Patent ID: 8723630

Claim:
A current transformer for supplying power to electronic controller, comprising: a first core magnetic circuit and a second core magnetic circuit independent of each other, wherein the first core magnetic circuit is a closed loop formed by connecting a U-shaped core and a linear core, and a primary core-extending conductor extends through the closed loop of the first core magnetic circuit, and a secondary winding for power supply is wound on the linear core of the first core magnetic circuit; and the second core magnetic circuit having an opening shape is disposed in parallel to the linear core of the first core magnetic circuit, and open ends of the second core magnetic circuit are coupled to the first core magnetic circuit through air gaps, wherein, an area of the cross section of the linear core is less than an area of the cross section of the U-shaped core, so that the linear core can be magnetically saturated earlier than the U-shaped core, wherein a centerline length of the U-shaped core is 1.5 to 4 times of a centerline length of the linear core; said U-shaped core and the linear core of the first core magnetic circuit have a spacing of 2-3 mm from the primary core-extending conductor surrounded by the first core magnetic circuit, so that electrical isolation is formed between the first core magnetic circuit and the primary core-extending conductor surrounded by the first core magnetic circuit, and simultaneously, the first core magnetic circuit surrounding the primary conductor has a shortest length.