Downsizing effects of integrated magnetic components in high power density DC-DC converters for EV and HEV

The interleaved DC-DC converters with integrated magnetic components that achieve high power density have recently gained attention in automotive market for eco-friendly cars such as electric vehicles (EV) and hybrid electric vehicles (HEV). Interleaved converters with close-coupled inductors and loose-coupled inductors are well known as the converters capable to achieve high efficiency with low volume and weight. As a new approach, an interleaved converter with integrated winding coupled inductors is proposed. This paper proposes a novel inductor size calculation model. By using this model, the downsizing effects of the integrated magnetic components are discussed at 1 kW output. As a result, interleaved converter with integrated winding coupled inductors is effective for downsizing of the magnetic components with the condition that duty ratio is higher compared to interleaved converters with loose-coupled inductors and close-coupled inductors. In contrast, it is also found that interleaved converter with loose-coupled inductors achieves downsizing of the magnetic component when duty ratio is close to 50 %. The validity of the calculation model is estimated from the experimental viewpoints.