Research On Compound Sliding Mode Control Of External Rotor Permanent Magnet Synchronous Motor

External rotor permanent magnet synchronous motor is widely used in all walks of life due to its characteristics of high accuracy,high efficiency,high reliability and large torque.Its control performance is excellent,but there is a lot of disturbance and uncertainty in the system,which has a great influence on the stability,accuracy and performance index of the control system.Sliding mode variable structure control has strong adaptability and robustness to system parameter changes,and is widely used in motor control systems.In this paper,according to the control requirements of external rotor permanent magnet synchronous motor,the development and application of sliding mode control theory in motor control are studied in detail.In view of the disturbance and uncertainty of the system,the control system of composite sliding mode control under the condition of low speed and high speed is studied.The high precision control demand of current and speed is realized.Two kinds of composite sliding mode controller are designed,and its validity is verified.The research work of this paper is as follows:(1)Firstly,the working principle,structure and classification of the motor are introduced,and the mathematical model of the external rotor motor in the two-phase rotating coordinate system is derived.The physical structure parameters and electromagnetic analysis of outer rotor motor are studied by Ansoft/RMxprt software,and the physical structure and electrical parameters are shown.(2)An adaptive nonsingular terminal sliding mode controller based on a finite time disturbance observer is proposed to solve the mismatch disturbance problem.The speed loop adopts a non-singular terminal sliding mode controller,introduces the adaptive law of switching term of the non-singular terminal sliding mode controller,and a nonlinear disturbance observer is introduced as a real-time compensator.Finally,through the design of numerical simulation,compared with the traditional sliding mode control.(3)Considering the multi-source time-varying uncertainty in the system,an auto-disturbance-impaired sliding mode controller is designed.Based on the ADRC control framework,combined with the advantages of sliding mode control law to overcome the time-varying interference,a high-performance speed control method is proposed.Finally,through the design of numerical simulation and comparison with ADRC control,the effectiveness of the composite controller is verified.(4)Hardware system is designed,including main control DSP28335 development board,driving power module,sampling circuit,detection circuit,motor and power supply;then,the controller software program design is introduced,including the main program,interrupt service routines,control algorithm program and so on.The design process of the whole software is described in detail.Finally,the experimental results are obtained,and the modulation waveform of SVPWM is generated by oscilloscope.