| Brushless DC motor(BLDCM)has the advantages of high efficiency,small size and good speed regulation performance,and is widely used in motor drive system.Under normal operation,the BLDCM 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,Therefore,the research on the fault diagnosis and compensation method of BLDCM Hall position sensor has important practical engineering significance.In this thesis,a fault diagnosis method based on Event Finite State Machine(EFSM)logic sequence combined with time threshold constraint is proposed.The Hall signal is used to define the system state transition logic,and the fast sampler is used to obtain the system state time.The Hall fault type is diagnosed by comparing the sampling time with the estimated state time difference at the Hall transition edge,Considering the time estimation error in dynamic operation,the reliability of fault diagnosis is improved by improving the threshold coefficient.At the same time,the existing methods of speed and rotor position estimation and fault-tolerant compensation are summarized,and an improved hybrid observer is proposed to estimate the actual rotor position and reconstruct Hall signal to realize fault-tolerant compensation.The motor driver is designed for the proposed fault compensation system,including power supply circuit,inverter circuit,driving circuit,current and voltage sampling circuit and rotor position detection circuit.Finally,establish an experimental platform for the BLDCM control system,conduct software programming design,and conduct steady-state and dynamic operation(including speed sudden changes and variable load operation)experiments under simulated Hall faults.Analyze the waveform of phase current and rotor position to verify the effectiveness of the proposed calculation method.The experimental results show that the proposed method can quickly diagnose Hall faults and effectively compensate,and the system has good operational performance. |
