Integrated magnetics for switch-mode DC-DC converters

The quest for high power density in switch-mode DC-DC converter motivates concerted research efforts in integrated magnetics (IM), which combines several magnetic components into a single magnetic structure to reduce core size, while simultaneously improving several other performance measures. This dissertation develops IM solutions for buck cascaded current-fed push-pull (BCCFPP) converter and Zero-Voltage-Switching (ZVS) hybrid converter, and proposes a new buck cascaded two-inductor boost (BCTIB) converter with IM implementation. All the proposed schemes are analyzed using gyrator-capacitor model and validated on hardware prototypes.; The proposed IM scheme for BCCFPP converter improves power density by integrating the transformer and inductor into a common structure. It also alters the operating characteristics of the basic converter, leading to several advantages such as continuous output current, ZVS and Zero-Current-Switching for the push-pull switches, reduced conduction losses and self-driven synchronous rectification.; This dissertation also proposes an IM scheme for ZVS hybrid converter. One of the main drawbacks of the basic hybrid converter had been the requirement of two power transformers. The proposed IM scheme combines the two transformers into a single structure resulting in reduction of overall size, as well as improved converter performance.; The IM implementation of BCCFPP converter increases the voltage stress for the push-pull switches. The proposed BCTIB converter overcomes this drawback while retaining the main advantages of BCCFPP converter. In addition, the IM implementation of BCTIB converter achieves several advantages, such as reduced core size, reduced AC flux ripple, improved filtering inductance, and continuous output current.; Blending several magnetic components into one magnetic core results in unevenly distributed flux in the core. The magnetic design for IM schemes cannot be simply carried out by the conventional approaches. This dissertation presents a detailed design example of planar magnetic device for the proposed IM implementation of BCCFPP converter, along with simulation and experimental results.; Suggested future work in this area include use of finite element methods to analyze and design integrated magnetics, and a systematic study to quantitatively determine the savings in size and volume of magnetic components that can be achieved by adopting integrated magnetics schemes.