New Return Path Inductor Buck–Boost Y-Inverter Motor Drive With Reduced Current Stresses

Abstract

Variable speed drives (VSDs) for electric motors are a foundational component of global electrification, with electric motors consuming 45% of global electricity. Conventional three-phase buck–boost inverter topologies have substantial low-frequency current stresses in the buck–boost inductor, driving size, losses, and cost in VSD systems. In this letter, we propose a novel circuit topology for phase-modular three-phase buck–boost inverter systems based on the four-switch noninverting buck–boost concept, which we call the return path inductor Y-inverter (RPI-YI). By relocating the buck–boost inductors from the forward current path to the return path, the RPI-YI concept reduces the inductor rms and peak current stresses by up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$90 \%$</tex-math></inline-formula> compared to a conventional topology, resulting in a potential magnetics volume reduction of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$80 \%$</tex-math></inline-formula> . The RPI-YI concept, therefore, supports more compact, efficient realizations of modular buck–boost VSD systems.