A method for automatic energy saving of asynchronous motor

Abstract

The invention provides an automatic energy-saving method for an asynchronous motor, which includes the following steps: processing the detected three-phase output current to obtain the active current and reactive current when the motor is running; obtaining the current voltage drop coefficient and the target value of the voltage adjustment coefficient ;Automatic energy-saving voltage regulation control: adjust the voltage according to the current voltage drop coefficient and the target value of the voltage regulation coefficient. The present invention is applicable to occasions where the motor runs for a long time with a light load. It does not need to provide a specific load frequency characteristic curve, but only needs a V / f reference curve based on the principle of constant magnetic flux. The method can automatically adjust the output voltage, reduce the The total output current and excitation current make it work near the optimal point, effectively reducing the loss of the system; this method has a strong adaptability to different loads at different frequencies, and can better realize energy-saving control.

Description

technical field [0001] The invention relates to motor technology, in particular to a technology for saving energy by automatically adjusting the output voltage when the motor operates under V / F mode for a long time with light load. Background technique [0002] The frequency converter runs with the motor in V / f mode, and its output frequency and output voltage are given separately. Generally, the constant magnetic flux principle is used to determine the given curve of the output voltage at the corresponding frequency. The constant magnetic flux is generally rated Excitation flux. This method can ensure that the motor can have a torque output capability not lower than the rated torque in the entire frequency range. However, in some light-load or no-load situations, when using this curve, most of the current in the system is used to maintain the excitation, so that the overall efficiency of the system is not very high. [0003] The loss of the motor is mainly concentrated in...

AI Technical Summary

Problems solved by technology

However, the following problems exist in the acquisition of V / f operating curves: on the one hand, the load and frequency characteristics of some systems are not completely fixed; on the other hand, for some systems that have been installed and operated, there are no conditions for complete testing

However, this involves how to ensure that the system does not lose synchronization when the voltage drops, and what quantities are used to determine the magnitude of the voltage drop. There are few discussions on this issue in the current literature.

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