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A method for systematic synthesis of quasi-resonant (QR) topologies by addition of resonant elements to a parent pulse-width modulation (PWM) converter network is proposed. It is found that there are six QR classes with two resonant elements, including two novel classes. More complex QR converters can be generated by a recursive application of the synthesis method. Topological definitions of all known and novel QR classes follow directly from the synthesis method and topological properties of PWM parents. The synthesis of QR converters is augmented by a study of possible switch realizations and operating modes. In particular, it is demonstrated that a controllable rectifier can be used to accomplish the constant-frequency control in all QR classes. Links between the QR converters and the underlying PWM networks are extended to general DC and small-signal AC models in which the model of the PWM parent is explicitly exposed. Results of steady-state analyses of selected QR classes and operating modes include boundaries of operating regions, DC characteristics, a comparison of switching transitions and switch stresses, and a discussion of relevant design trade-offs.

An additional independent control needed to eliminate the undesirable variable switching frequency of quasi-resonant converters can be obtained if the output rectifier is replaced by an active switch. The concept is applicable to all classes of quasi-resonant converters. It is demonstrated that in addition to operation at constant switching frequency, selected classes of constant-frequency quasi-resonant (CF-QR) topologies feature extended range of accessible conversion ratios and load currents. A practical example of a constant-frequency multi-resonant (CF-MR) buck converter operating at 2 MHz is described.

Three discontinuous operating modes of PWM (pulsewidth modulated) converters are considered: the discontinuous inductor current mode (DICM), the discontinuous capacitor voltage mode (DCVM), and a previously unidentified mode called the discontinuous quasi-resonant mode (DQRM). DC and small-signal AC analyses are applicable to all basic PWM converter topologies. Any particular topology is taken into account via its DC conversion ratio in the continuous conduction mode. The small-signal model is of the same order as the state-space averaged model for the continuous mode, and it offers improved predictions of the low-frequency dynamics of PWM converters in the discontinuous modes. It is shown that converters in discontinuous modes exhibit lossless damping similar to the effect of the current-mode programming.

In dc-to-dc conversion applications that require a large range of input and/or output voltages, conventional PWM converter topologies must operate at extremely low duty ratios, which limits the operation to lower switching frequencies because of the minimum ON-time of the transistor switch. This is eliminated in a new class of single-transistor PWM converters featuring voltage conversion ratios with quadratic dependence on duty ratio. Practical circuit examples operating at 0.5 MHz are described.

A method for systematic synthesis of quasi-resonant (QR) topologies by addition of resonant elements to a parent pulse-width modulation (PWM) converter network is proposed. It is found that there are six QR classes with two resonant elements, including two novel classes. More complex QR converters can be generated by a recursive application of the synthesis method. Topological definitions of all known and novel QR classes follow directly from the synthesis method and topological properties of PWM parents. The synthesis of QR converters is augmented by a study of possible switch realizations and operating modes. In particular, it is demonstrated that a controllable rectifier can be used to accomplish the constant-frequency control in all QR classes. Links between the QR converters and the underlying PWM networks are extended to general DC and small-signal AC models in which the model of the PWM parent is explicitly exposed. Results of steady-state analyses of selected QR classes and operating modes include boundaries of operating regions, DC characteristics, a comparison of switching transitions and switch stresses, and a discussion of relevant design trade-offs.

An additional independent control needed to eliminate the undesirable variable switching frequency of quasi-resonant converters can be obtained if the output rectifier is replaced by an active switch. The concept is applicable to all classes of quasi-resonant converters. It is demonstrated that in addition to operation at constant switching frequency, selected classes of constant-frequency quasi-resonant (CF-QR) topologies feature extended range of accessible conversion ratios and load currents. A practical example of a constant-frequency multi-resonant (CF-MR) buck converter operating at 2 MHz is described.

