Abstract: A building management system includes building equipment configured to operate in accordance with an input to alter a variable state or condition of a building as a process function of the input while incurring a cost of operating the equipment as a cost function of the input. The building management system also includes a controller configured to calculate a value of a self-optimizing control variable as a function of a measured state of the building equipment and drive the value of the self-optimizing control variable towards a setpoint value by generating the input based on the self-optimizing control variable and providing the input to the building equipment. The function comprises multiplying the measured state by a matrix and adding an offset vector. Values of elements of the matrix and the offset vector are determined using a non-optimal reference.

Abstract: A plant includes equipment that operate to affect a variable state or condition of the plant in response to a control signal. A feedback controller monitors a process variable received via a feedback signal from the plant and uses an error signal representing a setpoint error between the process variable and a setpoint to generate the control signal for the plant. An exponentially-weighted moving average (EWMA) calculator generates EWMA values based on the setpoint error. A normalized index generator uses the EWMA values to calculate a normalized performance index. A threshold generator generates a threshold based on a first alarm parameter ? representing a normalized magnitude of the setpoint error and a second alarm parameter ? representing a normalized duration that the setpoint error has persisted. An alarm manager generates an alarm in response to the normalized performance index crossing the threshold.

Abstract: An on/off system operates to affect a variable state or condition of a building by switching between an on state and an off state. An extremum-seeking controller operates the on/off system by providing a pulse width modulated (PWM) control signal having a duty cycle to the on/off system. The extremum-seeking controller is configured to generate the PWM control signal by receiving a performance variable as feedback from the on/off system, extracting a gradient of the performance variable with respect to the duty cycle, modulating the duty cycle using an extremum-seeking control technique to determine an optimal value of the duty cycle that drives the gradient toward zero, and generating the PWM control signal such that each period of the PWM control signal has a pulse width proportional to the duty cycle.

Abstract: A control system is configured to operate a multiple-input system to achieve an optimal value for a performance variable of the multiple-input system. The control system includes a mapper configured to generate a mapping from a first number of manipulated variables to a second number of latent variables. The second number is smaller than the first number and each of the latent variables includes a linear combination of the manipulated variables. The control system also includes an extremum-seeking controller configured to receive the performance variable from the multiple-input system as a feedback and modulate values of the second number of latent variables to drive the performance variable to the optimal value. The mapper is further configured to use the mapping to translate modulated values of the second number of latent variables to modulated values of the first number of manipulated variables and provide the modulated values of the first number of manipulated variables to the multiple-input system.

Abstract: A system for monitoring and controlling flow rate of a fluid through a valve is disclosed. The system includes a flow rate sensor to measure the flow rate of the fluid through the valve, and a controller. The controller is configured to receive the measured flow rate from the flow rate sensor, and determine if the measured flow rate is equal to a predetermined flow rate value. The controller is further configured to, in response to a determination that the measured flow rate is equal to the predetermined flow rate value, determine a minimum valve position threshold (xmin). Additionally, the controller is configured to determine a minimum flow rate threshold (ymin) corresponding to xmin, and configured to generate a PWM signal and calculate a corrected flow rate (?f) using the PWM signal. The controller controls a valve operation using ?f. The PWM signal switches between zero and ymin.

Abstract: A space controller and method for determining energy savings of the space controller are provided. The method includes estimating, by one or more processing circuits, a steady state gain of a controlled variable of a heating, ventilation, and air conditioning (HVAC) system; determining, by the one or more processing circuits, an actual runtime that HVAC equipment of the HVAC system is in an on state based on a first setpoint or schedule; predicting, by the one or more processing circuits, a reduction of runtime that the HVAC equipment is in the on state for a second setpoint or schedule based on the actual runtime and the steady state gain; and adjusting, by the one or more processing circuits, the first setpoint or schedule to the second setpoint or schedule based on the reduction of runtime.

