Reasearch And Design Of BLDCM Control System Without Position Sensor

Brushless DC motor is widely used in industrial and smart home due to its advantages of simple operation,high operation efficiency and convenient daily maintenance.The position sensor in the traditional brushless DC motor weakens the interference resistance of the system and increases the motor failure rate,which is avoided by using the sensor brushless DC motor.However,the rotor position detection of the brushless DC motor is a key problem to suppress the torque pulsation generated during the motor conversion.Therefore,it is important to study the rotor position detection and torque pulsation inhibition control strategy of the brushless DC motor.This paper first illustrates the basic structure and working principle of brushless DC motor,establishes the mathematical model of brushless DC motor,and lays the foundation for the subsequent theoretical analysis.Secondly,in view of the problem of not easily obtaining the antielectric potential value of the rotor position when the motor runs at low speed of the motor,the linear voltage difference and the reverse electric potential are combined with the bipolar PWM modulation mode to obtain the rotor position information at different speeds of the motor.Finally,in view of the torque pulsation problem generated by the phase change process of the brushless DC motor,the current prediction and the phase current of the DC bus method are adopted to calculate the duty cycle of the switch in the controller according to the current change,and make the current rate of the stator winding equal to the current change during the motor phase change.Simulation experiment results show that the proposed method can detect the rotor position in a wide motor speed range,with a high detection rate,while avoiding the influence of different PWM modulation modes.For torque pulsation inhibition,the proposed method can also effectively inhibit the torque pulsation generated in the full speed range of the motor.This paper also built a position-free sensor brushless DC motor control system,designed the hardware circuit and software programs,and verified the designed control system through experimental results showing high feasibility and stability.Figure[52]table[2]reference[66]...