Synthesis of Energy-Saving Temperature Control Systems for Electric Resistance Furnaces

Abstract

The article formulates the task of synthesizing closed-circuit control systems for electric resistance furnaces (ERF) according to a complex criterion for minimizing energy costs and transient time in these systems. This quality criterion relatively fully takes into account the basic requirements for the functioning of ERF, which form a fairly wide class of control object (their number reaches up to 90 % of all electrothermal installations in the country), characterized by high energy consumption and inertia of processes. The optimal control problem uses a generally accepted mathematical model of ERF dynamics in the form of a transfer function describing the dependence of the temperature in the furnace (adjustable value) on the control action, which is the electric power released on the heating element. А method for solving it is proposed, which provides a significant reduction in energy costs when controlling the furnace in comparison with known methods, high accuracy of temperature control, as well as the possibility of taking into account restrictions on the values of the controlled value and control action. The method is based on the transformation of this quality criterion into a kind of generalized functional and the application of the theory of analytical design of optimal regulators by А. A. Krasovsky using the predictive model of free movement of ERF. The proposed energy-saving positional control algorithms allow for a relatively simple implementation using modern microprocessor control devices. An example of the synthesis of energy-saving feedback algorithms for a specific object is considered.