Nonlinear Compensation Control Method for Inlet Steam Regulating Valve of Steam-driven Feedwater Pump

Abstract

A non-linear compensation control method for a steam-driven feedwater pump inlet steam regulating valve, the method obtains the opening command signals of each regulating valve used to control the speed of the steam pump in the following manner: dividing the difference between the speed command signal and the speed feedback signal of the steam pump The quotient obtained from the total gain coefficient signal after inertial filtering is sequentially processed by the PID controller and the manual / automatic operation station module to obtain the integrated valve position signal, and the difference between the integrated valve position signal and the output signal of the first analog constant module passes through The HP opening command signal is obtained after the first high and low limiting module, and the LP opening command signal is obtained after the comprehensive valve position signal passes through the second high and low limiting module. The present invention separately designs nonlinear gain calculation logics for the three nonlinearities, and finally combines them into a total gain coefficient in the form of a product to compensate the gain of the steam pump speed control system, thereby realizing centralized compensation for the three nonlinearities. This method can effectively improve the control quality of the steam-driven feedwater pump, and avoid the failure of the steam pump speed out of control caused by it.

Description

technical field [0001] The invention relates to a method for controlling a steam inlet regulating valve of a steam-driven feedwater pump of a thermal power unit, and belongs to the technical field of control. Background technique [0002] Due to the advantages of low comprehensive energy consumption and good regulation characteristics, most thermal power units use steam-driven feed water pumps (referred to as steam pumps) as the boiler feed water power source under normal working conditions. The main body of the steam pump is composed of a small steam turbine driving a feed water pump. The steam flow into the small steam turbine is adjusted through a set of regulating valves to control the speed of the small steam turbine, and then control the feed water flow. [0003] The steam source of the steam pump comes from the four-stage extraction steam of the steam turbine, the second-stage extraction steam, and the auxiliary steam header steam. The thermal system structure is as f...

AI Technical Summary

Problems solved by technology

Due to the existing steam pump speed control logic (see figure 2 ) There is no ideal compensation method, and it is difficult to set the compensation parameters of the three nonlinear superpositions, which may easily lead to difficulty in controlling the speed of the steam pump at certain operating points, which in turn leads to severe fluctuations in the feedwater flow

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