Synthesis of DC-to-DC converter topologies in the two largest families - PWM and Quasi-Resonant (QR) - is completed in this thesis. In a PWM converter, two linear time-invariant networks, consisting of only capacitors and inductors, source and load, are switched at constant frequency with duty ratio D. From defining assumptions, several general properties of PWM converter networks are derived. The established general properties interrelate the number of elements, attainable DC conversion ratio M(D), and features such as continuous terminal currents or possible coupling of inductors. Based on matrix representation of the converter topology, the systematic synthesis procedure for generation of PWM converters with a given number of reactive elements is constructed. A prescribed set of requirements is the input for the procedure. The requirements may include desired DC conversion ratio, continuous terminal currents, possible coupling of inductors and a given number of switches. In particular, the number of switches implemented as transistors can be specified. Outputs of the procedure are complete classes of PWM converters that satisfy the input requirements. A number of useful PWM topologies, which have not been identified before, are uncovered. A comparison of members of the classes is included. Several extensions of PWM converters are considered, including insertion of the isolation transformer and two discontinuous operating modes for which unified DC analyses are completed. Quasi-Resonant converters are defined as two-switch PWM converter networks to which resonant elements are added. Synthesis of QR, converters is based on the recognition that there are only a finite number of topologically distinct positions for resonant elements within a two-switch PWM parent converter. If a single resonant inductor and a single resonant capacitor are added to a two-switch PWM topology, examination of all possible positions yiel

Synthesis of DC-to-DC converter topologies in the two largest families - PWM and Quasi-Resonant (QR) - is completed in this thesis. In a PWM converter, two linear time-invariant networks, consisting of only capacitors and inductors, source and load, are switched at constant frequency with duty ratio D. From defining assumptions, several general properties of PWM converter networks are derived. The established general properties interrelate the number of elements, attainable DC conversion ratio M(D), and features such as continuous terminal currents or possible coupling of inductors. Based on matrix representation of the converter topology, the systematic synthesis procedure for generation of PWM converters with a given number of reactive elements is constructed. A prescribed set of requirements is the input for the procedure. The requirements may include desired DC conversion ratio, continuous terminal currents, possible coupling of inductors and a given number of switches. In particular, the number of switches implemented as transistors can be specified. Outputs of the procedure are complete classes of PWM converters that satisfy the input requirements. A number of useful PWM topologies, which have not been identified before, are uncovered. A comparison of members of the classes is included. Several extensions of PWM converters are considered, including insertion of the isolation transformer and two discontinuous operating modes for which unified DC analyses are completed. Quasi-Resonant converters are defined as two-switch PWM converter networks to which resonant elements are added. Synthesis of QR, converters is based on the recognition that there are only a finite number of topologically distinct positions for resonant elements within a two-switch PWM parent converter. If a single resonant inductor and a single resonant capacitor are added to a two-switch PWM topology, examination of all possible positions yiel

Synthesis of DC-to-DC converter topologies in the two largest families - PWM and Quasi-Resonant (QR) - is completed in this thesis. In a PWM converter, two linear time-invariant networks, consisting of only capacitors and inductors, source and load, are switched at constant frequency with duty ratio D. From defining assumptions, several general properties of PWM converter networks are derived. The established general properties interrelate the number of elements, attainable DC conversion ratio M(D), and features such as continuous terminal currents or possible coupling of inductors. Based on matrix representation of the converter topology, the systematic synthesis procedure for generation of PWM converters with a given number of reactive elements is constructed. A prescribed set of requirements is the input for the procedure. The requirements may include desired DC conversion ratio, continuous terminal currents, possible coupling of inductors and a given number of switches. In particular, the number of switches implemented as transistors can be specified. Outputs of the procedure are complete classes of PWM converters that satisfy the input requirements. A number of useful PWM topologies, which have not been identified before, are uncovered. A comparison of members of the classes is included. Several extensions of PWM converters are considered, including insertion of the isolation transformer and two discontinuous operating modes for which unified DC analyses are completed. Quasi-Resonant converters are defined as two-switch PWM converter networks to which resonant elements are added. Synthesis of QR, converters is based on the recognition that there are only a finite number of topologically distinct positions for resonant elements within a two-switch PWM parent converter. If a single resonant inductor and a single resonant capacitor are added to a two-switch PWM topology, examination of all possible positions yiel