Abstract:
The interest in sensor less three-phase BLDC motor for medical applications has been growing
in recent years due to their potential advantages over other electric motors. The most popular
form of treatment for those who have sleep apnea is the use of a continuous positive airway
pressure (CPAP) machine, which keeps the patient's airway open while they sleep by forcing
pressurized air down their throat. According to the patient's breathing pattern, the motor's
blower fan or rotor speed will, in this application, increase or decrease the patient's airway
pressure.
This paper presents a unique methodology for sensor-less BLDC motors in CPAP device. The
BEMF observer method enables high performance within line-to-line back emf estimation using
unknown input because the relationship between magnitude of BEMF and rotor speed is directly
proportional. For control of the motor genetic algorithm FOPID and FPID speed controller is
implemented to adjust DC-link voltage based on the error between estimated rotor speed and
desired speed reference. The controlled gain output of the FOPID and FPID controller is fed to
the hysteresis current controlled DC-link voltage source inverter. The result of the FOPID
controller has good performance is investigated and the speed of the motor for different speed
level using MATLAB/Simulink software. And the result of the simulated speed response of the
controller for different speed has been done and settling time is 0.1610sec and rise time is
0.2033sec speed response controller. switching of three-phase voltage source inverter controlled
has been done effectively based on the BEMF observer and hysteresis. The simulation results
obtained agree with the design objective.