Abstract: A variable refrigerant flow (VRF) system for a building includes a plurality of outdoor VRF units configured to heat or cool a refrigerant for use in heating or cooling the building and an extremum-seeking controller. The extremum-seeking controller is configured to determine a total power consumption of the plurality of outdoor VRF units, generate a pressure setpoint for the plurality of outdoor VRF units using an extremum-seeking control technique that drives the total power consumption toward an extremum, and use the pressure setpoint to operate the plurality of outdoor VRF units.

Abstract: An extremum-seeking control system for a plant includes a feedback controller for operating the plant to achieve a value of a manipulated variable, and an extremum-seeking controller. The extremum-seeking controller is configured to provide the value of the manipulated variable to the feedback controller and to determine a value for the manipulated variable. The extremum-seeking controller determines the value for the manipulated variable by perturbing the manipulated variable with an excitation signal and monitoring a performance variable of the plant resulting from the perturbed manipulated variable, estimating a normalized correlation coefficient relating the performance variable to the manipulated variable, and modulating the manipulated variable to drive the normalized correlation coefficient toward zero using a general set of tuning parameters. The general set of tuning parameters are adapted for use with the normalized correlation coefficient, independent of a scale of the performance variable.

Abstract: A control system is configured to operate a plant to achieve an optimal value for a performance variable of the plant. The system comprise a feedforward controller configured to receive a measurable disturbance to the plant and generate a feedforward contribution to a control input to the plant using the measurable disturbance. The system also comprises an extremum-seeking controller configured to receive the performance variable from the plant and generate an extremum-seeking contribution to the control input to drive the performance variable to the optimal value. The system further comprises a control input element configured to generate the control input by combining the extremum-seeking contribution and the feedforward contribution and provide the control input to the plant.

Abstract: A system for monitoring and controlling flow rate of a fluid through a valve is disclosed. The system includes a flow rate sensor to measure the flow rate of the fluid through the valve, and a controller. The controller is configured to receive the measured flow rate from the flow rate sensor, and determine if the measured flow rate is equal to a predetermined flow rate value. The controller is further configured to, in response to a determination that the measured flow rate is equal to the predetermined flow rate value, determine a minimum valve position threshold (xmin). Additionally, the controller is configured to determine a minimum flow rate threshold (ymin) corresponding to xmin, and configured to generate a PWM signal and calculate a corrected flow rate (?f) using the PWM signal. The controller controls a valve operation using ?f. The PWM signal switches between zero and ymin.

Abstract: A controller includes a communications interface configured to provide a control input to and receive feedback from a plant. The feedback is representative of a response of the plant to the control input over a response period. The controller further includes a time constant estimator. The time constant estimator calculates a normalized variable based on the feedback, each value of the normalized variable representative of the response of the plant at a different time during the response period. The time constant estimator calculates a plurality of time constant estimates, based on the plurality of values of the normalized variable. The time constant estimator determines a maximum time constant from the time constant estimates. The controller further includes a control input generator that generates the control input for the plant using the maximum time constant. The control input affects a variable state or condition of the plant.

Abstract: A HVAC system for a building includes a plant and a plurality of single-variable extremum-seeking controllers (ESCs). The plant includes HVAC equipment operable to affect an environmental condition in the building. Each of the single-variable ESCs is configured to perturb a different manipulated variable with a different excitation signal and provide the manipulated variables as perturbed inputs to the plant. The plant uses multiple perturbed inputs to concurrently affect a performance variable. The single-variable ESCs are configured to estimate a gradient of the performance variable with respect to the each manipulated variable and independently drive the gradients toward zero by independently modulating the manipulated variables.

Abstract: An extremum-seeking control system for a chilled water plant includes a feedback controller and an extremum-seeking controller. The feedback controller is configured to operate equipment of the chilled water plant to achieve a condenser water temperature setpoint. The equipment include at least one of a chiller compressor, a condenser water pump, and a cooling tower fan. The extremum-seeking controller is configured to provide the condenser water temperature setpoint to the feedback controller.

