Abstract: A system comprises a rotary apparatus, a control law and a processor. The rotary apparatus comprises a rotor and a housing forming a gas path therebetween, and the control law controls flow along the gas path. The processor comprises an output module, a plurality of temperature modules, a thermodynamic module, a comparator and an estimator. The output module generates an output signal as a function of a plurality of rotor and housing temperatures defined along the gas path, and the temperature modules determine time derivatives of the rotor and housing temperatures. The thermodynamic module models boundary conditions for the gas path, and the comparator determines errors in the boundary conditions. The estimator estimates the rotor and housing temperatures based on the time derivatives, such that the errors are minimized and the flow is controlled.

Abstract: A control system comprises an actuator, a control law and a processor. The actuator positions a control surface and the control law controls the actuator. The processor comprises an open loop module, a corrector, a comparator, and an estimator, and generates model output to direct the control law. The open loop module generates the model output as a function of a model state and a model input. The corrector generates a corrector output as a function of the model output. The comparator generates an error by comparing the corrector output to the model input. The estimator generates the model state as a function of the error, such that the error is minimized as a function of single-input, single-output gain matrix.

Abstract: A control system comprises an actuator, a control law and a processor. The actuator positions a control surface and the control law controls the actuator. The processor comprises an open loop module, a corrector, a comparator, and an estimator, and generates an output vector to direct the control law. The open loop module generates the output vector as a function of a state vector and an input vector. The corrector generates a corrector vector as a function of the output vector. The comparator generates an error vector by comparing the corrector vector to the input vector. The estimator generates the state vector as a function of the error vector, such that the error vector is minimized.

Abstract: A control system comprises a controller for positioning an actuator in a working fluid flow and a model processor for directing the controller as a function of a model feedback. The model processor comprises an output module, a comparator and an estimator. The output module generates the model feedback as a function of a constraint, a model state and a model input describing fluid parameters measured along the working fluid flow. The comparator generates an error by comparing the model feedback to the model input. The estimator generates the constraint and the model state, such that the error is minimized.

Abstract: A control system comprises an actuator, a control law and a processor. The actuator positions a control surface and the control law controls the actuator. The processor comprises an open loop module, a corrector, a comparator, and an estimator, and generates model output to direct the control law. The open loop module generates the model output as a function of a model state and a model input. The corrector generates a corrector output as a function of the model output. The comparator generates an error by comparing the corrector output to the model input. The estimator generates the model state as a function of the error, such that the error is minimized as a function of single-input, single-output gain matrix.

Abstract: A control system comprises an actuator, a control law and a processor. The actuator positions a control surface and the control law controls the actuator. The processor comprises an open loop module, a corrector, a comparator, and an estimator, and generates an output vector to direct the control law. The open loop module generates the output vector as a function of a state vector and an input vector. The corrector generates a corrector vector as a function of the output vector. The comparator generates an error vector by comparing the corrector vector to the input vector. The estimator generates the state vector as a function of the error vector, such that the error vector is minimized.

Abstract: A control system comprises a controller for positioning an actuator in a working fluid flow and a model processor for directing the controller as a function of a model feedback. The model processor comprises an output module, a comparator and an estimator. The output module generates the model feedback as a function of a constraint, a model state and a model input describing fluid parameters measured along the working fluid flow. The comparator generates an error by comparing the model feedback to the model input. The estimator generates the constraint and the model state, such that the error is minimized.

Abstract: A system comprises an apparatus, an actuator and a processor. The apparatus defines a flow path through an aperture, the aperture defines a pressure drop along the flow path, and the actuator regulates fluid flow across the pressure drop. The processor comprises a flow module, a comparator, an estimator and a control law. The flow module maps a flow curve relating a flow parameter to a pressure ratio, and defines a solution point located on the flow curve and a focus point located off the flow curve. The comparator generates an error as a function of a slope defined between the focus and solution points. The estimator moves the solution point along the flow curve, such that the error is minimized. The control law directs the actuator to position the control element, such that the flow parameter describes the fluid flow and the pressure ratio describes the pressure drop.

