Research On Sensorless Control Strategy Of Permanent Magnet Synchronous Motor In Full Speed Rang

With the implementation of the "double carbon" and "1+N" policies,motors will face unprecedented development opportunities in the fields of automatic,semiconductors and artificial intelligence.Permanent magnet synchronous motor(PMSM)has been widely used in control fields such as new energy hybrid vehicles,robots,aircraft and biomedicine due to its high power to mass ratio,excellent braking performance and greater output torque.The Permanent magnet synchronous motor drive control systems often need to obtain rotor position information,in the traditional control method usually use the installation of sensors to identify the rotor position,which not only makes the system mechanical complexity increased,but also reduces the accuracy due to the inherent characteristics of the sensor itself,which is easy to be distorted when used in harsh environments,resulting in the unstable operation of the system.Therefore,sensorless control strategy is required.To realize sensorless control in the full speed domain range,this paper performs theoretical analysis and experimental research in two distinct areas:zero low speed and medium high speed.(1)In the low speed operation stage of permanent magnet synchronous motor(PMSM),in order to solve the problems of weak back electromotive force signal,low signal to noise ratio,and difficulty in extraction,an I/F open loop start control method is proposed.In addition,because the initial rotor position is unknown and there is a blind spot in the primary positioning,the secondary positioning method is used to accurately locate it.Finally,through Matlab/Simulink simulation,it is verified that I/F control can relatively stably start the motor.(2)At the motor’s mid-and high-velocity operation stage.A sliding mode observer that is adaptive is suggested to counterbalance the jitter generated by the symbol function’s transition to zero point and the phase lag of rotor position recognition in the conventional sliding mode observer.A hyperbolic tangent function,which is controllable and continuous,supplants the traditional symbolic one,thereby augmenting the buffeting suppression effect.Phase-locked loop-based position detection can be substituted for the traditional inverse tangent to ascertain rotor position,thus bringing the estimated value nearer to the true value.The inverse difference technique is employed to compute the differential equation,thereby diminishing system noise and intricacy concurrently.Verification of the adaptive sliding mode observer’s superiority over the traditional sliding mode observer in suppressing chattering is achieved through Matlab/Simulink simulation analysis.At the same time,to ensure a smooth transition from zero low speed to medium high speed,a non-linear weighted switching based on Sigmoid function is used to achieve sensorless control in the full speed domain.(3)The PMSM position sensorless inverter drive hardware experimental platform was constructed using a combination of the Texas Instruments TMS320F28335 digital chip and its corresponding control circuit.The paper’s position sensorless control algorithm was put to the test,with corresponding software and hardware design being executed respectively.The upper computer’s experimental results,when analyzed,demonstrate that the algorithm can commence at a steady low speed and swiftly transition to a medium high speed,with remarkable precision and minimal mistakes,as well as excellent dynamic properties,thereby confirming the efficacy of the control strategy.