Automatic HVAC Air Recirculation

This paper highlights the system requirements and operating conditions of automatic air recirculation valves and reviews compatibility of existing actuator types with these requirements. When comparing the available technologies, it becomes clear that air recirculation flap actuators containing a bipolar stepper motor offer key advantages over actuators with other motor types. It is shown how specific bipolar stepper motor drive techniques can contribute to the overall system performance while the total system cost is minimized. The paper elaborates on availability and key features of motor driver integrated circuits that allow advanced control of these novel actuators.