Temperature regulator in control circuits

Automatic control systems are designed to control parameters such as current, voltage, power, pressure, etc. A special place in such systems is assigned to control schemes. Depending on the object, this or that control principle is used. If we are interested in heating elements, then in most devices there is no need to build high-speed circuits. This simplifies the circuit implementation of the device and, most importantly, allows the use of a "sparing" mode for power modules. This approach significantly prolongs their service life and shortens the time of forced downtime when repairing equipment. In terms of production, this is an important factor. Each unplanned stop of the production line leads to a decrease in the output of the final product, which, naturally, affects its cost price.

As an example, consider a small system where a temperature controller is used. The control system has two inputs - the reference and feedback signals. Suppose that the parameter signal must be brought to a certain value from the reference signal. The temperature controller used will gently increase the current in the heating elements to the maximum. After that, it will compare the feedback signal and the task. As soon as they equalize, the object will smoothly turn off. Typically, such systems are hysteresis for reverse switching on / off - this is necessary to ensure the stable operation of the entire system.

Previously, switching circuits of heating devices used contact circuits with a number of disadvantages: a sharp increase in the load current, rapid wear of the power contacts, etc. The modern temperature controller controls power modules based on thyristors, triacs, IGBT transistors, etc. Each such unit has its own features in control, which should be taken into account when designing the device.

Good prospects for the management of powerful production facilities, for example, induction furnaces, has a thyristor temperature controller. The element has excellent performance characteristics and showed itself very well when working with an active load. In the management of other types of loads, these devices, which were innovative at the time, gradually give way to more modern schemes.

Sometimes it becomes necessary to use the air temperature regulator. A good example in this case can serve as a small device that works in the sauna. As you can see, there is a reference signal (degrees Celsius). The feedback in this case is the signal from the temperature sensor, which is located inside the sauna. By the same principle, the water temperature regulator also works, only the type of sensor used changes. Such devices are also used in production (of course, they are characterized by much greater power).

With the advent of innovative power cells on the basis of semiconductor devices , the "obsolete" schemes are gradually replaced. Only the principles of regulation by which these devices operate remain unchanged.