Variable-Width Hysteretic Analog Control for QSW-ZVS and TCM Source/Sink Converters

This paper proposes a very simple analog control for quasi-square-wave zero voltage switching (QSW-ZVS) and triangular current mode bidirectional converters. The proposed circuit controls the inductance current, thanks to the use of a variable-width hysteretic current mode control. The upper and lower bounds of the hysteretic band are clamped to ensure QSW-ZVS operation with a single current command and independently from power flow direction. This enables the control to achieve a seamless transition between source and sink modes. The advantages and disadvantages of the proposed analog control are analyzed and two different power converters are built to demonstrate the validity of this solution: a 50 W, 48 to 24 V bidirectional buck converter and a 100 W, 24 to 48 V bidirectional boost converter.