Lem International Sa

Stéphan Trombert

Steve Mouchet

Dominik Schläfli

Félix Buhlmann

Fabien Millet

Steve Moureaux

Luc Bossoney

Pascal Maeder

Fluxgate current transducer including a control circuit and a fluxgate measuring device comprising a fluxgate magnetic field detector, the fluxgate magnetic field detector comprising a saturable soft magnetic core surrounded by an excitation coil, the control circuit comprising an excitation coil drive circuit connected to the excitation coil and a controller connected to the excitation coil drive circuit configured to generate an alternating excitation current Ito alternatingly saturate the soft magnetic core. The controller is in the form of a FPGA (Field Programmable Gate Array) comprising at least one input comprising a 1 bit sigma delta analog-to-digital converter (ADC) connected to the excitation coil to receive a measurement signal output by the excitation coil.

Fluxgate current transducer

Electric current transducer comprising a housing, a magnetic core and a magnetic field detection system, the magnetic core surrounding a primary conductor passage for receiving a primary conductor therethrough, the magnetic core comprising a first part and a second part assembled in the housing so as to form a first magnetic circuit gap and a second magnetic circuit gap, the magnetic field detection system comprising a first magnetic field detector positioned in the first magnetic circuit gap and a second magnetic field detector positioned in the second magnetic circuit gap, the first and second magnetic circuit gaps being disposed on opposing sides of magnetic core, each of the first and second parts comprising a pair of lateral branches, joined by a bridging branch.

Current transducer

Fluxgate current transducer including a fluxgate device comprising a saturable soft magnetic core and an excitation coil, and a processing circuit comprising a control circuit and a voltage generator connected to the control circuit for generating an alternating current in the excitation coil, the voltage generator generating a voltage oscillating between a maximum positive voltage (+Umax) and a maximum negative voltage (−Umax) configured to alternatingly saturate the soft magnetic core. The control circuit is configured to generate a voltage having an absolute value of amplitude less than an absolute value of said maximum positive voltage (+Umax) and said maximum negative voltage (−Umax) voltage during a variable time window (Tn, Tn+1, Tn+2, Tn+3) after detection of the excitation coil current reaching a threshold current (S) representative of saturation of the magnetic core during at least a subset of a plurality of alternating voltage periods (P).

Method of reducing noise in a fluxgate current transducer

An electronic power switch drive module for a power semiconductor unit, comprising a gate drive and a current transducer mounted on one or more circuit boards, the gate drive comprising at least one circuit portion for controlling at least one transistor of a power semiconductor module of said power semiconductor unit, the current transducer configured to be coupled to an output of the power semiconductor module for measuring an output current of the power semiconductor module, said at least one circuit portion connected to an output potential of the output current to be measured. The current transducer comprises at least one magnetic field sensor, the current transducer being connected to said at least one circuit portion of the gate drive at said output potential in a non-isolated manner.

Electronic power switch drive module

Fluxgate current transducer including a fluxgate device comprising a saturable soft magnetic core and an excitation coil, and a processing circuit comprising a control circuit and a voltage generator connected to the control circuit for generating an alternating current in the excitation coil, the voltage generator generating a voltage oscillating between a maximum positive voltage (+U) and a maximum negative voltage (&#x2212;U) configured to alternatingly saturate the soft magnetic core. The signal processing circuit comprises an overload circuit portion connected to the control circuit, configured to generate overload currents through the excitation coil over time windows (Tn) after detection of the excitation coil current reaching positive and negative threshold currents (+S, &#x2212;S) representative of saturation of the magnetic core, during at least one of a plurality of alternating voltage periods (P).

A current transducer including a housing comprising an outer casing, a magnetic circuit core configured to encircle at least one primary conductor, and a magnetic field detector positioned in a magnetic circuit gap of the magnetic circuit core. The housing further includes an inner support part comprising a main body portion and a magnetic core support portion. The magnetic circuit core is in the form of a thin strip of amorphous material supported on the main body portion and magnetic core support portion, the magnetic circuit gap being formed between overlapping ends of the strip.

Growing community of inventors

Leschaux, France

Stéphan Trombert