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High-power current sources with high dynamic performance, ultralow current ripple, and absolute reference tracking accuracy are the key elements for magnets (bumper and septum) that are used in accelerators. Similar requirements are also encountered in plasma research applications in fusion reactors, as well as plasma research for the future high voltage direct current circuit breakers. Therefore, the current source must be able to drive resistive/inductive and highly fluctuating loads without any compromise in its performance. In this paper, such a flexible, dynamic, and accurate current source is introduced, which able to provide amplitudes up to 30 kA and bipolar voltages up to 10 kV. The system’s operating concept is presented and its design procedure in order to fulfill a list of demanding specifications is demonstrated. In addition, a detailed description of its near-optimal, advanced control system is presented. Finally, the theoretical considerations are verified by extensive simulation results for various operating scenarios, including driving chaotic arc loads. [ABSTRACT FROM AUTHOR]

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]

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]

Pulse loads, like solid-state pulse modulators, generate short pulses with a high peak power that exceeds the average power by 100-1000 times depending on the pulse repetition rate. There, the peak power usually is drawn from an energy buffer such as a capacitor bank. The pulse discharges the energy buffer, and it is fully recharged in the time between the pulses by a power supply, which is usually connected to the mains. Due to the worldwide variation in mains voltages and the desired ability to adapt to the capacitor voltage of the modulator, the power supply has to support a wide input and output voltage range. Additionally, the supply should draw a sinusoidal current from the mains while providing energy to the pulse modulator due to electromagnetic interference regulations. Therefore, a general control concept for pulse load applications, which guarantees continuous power consumption from the mains and power factor correction, is described in this paper. Furthermore, measurements of the control principle, which is independent from the converter topology, are presented for a three-phase buck-boost rectifier. [ABSTRACT FROM AUTHOR]