US 10,558,227 B2
System and method for output compensation in flow sensors using pulse width modulation
Carlos Felipe Alcala Perez, Milwaukee, WI (US); Kirk H. Drees, Cedarburg, WI (US); and Timothy I. Salsbury, Mequon, WI (US)
Assigned to Johnson Controls Technology Company, Auburn Hills, MI (US)
Filed by Johnson Controls Technology Company, Auburn Hills, MI (US)
Filed on Feb. 28, 2018, as Appl. No. 15/908,041.
Application 15/908,041 is a continuation in part of application No. 15/897,987, filed on Feb. 15, 2018.
Prior Publication US 2019/0250647 A1, Aug. 15, 2019
Int. Cl. F16K 31/02 (2006.01); G05D 7/06 (2006.01); F24F 11/74 (2018.01); F24F 140/40 (2018.01)
CPC G05D 7/0635 (2013.01) [F24F 11/74 (2018.01); G05D 7/0623 (2013.01); F24F 2140/40 (2018.01)] 20 Claims
OG exemplary drawing
 
1. A system for monitoring and controlling flow rate of a fluid through a valve, the system comprising:
a flow rate sensor configured to measure the flow rate of the fluid through the valve; and
a controller in communication with the flow rate sensor and configured to:
receive the measured flow rate from the flow rate sensor;
determine if the measured flow rate is equal to a predetermined flow rate value; and
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);
determine a minimum flow rate threshold (ymin) corresponding to xmin;
generate a pulse-width modulated (PWM) signal;
calculate a corrected flow rate (ŷf) using the PWM signal; and
control a valve operation using the corrected flow rate (ŷf);
wherein the PWM signal is configured to switch between zero and ymin.