A generalized, discrete-time modeling and simulation program, applicable to any PWM, resonant or quasi-resonant converter, has been developed. From a circuit description, this program automatically generates state-space equations corresponding to each switching interval and performs time-domain simulations by using state-transition equations with a fast-convergence algorithm for topological changes. / M.S.

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Two novel clamped-mode resonant converters are analyzed. These clamped-mode converters operate at a constant frequency while retaining many desired features of conventional resonant converters such as fast responses, zero-voltage turn-on or zero-current turn-off, and low EMI levels, etc. The converters are able to regulate the output from no load to full load and are particularly suitable for off-line, high-power applications. To provide insights to the operations and derive design guidelines for the clamped-mode resonant converters, a complete dc characterization of both the clamped-mode series-resonant converter and the clamped-mode parallel-resonant converter, operating above and below resonant frequency, is performed. State-plane analysis techniques are employed. By portraying the converters' operation on a state-plane diagram, various circuit operating modes are identified. The boundaries between different operating modes are determined. The regions for natural and force commutation of the active switches are defined. Important dc characteristics, such as control-to-output transfer ratio, rms inductor current, peak capacitor voltage, rms switch currents, average diode currents, switch turn-on currents, and switch turn-off currents are derived to facilitate the converter designs. To illustrate the converter designs in different operating regions, several design examples are given. Finally, three prototype circuits are built to verify the analytical results. / Ph. D.

The power requirements for future spacecraft power systems will be on the order of a few hundred kilowatts to a few megawatts. Because of these power levels, a high-voltage, high-power distribution subsystem may be utilized to transmit power from the source to the different loads. Using current state-of-the-art power conditioning electronics, complex series and parallel configurations will be required at the interface between the source and the distribution subsystem and between the distribution subsystem and the loads. The dynamic response of such a spacecraft power system may be obtained using a general purpose program such as SPICE2. However, for large and complex spacecraft power systems, the input file will be large and complex with correspondingly large computation times. As an alternative, the spacecraft power system can be considered as an interconnection of modular components. Each component is treated as a two-port network, and a state model is written with the port voltages as the inputs. The state model of each component is solved using the state transition matrix and assuming that the port voltages are . clamped for each time step. This calculation proceeds as if all two-port networks are decoupled. After the state variables have been updated, the inputs to all components are calculated using network analysis principles. The solution procedure alternates between solving the dynamic model of all components and the network equations for the component inputs. The modular state variable approach and SPICE2 are compared using two example systems. This comparison shows the advantages of the modular state variable approach. First, for the modular state variable approach the system is considered as an interconnection of modular components. In SPICE2, the system is treated as an interconnection of circuit elements. As a result, the system description for large and complex spacecraft power systems is much _ larger and more complex than a modular state variable description. Secondly, the modular state variable approach requires less CPU time than SPICE2. For one of the example systems presented here, the modular state variable approach uses one-twentieth of the CPU time used by SPICE2. / Ph. D.

Basic PWM dc-to-dc converter structure is examined wherein a basic substructure of converters, known as a converter cell, is identified. Converter cells can be used in generation and classification of basic PWM dc-to-dc converters. A large number of new converters are generated. Converter analysis, whereby the nonlinear response of the system to perturbations in the control or the input, is determined by two different methods. A classical approach to nonlinear systems analysis is first used wherein the system is represented by a Volterra functional series. The alternative approach presented concentrates on deriving circuit models for the PWM switch. The PWM switch represents the static nonlinear substructure of the vast majority of converter cells. Analysis of converters then proceeds in an analogous fashion to ordinary transistor circuit analysis whereby the nonlinear device is replaced by its circuit model. Topological considerations of single-phase dc-to-ac inverters are discussed. A number of zero-current switching quasi-resonant inverter topologies are derived. Schemes that permit these topologies to handle reactive loads are identified. / Ph. D.

A method to obtain the exact control-to-output and input-to-output transfer functions for switched DC-to-DC pulse-width modulated power converters is applied to different combinations of operating conditions such as continuous conduction mode (CCM), discontinuous conduction mode (DCM), and discontinuous voltage mode (DVM) and methods of control such as normal voltage mode (NVM), current programming mode (CPM), and V-squared control. The majority of these combinations have not previously had their transfer functions of interest derived to the accuracy provided by the method. The derivation of the method is covered, and the results from its application are verified by simulation. The simulation method is also justied and proposed as an improvement to the methods used by simulation engines for switched mode power supply design such as SIMPLIS.

Fabrication technology, based on MEMS processes, for constructing components for use in switched-mode power supplies are developed and presented. Capacitors, magnetic cores, and inductors based on sacrificial multilayer electroplating are designed, fabricated, and characterized. Characterization of the produced inductors' core losses at high frequency and high flux is presented, confirming the aptness of the featured microfabrication processes for reducing eddy current losses in magnetic cores. As well, the demonstration of the same inductors in DC/DC converters at high switching frequencies, up to 6 MHz, is presented. Initial work addressing the top-down development of a fully-integrated DC/DC converter is presented. As well, the comprehensive advancement of the central process - sacrificial multilayer electroplating - is presented, including the development of a second-generation automated multilayer electroplating system. The advanced sacrificial multilayer plating process is applied to produce microfabricated capacitors, which achieved in excess of 1.5 nF/mm² capacitance density, The fabrication of highly-laminated magnetic cores and power inductors based on sacrificial multilayer electroplating is presented, along with the design and development of a system for characterizing inductor behavior at high-frequency, high-flux conditions. The design and operation of both buck and boost DC/DC converters, switching at up to 6 MHz, built around these highly-laminated-core inductors are presented.