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Hybrid excited (HE) machines, which combine the high torque density of permanent magnet (PM) machines and the excellent flux controllability of electrical-excited (EE) machines, are of great interest in variable-speed electric drive systems. An additional degree of freedom, i.e. the ratio between the PM and field winding (FW) flux, is obtained. Among a variety of HE machine topologies, the stator-excited configurations employing both PMs and FWs on the stator are attracting increasing attention. This is thanks to the elimination of sliding contacts and complicated structures for three-dimensional (3-D) flux paths. Nevertheless, the statorexcited HE machines suffer from the sacrificed performance due to space conflict, with the stator accommodating PMs, FWs, and armature windings. Partitioned stator (PS) machines were recently proposed to improve the space utilization of conventional stator-PM machines, in which two separate stators are employed to allocate armature windings and PMs respectively, with a salient iron-piece-rotor sandwiched between the two stators. As a result, more space is available for PM and/or copper, with which the torque density and efficiency are both remarkably boosted. In this thesis, based on the analysis on the existing PS machines and the inspiration from diverse rotor topologies in conventional rotorPM synchronous machines, the new PM excitation stator topologies are proposed to extend the family of PS machines. Meanwhile, the ferrite PM is introduced to PS machines to take advantage of the enlarged available space whilst balancing performance and cost. Moreover, the HE concept and the PS configuration can be integrated, providing the benefits of the stator-excited HE machines while relieving the space conflict. With tangentially magnetized PMs, the flexibility of PM and FW locations is identified by allocating the PMs to share the stator with either armature windings or FWs. The comparison between the proposed machines and the corresponding conventional HE machines reveals that the proposed machines can exhibit not only higher torque density, but also better flux controllability. Furthermore, a pair of PS-HE machines with radially magnetized PMs are investigated, based on which the series and parallel connections between the PMs and FWs are obtained respectively. It is found that the series PS-HE machines can exhibit higher torque while the parallel PS-HE machines benefit from better flux controllability. However, it should be noted that the mechanical weakness of the cup-rotor in the PS machines requires further work in the future.

Three-Dimensional Integrated Circuits (3DICs) have recently attracted great interest from researchers and IC designers as a possible solution to fill the gap between device and interconnect scaling. Various studies have demonstrated the potential performance improvement of 3DICs by eliminating long interconnects, repeaters, and clock buffers. Though 3DICs are attractive, there are significant challenges associated with this topic. The most fundamental issue in 3DIC is heat dissipation. The thermal effect has impacted the conventional high-performance 2DICs in deep sub-micron technology nodes. Its effect will aggravate 3DICs due to two major reasons: higher power density, and lower thermal conductivity caused by more insulating dielectric layers. Furthermore, while 3D integration provides more design flexibility, this technology also introduces much higher design complexity. The existing 2D physical design methodology cannot be simply extended to a 3D case because of the huge obstacles in the z-direction and thermal constraints. Efficient design flows and algorithms must be developed to facilitate 3DIC design. This dissertation proposes a design and verification methodology, along with analyses of delay, thermal, and reliability of a 3D system. The methodology uses commercial 2D CAD tools with Python and Tcl scripts to link them together. The scripts modify the output files (or databases) of the commercial tools and add 3D features to them. The entire flow achieves RTL-to-GDSII physical design automation for 3DICs. Design trade-offs and timing reliability of 3D systems are two other major issues of this dissertation. Non-idealities threaten to diminish the benefit and may cause reliability problems in 3D systems. These non-idealities must be monitored during the design procedure. With a fast yet accurate temperature dependency model, these non-idealities were successfully taken into consideration during both design and verification phases. The final performance analyses of two benchmark circuits show that the 3DIC achieves a maximum reduction of 27% on energy and 20% on delay compared to the conventional 2DIC approach. Finally, a performance trend study of 3DIC as the technology node shrinks is also performed to guide future 3DIC designs.