Prototyping of a PMSM Drive Controller and Test Bench

Manfred Pross

Wednesday, January 17, 2024, 11:00

Room 01-012, Georges-Köhler-Allee 102, Freiburg 79110, Germany

This thesis is about designing and prototyping a drive controller for a miniature permanent magnet synchronous motor (PMSM). A succession of implementation steps covering circuit design, digital signal processing and embedded software, each including results and measurements, is presented. An inverter is described that has little space requirements and reduced switching losses. Both is achieved through the implementation of enhancement mode Gallium nitride FETs (eGaNs). A method for realtime evaluation and linearization of rotor position and velocity from three phase analogue Hall sensors is proposed. A test bench is designed to provide feedback of the motors mechanical output power, torque ripple and speed. Circuitry, software and tools for the instrumentation of both, drive controller and test bench are presented. The successful interaction of all components is demonstrated using a basic vector control algorithm. An approach to estimate quality of the stator currents during runtime is proposed. The deviation from desired sinusoidal shape can thus be quantified distinctively. This may help for automatic tuning of control parameters in order to ensure efficient and smooth run of the motor. Finally, a method for measuring stator ripple current is described. This allows the inverter settings to be adapted during commissioning and operation of the motor.