Position Sensorless Control Combined With Improved Sliding Mode Observer And I/F Start

"Made in China 2025" clearly proposes to accelerate the healthy development of industrial servos,new energy vehicles,energy-saving systems,and enhance the competitiveness of manufacturing to reach the world's leading level.The core component of equipment manufacturing is servo motor,and the independent development of high-end servo motor drive control system is the key to intelligent manufacturing.Permanent magnet synchronous motors are widely used in aerospace,intelligent furniture,numerical control(CNC)machines,etc.due to their high starting torque,high overload capability,wide speed range and high operational reliability.Permanent magnet synchronous motors Traditional drive control systems typically use position sensors(such as resolvers)to obtain rotor position and speed information.These position sensors are not only expensive but also have reliability problems and cannot be used in special occasions.Therefore,position sensorless control has become an important research direction in the field of modern motor control.This paper first introduces the research background and significance of PMSM sensorless control technology.It analyzes and compares several commonly used position sensorless control methods,and selects the highly robust sliding mode observer method(SMO,Slide Mode Observer)as the research focus of this paper.In addition,the mathematical model of permanent magnet synchronous motor and its coordinate transformation are deduced.The common control 0dI(28)strategies of permanent magnet synchronous motor are analyzed.The realization of seven-segment SVPWM in hardware is introduced in detail.Then the sliding mode observer control method is deeply studied.According to the sliding mode variable structure control theory,choose the appropriate sliding mode switching surface.The design method of the traditional sliding mode observer is introduced.Then the dynamic boundary layer idea is proposed,and the dynamic saturation function is used instead of the switching function to establish the improved state equation of the sliding mode observer to realize the position sensorless control in the medium and high speed and wide speed range.Using the Matlab R2014a/Simulink simulation tool,the improved sliding mode observer method Simulink simulation model based on dynamic boundary layer is built.The simulated waveforms show that the improved sliding mode observer method effectively attenuates the chattering of the system,making rotor speed and position estimation more accurate over a wider range of speeds.In addition,in view of the problem that the traditional starting mode has large torque and speed fluctuations when the load changes,this paper adopts the current closed-loop I/F open-loop starting strategy with strong carrying capacity.In-depth study of the switching problem,after the pre-positioning,the motor through the start acceleration,stable operation,angle switching,speed closed loop four steps to achieve smooth switching of the motor.Finally,the permanent magnet synchronous motor test platform was built with TI DSP28335 as the microcontroller,and the hardware circuit design and debugging and software algorithm implementation were completed.The test results demonstrate the effectiveness of the sensorless solution proposed in this paper.The solution is simple and easy to implement by digital processor,and has strong engineering practical value.