Abstract: The present disclosure provides pumped thermal energy storage systems that can be used to store and extract electrical energy. A pumped thermal energy storage system of the present disclosure can store energy by operating as a heat pump or refrigerator, whereby net work input can be used to transfer heat from the cold side to the hot side. A working fluid of the system is capable of efficient heat exchange with heat storage fluids on a hot side of the system and on a cold side of the system. The system can extract energy by operating as a heat engine transferring heat from the hot side to the cold side, which can result in net work output.

Abstract: The present disclosure provides pumped heat energy storage systems that can be used to store and extract electrical energy. A pumped heat energy storage system of the present disclosure can store energy by operating as a heat pump, whereby net work input can be used to transfer heat from the cold side to the hot side. A working fluid of the system is capable of efficient heat exchange with heat storage fluids on a hot side of the system and on a cold side of the system. The system can also extract energy by operating as a heat engine transferring heat from the hot side to the cold side, which can result in net work output. Shared powertrains and reversible powertrains are disclosed to circulate the working fluid.

Abstract: The present disclosure provides pumped heat energy storage systems that can be used to store and extract electrical energy. A pumped heat energy storage system of the present disclosure can store energy by operating as a heat pump, whereby net work input can be used to transfer heat from the cold side to the hot side. A working fluid of the system is capable of efficient heat exchange with heat storage fluids on a hot side of the system and on a cold side of the system. The system can also extract energy by operating as a heat engine transferring heat from the hot side to the cold side, which can result in net work output. Shared powertrains and reversible powertrains are disclosed to circulate the working fluid.

Abstract: The present disclosure provides pumped thermal energy storage systems that can be used to store and extract electrical energy. A pumped thermal energy storage system of the present disclosure can store energy by operating as a heat pump or refrigerator, whereby net work input can be used to transfer heat from the cold side to the hot side. A working fluid of the system is capable of efficient heat exchange with heat storage fluids on a hot side of the system and on a cold side of the system. The system can extract energy by operating as a heat engine transferring heat from the hot side to the cold side, which can result in net work output.

Abstract: An exemplary method includes determining an NH3 reference target in an exhaust conduit between a first SCR catalyst and a second SCR catalyst. The method includes determining a present amount of NH3 in the exhaust conduit between the first SCR catalyst and the second SCR catalyst, and determining an NH3 error term in response to the NH3 reference target and the present amount of NH3. The method further includes determining an amount of NOx downstream of the second SCR catalyst, and adjusting one of the NH3 reference target and a reductant doser command in response to the amount of NOx downstream of the second SCR catalyst. The method further includes providing a reductant doser command in response to the NH3 error term.

Abstract: Systems and methods to sample current measurements in energy storage assets while reducing bias errors such as aliasing are provided. One example current sampling system includes an integrator circuit that receives the current signal as an input and integrates the current signal to output a charge signal. The current signal is indicative of a current at an energy storage asset of an energy storage system. The current sampling system includes a charge signal sampler circuit that samples the charge signal at a charge signal sampling rate. The current sampling system includes a differentiator circuit that receives the samples of the charge signal from the charge signal sampler circuit and differentiates the samples of the charge signal to output an anti-aliased current signal.

Abstract: A control system for a power plant includes a sensor that measures a rotor surface temperature of a steam turbine rotor, where the temperature is a function of exhaust gasses from a heat source for heating steam to a target temperature. The control system includes a controller coupled to the sensor and configured to compute the target temperature using an inverse process model for steam turbine rotor stress dynamics, and based on a reference steam turbine rotor stress and a feedback steam turbine rotor stress, compute a measured steam turbine rotor stress based on a measured surface temperature of the steam turbine rotor, compute an estimated steam turbine rotor stress using a process model for the steam turbine rotor stress dynamics, and based on the target temperature, and compute the feedback steam turbine rotor stress based on the measured steam turbine rotor stress and the estimated steam turbine rotor stress.

