Resistor Sampling Reconstruction Of Position Sensorless Permanent Magnet Synchronous Motor Non-Observation Area Compensation

Permanent magnet synchronous motor(PMSM)with its many advantages of high efficiency,high performance,high power density,simple structure has been widely valued and used in many industrial fields.In the PMSM drive system,in order to complete the closed-loop vector control,real-time detection of motor three-phase winding current and rotor position information is an indispensable condition.However,location sensors and current sensors are expensive and will restrict its application.Therefore,from the perspective of further reducing the system cost and achieving high performance vector control,this paper takes the surface mounted permanent magnet synchronous motor(SPMSM)as the research targets,and studies the phase current sampling and reconstruction technology and position sensorless control technology.First,the structure characteristics of PMSM are analyzed,the mathematical model of PMSM in different coordinate systems is established according to the coordinate transformation principle,the space vector modulation method of PMSM is discussed,the position sensorless vector control scheme of PMSM is studied.The simulation model of the main modules in the control system is established,which lays a foundation for the subsequent research on sensorless vector control of PMSM.Secondly,the principle of multi-resistance current sampling is expounded,including three-resistance and dual-resistance current sampling.The three-resistance and dual-resistance current reconstruction methods are described in detail respectively,the three-resistance sampling method with high modulation ratio is studied,the problem of dual-resistance current sampling dead zone is studied and a suitable filtering method is proposed.The experimental platform is set up,and a series of experimental studies on the described three-resistance and dual-resistance current sampling and reconstruction methods are carried out respectively with the upper computer and oscilloscope,which proves the effectiveness of the proposed theory and methods.Thirdly,the principle of single-resistance current sampling is expounded,and the method of phase current reconstruction in the observable area is studied.Based on the definition of the non-observation area,the difficulties of current reconstruction in the non-observation area are deeply analyzed,the compensation control method in the non-observed area is discussed,and the three-phase AC current in the whole area isreconstructed.Correct the problem in the minimum pulse width mode by modifying the space vector modulation mode,and the problem that only single-phase current can be sampled but no current reconstruction can be performed after compensation is solved by designing the current observer.The experimental platform is set up,and a series of experimental studies on the described single-resistance current sampling and reconstruction methods are carried out respectively with the upper computer and oscilloscope,which proves the correctness of the proposed theory and methods.Finally,in order to make further efforts to reduce the system cost,based on the phase current reconstruction technology,the position sensorless technology is introduced,and the two technologies are integrated into one system.The principle of Luenberger observer is described,and Luenberger observer is designed.Two new estimation methods for rotor speed and position of PMSM are studied,the first one combines the phase-locked loop(PLL)technology and the variable low pass filter,and the second one combines the wavelet de-noising and the fuzzy PLL technology.Simulation models are built in the Matlab/Simulink simulation environment,and the comparative study is carried out.Simulation results verify the feasibility of the proposed methods.