Reset circuit for resetting magnetic field inside iron core of transformer

Abstract

In circuit theory, the internal magnetic field is treated as an exciting inductance inside transformer. The invented circuit includes a first capacitor, an auxiliary switch, a rectifier and a second capacitor. The resetting steps are: turning on main switch, and turning off the auxiliary switch instantly to release energy of the exciting inductance; storing exciting energy to the exciting inductance of transformer from input power source, and charging the first capacitor through auxiliary winding of transformer; turning on the auxiliary switch and turning off the main switch instantly, transferring energy in exciting inductance and the first capacitor through auxiliary winding to second capacitor; after releasing energy in the exciting inductance completely, the second capacitor charges the first capacitor and the exciting inductance in inverted direction making magnetic field of the exciting inductance be reversed.

Description

technical field [0001] The present invention provides a circuit for resetting the magnetic field inside a transformer core, wherein the transformer is used in a power conversion device, especially a circuit capable of efficiently transferring the excitation energy stored inside a transformer core of the power conversion device The reset circuit and method can extend the switch duty cycle of the power conversion device without causing it to dissipate. Background technique [0002] The three techniques used today to reset the excitation energy stored inside the transformer core mainly include tertiary winding demagnetization circuits, RCD type reset circuits, and resonant reset circuits, which are used to properly clamp and reset the power conversion main transformer of the device to eliminate potential transformer core saturation problems. Please refer to figure 1 and figure 2 , figure 1 It is a schematic diagram of a known third winding demagnetization circuit, figure...

AI Technical Summary

Problems solved by technology

When the first switch 12 is turned on, the transformer T charges the magnetizing inductor 14 until the first switch 12 is turned off, and the magnetizing current discharges through the loop formed by the magnetizing inductor 14, the resistor 19 and the capacitor 18. This loop can be regarded as an inductor-capacitor (LC ) resonant circuit, the magnetic field inside the transformer is reset by the inductance-capacitance resonant circuit, which can improve the working efficiency of the transformer T, but due to the harmonics generated during resonance, an unpredictable high voltage may appear at both ends of the first switch 12 voltage, such as Image 6 V S1 shown

As can be seen from the above, the biggest disadvantage of the resonant degaussing circuit is that the harmonics generated during resonance will cause the first switch 12 to withstand a very large voltage, so the transformer T needs to use a switch with high withstand voltage as the first switch. switch 12

Images