Power Quality Evaluation and Optimization of Sensor-less Field Oriented Controller on 32-bit ARM Cortex Microcontroller

Abstract

Electronic speed controller (ESC) is an important subsystem in drones, which are used to control and regulate the speed of its electric motor. For the high-end drones which require longer flight times, higher dynamic behavior with smooth and stable performance, Field Oriented Controllers (FOC) which power three-phase sinusoidal back-EMF motors are typically used to provide the required high efficiency, small torque ripple and dynamic performance. This paper proposes an analysis method based on discrete Fourier transform (DFT) over the measured motor current, in order to optimize the system parameters such as modulation period, CPU clock frequency and power supply voltage. As proof of concept, a FOC-based ESC implemented in a generic 32-bit microcontroller is studied. Findings show that the power quality and motor dynamic performance of a FOC ESC depends strongly on modulation period and relatively insensitive with respect to CPU voltage and frequency scaling.