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This paper presents the interleaved operation of a soft-switching boost converter operated in boundary conduction mode. First, the operating principle of the converter as well as the basic concept of the interleaving is presented. Then, the dynamic behavior is modeled using the z-transform to obtain a converter model that is independent of the switching frequency. With the model, the stability of the closed-loop system with a proportional–integral (PI) controller is analyzed. It is shown that an adaptive PI controller can be easily implemented to achieve a minimal settling time over a wide operating range. Finally, the controller is validated with two converters with a 40-kW nominal output power and an output voltage of 3 kV. The tests at different output voltages under different load conditions show a stable interleaved operation. [ABSTRACT FROM PUBLISHER]

In this paper, the charging precision of a 40-kW 3-kV soft-switching boost converter for capacitor charging is investigated. At the beginning, an overview on the topology and the control of the converter is given. Then, two different feedback controllers are presented and compared analytically to determine their sensitivity on noisy input variables. An algorithm to investigate the charging precision is illustrated. This algorithm considers the signal-to-noise ratio (SNR) of all measured signals, the controller output limitations, quantization related errors, the finite resolution in the digital domain, and the switching signal jitter to calculate the charging precision. All effects mentioned before are analyzed separately. This analysis shows that the output voltage measurement SNR is the key parameter for the charging precision. Then, measurements are performed to verify the model used to calculate the precision. These measurements show that the measured precision is only 6% higher than the precision predicted by the model for the used setup. Finally, the charging precision of the presented converter is analyzed including all considered effects. The repetition accuracy of the converter is determined to be 8.3 ppm at an output voltage of 3 kV, neglecting the load connection and the input voltage variation during one switching cycle. [ABSTRACT FROM PUBLISHER]

The development of new converter systems with higher power density and/or efficiency offers many degrees of freedom for the design parameters as a large number of system component values have to be defined, where all of which are interdependent, to some extent, on another. Therefore, an automated optimization procedure, based on comprehensive analytical models and the resulting optimal design parameters, e.g., switching frequency or transformer design, to achieve the most compact and/or efficient design, is presented in this paper. In addition, the design of a volume-optimized 400/46–56-V phase-shift dc–dc converter with a current doubler rectifier and the underlying analytical models are also introduced. The power density of the converter is increased by integrating the output inductors in the transformer's core. A new lossless magnetic snubber circuit is introduced, which damps the intrinsic voltage ringing of the rectifier diodes and feeds the ringing energy to the output. The experimental results prove the analytical models and the design procedure. The 5-kW dc–dc converter prototype has a power density of 147 \W/in^3 (9 kW/L) and a maximum efficiency of 94.4% at 54-V output voltage and full load. [ABSTRACT FROM AUTHOR]

This paper presents a novel closed-loop current-control strategy for a hybrid 12-pulse rectifier that uses a two-switch boost stage for output-voltage regulation. Unlike previous attempts to mitigate input-current distortion, e.g., by modulating the rectifier output voltage with open-loop control, this new closed-loop current-control scheme directly controls the line-interphase-transformer input voltage and/or impresses sinusoidal input currents. In this paper, the control strategy is explained and the modulation functions for each (\pi /6)-wide mains voltage sector are derived. The hardware implementation is described, and experimental results demonstrate that the control strategy ensures a high-quality input current for ideal as well as for distorted/unbalanced mains. [ABSTRACT FROM PUBLISHER]

In many pulsed-power applications, the flatness of the output pulse is an important characteristic to enable proper system operation, whereas a pulse flatness within less than a few percent has to be achieved. In power modulators based on capacitor discharge, this voltage droop is mainly defined by the input capacitance. In order to overcome this problem, in power modulator systems, compensation circuits are added, whereby in spite of a smaller storage capacitor, a flat pulse top is achieved. Depending on the pulse duration, different approaches for voltage droop compensation exist. For short pulse durations, in the range of several microseconds, only passive solutions or bouncer circuits are applicable. In this paper, the design and optimization of a two-winding inductor bouncer circuit are presented in order to achieve an output voltage droop of less than 1%. Due to the realized galvanic isolation, a new degree of freedom is obtained, which allows an adaptation of the bouncer circuit's voltage and current ratings to standard semiconductor switches. With an optimal design of the two-winding inductor bouncer circuit for the existing system, the volume of the input capacitor is reduced by a factor of 10.5, and the stored energy is decreased by a factor of 24 compared to a system without a bouncer circuit. [ABSTRACT FROM PUBLISHER]