Abstract: A system comprises a rotary apparatus, a control law and a processor. The rotary apparatus comprises a rotor and a housing forming a gas path therebetween, and the control law controls flow along the gas path. The processor comprises an output module, a plurality of temperature modules, a thermodynamic module, a comparator and an estimator. The output module generates an output signal as a function of a plurality of rotor and housing temperatures defined along the gas path, and the temperature modules determine time derivatives of the rotor and housing temperatures. The thermodynamic module models boundary conditions for the gas path, and the comparator determines errors in the boundary conditions. The estimator estimates the rotor and housing temperatures based on the time derivatives, such that the errors are minimized and the flow is controlled.

Abstract: There is provided a refrigerant system 100 including at least one or a plurality of refrigerant flow control devices 125 for regulating operational parameters of the refrigerant system 100, at least one sensor 135, 140 connected to the refrigerant system 100 for monitoring the operational parameters of the refrigerant system 100, and a controller 130.

Abstract: A system and method of controlling clearance in a turbomachine includes adjusting the machine case cooling air in response to the difference between the desired clearance and the actual clearance. An accurate estimate of the actual clearance is made with a real time mathematical model on-board engine controller. The model computes thermal growth of the turbomachine components each with a difference equation derived from a closed form solution to the 1st order differential equation obtained through the application of 1st law of thermodynamics. The resulting equation is conveniently formulated in terms of equivalent time constant and steady state growth both correlated with thermo-physical characteristics of multiple fluid streams exchanging heat with the component. The solution is applied over a time step of the control software. Approximating coefficients are strategically placed in the model to allow calibration of the model to a particular version of the engine hardware.

Abstract: An optimized position for an economizer shut-off valve, or other method of increasing the volume in an economizer line is disclosed In one embodiment, the economizer shut-off valve is positioned directly downstream of the economizer heat exchanger. In a second embodiment, the valve is positioned upstream of the economizer expansion valve and the economizer heat exchanger. In a third embodiment, the economizer expansion valve is also provided with an appropriate control such that it can be utilized as the shut-off valve. In the fourth embodiment, additional volume is added to the economizer line. With each of these embodiments, the volume of the economizer line between the compressor and the economizer shut-off valve is relatively large compared to the prior art. Benefits with regard to temperature control, efficiency and capacity increase are achieved by this invention. Moreover, a less expensive shut-off valve can be utilized.

Abstract: A method is disclosed for identifying when a compressor is being run in reverse due to improper wiring. In a preferred embodiment, sensors sense the condition of a refrigerant at the inlet line and a refrigerant at the outlet line. If an expected pressure differential is not seen, then the determination is made that the compressor is running in reverse. In embodiments the control system may shut down the compressor, provide an alarm, or reverse a phase of two of the three wires of a three phase power input to correct the rotation direction.

Abstract: A method of operating a refrigeration system in steady state operation drives the refrigerant system to the lowest capacity state which is still able to maintain operation within acceptable pressure and temperature limits. Generally, the system seeks to minimize the on and off compressor cycling. The lowest capacity state is achieved by throttling the compressor suction and by staging down the compressor operation from economized to normal and to unloaded mode while assuring that desired box temperature is maintained. Safety methods are incorporated into the system to ensure that the operation does not violate limits on suction pressure, discharge pressure, and compressor discharge temperature.

Abstract: Hot gas bypass of compressed fluid is accomplished using standard components of an oil separation circuit. In this method, an electronically controlled valve, which is selectively opened and closed for returning oil accumulated in the oil separator is also selectively opened when a determination is made that hot gas bypass is desired. This electronically controlled valve is placed in the oil separator return line. When the valve is opened, hot gas is bypassed from compressor outlet into compressor inlet through the oil separator.

Abstract: A unique method of operating a refrigeration system for rapidly pulling down a refrigerated container temperature includes the use and algorithm for operating several system components. The refrigeration system is preferably provided with a suction modulation valve, a compressor unloader and an economizer circuit. By utilizing each of these components in combination with one another, and at various stages during the pull down capacity and energy efficiency of the refrigeration system are optimized, while maintaining the system operation within preset limits.