Abstract: An electronic control system is adapted to control a system including an internal combustion engine and an exhaust aftertreatment system including an SCR catalyst. The electronic control system provides a first dynamically determined weighting factor in response to performing a selected one of a plurality of calculations, determines an operating mode of the engine in response to an engine load and an engine speed, selects one of a plurality of inputs in response to the operating mode of the engine to provide an interpolation weighting factor, the plurality of inputs including the first dynamically determined weighting factor and one or more predetermined weighting factors, utilizes the interpolation weighting factor to interpolate between a first set of combustion control data and a second set of combustion control data to determine a set of combustion control values, and controls operation of the engine using the set of combustion control values.

Abstract: The present disclosure is directed to a system and method for controlling an energy storage device by more accurately detecting an end-of-discharge voltage of the energy storage device. More specifically, in one embodiment, the method includes determining an end-of-discharge voltage threshold for the energy storage device. Another step includes filtering the end-of-discharge voltage threshold via a filter. The method also includes adjusting a time constant of the filter based on at least one voltage-current condition. Still a further step includes comparing the filtered end-of-discharge voltage threshold and a terminal voltage of the energy storage device. Based on the comparison, the method includes determining a change of state of the energy storage device. Thus, the energy storage device can be controlled based on the change of state.

Abstract: A cooling fluid flow control system for a turbine section of a steam turbine system and a related program product are provided. In one embodiment, a system includes at least one computing device operably connected to a cooling system. The computing device may be configured to control a flow rate of cooling fluid supplied to a steam turbine system by the cooling system by performing actions including modeling a sensitivity of a wheel space temperature to a change in the flow rate in the form of a piecewise linear relationship, the piecewise linear relationship including a flooded flow rate above which the wheel space temperature becomes insensitive to increased flow rate. The computing device also periodically modifies the flow rate of the cooling fluid supplied to the wheel space of the turbine section to approximate a minimum flooded flow rate based on the measured flow rate and the modeling.

Abstract: An electronic control system is adapted to control a system including an internal combustion engine and an exhaust aftertreatment system including an SCR catalyst. The electronic control system provides a first dynamically determined weighting factor in response to performing a selected one of a plurality of calculations, determines an operating mode of the engine in response to an engine load and an engine speed, selects one of a plurality of inputs in response to the operating mode of the engine to provide an interpolation weighting factor, the plurality of inputs including the first dynamically determined weighting factor and one or more predetermined weighting factors, utilizes the interpolation weighting factor to interpolate between a first set of combustion control data and a second set of combustion control data to determine a set of combustion control values, and controls operation of the engine using the set of combustion control values.

Abstract: A control system for a power plant includes a sensor that measures a rotor surface temperature of a steam turbine rotor, where the temperature is a function of exhaust gasses from a heat source for heating steam to a target temperature. The control system includes a controller coupled to the sensor and configured to compute the target temperature using an inverse process model for steam turbine rotor stress dynamics, and based on a reference steam turbine rotor stress and a feedback steam turbine rotor stress, compute a measured steam turbine rotor stress based on a measured surface temperature of the steam turbine rotor, compute an estimated steam turbine rotor stress using a process model for the steam turbine rotor stress dynamics, and based on the target temperature, and compute the feedback steam turbine rotor stress based on the measured steam turbine rotor stress and the estimated steam turbine rotor stress.

Abstract: Systems and methods to sample current measurements in energy storage assets while reducing bias errors such as aliasing are provided. One example current sampling system includes an integrator circuit that receives the current signal as an input and integrates the current signal to output a charge signal. The current signal is indicative of a current at an energy storage asset of an energy storage system. The current sampling system includes a charge signal sampler circuit that samples the charge signal at a charge signal sampling rate. The current sampling system includes a differentiator circuit that receives the samples of the charge signal from the charge signal sampler circuit and differentiates the samples of the charge signal to output an anti-aliased current signal.

