Patent ID: 9568204
Date: 2017-02-14
CPC Classifications: F24F,G01D

Claim:
1. A method for detecting and responding to disturbances in a HVAC system using a noisy measurement signal and a signal filter, the method comprising: detecting a deviation in the noisy measurement signal, wherein the noisy measurement signal measures a supply line voltage of the HVAC system; resetting the signal filter in response to the detected deviation exceeding a noise threshold, wherein resetting the signal filter comprises increasing a covariance parameter used by the signal filter to calculate a weight assigned to a current value of the noisy measurement signal, which causes the signal filter to assign a relatively lesser weight to a previous estimate of the supply line voltage and a relatively greater weight to the current value of the noisy measurement signal, thereby increasing a responsiveness of the signal filter to changes in the noisy measurement signal; filtering the noisy measurement signal using the reset signal filter to determine a new estimate of the supply line voltage; determining whether a disturbance has occurred by comparing the new estimate of the supply line voltage to both a brownout voltage threshold and a blackout voltage threshold less than the brownout voltage threshold, wherein both the brownout voltage threshold and the blackout voltage threshold are different from the noise threshold; deactivating one or more active power relays in response to a determination that the new estimate of the supply line voltage is less than the blackout voltage threshold; and preventing one or more inactive power relays from activating in response to a determination that the new estimate of the supply line voltage is between the blackout voltage threshold and the brownout voltage threshold.