The development of current, speed and torque measurement system for low power electric vehicle motion control applications

Abstract

To design motor drives for optimal motion control, and to obtain precise Brushless DC motor model, accurate measurement of motor parameters like phase current, speed and torque are required. Speed and current are also required to provide feedback between the BLDC motor and its controller to develop a robust BLDC motor control algorithm. In this paper, phase current, speed and torque measurement technique for Hub BLDC motor is presented to analyze its performance for low power electric vehicle applications. For the phase current measurement, the Hall-Effect current sensor ACS712 is used. The speed of the motor is calculated using an internal hall sensor that is connected to dsPIC33F’s input capture pin that generates an interrupt whenever a change in the hall sensor signal value occurs. Further, an experimental setup is established in the laboratory to measure the torque at varying load and to determine the relationship between motor torque, input current, output power, speed and efficiency.