Methods and systems relating to improved AC signal performance of dual stage transformers

A dual stage AC transformer comprising:

• first and second transformer stages, a primary winding, a first secondary winding, and a second secondary winding;
• a first resistor across only the first secondary winding thereby generating a first voltage in dependence of a current flowing within a first stage of the dual stage AC transformer;
• a second resistor across only the second secondary winding, the second resistor disposed in series with the first resistor in order to add a compensating voltage to the first voltage, the compensating voltage generated in dependence of a current flowing within a second stage of the dual stage AC transformer;
• a DC magnetic sensor coupled to the second stage of the dual stage AC transformer for generating a signal proportional to a DC magnetic field within the dual stage current transformer;
• and a processing circuit for generating a corrected AC signal measurement in dependence upon the output of the DC magnetic sensor and the voltage across the first resistor and the second resistor.

A dual stage AC transformer comprising:

• first and second transformer stages, a primary winding, a first secondary winding, and a second secondary winding, wherein a first end of the first secondary winding is coupled to a first end of the second secondary winding at a midpoint of a pair of load resistors disposed in series;
• a second end of the first secondary winding is coupled to another end of a first load resistor of the pair of load resistors and to a first input of a differential amplifier via a first resistor;
• and
• a second end of the second secondary winding is coupled to another end of the other load resistor of the pair of load resistors and to a second input of a differential amplifier via a second resistor;
• wherein the first ends of the first and second secondary windings are both disposed in the same direction along a magnetic core of the plurality of magnetic cores relative to their respective second ends;
• a DC magnetic sensor coupled to a second stage of the dual stage AC transformer for generating a signal proportional to a DC magnetic field within the dual stage current transformer;
• and
• a processing circuit for generating a corrected AC signal measurement in dependence upon the output of the DC magnetic sensor and the voltage across the first and second resistors.

A coreless AC transformer comprising:

• a magnetic field sensor;
• a primary winding for connection to an electrical circuit;
• a secondary winding for generating a measurement current to be employed in determining a current flowing within the electrical circuit to which the primary winding is connected;
• and
• the primary winding and secondary winding are in either;
• a first configuration wherein the primary winding and secondary winding are axially aligned and disposed either side of the magnetic field sensor;
• or
• in a second configuration wherein the primary winding and secondary winding are axially aligned and disposed such that the magnetic field sensor is disposed within both the primary winding and the secondary winding;
• wherein
• the primary winding, second winding, and magnetic field sensor are not coupled via a magnetic material.