Alternating current heater control device and method

Abstract

The invention discloses an alternating current heater control device and method, and relates to the field of heater controlling. First, a mains zero passage point is detected by a mains zero passage detection circuit, high voltage is produced at the zero passage point to form a zero passage impulse sequence serving as an interrupt input of a central processing unit. Then, an on-off state of the heater voltage in a half-wave period after a next zero passage impulse is determined by the central processing unit, and after external interruption is generated, an on-off signal controlling the heater voltage is output after delay. At last, the on-off signal is converted into a driving signal of a relay through a control circuit, the on-off state of the heater voltage is controlled through a solid relay, and the control on alternating current heater power is achieved. According to the device and method, the control period of the heating power is controlled within 40 milliseconds. By means of using of the zero passage type solid relay and the introduction of the mains zero passage detecting circuit, a transient effect of a switch is reduced, and stability and reliability of the system are greatly improved.

Description

Technical field [0001] The invention relates to the field of heater control, in particular to an industrial AC heater control device and control method. Background technique [0002] In various production processes, almost all products need to be heated. Before molding, the coating needs to be dried, the adhesive needs to be activated, and the plastic needs to be heated. Efficient use of energy can make the heating process more efficient, and the heating time is shorter, and the space required is smaller, thereby reducing the overall production cost. [0003] In order to make the heating process more efficient and more accurate, the control of the heater power becomes particularly important. There are mainly the following two traditional heater control methods. The first type is intermittent heating. The control period is generally several seconds or even tens of seconds, which cannot achieve rapid adjustment of heating power and has poor stability. The second method is to impl...

AI Technical Summary

Problems solved by technology

The first type is intermittent heating, and the control period is generally several seconds or even tens of seconds, which cannot realize rapid adjustment of heating power, and the stability is not good

The second is to realize fast chopping of the load supply voltage through devices such as IGBT thyristors. This method can realize accurate and continuous adjustment of heater power, but the increased cost is relatively high, and because the control switch needs to be continuously switched under high voltage for a long time, Therefore, the switch contact loss is very large, and the product cannot work reliably for a long time

In addition, the on-off period is too long, which is not conducive to the uniform distribution of power in time and rapid adjustment, and cannot reflect the advantages in the traditional intermittent heating method

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