Simulation and experimental validation of hysteresis current control technique for speed control of brushless DC motor

Abstract

Brushless DC Motors (BLDC) are finding wide applications in household appliances and electrical vehicles. Microcontroller are widely used for controlling the BLDC motors however the realization of BLDC drive requires expertise in microcontroller programming. In this paper modelling, simulation and easy hardware implementation of BLDC motor having shaft encoder using STM32F4 series ARM Cortex-M4 microcontroller is demonstrated. A simple method of controlling the BLDC motor in closed loop, using a hysteresis current controller is implemented. The hall sensors are used to find the exact rotor position for the electronic commutation and the encoder is used to measure actual motor speed. The closed loop operation consists of an inner loop which is hysteresis current controller. The gate pulses for the three phase inverter bridge are produced by comparing the actual currents with the reference currents. The outer speed loop consists of a PI controller which compares the actual speed with the reference speed to obtain smooth speed control under varied load condition. The complete hardware circuits and MATLAB/Simulink environment blocks for programming are discussed in detail. The hardware results demonstrate the easy and accurate realisation of closed loop speed control of BLDC Motor.