Permanent magnet synchronous motor weight-coefficient-free prediction torque control method based on normalization

Abstract

The invention provides a permanent magnet synchronous motor weight-coefficient-free predictive torque control method based on normalization, and the method comprises the following steps: sampling a three-phase current, angular velocity and a rotor position angle of a permanent magnet synchronous motor at a moment k, and obtaining an output current and an equivalent counter electromotive force through coordinate transformation; calculating an output voltage vector and a stator voltage according to the switching state of the voltage source inverter, and predicting an output current, a stator flux linkage and stator flux linkage amplitude and torque at a moment k + 1 according to the stator voltage; calculating a torque objective function, a stator flux linkage objective function and respective corresponding standard deviations by using the stator flux linkage amplitude and the torque, thereby obtaining a new objective function; and finally, using the voltage vector corresponding to the minimum objective function for controlling the permanent magnet synchronous motor. According to the invention, standard deviation normalization is carried out on the torque and the flux linkage objective function, weight-coefficient-free torque prediction control over the permanent magnet synchronous motor is achieved, the system complexity is simplified, torque ripples are reduced, and the torquecontrol precision is improved.

Description

technical field [0001] The invention relates to the field of power electronics, in particular to a method for predicting the torque of a permanent magnet synchronous motor based on per unitization without weight coefficients. Background technique [0002] In recent years, in order to cope with the energy crisis, new energy electric vehicle technology has been vigorously developed. Compared with asynchronous motors, permanent magnet synchronous motors (Permanent Magnet Synchronous Motor, PMSM) have been widely used in the field of electric vehicles because of their high efficiency, high power density and many other advantages. In order to improve the torque dynamic control characteristics of permanent magnet synchronous motors, model predictive control is widely used in the drive control of permanent magnet synchronous motors. However, the conventional predictive torque control method of permanent magnet synchronous motor has the disadvantage of needing to design weight coef...

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Problems solved by technology

[0004] Aiming at the technical problem of complicated calculation amount existing in the existing permanent magnet synchronous motor torque prediction control method, the present invention proposes a permanent magnet synchronous motor torque prediction control method based on p.u. The two objective functions of torque and flux linkage are obtained, and a new objective function without weight coefficient is obtained through standard deviation per unitization, so that the predictive torque control of permanent magnet synchronous motor without weight coefficient is finally realized, which simplifies the complexity of the algorithm , and reduces the torque ripple

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