Research And Implementation Of Key Technology Of Position Sensorless Fielded Oriented Control

Permanent magnet synchronous motor is widely used in the field of motion control because of its high power density,high reliability and low consumption.Its performance advantage requires mechanical position sensor to collect rotor position,speed data to achieve magnetic field orientation control to ensure.The installation position sensor increases the complexity of the system and reduces the reliability.At the same time,the rise of cost hinders the enthusiasm of the manufacturers to use permanent magnet synchronous motor,and restricts its application.Therefore,the study of low-cost sensorless drive control and promote the application of permanent magnet synchronous motor are significance to the extension and expansion of the industrial chain of permanent magnet materials in China.Aiming at the key technical problems of sensorless PMSM drive control,the main research results are as follows:(1)Based on the mathematical model of the permanent magnet motor,the field oriented control method is analyzed and simulated.The principle of decoupling control of d and q axis are described,and the technical method of rotating magnetic field based on space vector pulse width modulation is designed and realized.(2)Based on the electrical parameters of the motor,the digital model of the relationship between the inverter command voltage and the motor feedback current is established.An adaptive sliding mode observer is designed to reconstruct the state of the rotor,and the rotor position and speed are estimated on line.(3)For the start-up problem,the open-loop V/f and semi-closed-loop I/f control strategy are adopted.When the EMFs of the motor are increased to meet the accuracy requirements of the sliding mode observer,the control method will switch to sensorless FOC automatically.The multi state transition control strategy is designed and implemented,which can solve the problem of the motor’s jitter and current fluctuation.(4)In the hardware design of the driver,combined with the control timing of SVPWM,a variety of current sampling schemes are given.A cost optimal scheme and the current acquisition software corresponding are designed and implemented.(5)The design of the 1.5KW permanent magnet motor hardware development platform is developed,which is based on DSP-based sensorless drive system prototype.It realizes the FOC,position estimation,motor starting and controlstrategies switching,speed control and so on.The experimental results show that the motor system is stable and achieved a better control effect.