A Non-isolated Bidirectional DC--DC Converter With Current Ripple Cancellation at a Selectable Duty Ratio

This article proposed a non-isolated bidirectional DC-DC converter. The converter is designed to ensure current ripple through the two inductors on the low voltage (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LV</i>) side counter balance each other, resulting in a smooth and ripple free current on the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LV</i> side of the converter. Along with that, current on the high-voltage (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">HV</i>) side of the converter is continuous with low ripple content. The unidirectional topologies reported in literature were focused on current ripple cancellation using synchronous switching exhibited buck-boost voltage gain. However, the proposed converter has step-up characteristic in forward mode and step-down characteristic in reverse mode. Some of the notable characteristics of the converter are: lower voltage stress on switches and capacitors, common ground between <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LV</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">HV</i> side ports. The steady-state analysis and small-signal modelling are provided for both step-up and step-down modes in order to investigate the converter steady-state and dynamic performance respectively. This work presents the testing and performance evaluation of proposed topology on a laboratory prototype with 150 W power output and the voltages adopted for two ports are 36 V and 110 V. The measured performance is in close agreement with the analytical predictions.