Intelligent adjusting and controlling method for setting safe operation frequency in overfrequency of frequency converter

Abstract

The invention discloses an intelligent adjusting and controlling method for setting the safe operation frequency in the overfrequency of a frequency converter. The method includes the steps that self-adaptation safety adjusting control of the operation frequency is performed when the frequency converter operates at the overfrequency, when the set target frequency of the frequency converter is changed and exceeds the rated frequency of a motor, when the current frequency of the frequency converter is accelerated to the rated frequency of the motor, the frequency converter keeps operate at the rated frequency for a certain time through a corresponding intelligent operation control module, the practical operation current or the practical output power of the frequency converter during operation in the period of the rated frequency under the current load condition is compared with the rated current or the rated power of the motor, the maximum frequency allowed to be output by the frequency converter is determined under the current load condition of the frequency converter or the motor according to a comparison result.

Description

technical field [0001] The invention relates to an intelligent adjustment control method for a given safe operating frequency of a frequency converter overfrequency. Background technique [0002] Inverter is a device that converts power frequency power into a variable frequency and voltage power supply. The variable power supply of the device drives a three-phase AC motor to achieve variable speed operation of the motor. The frequency adjustable range of traditional inverters is generally It is 0~200Hz, and the industrial frequency power supply is generally 50Hz (60Hz). Since the running speed of the motor is proportional to the frequency of the power supply, the running speed of the motor after being driven by a frequency converter can reach 4 times the rated speed. [0003] With the continuous development of frequency conversion technology, the frequency converter is used more and more widely. Driving the motor through the frequency converter can not only realize the varia...

AI Technical Summary

Problems solved by technology

[0004] In many industries, especially the construction machinery industry (such as tower cranes, construction elevators, etc.), in order to improve work efficiency, the frequency converter generally needs to be overclocked when the load is light. It is especially important. If the judgment is wrong and there is heavy-duty overclocking operation, the motor will stall during operation due to insufficient output, resulting in the danger of slipping. How to judge the weight of heavy objects and whether it can be overclocked to improve work efficiency? The weight sensor sends a signal to the control system to detect the current lifting level, and the control system restricts the operation of the overfrequency high-speed gear of the inverter. However, in reality, the error rate of the weight sensor is large and the failure rate of the circuit is very high. danger of misjudgment

The current inverters run according to the speed signal given by the user. If the signal given by the user is inaccurate or wrong, and the inverter cannot recognize the error and run according to the given speed, it will cause danger.

The most direct way is that the frequency converter itself has the identification of the weight signal, and it is most effective to limit the high-speed overfrequency operation