Induction machine rotor field directional deviation correction method based on torque estimation

Abstract

The invention provides an induction machine rotor field orientation deviation correction method based on torque estimation. Two methods are respectively adopted in the induction machine rotor field orientation deviation correction method to calculate the output torque of an induction machine. First, voltage and current under a two-phase static coordinate in a vector control system is utilized to calculate output power of the induction machine, and the output torque of the sensing motor is obtained through estimation. Second, by means of current instruction values of a d shaft and a q shaft under a rotating coordinate of the vector control system and a magnetic field orientation deviation angle, the output torque of the sensing motor is obtained through calculation, then an equation of torque composition comprising the magnetic field orientation deviation angle is obtained through calculation of the two methods, the magnetic field orientation deviation angle is solved through the equation, and deviation correction is achieved. The induction machine rotor field orientation deviation correction method based on torque estimation improves accuracy of magnetic field orientation in a traditional sensing motor vector control method, particularly the orientation precision of speed operation of a weak magnetic region.

Description

technical field [0001] The invention belongs to the technical field of AC induction motor control, and in particular relates to a method for correcting the magnetic field orientation deviation angle of an induction motor vector control system. Background technique [0002] AC motor frequency conversion speed regulation methods mainly include open-loop V / f speed regulation and closed-loop speed regulation. Closed-loop speed regulation is also called vector control method, which specifically includes indirect rotor field orientation, direct rotor field orientation, and direct stator field orientation. Among them, the indirect rotor field orientation is widely used because it needs less hardware and has high control performance. [0003] The principle of indirect rotor field-oriented vector control of induction motors is as follows: the rotating coordinate system is established on the direction of the rotor magnetic field, and through this coordinate, the stator current is deco...

AI Technical Summary

Problems solved by technology

The calculation of the rotor field orientation angle in the actual system involves some parameters of the motor and the d-axis and q-axis command currents in the rotating coordinate system, so the inaccurate parameters used in the calculation process will cause a large deviation in the field orientation angle, especially When the motor works in the field-weakening high-speed area, due to the change of the magnetic field caused by temperature rise and field weakening, the motor parameters will change more obviously. If real-time and accurate parameter updates cannot be performed, the error change of the magnetic field orientation will be further aggravated. At the same time, Due to the inaccurate field orientation and the decline of current control performance in the field weakening area, the d-axis and q-axis current command values ​​are different from the actual values, which will also lead to deviations in field orientation

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