Phase Current Detection And Reconstruction Of Permanent Magnet Synchronous Motor On Resistance Sampling

Permanent magnet synchronous motor(PMSM)has attracted widespread attention because of its high-performance,high-power density,high efficiency and simple structure,and has been extensively applied in multiple industrial fields.In its transmission system,the accuracy of motor phase current detection and reconstruction is positively related to the stability and accuracy of the system.Accordingly,the phase current detection and reconstruction technology is discussed based on the surface-mounted PMSM,so as to realize the high-performance control of the motor vector system.Firstly,the structure of permanent magnet synchronous motor is analyzed in detail,the mathematical model of PMSM is established in three kinds of coordinate system respectively according to the coordinate transformation principle of vector control system,the current control method of PMSM is studied,the application principle of space vector pulse width technology in vector control system is deeply explored,and the simulation model of vector control is built by establishing the model of the main modules in the system,which lays the foundation for the later analysis of phase current detection and reconstruction technology.Then,single-resistance method,double-resistance method,three-resistance method and MOS-based internal resistance sampling method are studied in multi-resistance detection technology,in which the reason why single MOS internal resistance sampling cannot reconstruct three-phase current is analyzed,and the three-resistance method is determined as the current detection mode of motor controller.Aiming at the problem of the phase difference between the current phase and the actual current caused by the phase current sampling point offset,and the motor current phase shift is corrected by data fusion based on the rotor electric angle and the reconstructed phase current synthesis vector.Finally,the hardware circuit design and program design of the motor controller are completed.The hardware circuit includes the design of system core circuit,motor drive circuit,current sampling circuit and man-machine communication circuit.The program mainly involves the design of the phase current sampling program,the rotor position estimation program,the phase current phase correction program and etc,and completes the production of the motor controller through the DXP software.The vector control model of PMSM with phase current correction function is established in the Simulink platform of MATLAB software,and the correctness of the basic theory of vector control is verified.The phase shift of the motor current generated by the software simulation is tested by the simulation model,and the experimental results confirm the feasibility of the phase current correction algorithm.The Hall filter and drive circuit are surveyed on the hardware platform of the motor controller,and the correction algorithm is implanted into the control chip to correct and assess the current phase shift.The practical feasibility of the phase current correction algorithm is proved again.