Invariant Method of Load Independent Pressure Control in Steam Boiler

Abstract

The paper considers the possibility of steam production and supply process improvement by perfection of the steam boiler control system, applying invariance principle that makes possible preemptive compensation of the influence of steam expenditure as a disturbance on the control process quality and efficiency. For the development of invariant control system, the mathematical modeling and simulation in MATLAB - SIMULINK environment is made. The control unit is low pressure steam boiler with one input impact to control - the heat flow of burning gas mixture fuel, one measured output parameter of the process - the steam pressure, and the main disturbance as a load impact - the steam expenditure. The mathematical and virtual models and block-diagrams for transient process simulation is compiled, allowing to start practical design and investigation of steam boiler invariant control system with high operation stability under essentially fluctuating load. The simulation results prove that the optimal solution for the transient process improvement in steam boiler, taking in account fluctuating load, is invariant PID-DPC two loop control system with disturbance impact on steam pressure preemptive compensation. Under invariant control the steam pressure overshoots decreases substantially in comparison with the traditional PID-feedback control method.

PLC-Based Pressure Control in Multi-Pump Applications

“…Using a new fuzzy PID control approach it has been explained in [8] how the collecting pressure performance can be improved with the PLC help. Under invariant control presented in [9], the steam pressure overshoots were decreased in comparison with the traditional PID-feedback control methods.…”

Optimal supervisory control of steam generators operating in parallel

“…The resulting states evolutions are illustrated in Figure 5. The optimal cost J was compared against the outcome of applying di¤erent constant set-points of magnitude u 1 k ; u 2 (1 k) , and by calculating the corresponding costs J k arising from equation (6). Relative cost savings…”

“…(48) where the weight k i is the fraction of the total demand assigned to the boiler i; and evaluating their corresponding costs J k1k2 through equation (6). The relative cost savings D k1k2 are computed analogously to the two-boilers case: The numerical values are reported in Table 2 for di¤erent admissible combinations of (u 1 ; u 2 ; u 3 ).…”

“…One of the main concerns in recent years about the operation of a boiler unit has been the improving its controls as shown by the survey and consecutive experiments carried out in [2]. However, in the current literature and in the industrial environment, many control strategies have been applied to control the boiler as a process unit, ranging from standard methods like proportional integral derivative (PID) control [4] to intelligent and sophisticated methodologies as optimal control, sliding mode control, model predictive control and others, see [4,6,5] and their references.…”

Invariant Control of the Technological Plants to Compensate an Impact of Main Disturbances Preemptively

“…General concept of steam boiler control improvement by active disturbance rejection is invariant control. Main advantages of this control method are verified in the simulation model of steam boiler output variable (steam pressure) control, invariant to steam flow [11].…”