Real-time correction method for rotor time constant of three-phase asynchronous motor

Abstract

The invention relates to a real-time correction method for a rotor time constant of a three-phase asynchronous motor. An excitation mutual inductance lookup table and a rotor resistance temperature lookup table are established, the excitation mutual inductance Lm is queried according to excitation current, the excitation mutual inductance Lm and the rotor leakage inductance Lsigma are added to obtain the rotor inductance Lr, the rotor resistance Rr is queried according to the stator winding temperature of the motor, namely the rotor temperature, and the rotor time constant can be calculated according to the rotor inductance Lr and the rotor resistance Rr, and thus the real-time correction of the rotor time constant is realized. According to the scheme of the invention, the real-time correction method for the rotor time constant is easy to implement in engineering, the influence of the rotor temperature on the rotor resistance is considered, and the influence of flux saturation on the rotor inductance is also considered; the scheme is not only applicable to the operation area within the base speed of the motor, but also to the high-speed flux weakening area of the motor; and moreover, the rotor time constant of the three-phase asynchronous motor can be corrected in real time, the rotor field orientation accuracy, torque control accuracy, flux weakening control stability and system operation efficiency can be improved, and the dynamic and static performance of vector control can be improved.

Description

technical field [0001] The invention belongs to the technical field of motor-to-drag testing, and in particular relates to a method for real-time correction of the rotor time constant of a three-phase asynchronous motor. Background technique [0002] The appearance of the vector control theory based on the rotor field orientation makes the three-phase asynchronous motor obtain the same static and dynamic performance as the DC speed control system, which makes the three-phase asynchronous motor widely used in the field of AC drive. However, accurate magnetic field orientation must depend on accurate motor parameters. Among the many parameters of asynchronous motors, the rotor time constant T r (T r =L r / R r , L r is the rotor inductance, R r is the rotor resistance) has the greatest influence on the magnetic field orientation. The deviation of the rotor time constant will directly affect the calculation of the slip frequency, resulting in inaccurate magnetic field orie...

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Problems solved by technology

[0003] At present, the commonly used rotor time constant correction mainly adopts rotor time constant identification methods based on model reference adaptive, extended Kalman filter, extended Romberg observer, least square method, signal injection, artificial neural network, etc., but the above methods are theoretically complex , the engineering practice is poor; or only consider the temperature on the rotor resistance R r , regardless of the influence of flux saturation on the rotor inductance L r or can only identify the rotor time constant within the base speed, but can't do anything about the high-speed field weakening region

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