Emerson Process Management Power & Water Solutions, Inc.

Robert Allen Beveridge

Richard J Whalen, Jr

Richard J Whalen

Embodiments of methods and systems for controlling a load generated by a power generating system may include controlling at least a portion of the system using model-based control techniques. The model-based control techniques may include a dynamic matrix controller (DMC) that receives a load demand and a process variable as inputs and generates a control signal based on the inputs and a stored model. The model may be configured based on parametric testing, and may be modifiable. Other inputs may also be used to determine the control signal. In an embodiment, a turbine is controlled by a first DMC and a boiler is controlled by a second DMC, and the control signals generated by the first and the second DMCs are used in conjunction to control the generated load. Techniques to move the power generating system from Proportional-Integral-Derivative based control to model-based control are also disclosed.

Model-based load demand control

A technique of controlling a steam generating boiler system having multiple superheater sections includes determining multiple control signals to control a temperature of output steam to a turbine. The technique uses a first control block to determine an offset value based on multiple input temperatures and a dynamic matrix control (DMC) block to determine input steam control signals based on an output temperature and an output temperature setpoint. The technique modifies one of the input steam control signals based on the offset value. The modified input steam control signal and the unmodified input steam control signal are provided to respective field devices to control the input temperatures and, as a result, the output temperature.

Steam temperature control using model-based temperature balancing

A technique of controlling a steam generating boiler system includes dynamically tuning a rate of change of a disturbance variable (DV) to control operation of a portion of the boiler system, and in particular, to control a temperature of output steam to a turbine. The rate of change of the DV is dynamically tuned based on a magnitude of an error or difference between an actual and a desired level of an output parameter, e.g., output steam temperature. In an embodiment, as the magnitude of the error increases, the rate of change of the DV is increased according to a function f(x). A dynamic matrix control block uses the dynamically-tuned rate of change of the DV, a current output parameter level, and an output parameter setpoint as inputs to generate a control signal to control a field device that, at least in part, affects the output parameter level.

Dynamic tuning of dynamic matrix control of steam temperature

A technique of controlling a steam generating boiler system includes using a rate of change of disturbance variables to control operation of a portion of the boiler system, and in particular, to control a temperature of output steam to a turbine. The technique uses a primary dynamic matrix control (DMC) block to control a field device that, at least in part, affects the output steam temperature. The primary DMC block uses the rate of change of a disturbance variable, a current output steam temperature, and an output steam temperature setpoint as inputs to generate a control signal. A derivative DMC block may be included to provide a boost signal based on the rate of change of the disturbance variable and/or other desired weighting. The boost signal is combined the control output of the primary DMC block to more quickly control the output steam temperature towards its desired level.

Steam temperature control using dynamic matrix control

A technique of controlling a steam generating boiler system using dynamic matrix control includes preventing saturated steam from entering a superheater section. A dynamic matrix control block uses a rate of change of a disturbance variable, a current output steam temperature, and an output steam setpoint as inputs to generate a control signal. A prevention block modifies the control signal based on a saturated steam temperature and an intermediate steam temperature. In some embodiments, the control signal is modified based on a threshold and/or an adjustable function g(x). The modified control signal is used to control a field device that, at least in part, affects the intermediate steam and output steam of the boiler system. In some embodiments, the prevention block is included in the dynamic matrix control block.

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New Kensington, PA, United States of America

Robert Allen Beveridge