Siemens Aktiengesellschaft

Abderrahim Chahid

Ingolf Hoffmann

Roland Weiss

Alexander Itzke

Karl Fleisch

Horst Geyer

Anja Schnieders

Florian Zapf

A current measuring device for generating an output current proportional to a current to be measured includes at least two Hall sensors arranged on a circular path and oriented identically in relation to a center point. The current measuring device includes an adding circuit summing measurement signals of the Hall sensors, a subtracting circuit for eliminating an offset, a voltage-controlled current source, and a current supply with a toroidal coil having a paramagnetic and/or diamagnetic core and a DC/DC converter supplying the Hall sensors. In a method for measuring a current, a current measuring device has an adding circuit for adding the measurement signals of the Hall sensors and generating a voltage proportional to the current to be measured. An offset of the voltage is subtracted by a subtracting circuit, generating an output current with a predefined transformation ratio relative to the measured current.

Current measuring device with hall sensors

A conversion device converts an input power into an output power, and gives rise to a power loss. The conversion device is cooled by a coolant circuit in which a coolant flows. A monitoring device determines, using operating data of the conversion device and/or of the coolant circuit, a flow velocity of the coolant and compares the flow velocity with a limit velocity. If the flow velocity reaches or exceeds the limit velocity, the monitoring device resorts to a special reaction. As long as the flow velocity does not reach the limit velocity, the monitoring device resorts either to no reaction or to a normal reaction that is not the same as the special reaction. The monitoring device determines the flow velocity by using a quantity of heat that is to be removed by the coolant per unit time, a local temperature of the conversion device, and an inflow temperature.

Determining the flow velocity in a coolant circuit

In a method for measuring a current, a plurality of flux-gate field sensors is arranged with radial symmetry on a first circumferential path, and a plurality of Hall sensors is arranged with radial symmetry on a second circumferential path such that a one of the flux-gate field sensors is placed adjacent a one of the Hall sensors, with the flux-gate field sensors having a sensitivity which is higher by a factor 5 to 20 than a sensitivity of the Hall sensors. At least one of the plurality of flux-gate field sensors is evaluated so as to determine a current intensity, when two of the flux-gate field sensors generate measurement values within a measurement range, or at least one of the plurality of Hall sensors is evaluated so as to determine a current intensity, when the measurement values of the two flux-gate field sensors are outside of the measurement range.

Method for measuring a current, and current-measuring device

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Hemhofen, Germany

Abderrahim Chahid