Research And Design Of PMSM Control System Based On Compound Control Strategy

The permanent magnet synchronous motor has many advantages such as small size,high power density and high efficiency.So it has been widely used in electric vehicles,aerospace,industrial control and other fields.In the speed-regulating control system of permanent magnet synchronous motor,the rotor position and speed of the motor must be obtained by installing mechanical sensors,which inevitably increases the cost and volume of the system and is limited by the application occasions.In this context,the research on sensorless PMSM control system has become a hot topic in many industries.In this paper,the composite control strategy without position sensor is studied for the surface mount permanent magnet synchronous motor(SPMSM).By referring to a large number of relevant literatures and on the basis of other studies,SPMSM sensorless vector control technology is studied for motor low-speed performance,high-speed performance,rotor initial position detection,speed and rotor position dynamic tracking and other aspects.The sensorless permanent magnet synchronous motor control technology is discussed in detail.Mathematical model of permanent magnet synchronous motor is established.The sensorless control strategy of surface mount permanent magnet synchronous motor at low speed and zero speed is studied.The position signal of motor is identified by pulsed high frequency voltage injection.And a method to judge the direction of the d axis is designed.The simulation model of dual closed-loop vector control system is built on PLECS platform,and the correctness of the method is verified.The control strategy of sensorless motor running at high speed is studied,and the sliding mode variable structure control method is adopted to solve the problem of high frequency chattering of traditional sliding mode observer.In order to solve the problem of complex position compensation algorithm for sliding mode observer,an improved method is proposed to normalize the phase locking link.By improving the sliding mode observer,the problem of high frequency chattering and the complex position compensation algorithm are reduced,and the simulation model of the control system based on the improved model is established to verify the correctness of the method.The method of motor running in full speed range is studied.Combining high frequency injection method with sliding mode variable structure control method,a speed weighting method is designed to achieve smooth switching from low speed to high speed operation of motor.A composite observer for the control system running at full speed is established,and a simulation platform is built to verify the correctness and feasibility of this observation method.Finally,the proposed PMSM control system based on composite control strategy was designed with hardware and software.STM32F103VET6 chip was used as the control core.And the main circuit,power circuit,voltage and current sampling circuit and other hardware circuits were designed.The detailed principle of the control system,and designs the main program,interrupt program,initial position detection and speed switcher and other sub-module programs are expounded in the part of software.The feasibility and correctness of the whole control system are verified by experiments on the platform and detailed analysis of experimental waveforms and data.