thermal solution is offered to this tightly packed integrated motor drive system. The machine is driven using field-oriented control up to 5000 RPM and 0.36 N.m torque. The system efficiency is found to be 82% at this operating point.