Efficient power supply for an electromagnetic flow meter

摘要

A DC-DC power converter used in an electromagnetic flowmeter supplies a constant current from a capacitive output to an excitation coil during a measurement portion of the operating cycle. During a relatively longer charging portion of the operating cycle the capacitive output is charged from an unregulated supply. When the unregulated supply voltage of the of the DC-DC converter is less than the regulated output voltage repeated high voltage pulses are generated by the excitation coil to charge the output capacitor.

主权项

1. A method of providing a selected value of an output voltage from an output capacitor portion of a DC-DC power converter powering an excitation coil portion of an electromagnetic flow meter, the method comprising the steps of:
providing the excitation coil with thermal contact to a flowing fluid; providing a unipolar supply voltage less than the selected value of the output voltage; operating an oscillator to repetitively drive the excitation coil to generate voltage pulses exceeding the selected value of the output voltage and to transfer heat to the flowing fluid; and charging the output capacitor portion by applying the voltage pulses thereto until the output voltage attains the selected value.