Sensorless field-oriented control inverter of BLDC motor for copter

Dávid Rau – Tomáš Vršanský

   This paper focuses on optimizing the propulsion system, specifically the control aspect. It presents the design of a sensorless inverter with field-oriented control for BLDC motors, primarily intended for copters. The theoretical part covers motor modeling and the design of the control structure, employing field-oriented control and a sensorless approach using back-electromotive force observer to estimate the rotor position. The physical implementation of the control system is based on an electronic inverter with two logical components. The control component utilizes a microprocessor for FOC control and incorporates memory, sensor systems, and peripherals. The power component ensures controlled energy transfer through complementary signals and feedback measurement. Communication between components and with the higher-level system, regarding control and configuration, is also addressed. Finally, the inverter underwent testing on a measurement platform and during copter flights. The measurements focused on motor speed estimation and control performance under load and no-load conditions. The assessment concludes with trust scaling and temperature measurements of the inverter.

Keywords: Drone, copter, BLDC, FOC, vector control, observer, invertor, sensorless

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