Flux gate-type residual current detection device and control method of same device

A residual current detection device, the device comprising:

• an oscillation unit that generates a pulse current having a preset frequency;
• a core unit comprising at least one first core having at least one first coil wound thereon to be magnetized according to the pulse current, a second core having a second coil wound thereon, and a third coil wound on the first core and the second core and to which a compensation current is applied, one end of the first coil being connected to the oscillation unit, one end of the second coil being grounded;
• a residual current detection unit connected to the other end of the at least one first core and the other end of the second core to sum a voltage signal detected from the first core and a voltage signal detected from the second core;
• an amplification unit that inverts and amplifies a voltage signal according to a voltage signal summation result of the residual current detection unit to generate a compensation current applied to the third coil;
• and
• a control unit that determines a frequency of the pulse current according to at least one of the characteristics of the at least one first core, and detects a DC component leakage current flowing through the conductor to be measured based on the compensation current.