Bi-Polar Buck-Boost Converter

Abstract

In this brief, a bi-polar buck-boost DC-DC converter is formulated. A three-switch based LC-cell (TSLC) is responsible for bi-polar load voltage realization while front-end quadratic boost cell (QBC) effectively gives buck-boost voltage gain feature. The existence of front-end QBC ensures low source ripple current profile. This bi-polar converter is established with a lower number of controlled switching devices, yet it exhibits better boosting capability even in the positive output load voltage operating conditions. Also, a simple complementary gating scheme without any dead-band is employed to realize bi-polar load voltages. Detailed analysis (steady-state and small-signal models) is formulated and performance aspects are investigated. For concept demonstration, a 12 to ±42 V, 50 kHz prototype bi-polar converter system is built. The experimental results are in close agreement with the analysis.