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This paper suggests a design of pulsewidth modulation series-resonant converter (PWM SRC) for magnetron power supplies. The goal of this design is to make the PWM SRC have a wide output voltage maintaining mode 3 operation that shows good switching characteristics. To keep the mode 3 operation, a systematic design is required because the design is related to various parameters, such as resonant tank, transformer turns-ratio, magnetizing inductance, and duty-ratio. To establish the design procedure, converter analysis is performed related to the steady-state operation, input–output relationship, and critical design conditions, and several design equations are derived based on the analysis. Based on the design procedure, a PWM SRC with parallel-input-series-output-connected transformer has been designed for magnetron power supplies and verified. [ABSTRACT FROM AUTHOR]

A magnetic pulse compressor (MPC) transfers energy via $C$ – $L$ – $C$ resonance. The pulse width of the MPC is determined by the saturation inductance of the magnetic switch (MS). When using the MS, the pulse width is limited due to the stray elements. To increase the pulse compression rate, the number of stray elements must be reduced. In this paper, we propose an optimum design for an MS having the lowest impedance of stray elements, along with its analysis and experimental verification. The proposed model is designed to have a reduced magnetic path length while retaining the same saturation inductances as that of a common MS; this is accomplished by using the relationship between the magnetic field path length and the number of inductor turns. The experimental results show that the proposed MS decreases the full width at half maximum by 18% and increases the rise rate by 69%. This result demonstrates that the proposed MS increases the pulse compression rate of the MPC by reducing impedance of stray elements in the system. [ABSTRACT FROM AUTHOR]

Magnetic compression (MC) technology was recommended for tokamak to study compressed plasma and a power module have been designed here for developing its server power supplier. The minor-radius compression is one of the most effective methods to improve the performance parameters of existing tokamaks, enabling the fusion plasmas operated at high density, high temperature, and high beta. In this paper, a high-frequency and high-power supply system is proposed, used for powering coils of MC within the vacuum chamber of the experimental advanced superconducting tokamak. The basic of the power module is an ac/pulse converter, implemented by a series-resonant full-bridge circuit and controlled by pulsewidth modulated. Also, control method adopts current closed-loop proportional–integral control, which has less than 3-ms current response time in real time. The converter is analyzed and the design procedure is discussed. Experimental results obtained from a 3-kW converter prototype are presented to validate the converter’s performance with the redesigned control board. [ABSTRACT FROM AUTHOR]

In a magnetic pulse compressor (MPC), the saturation inductance of the magnetic switch (MS) determines the energy transfer time. Thus, in general, the number of windings on the MS is modulated to vary the saturation inductance. Changing the number of windings also changes the energy transfer time and the saturation time. In this paper, we propose and analyze an MS with multiwindings to modulate the pulse width without affecting the saturation time of the MS. The parallel structure of the multiwindings on the MS decreases the energy transfer time without affecting the saturation time. Through experiments, we show that the energy transfer time is decreased by 13% via a double winding MS. Therefore, an MS with multiwindings can be used to modulate the pulse width at the last stage of the MPC without affecting the saturation time of the MS. [ABSTRACT FROM AUTHOR]

This paper describes a high-frequency pulsed-power generator for various industrial applications such as water treatment, food and medical apparatus for sterilization, or polluted gas treatment. The system is made of silicon-controlled rectifier as a main trigger switch, capacitors, two-stage magnetic pulse compression stages, and a linear transformer to generate a maximum of 120-kV, 5-kA pulse. The parameters obtained through the development are: output voltage: 120 kV (maximum), pulse repetition ration: 300 pulse per second, pulsewidth: 0.25~\mu \texts , and mean power: 30 kW. The designed pulsed-power generator is confirmed to be used effectively for many high-voltage pulsed-power applications related to environmental industry by simulation and experiments. [ABSTRACT FROM AUTHOR]

This paper presents a novel technique for the voltage droop compensation of long pulses in solid-state bipolar high-voltage Marx generators. Considering the modularity of Marx generators the compensation consists in adding one extra stage to perform as a pulsewidth modulation circuit. This stage voltage is added to the output positive or negative pulses, and an output LfCf filter is included to smooth the voltage pulse waveform. A five-stage laboratory prototype of this circuit has been assembled using 1200-V Insulated Gate Bipolar Transistors and diodes with 1000-V dc input voltage. The circuit was operated at 50-Hz bipolar pulse rate, giving 4-kV bipolar pulses, into a resistive load, with 100- \mu \texts pulsewidth and 9.5-ms relaxation time. The circuit was able to compensate 10% of bipolar pulse voltage droop. [ABSTRACT FROM PUBLISHER]

A 100-kV/60-A high-voltage power supply (HVPS) has been established to energize the electron cyclotron resonance heating system for the J-TEXT tokamak. The HVPS based on the pulse step modulation technique has many advantages, including low stored energy and short protective time in case of a short circuit fault. This paper describes and provides the key design features of isolated transformers, switch power supply (SPS) modules, measurement equipment, and controllers. In this HVPS, four dry-type transformers with 36 secondary windings drive the 144 series SPS modules and isolate the high voltage between the rectifiers and the 6.3-kV ac bus. A controller based on PXI technology, which conforms to the ITER CODAC standard, has been developed to operate the series switches in each SPS module. The error signals from all the modules are monitored by the controller, and the fast protection responds to any current fault in <5~\mus. A control strategy improved from the conventional pulsewidth modulation phase-shift modulation method has also been proposed to acquire better dynamic response and stability. Experimental results show that the power supply system performs well. [ABSTRACT FROM PUBLISHER]