A method for feedforward decoupling flux weakening control of surface permanent magnet synchronous motor

Abstract

The invention relates to a method for feedforward decoupling flux weakening control of a surface permanent magnet synchronous motor, the method comprising the following steps: S1, a motor controller receives a torque command and inputs it into a MTPA module, and converts the torque command into a target quadrature axis current according to the motor inductance and the permanent magnet flux linkage; S2, obtaining the actual rotational speed omega of the permanent magnet synchronous motor, and obtaining the real-time flux weakening magnetic advance angle beta according to the rotational speed and the weak magnetic advance angle off-line table Look Up Table; S3, calculating the target direct-axis current; S4, limiting the target quadrature axis current iq_ref and the target direct axis current id_ref; S5, obtaining the currents ia, ic of the actual A-phase and C-phase of the permanent magnet synchronous motor through the sensor, obtaining the actual quadrature axis current iq and the actual straight axis current id of the permanent magnet synchronous motor; S6, obtaining the quadrature-axis target voltage uq and the straight-axis target voltage ud; S7, obtaining the alpha-axis voltageu[alpha] and the beta-axis voltage u[beta]; and S8, performing space vector pulse width modulation and completing the voltage input to the permanent magnet synchronous motor through an inverter circuit. Compared with the prior art, the invention has the advantages of simplicity and convenience, simplicity and easy operation of the algorithm regulator and the like.

Description

technical field [0001] The invention relates to the field of automatic control of permanent magnet synchronous motors, in particular to a feedforward decoupling field weakening control method for surface type permanent magnet synchronous motors. Background technique [0002] Limited by the maximum voltage and output current capability of the DC side of the inverter, there are limit values ​​for the stator voltage and current of the motor, which affect the maximum speed and output range of the motor drive system when it works at constant torque. However, above the base speed, if the magnetic flux remains constant, the back electromotive force of the motor will inevitably be greater than the maximum input voltage of the motor, causing the reverse flow of the motor winding current, which is not allowed when the motor is actually running and the field is weakened , the magnetic flux is inversely proportional to the stator frequency, so that the induced electromotive force remain...

AI Technical Summary

Problems solved by technology

The speed difference feedback method uses the deviation between the given speed and the actual speed through the PI controller as the given of the direct-axis current component. The advantage is that it has good robustness and no error in the steady state of the quadrature-axis current, but the response is slow.

Images