Performance enhancement of powertrain DC-DC converter using variable inductor

Performance enhancement of a powertrain DC-DC converter is provided using a current-controlled magnetic device, the variable inductor (VI). The VI is composed of two groups of windings, main and auxiliary. The auxiliary winding is used to regulate the permeability of the magnetic core over a wide range of load variations. To regulate the saturation level of the magnetic core and avoid postsaturation operation of the power inductor, an appropriate level of auxiliary winding current is needed. To this end, a simple and dynamic strategy is proposed to estimate the auxiliary winding currents of the VI. The proposed approach is validated using simulation studies of a large-scale VI-based powertrain DC-DC converter. The results reveal the significance of the proposed approach in continuous regulation of the magnetic property of the power inductor core, enhancing powertrain DC-DC converter performance by up to 13.70% and reducing stress on switching devices by 17.87%. Furthermore, energy source current variation is reduced by 6.73%, leading to reduced stress on energy storage systems.