Turbine Control Device Using Analog Signals to Eliminate Valve Time Lag
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Solution Overview
Problem
In marine exhaust heat recovery systems, the existing control methods using pulse signals for adjusting available power values in power generation systems face instability due to delays and inaccuracies in reflecting changes in plant conditions, leading to potential hunting and suboptimal control of governor valves.
Innovation Solution
A control device that calculates actual available power values based on the difference between target and actual governor valve opening degrees, using analog signals to control the governor valve, thereby avoiding the time lags associated with pulse signal adjustments and ensuring stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If pulse signals are used to adjust available power values in stages, then the control system can operate with simple signaling, but the response time increases and control stability deteriorates due to delays in reflecting plant condition changes
Solution Approach 1:
The patent replaces the pulse signal control mechanism with an analog signal-based calculation system. The control device continuously calculates actual available power values using analog signals from sensors and directly controls the governor valve opening degree, eliminating the discrete pulse signal delays and achieving continuous, real-time control response.
Solution Approach 2:
The control device pre-calculates the actual available power value based on current plant conditions (steam pressure, governor valve position, power turbine output) before control action is needed. This allows the system to respond immediately to condition changes without the lag inherent in pulse signal accumulation and stage-based adjustments.
2Measurement precision
If pulse signals are used for governor valve control, then the control mechanism remains simple, but measurement precision and control accuracy deteriorate due to inability to accurately reflect absolute available power values
Solution Approach 1:
The patent substitutes the pulse signal counting mechanism with an analog calculation system that directly computes absolute available power values. The control device uses analog signals from pressure sensors, position sensors, and power measurements to continuously calculate the actual available power value, providing precise measurement without the quantization errors of pulse-based staging.
Solution Approach 2:
The control device acts as an intermediary that receives multiple analog input signals (steam pressure, governor valve position, power turbine output) and synthesizes them into an accurate calculation of actual available power value. This intermediary calculation layer provides precise measurement capability while maintaining relatively simple control architecture through direct analog-to-analog processing.
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 enables more stable control of power generation systems during changes in plant conditions, preventing hunting and maintaining optimal power output without the delays inherent in pulse signal adjustments.
Implementation Method 1
a steam turbine (9) which is driven by steam generated by the exhaust gas to be used as a power generation output
Implementation Method 2
a power turbine (7) which is driven by the exhaust gas to be used as a power generation output
Implementation Method 3
a governor valve (37) that controls a flow rate of steam to be introduced to the steam turbine (9)
Data Source
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AI summary
In the present invention, a turbine control panel (TCP) (57) performs a pressure-changing operation wherein the pressure of steam introduced into a steam turbine is changed. In addition, a load capacity value calculation unit (70) with which the TCP (57) is provided calculates the actual load capacity value obtained from the steam turbine on the basis of the deviation between a target degree of opening of a speed adjustment valve and the actual degree of opening of the speed adjustment valve, and controls the degree of opening of the speed adjustment valve on the basis of the calculated load capacity value. Thus, the TCP (57) does not use a pulse signal, as in the prior art, to change the load capacity value used in controlling the degree of opening of the speed adjustment valve, so the speed adjustment valve can be controlled without the occurrence of a time lag that is typical of a pulse signal.