Steam Temperature Control via Linear State Regulator
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Solution Overview
Problem
Current steam temperature control methods in steam power plants face challenges such as delayed response, sensitivity to dynamic changes, high computational costs, and increased hardware requirements, making precise and stable control difficult and costly.
Innovation Solution
A method using a simplified linear state regulator with a feedback matrix determined through matrix Riccati equations, which reduces computational complexity and hardware needs, combined with a parameter observer to estimate combustion parameters, allowing for real-time adaptation and improved control quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional PI controller is used for steam temperature control, then the control structure is simple, but the response is delayed and control precision is insufficient due to the inert behavior of the superheater
Solution Approach 1:
The patent transforms the control approach from conventional PI control to state regulator control based on matrix Riccati equations. This fundamental parameter change in control strategy enables the system to overcome the inert behavior of the superheater by using a more advanced control algorithm that can handle the system's dynamic characteristics more effectively, achieving faster response without excessive complexity
Solution Approach 2:
The patent replaces the conventional mechanical/proportional control mechanism with a computational control system that solves matrix Riccati equations. This substitution allows the system to process multiple medium states and calculate optimal control actions in real-time, overcoming the limitations of simple PI controllers while maintaining manageable device complexity
2Manufacturing precision
If a state regulator with full feedback of medium states is implemented, then control precision is improved, but computational costs and hardware requirements increase
Solution Approach 1:
The patent pre-calculates and stores the feedback matrix based on matrix Riccati equations during the commissioning phase. This preliminary action allows the system to use pre-computed optimal gain values during operation, eliminating the need for real-time solution of complex matrix equations while maintaining high control precision. The system only needs to perform matrix-vector multiplication using the pre-stored feedback matrix
Solution Approach 2:
The patent creates a simplified representation of the complex control problem by using a state regulator model with pre-computed feedback matrix. Instead of solving the full matrix Riccati equations in real-time, the system uses the pre-computed feedback matrix as a simplified copy that captures the essential control characteristics, significantly reducing computational requirements while maintaining control precision
3Productivity
If the steam temperature is controlled closer to the permissible material limit, then efficiency is improved, but the risk of exceeding temperature limits increases
Solution Approach 1:
The patent implements comprehensive feedback of multiple medium states (steam temperature, pressure, flow rates) to the state regulator. This multi-parameter feedback enables the system to continuously monitor the system state and adjust control actions to maintain temperature within safe limits while maximizing efficiency. The feedback mechanism allows real-time detection of approaching temperature limits and automatic corrective action
Solution Approach 2:
The patent uses a dynamic state regulator that adapts its control actions based on the current system state. The controller adjusts its behavior according to real-time measurements of medium states, enabling the system to operate closer to temperature limits when conditions permit while automatically retreating to safer operating points when limits are approached, thus dynamically balancing efficiency and reliability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach achieves precise and stable steam temperature control with reduced computational time and hardware costs, enabling faster commissioning and improved responsiveness to disturbances, while maintaining robustness and control quality.
Implementation Method 1
a state regulator controls the temperature of the steam at an outlet of a superheater with feedback of a plurality of medium states of the steam in the superheater
Implementation Method 2
The steam temperature is controlled, inter alia, by injecting water into the steam line upstream of the steam generator or upstream of the evaporator and the superheater stages via corresponding injection valves of a spray-type desuperheater
Data Source
AI summary
A method for controlling a temperature of steam for a steam power plant is provided. A state regulator controls the temperature of the steam at an outlet of a superheater using a feedback of multiple medium states of the steam in the superheater. An aim herein is to achieve a stable and precise control of the steam temperature. This is achieved in that the state regulator is a linear regulator, the feedback matrix of which is ascertained such that the regulator has the control quality of a linear-quadratic regulator.