US 12,405,142 B2
Magnetic field generator for a magnetic-inductive flowmeter, method of operating the same, magnetic-inductive flowmeter and method of operating the same
Helmut Brockhaus, Oberhausen (DE); and Markus Dabrowski, Duisburg (DE)
Filed by KROHNE Messtechnik GmbH, Duisburg (DE)
Filed on Jun. 20, 2023, as Appl. No. 18/211,794.
Claims priority of application No. 10 2022 115 271.5 (DE), filed on Jun. 20, 2022.
Prior Publication US 2023/0408311 A1, Dec. 21, 2023
Int. Cl. G01F 1/58 (2006.01); G01F 1/60 (2006.01)
CPC G01F 1/586 (2013.01) [G01F 1/60 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A method for operating a magnetic field generator for a magnetic-inductive flowmeter, wherein the magnetic field generator includes a coil, a bridge circuit with at least one current regulator, a voltage regulator and a controller, wherein the bridge circuit is designed to direct a current through the coil in one direction, the direction being either a first direction or a second direction, and the bridge circuit can be set to the direction by the controller, wherein the current regulator is designed to generate the current according to a target current through the coil and the target current can be set in the current regulator by the controller, wherein for a control operation of the current regulator, a current regulator voltage present across the current regulator is greater than or equal to a control voltage value and for a minimum operation of the current regulator the current regulator voltage is greater than a minimum voltage value and the control voltage value is greater than the minimum voltage value, wherein the voltage regulator is designed to generate a supply voltage according to a target voltage across the bridge circuit and the target voltage can be set in the voltage regulator by the controller, the method comprising:
in a first method step performed by the controller, the first direction, a target current value as target current and a first target voltage value as target voltage are set at a first reversal time, wherein the first target voltage value is greater than a second target voltage value and the second target voltage value as target voltage effects the control voltage values of the current regulator voltage in a steady state of the magnetic field generator;
a second method step performed by the controller, a first switching time is determined, wherein the first switching time occurs after the first reversal time, the current between the first reversal time and the first switching time reaches the target current value, and the current regulator voltage at the first switching time is greater than the minimum voltage value and less than the control voltage value, and the second target voltage value is set as the target voltage at the first switching time; and
in a third method step performed by the controller, after the first switching time and before a second reversal time, a first measuring voltage present between two measuring electrodes of the magnetic-inductive flowmeter is measured and a flow rate of a medium flowing through a measuring tube is determined using the first measuring voltage, wherein the first measuring voltage in the medium is caused by a magnetic field generated by the coil in the flowing medium.