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This paper presents an active-clamp push--pull converter for battery sourcing applications. A pair of auxiliary switches, resonant inductors, and clamping capacitors is added to the primary side of the transformer to clamp voltage spike and recycle the energy trapped in the leakage inductors. In the proposed active-clamp push--pull converter, since both main and auxiliary switches can be turned ON with zero-voltage switching, switching loss can be reduced and conversion efficiency therefore can be improved significantly. Furthermore, the proposed converter can eliminate potential flux-imbalance problems existing in the conventional push--pull converter. In this paper, a 1 kW active-clamp push--pull converter was implemented, from which experimental results have shown that efficiency improvement and surge suppression can be achieved effectively. It is relatively feasible for applications to battery sourcing converters. Index Terms--Active clamp, push-pull converter, zero-voltage switching (ZVS).

This paper presents the analysis, design, and implementation of a parallel-inverter system with failure isolation and hot-swap features. The system is controlled with a system control unit to achieve output voltage regulation, inverter synchronization, and the aforementioned features. By incorporating a current-weighting-distribution control, the system allows inverters with identical or different power ratings. The failure isolation feature is achieved with a scanning circuit, a resistor-capacitor filter, and transistors, which are also used in achieving the hot-swap one. In the proposed system, power capacity can be readily expanded, and inverter-failure disturbance can be correspondingly reduced. Experimental results that are obtained from a six-inverter system have illustrated the discussed features and significantly demonstrated its feasibility, improving system reliability, and stability. Index Terms--Failure isolation, hot-swap feature, parallel-inverter system, scanning circuit.

This paper presents a half-bridge single-phase two-wire (1[phi]2W) photovoltaic (PV) inverter system that can perform both active power filtering and real power injection. In the proposed system, it needs only two active switches, reducing cost significantly. In addition, output current of the inverter can be controlled to prevent switches from exceeding their current ratings. Thus, power rating of the inverter can be effectively used and power quality can be improved. For controlling inverter output current, an amplitude-clamping algorithm and an amplitude-scaling algorithm are proposed, which can determine inverter current command without needs of complicated calculation. Simulations and experimental results have verified the feasibility of the proposed PV inverter system and the two current control algorithms. Index Terms--Active power filtering (APF), amplitude-clamping algorithm (ACA), amplitude-scaling algorithm (ASA), half-bridge inverter, photovoltaic (PV) power injection.

This paper proposes a single-phase two-wire inverter system for photovoltaic (PV) power injection and active power filtering (APF) with nonlinear inductor consideration. The proposed system can fully or partially perform APF, process PV power, eliminate harmonic currents, improve power factor, and take into account the nonlinear effect of its output filter inductor. In the system, even though only the utility current is sensed, both APF and maximum power point tracking features can be still achieved, reducing the number of current sensors and cost significantly. To prevent output current from exceeding switch ratings, inverter current is properly controlled through a current estimator and a defined limit circle. A self-learning algorithm is also proposed to determine nonlinear inductance, which can increase the accuracy of the estimated current. Simulations and experimental results have verified the feasibility of the proposed PV inverter system and the algorithm. Index Terms--Current estimator, nonlinear inductor consideration, photovoltaic (PV) power injection, self-learning algorithm, single-phase two-wire (1 [empty set] 2W) inverter system.

This paper presents a switch-mode approach to efficiently and flexibly generating reset waveforms for ac plasma display panels (PDPs). In the paper, the existing reset waveforms and circuits are first reviewed, and the proposed reset circuits for generating reset waveforms are then discussed. The proposed reset circuits are based on a flyback converter topology, which can generate reset waveforms more efficiently and can have more degrees of freedom in programming the waveforms. With the proposed approach, high-contrast ratio and resolution can still be sustained. Moreover, power conversion efficiency can be improved significantly, and components for generating various voltage levels can be reduced. Hardware implementation and measurements from a 46-in PDP system have verified the theoretical discussions. Index Terms--AC plasma display panel (PDP), high-definition TV, linear-ramp waveform, self-erasing discharge.

This paper presents the analysis, design, and practical consideration of a single-stage electronic dimming ballast with unity power factor. The power stage of the ballast is derived from combining a buck-boost converter and a half-bridge series-resonant parallel-loaded inverter (SRPLI). With the plasma model of the lamp, the analysis of the ballast is carried out, from which the key equations used for dimming control are derived. Starting performance and dimming consideration are also addressed in the paper. In this dimming ballast, both pulsewidth modulation (PWM) and variable-frequency control strategies are employed. The discussed ballast with the controls can save a controller and a switch driver, reduce size and cost, and possibly increase system reliability over conventional two-stage systems in the applications with moderate power level. Simulated and experimental results of the ballast for an OSRAM T8 32-W lamp are used to verify the discussion. Index Terms - Electronic ballast, power factor correction, single stage.

This paper presents the analysis and design of a series-resonant parallel-loaded inverter applied to electronic dimming ballasts with bifrequency and fuzzy logic control. The analysis of the ballast is carried out in conjunction with the fluorescent lamp represented in a plasma model. The component values of the power stage, as well as two switching frequencies, according to the desired maximum and minimum power levels are, therefore, determined. The power levels in between are controlled by varying the ratio between two time intervals for which the two frequencies last, respectively. This mechanism is achieved by using a fuzzy logic controller (FLC). A ballast prototype with the FLC which is implemented on an 8-bit microprocessor with a reduced instruction set computer architecture has been built. Experimental measurements have shown the feasibility of the ballast with the proposed control strategy. Index Terms--Ballast, fuzzy control.