Thermoanemometric flow sensor control using pulse width modulation

Abstract

PWM control of the heated element in constant temperature difference mode was designed and tested for the thermal flowmeter. The reason for using this solution is to extend the operating range and reduce the power losses of the control elements. The proposed solution allows linearization and adjustment of the operating point to the desired flow range and fluid temperature without any change in the wiring or electronics. The functionality of this solution was demonstrated over a range of 80 kg/h with a repeatability of 2 %.