Automatic energy-saving method of asynchronous motor

Abstract

The invention provides an automatic energy-saving method of an asynchronous motor. The method includes the following steps that a detected three-phase output current is processed, and an active current and a reactive current generated when the motor runs are obtained; the current voltage drop coefficient and a voltage regulation coefficient target value are obtained; automatic energy-saving voltage regulating control is performed; according to the current voltage drop coefficient and the voltage regulation coefficient target value, voltage regulation is performed. The automatic energy-saving method of the asynchronous motor is applicable to occasions where the motor drives light loads to run for a long time, a specific load frequency characteristic curve does not need to be given, and only a V / f reference curve based on the principle of constant magnetic flux is needed. With the method, a total output current and an exciting current can be reduced by automatically regulating an output voltage, the motor is finally made to work near an optimal point, and loss of a system is effectively reduced; the method has strong adaptive capacity for different loads at different frequencies, and energy-saving control can be achieved better.

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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