Research On Improved MRAS Control Of Permanent Magnet Synchronous Motor

Permanent magnet synchronous motors have the advantages of high efficiency,large moment of inertia,and fast dynamic response speed.They have obvious advantages in the field of high-power AC drives.The permanent magnet synchronous motor is a strongly coupled and complex nonlinear system.Its high-performance control depends on accurate rotor position information.However,to obtain the rotor position and speed,it depends on the use of mechanical sensors such as photoelectric encoders,resolvers,etc..As a result,the motor system is large in size,high in cost,and anti-jamming capability is reduced.In recent years,sensorless control of motors becomes a research hotspot.This paper is based on the model reference adaptive speed identification method.In order to allow it to work at lower speeds to obtain a wider speed range,a new type of integrator is designed based on the compensation algorithm of the stator flux linkage and the back EMF orthogonal,because of the defects of the traditional voltage model due to the error accumulation and zero drift of the pure integrator when the motor is running at low speed.In contrast to using a first-order low-pass filter,amplitude-limited integrator,etc.to replace the pure integrator,the integrator designed in this paper is adaptive.It can compensate the stator flux in real time,and automatically adjust the compensation to the best.It improves the system's dynamic response characteristics and essentially eliminates the problems caused by pure integration.Based on this method,an improved voltage model based on the new integrator is designed,a stator flux observer based on the new voltage model is built,and a simplified adjustable model is used to build the MRAS model.The improved MRAS algorithm can also have good speed measurement performance at lower speed occasions,allowing it to obtain a wider speed range than the traditional algorithm.In addition,in the ??0 coordinate system,the MRAS model uses magnetic flux as a state variable,avoiding differential operations,reducing the complexity of the algorithm,and it is more conducive to the programming of the algorithm.In this paper,a sensorless vector control system for a permanent magnet synchronous motor is constructed.The vector control system is simulated in MATLAB /Simulink environment.The results show that the improved MRAS model based on the new voltage model can observe the flux linkage and track the speed of the motor quickly and accurately.In this paper,the method is applied to the real applications.An experimental platform consisting of a permanent magnet synchronous motor and a three-level inverter is built.The control circuit is based on the DSP28335.The NPC three-level inverter with control method has wide application prospects in many fields.