Design Of Hall Fault Tolerant Control System For Brushless DC Motor In Washing Machine

People's living standards have been improved with the development of science and technology continuously.Household appliances,such as washing machines and air conditioners,have gradually become indispensable.And the green appliances with excellent performance energy saving and environmental protection are becoming more and more popular among everyone.Brushless DC motor relying on excellent performance has been gradually gaining popularity in household appliances.The Hall sensor has characteristics of small size and high sensitivity,it is an important component in the motor drive of the brushless DC motor.However,the Hall sensor may broke down in the case of writing failure,poor working conditions or severe vibration.In this paper a fault tolerant control system has been designed for the problem of Hall sensor in the operation of brushless DC motor combined with its actual situation in the application of washing machine.The problem that the washing machine cannot be operated due to the failure of the Hall sensor has been solved.Firstly,this paper started with the basic structure and principle of brushless DC motor,analyzed the fault condition of one-phase or two-phase Hall sensor of brushless DC motor.Then both a method for judging the failure of a Hall sensor and a fault tolerant method has a proposed.At the same time,a fuzzy PI control algorithm is added to the speed loop of the double closed-loop control system on the brushless DC motor in order to improve the dynamic performance of the control target.The proposed control method the simulation model of the whole control system is built in the MATLAB/Simulink environment based on the previous analysis and the proposed control method.The simulation and analysis of one fault or two faults in the Hall sensor are carried out.The simulation results show that the fault tolerant control system can ensure reliable and safe operation in the event of the brushless DC motor's one or two Hall sensors failure.Moreover,the system with the fuzzy PI control module has a faster response speed indicating that the fault tolerant control system has a good control effect.Finally,this paper designs and builds a DSP-based experimental platform for fault tolerant control system of brushless DC motor.The TMS320F2812 DSP is used as a core and the simulation results are tested with the corresponding additional circuits.The experimental results are consistence with the simulation results which proved the correctness and feasibility of proposed scheme.