Abstract: A controller system includes at least one computing device operably connected to a process having a target value for a variable parameter. The computing device(s) is configured to control the variable parameter by performing actions including: computing an error between the target value and an actual value of the variable parameter. Based on the error, the computing device(s) may calculate a desired gain adjustment of the variable parameter, and a desired mean adjustment of the variable parameter. A correction signal may be created for modifying the process by: in response to the error being positive, creating the correction signal by adding the desired mean adjustment and the desired gain adjustment, and in response to the error being negative, creating the correction signal by differencing the desired mean adjustment and the desired gain adjustment. A related program product may carry out similar functions.

Abstract: An exemplary method includes determining an NH3 reference target in an exhaust conduit between a first SCR catalyst and a second SCR catalyst. The method includes determining a present amount of NH3 in the exhaust conduit between the first SCR catalyst and the second SCR catalyst, and determining an NH3 error term in response to the NH3 reference target and the present amount of NH3. The method further includes determining an amount of NOx downstream of the second SCR catalyst, and adjusting one of the NH3 reference target and a reductant doser command in response to the amount of NOx downstream of the second SCR catalyst. The method further includes providing a reductant doser command in response to the NH3 error term.

Abstract: Various approaches include: obtaining temperature data indicating temperatures of distinct zones in an upper half of a steam turbine shell and a lower half of a steam turbine shell; determining whether a difference between a temperature of a zone in the upper half of the steam turbine shell and a temperature of a neighboring zone in the lower half of the steam turbine shell exceeds a threshold; and initiating a change in a state of a thermal element in at least one of an adjacent zone to at least one of the zone in the upper half of the steam turbine shell or the neighboring zone in the lower half of the steam turbine shell in response to determining the difference exceeds the threshold.

Abstract: Systems and methods for managing aftertreatment systems that include passive NOx adsorption devices and SCR catalyst elements are disclosed. Temperature generation devices upstream of the passive NOx adsorption devices facilitate control of the aftertreatment systems to improve fuel economy and NOx conversion efficiency.

Abstract: A system includes an internal combustion engine providing exhaust gases to an exhaust conduit, an aftertreatment system having an SCR catalyst component and disposed in the exhaust conduit. The system further includes a first NH3 sensing element preferentially sensitive to NH3 and a second NH3 sensing element preferentially sensitive to NO2 in the exhaust conduit. Both NH3 sensing elements are positioned downstream of the SCR catalyst component. The system includes a controller having a test conditions module that determines whether an NO2 concentration downstream of the SCR catalyst component is below a threshold value, an NH3 diagnostic module that provides a detection comparison value in response to the NO2 concentration, a first signal from the first NH3 sensing element, and a second signal from the second NH3 sensing element. The controller includes a sensor condition module that provides an NH3 sensor condition value in response to the detection comparison value.

Abstract: An exemplary method includes determining an NH3 reference target in an exhaust conduit between a first SCR catalyst and a second SCR catalyst. The method includes determining a present amount of NH3 in the exhaust conduit between the first SCR catalyst and the second SCR catalyst, and determining an NH3 error term in response to the NH3 reference target and the present amount of NH3. The method further includes determining an amount of NOx downstream of the second SCR catalyst, and adjusting one of the NH3 reference target and a reductant doser command in response to the amount of NOx downstream of the second SCR catalyst. The method further includes providing a reductant doser command in response to the NH3 error term.

Abstract: An example method includes interpreting an NH3 composition value at a position upstream of a selective reduction catalyst (SCR) element fluidly disposed in the exhaust conduit of an engine, interpreting a NOx composition value at a position downstream of the SCR element, and determining an NH3 sensor rationality threshold in response to the upstream NH3 composition value. The method further includes determining an NH3 sensor health value as indicating a sensor failure in response to the downstream NOx composition value exceeding the NH3 sensor rationality threshold.