Asynchronous motor energy efficiency estimation method based on online monitoring

Abstract

The invention relates to the asynchronous motor energy efficiency estimation method based on online monitoring; the method comprises the following steps: analyzing fixed eccentric harmonic wave signals gathered from the asynchronous motor stator current and identifying the signals to obtain the rotor rotating speed; secondarily, using the linear portion of the asynchronous motor machinery featuresand the rotating speed to obtain the motor rotor shaft electromagnetic torque; finally, using the electromagnetic torque and a motor synchronization angular velocity to solve the motor output power,thus identifying the motor operation energy efficiency. The method analyzes the fixed eccentric harmonic waves in the stator current so as to estimate the motor rotating speed, thus preventing photoelectric encoder installation, and realizing speedtransmitter-free rotating speed estimation; the method obtains the motor rotor shaft electromagnetic torque according to the linear portion of the asynchronous motor machinery features and the rotating speed, and solves the problems that the motor rotor shaft electromagnetic torque cannot be directly measured; the method is simple in operation, can reduce the system cost, and can fast obtain the motor operation energy efficiency.

Description

technical field [0001] The invention relates to the field of state monitoring of asynchronous motors, in particular to a method for estimating energy efficiency of asynchronous motors based on online monitoring. Background technique [0002] As the driving force of various equipment, electric motors are widely used in various fields such as industry, agriculture, commerce and public facilities. From a global perspective, the electricity consumption of motor systems accounts for more than 50% of the world's total electricity consumption and about 70% of industrial electricity consumption. In the current situation of energy shortage and rising energy prices, it is of great practical significance to study the online monitoring of energy efficiency of asynchronous motors. [0003] At present, the monitoring methods for motor energy efficiency mainly include nameplate method, slip method, special instrument method, loss analysis method and equivalent circuit method. Moment iden...

AI Technical Summary

Problems solved by technology

This type of method mainly uses the stator current signal of the motor to analyze the tooth harmonics to estimate the speed. However, recent research practices have shown that tooth harmonics may not exist in asynchronous motors, making it impossible to use tooth harmonics to estimate the speed.

For the identification of output torque, most of them are measured by torque meter, but the installation of torque sensor not only destroys the advantages of simple structure, reliable operation and convenient maintenance of asynchronous motor, but also limits its application range.

Images