Study on DC busbar structure considering stray inductance for the back-to-back IGBT-based converter

The back-to-back converter is widely used in 4-quadrant adjustable speed drive (ASD) system, active power filter (APF) and wind power grid system attributed to its high power factor and low current harmonics on grid side. In order to attain better performance in driving induction motor of 55kW, the nominal value of DC-link voltage is determined at 700V, which puts forward high request on converter design. As a result, this paper aims to design and analyze DC busbar properly, so that stray parameters can be reduced as much as possible. The impacts of laminated arrangement, dimension of busbar as well as mechanical layout on stray inductance are considered in detail. In this paper, Ansoft Q3D is used to discuss their impacts on stray inductance quantificationally. Equivalent circuit of commutation loop is also analyzed to extract inductance from experimental results accurately. Finally they are verified by the experiment results.