Frequency converter control method and frequency converter

Abstract

The present invention relates to a frequency converter control method and a frequency converter. The frequency converter control method comprises the steps of: obtaining the weight of an object to bemeasured in real time; controlling the rotating speed of a motor of a filling device according to the weight of an object to be measured, if the weight of the object to be measured is smaller than a preset first weight threshold value, controlling the motor to work with a first rotating speed; if the weight of the object to be measured is larger than or equal to a preset first weight threshold value, or smaller than a second weight threshold value, gradually reducing the rotating speed of the motor with increasing of the weight of the object to be measured; if the weight of the object to be measured is equal to the second weight threshold value, controlling the motor to stop work; after the motor stops work, continuously obtaining the weight of the object to be measured until the weight ofthe object to be measured to be stable; and obtaining a first difference between the stable weight of the object to be measured and a target weight, obtaining a weight regulation value according to the first difference, and taking difference of the second weight threshold value and the weight regulation value as a second weight threshold value of next filling. The control method can effectively control weight errors and can effectively reduce the weight errors through multi-times cycle filling.

Description

technical field [0001] The invention relates to the field of frequency converters, in particular to a control method for frequency converters and frequency converters. Background technique [0002] At present, most of the filling equipment adopts the following working methods: firstly, perform zero calibration and calibration operations for weighing instruments; secondly, start filling production. Put the empty filling barrel on the workbench, the filling liquid is pumped out by the pump and enters the canning barrel through the conveying pipe, and the motor of the pump is controlled by the frequency converter. Set two target weights on the weighing instrument, one is the final target weight, and the other is close to the final target weight (for example, 70% of the final target). Each target weight corresponds to an output terminal. After reaching a target weight, there will be An output terminal action (that is, a state change, such as from a closed state to an open state...

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Problems solved by technology

[0003] However, since the conveying pipe has a certain length from the position where the pump is located to the final outlet of the conveying pipe, there must be a certain amount of liquid. After the inverter stops, part of the liquid will still flow to the filling machine due to inertia and gravity. In the barrel, the final filling weight is inconsistent with the final target weight initially set, there is a weight error, and the weight error cannot be controlled, which increases the cost of the producer

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