Abstract: A control system for a plant includes a controller and a sensor. The controller is configured to estimate a response time of the plant and adjust a sampling rate based on the estimated response time. The response time is a parameter that characterizes a response of the plant to a disturbance. The sensor is configured to receive the adjusted sampling rate from the controller, collect samples of a measured variable from the plant at the adjusted sampling rate, and provide the samples of the measured variable to the controller.

Abstract: A thermostat is disclosed. The thermostat can include one or more temperature sensors configured to measure one or more temperature values. The thermostat can include a processing circuit. The processing circuit can receive the one or more temperature values from the one or more temperature sensors. The processing circuit can receive one or more central processing unit (CPU) usage values, wherein the one or more CPU usage values indicate computing usage of the processing circuit. The processing circuit can determine, based on an empirical model comprising one or more gain values and one or more filters and based on one or more signals, a temperature of the building. The one or more signals comprise the one or more temperature values and the one or more CPU usage values. The empirical model accounts for dynamics of heat generated by the processing circuit and airflow acting on the thermostat.

Abstract: A control system for a plant includes a controller configured to detect a disturbance in the control system. In response to detecting the disturbance, the controller is configured to evaluate a signal affected by the disturbance to estimate a response time of a plant. The response time is a parameter that characterizes a response of the plant to the disturbance. The controller is configured to adjust an operating parameter used by the control system based on the estimated response time. The controller is configured to use the adjusted operating parameter to generate and provide an input to the plant.

Abstract: Disclosed is a system to control a climate of a space via a first control loop and a second control loop interacting with the first control loop. The system includes a first controller of the first control loop to generate a first control signal based on a first modified set point and a first feedback signal. The system further includes a second controller of the second control loop to generate a second control signal based on a second modified set point and a second feedback signal. The system further includes a decoupler configured to predict a first effect of the first control signal on the second control loop and a second effect of the second control signal on the first control loop, and generate the first modified set point and the second modified set point to reduce the first effect and the second effect.

Abstract: A plant includes equipment that operate to affect a variable state or condition of the plant in response to a control signal. A feedback controller monitors a process variable received via a feedback signal from the plant and uses an error signal representing a setpoint error between the process variable and a setpoint to generate the control signal for the plant. An exponentially-weighted moving average (EWMA) calculator generates EWMA values based on the setpoint error. A normalized index generator uses the EWMA values to calculate a normalized performance index. A threshold generator generates a threshold based on a first alarm parameter ? representing a normalized magnitude of the setpoint error and a second alarm parameter ? representing a normalized duration that the setpoint error has persisted. An alarm manager generates an alarm in response to the normalized performance index crossing the threshold.

Abstract: A self-configuring extremum-seeking controller includes a dither signal generator, a communications interface, a phase delay estimator, and a bandwidth estimator. The dither signal generator identifies a stored dither frequency, generates a dither signal having the stored dither frequency, and uses the dither signal to perturb a control input for a plant. The communications interface provides the perturbed control input to the plant and receives an output signal from the plant resulting from the perturbed control input. The phase delay estimator estimates a phase delay between the output signal and the dither signal. The bandwidth estimator estimates a bandwidth of the plant based on the estimated phase delay. The dither signal generator updates the stored dither frequency based on the estimated bandwidth.

Abstract: Disclosed is a system to control a climate of a space via a first control loop and a second control loop interacting with the first control loop. The system includes a first controller of the first control loop to generate a first control signal based on a first modified set point and a first feedback signal. The system further includes a second controller of the second control loop to generate a second control signal based on a second modified set point and a second feedback signal. The system further includes a decoupler configured to predict a first effect of the first control signal on the second control loop and a second effect of the second control signal on the first control loop, and generate the first modified set point and the second modified set point to reduce the first effect and the second effect.