Device for measuring electric current, including a sensor sensitive to magnetic flux and intended in particular for electrically propelled vehicles

Device for measuring electric current, comprising:

• an annular magnetic core,
• at least one probe sensitive to magnetic flux and arranged in an air gap of said annular magnetic core through which at least one conductor of a current to be measured is intended to pass,
• a compensation winding wound on said core,
• a measuring resistor connected in series with said compensation winding,
• said magnetic core being a solid material element,
• a regulating circuit for regulating the supply current of the compensation winding, regardless of the direction of the current to be measured, and controlled by the output signal of said at least one probe which is sensitive to magnetic flux,
• said regulating circuit being connected in series with said compensating winding and said measuring resistor and including a first amplifier to input terminals of which said probe is connected and an output of which is connected to bases of a first pair of transistors of PNP and NPN types having emitter-collector paths connected between a supply voltage Vcc and earth, a junction of the collectors of said transistors being connected in series with the measuring resistor to a first terminal of the compensation winding, and a second inverter amplifier connected by an inverting terminal to an output of the first amplifier, and the output of which is connected to bases of a second pair of transistors of PNP and NPN type, emitter-collector paths of which are connected in series with said supply voltage Vcc and earth, a junction of the collectors of said second pair of transistors being connected to the second terminal of the compensation winding,
• the number of turns of the compensation winding being compatible with the current to be measured, the maximum available supply voltage and the measurement range of the measuring resistor of the device.