Design of Performance and Parameter Measurement System for Brushless Direct Current (BLDC) Motor

Abstract

The electric scooter needs a controller to drive and control a brushless direct current (BLDC) motor. To design a controller, the designer needs some motor parameters that may not be provided by the manufacturer. This paper presented a design of performance and parameter measurement system for BLDC in electric scooter application. The investigated parameters were stator resistance, stator inductance, battery current, Back Electromotive Force (BEMF) constant, speed, torque constant, inertia moment, and friction. To obtain these parameters, a microcontroller was used to process some output signals from voltage, speed, current, resistance, and inductance sensor. Resistance and inductance were tested before the motor was operated. The motor was then given a unit step. During 5 seconds of motor running, the microcontroller recorded speed and current data. After that, the motor was unpowered. Later, the microcontroller recorded speed and back EMF voltage on each motor phase. The results revealed that the proposed system could measure the main motor parameters, such as 0.078 ohm of stator resistance, 76.52 µH of stator inductance, 20.28 volt/krpm of back EMF constant, 0.1936 Nm/A of torque constant, 0.0174 Nms of friction, and 0.0471 kgm2,