Research On Fault Diagnosis And Fault-tolerant Control Of Hall Sensors In Brushless DC Motors

Permanent magnet brushless motors have the advantages of high efficiency,small size,and good speed regulation performance,and are widely used in motor drive systems.Under normal operation,the brushless DC motor obtains the rotor position information through the Hall sensor to achieve precise commutation.However,the rotor position and speed estimation is carried out under the fault-free state of the Hall sensor.In actual work,the Hall sensor failure caused by mechanical vibration and electromagnetic interference will seriously affect the running state and performance of the motor.Therefore,the research on fault diagnosis and fault-tolerant control of BLDC motor Hall sensors is of great significance.In this thesis,a fault diagnosis method based on Hall vector and Hall state sequence is proposed for the Hall faults caused by the failure of the Hall sensors during the BLDCM operation.By vectorizing the Hall state at the Hall jumping edge,summarizing the Hall state change characteristics under different fault types,and diagnosing 18 types of Hall faults without adding a hardware diagnostic circuit.By improving the existing fault-tolerant control method,two improved control strategies are used to complete the operation control under the state of motor fault: improved angle extrapolation estimation method and improved hybrid observer method.Finally,design motor hardware equipment on Altium Designer software,complete the design of inverter,power supply module,drive module,acquisition module,and design peripheral circuits.Finally,the Hall sensor fault-tolerant control strategy is tested on the built motor control experimental platform.Based on TMS320F2812 DSP software programming design,steady-state operation and dynamic operation(including speed mutation and variable load operation)experiments are carried out in the case of simulating Hall fault to verify the effectiveness and efficiency of the proposed algorithm.By analyzing the obtained operating experimental results,the steady-state performance and dynamic performance of the proposed fault-tolerant control strategy are verified,indicating that the Hall fault can be quickly diagnosed,and the improved fault-tolerant control method is feasible and effective.