The widespread adoption of Electric Vehicles (EVs) relies on achieving high
efficiency and precise motor control. Although Brushless DC (BLDC) motors offer
advantages for EVs, traditional control methods struggle to deliver the desired
performance. This chapter discusses the operation of BLDC and investigates the
development and evaluation of a Field-Oriented Control (FOC) system that enables
precise speed control of BLDC motors in an electric vehicle application. The developed
FOC with necessary coding is provided for a clear understanding of the control. FOC
offers superior control over more straightforward methods, allowing for independent
torque and flux control, improving efficiency and dynamic response.
This research implemented a novel angle-based strategy within the FOC system. This
approach controls the flux position of the motor using a constant 48V supply,
significantly reducing switching losses compared to traditional PWM or PID control
methods. Consequently, the system achieves a peak-to-peak speed ripple of less than
0.3 rpm and demonstrates improved efficiency. The machine dynamics, with the help
of currents, fluxes, and changes in rotor position, are explained in this work.
A practical urban cycle is developed to test the proposed control topology. The
successful operation of the vehicle with produced results highlights the effectiveness of
the developed FOC system with the novel angle-based strategy in achieving precise
speed control and improved efficiency for BLDC motors in EVs, contributing to the
development of EVs with extended range and reduced environmental impact, paving
the way for more sustainable transportation solutions.
Keywords: BLDC model, Back EMF, Developed torque, DC-AC inverter, Flux position estimation, Flux estimation, Hall effect sensing, Load variation, Positionbased speed control, Practical drive cycle, Practical wheel RPM, Position sensor, Switching scheme of inverter, Speed tracking, Torque ripple.
