Analys och minskning av effektförlusterna i en borstlös likströmsmotor med vektorstyrning

Sammanfattning: This report addresses power losses in an electric motor arising from various sources. The choice of motor control strategy can decrease efficiency if not implemented correctly or if the motor model in the control loop is overly simplified. BorgWarner, a key manufacturer of automotive components, experienced a significant increase in energy losses and reduced performance when switching their BLDC motors’ control strategy from block commutation to field-oriented vector control. The aim of this study is to analyze the differences between the implemented control algorithms at BorgWarner and identify and minimize the source of the increased losses. The report documents the approach taken to reduce power losses in the control of a brushless DC motor caused by an improper selection of currents in the dq-plane. The project strategy involves measurements and simulations to enhance the understanding of the specific motor in question, with the goal of identifying more energy-efficient combinations of control currents that better account for the motor’s electromagnetic properties. The simplified motor model in the control system was updated to select control signals that minimize losses based on operating conditions. The results demonstrate a drastic reduction in energy losses in the system with a maximum decrease of 50 W and 63 % (from 85 to 35 W) and an increased knowledge of the motor’s characteristics for the company. Furthermore, the project establishes a foundation for further development and improvement of the efficiency of BorgWarner’s implementation of field-oriented vector control.