Method for asynchronous motor rotor flux linkage observation and rotation speed identification

Abstract

The invention discloses a method for asynchronous motor rotor flux linkage observation and rotation speed identification, which comprises the following steps of: according to stator voltage and current signals measured in real time, observing to obtain a rotor flux linkage through a sliding mode observer based on a super-twisting theory and using the rotor flux linkage as a reference value; using a rotor flux linkage calculated according to a rotor flux linkage current model as an adjustable value; constructing a model reference self-adaptive system (MRAS) based on the rotor flux linkages; and identifying the asynchronous motor rotation speed through the self-adaptive law. The rotation speed identification method provided by the invention has high robustness for the variation of stator resistance, and can provide accurate rotor flux linkages and rotation speed values, thereby being especially suitable for an asynchronous motor vector control system.

Description

technical field [0001] The invention discloses a motor parameter identification method, in particular to a rotor flux observer with strong robustness, and a speed sensorless asynchronous motor vector control scheme based on the observer. Background technique [0002] At present, the control methods of three-phase asynchronous motors have matured, and vector control and direct torque control can meet the requirements of most working conditions. Regardless of the control method, the speed is a very important control quantity. However, the speed sensor is difficult to install in some cases, or sometimes in order to save this part of the cost, people hope to identify the speed in real time only based on the easily measured phase current and phase voltage data on the inverter, and realize speed sensorless control. [0003] The principle of asynchronous motor without speed sensor can be divided into two types: one type requires the rotor to have asymmetry, such as rotor slot harm...

AI Technical Summary

Problems solved by technology

The mathematical model of the motor is always not accurate enough, and some parameters will change with the operation of the motor, which greatly affects the accuracy of identification

At low speed, the stator resistance R s The change of rotor flux linkage ψ r Observation has the greatest impact, which in turn affects the identification accuracy of the speed sensorless sensor based on the flux linkage observer

for R s Some scholars added R to the observer s Adaptive identification to improve the low-speed performance, but this method has high requirements for the stability design of the observer, and the versatility is not strong

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