The stable operation of the motor is very important in all industrial fields such as household appliances, information communication equipment, and electric parts. Therefore, for the operation considering the stability and reliability of the motor, it is necessary to consider the control method in addition to the design and manufacture according to the characteristics of the motor. Recently, fault diagnosis and compensation methods of electric motors have been studied variously. The purpose of this research is to detect faults in advance before stopping the motor and to maintain and compensate for losses and faults.

The main motor proposed in this paper is brushless DC motor. In recent years, BLDC motors have been widely applied to various home appliances, robots, and automobile industries due to their advantages such as high output, low noise, and easy control. Furthermore, demand is expected to continue to increase in the future. The BLDC motor obtains the position information of the rotor based on the Hall sensor as the position sensor. Hall sensors are cheaper than other position sensors (encoders, resolvers, etc.) and are used in industrial fields in a relatively simple manner to determine only the polarity of the rotor. However, there is a possibility that the sensing error may be caused by a mechanical defect in the user''s carelessness and the severe condition. Therefore, it is necessary to control the jumping magnetic field of the 6-step stably to maintain the reliability of the motor operation. Finally, the sensorless control method should be considered.

This paper is based on the control method of two phase energized hall sensor of three phase BLDC motor. To be specific, we introduce the Fail Safe control method for driving the current ripple and torque ripple of the BLDC motor considering stability and reliability. The main control method is to introduce the sensorless automatic changing method after detecting the hall-signal position error in the section where the driving of the BLDC motor is difficult. In addition, a stable control method of BLDC motor is introduced by designing torque disturbance observer for stable driving. To verify the proposed techniques, we verify the validity of the proposed algorithm through Matlab/simulink simulation.