公开(公告)号：US20250085315A1

公开(公告)日：2025-03-13

申请号：US18567382

申请日：2022-12-29

Applicant: SOUTHEAST UNIVERSITY

Inventor： Qinsong QIAN ,  Song DING ,  Chunyan NIE ,  Yuanhang ZHOU ,  Weifeng SUN ,  Longxing SHI

IPC: G01R19/00 ,  H02M1/00 ,  H02M3/335

Abstract: A lossless exciting current sampling circuit for an isolated converter includes first and second voltage sampling circuits and a subtraction circuit formed by an operational amplifier. The two sampling circuits sample voltages of the primary winding of an isolation transformer, with outputs fed into the subtracter. The subtracter output is the circuit's output. RC low-pass filters with large time constants are used as primary voltage sampling circuits, realizing integration of voltage differences between the exciting inductance terminals, enabling lossless current sampling without resistors or transformers. The current sampling result is utilized for volt-second balance control, realized along with a hold circuit and comparator which compares the sampling hold result with the current sampling result to generate a control signal.