Research On PMSLM Full Speed Domain Position Sensorless Control Technology

Permanent Magnet Synchronous Linear Motor(PMSLM)has a huge scope for development due to its simple structure,high positioning accuracy and high thrust,and the ability to achieve linear motion without the need for a drive mechanism such as a screw or pulley.Traditional PMSLM closed-loop control systems often use position sensors such as raster scale and Hall sensors to obtain kinematic position information,which not only increases the cost of the system,but also makes the acquired signal susceptible to interference from the external environment,and the safety and stability of the system cannot be guaranteed.Therefore,the research of PMSLM position sensorless estimation algorithm has certain application value.Firstly,the motor control technology and the position sensorless control technology are systematically described,the structure,classification and working principle of PMSLM are introduced,the mathematical model of PMSLM is derived under three coordinate systems in combination with the coordinate transformation theory,and the space vector pulse width modulation(SVPWM)theory is developed based on vector control and space vector pulse width modulation(SVPWM).The simulation model of the double closed-loop system based on vector control and space vector pulse width modulation(SVPWM)theory is built to verify the effectiveness of the vector control method and to lay the foundation for the subsequent research on the position sensorless control technology.Then,the principle of the sliding mode variation structure is introduced and the Sliding Mode Observer(SMO)is optimised using a super-twisting algorithm to address the inherent jitter phenomenon of SMO,while the switching function in the SMO is improved and put into the higher order derivatives to weaken the system jitter.To reduce the magnetic chain amplitude disturbance,a phase-locked loop module is used to estimate the magnetic pole positions.A simulation model of the vector control system based on the Super-Twisting Sliding Mode Observer(STSMO)is developed and verified to be effective in reducing system jitter,with good estimation results in the medium and high speed domain.To compensate for the natural shortcomings of STSMO in terms of low accuracy at zero speed,the pulsed high frequency voltage injection method is used to detect the position information of PMSLM at low speed.Based on the principle of the high frequency voltage injection method,a high frequency mathematical model of the motor is derived and a simulation model of the pole position observer is built,and the simulation results show that the pulse oscillation high frequency voltage injection method is more accurate in the low speed domain.To address the problem that a single position sensorless estimation algorithm cannot have high observation accuracy in both zero-low speed and medium-high speed conditions,a composite control method is proposed,in which the pole position is detected by pulsed high frequency voltage injection in the zero-low speed domain and switched to the STSMO algorithm in the medium-high speed domain,and the output results of the two estimation algorithms are fused using a weighting function in the speed transition interval to achieve The PMSLM full speed position sensorless control.Finally,the PMSLM control experimental platform is set up and the system is experimented under different working conditions.The experimental results show that the system has good stability and high observation accuracy in the full speed range and can be used in general applications.Figure [87] able [5] reference [92]...