Constant temperature control method and constant temperature control system for power frequency skin-effect tracing system

Abstract

The invention discloses a constant temperature control method and constant temperature control system for a power frequency skin-effect tracing system and belongs to the field of control on the powerfrequency skin-effect tracing system. A temperature difference value between current temperature and a set temperature target can be calculated through collecting the current temperature of a target heating body at an outlet of a liquid transport tube in a timing manner, and output of a power controller is obtained through PID calculation according to the obtained current temperature difference value. According to the constant temperature control method, the temperature difference value between the current temperature and the set temperature target is calculated through timing collection, andoutput values of the power controller at different times are obtained through PID calculation by using the obtained current temperature difference value, so that output power can be timely adjusted according to the temperature of the target heating body, the number of on / off times of a heating power supply is reduced, the impact on a power supply transformer and load is reduced and the service life of the system is prolonged; and furthermore, skin-effect tracing output current is adjusted and controlled through PID calculation, so that the target heating body can be kept within a set range andthe control accuracy can be ensured.

Description

technical field [0001] The invention belongs to the control field of a power frequency heat tracing system, and in particular relates to a constant temperature control method of a power frequency heat tracing system. Background technique [0002] Pipeline skin effect electric heat tracing technology is a new technology for heating and heat preservation of heat transport pipelines in large petrochemical and other enterprises. The principle is mainly based on the "skin effect" and "proximity effect" of alternating current. In the skin heat tracing system, when the electric current passes between the cable in the heating pipe and the heat pipe, because there is a certain relationship between the size, material and frequency of the alternating current of the steel pipe, the alternating current does not flow uniformly through the cross section of the steel pipe, but flows concentratedly through it. The inner surface, and the current density decreases exponentially toward the out...

AI Technical Summary

Problems solved by technology

Both control methods will frequently turn on and off the power supply, which will have a large impact on the power supply transformer and load, and affect the service life of the system

And it will cause temperature overshoot, more heat will be wasted, and the outlet temperature will fluctuate. It is not suitable for places with high temperature requirements.

The long-term frequent start-stop system of the on-off method will have a negative impact on the skin equipment, the control accuracy is low, and it does not save energy and reduce emissions

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