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This paper proposes a solid-state pulsed power modulator (PPM) with fast rising/falling time and high repetition rates to drive pockels cells. Since the proposed circuit is based on the modular structure using silicon carbide (SiC) metal–oxide silicon field-effect transistors (MOSFETs) for bypass devices as well as for main switches, it can achieve fast switching speed and high reliability. In addition, by a control scheme employing the voltage difference, the proposed circuit can accomplish a high repetition rate and short pulsewidth. Design and implementation of 1.8-kV PPMs with repetition rate of 1 MHz and rising/falling time below 6 ns are presented. Also, important issues for the practical use of the SiC-based PPM are discussed. Experimental results from the developed PPMs are shown to verify the proposed works. [ABSTRACT FROM AUTHOR]

This paper describes the circuit of a capacitor charger for a solid-state Marx modulator. A high-efficiency LCC resonant inverter is proposed for the simultaneous charging of many capacitors in parallel using a multistage transformer and rectifier. Using a high-voltage insulation cable, the charging loop, which represents the primary winding of transformer, is implemented to transfer the power from the resonant inverter to each stage. In addition to the simultaneous charging of separate capacitors, the advantages of the proposed circuit and structure include compact design and reliable insulation performance against high-voltage pulses. Based on the relevant approximation, the simplified analysis of an LCC resonant converter with a trapezoidal shape of resonant current is provided and a 50-kW high-voltage capacitor charger is designed for a 40-kV solid-state Marx modulator. The power stage, which consists of a transformer with four voltage-doubled rectifiers, is designed, and six power stages are configured for generating a pulse output of 40 kV. The detailed implementation of the multistage transformer and rectifier is presented in accordance with the design requirements of a high voltage modulator. Finally, the developed charger achieves 96% of the maximum efficiency and 0.96 of the maximum power factor. The experimental results verify that the proposed circuit and structure can be effectively used for a solid-state Marx modulator. [ABSTRACT FROM PUBLISHER]

This study presents a simplified design for a solid state pulsed power modulator (SSPPM) based on a power cell structure. Similar to the Marx generator, the power cell structure has advantages such as reliability and modularity. In addition, the proposed SSPPM includes a capacitor charger that is simple and compact. The operating principle of, and the design considerations taken for, the SSPPM are discussed from a practical viewpoint. Based on a reasonable approximation, simplified design equations are developed for a capacitor charger and a high-voltage pulse-switching part, which are comprised of an LCC resonant converter and a power stage, respectively. Accordingly, detailed design procedures are proposed to develop the SSPPM with the following specifications: 40 kV, 20 A, 300 μs, 200 Hz, and 50 kW. The experimental results verify the specifications at the rated operating condition with an efficiency of 92.4%, and also confirm reliable arc-protection performance. Finally, the proposed design methodology, which utilizes simplified equations, can be used for designing an SSPPM based on the power cell structure for extensive applications. [ABSTRACT FROM PUBLISHER]

This paper proposes a new gate driving circuit for the solid-state pulsed power modulator (SSPPM) based on semiconductor devices. The proposed circuit can be easily implemented by applying a short gate signal to the bypass insulated gate bipolar transistor (IGBT), i.e., switches connected in parallel with the load instead of a pull-down resistor. The IGBT_BPs are turned on at the end-point of the pulse. It can quickly discharge the pulse voltage applied to the load. In addition, it can operate as bypass diode, which is used to protect the semiconductor switches when the gate signal malfunctions, by using the antiparallel diode of the IGBT. Moreover, power loss in the pull-down resistor used to achieve fast falling pulses can be eliminated by turning off the IGBT while applying the pulse state. Thus, the proposed circuit can be used for implementing SSPPM with small values of falling time and high efficiency. The circuit configuration, operational principle, relevant analysis results, and a PSpice modeling are presented and verified by the 10-kV SSPPM. [ABSTRACT FROM PUBLISHER]

This article describes the compact solid-state Marx modulator (SSMM) with a fast rising time and a short pulsewidth based on the modular structure. By stacking of the TO-263-7 packaged silicon carbide mosfets having high voltage and fast switching capabilities, the designed circuit consists of three components, including the Marx capacitor, an on switch for applying pulse to the load, and an off switch to pull down the pulse. The off switch connected in parallel with load is chosen as a mosfet instead of a diode that is used in the conventional Marx generator. Because the off switch provides a discharging path for the stored energy on the parasitic capacitance, it is highly related to the fast falling time. In order to provide complementary driving signal and power for on/off switches, the simple control algorithm with a minimum component count and a reliable drive circuit against the noise are proposed. In addition, the synchronization of all the gate signals and a compact configuration for minimizing the stray inductance are essential to shorten the rising, falling, and pulsewidth. Based on the proposed circuit, the following specifications of the developed SSMM are achieved: the output voltage of 10 kV, the pulsewidth of less than 50 ns, and the rising and falling times of less than 15 ns. [ABSTRACT FROM AUTHOR]

This letter proposes a high output voltage dc–dc converter topology with series stacked converter modules. To implement the proposed modular dc–dc converter structure, output voltage balancing of the modules and simplification of the control circuitry were considered the major design objectives. To achieve voltage balancing between the modules, we proposed a split-secondary transformer winding structure and distributed connections to the rectifier circuit blocks. Each transformer includes two secondary windings, with each wire pair connected to a different rectifier circuit. Consequently, one rectifier receives ac power simultaneously by sharing the secondary windings fed from two different transformers. The proposed method was verified using a modular LCC resonant converter, which is widely employed in high-voltage applications. As a result, the control circuit was simplified by using a single controller to regulate the total output voltage and by applying a compact sensing circuit referenced to the output voltage of the module placed at the lowest grounding point. [ABSTRACT FROM AUTHOR]

In this paper, a 25-kW bipolar pulsed-power supply for strategic mineral exploration has been described. A 500-V, 12.5-A unit module consisting of a highly efficient LCC resonant converter and a full-bridge-based bipolar pulse-switching unit is designed. The LCC resonant converter has a trapezoidal-shaped resonant current for reduced conduction loss. For achieving high power density, the leakage inductance of the transformer is used as resonant inductance without an external inductor. Moreover, the designed gate drive circuit based on the repetitive short pulse is proposed to operate the frequency range from dc to 8 kHz and reduce the size of the gate transformer. Four modules are connected in series and parallel in order to operate the power supply in either loop mode or grounded dipole mode. Depending on the load condition, the pulse power source capable of delivering the required high voltage and low current (2 kV, 12.5 A) or low voltage and high current (500 V, 50 A) is operated either in grounded dipole mode or loop mode, respectively. In order to satisfy the output voltage balancing of the four modules, the third wire is wound to compensate for the transformer of the LCC resonant converter. Finally, the design of the bipolar pulsed-power supply has been verified based on the experimental results of the field test. [ABSTRACT FROM AUTHOR]

This paper proposes a flyback-circuit-based design of a trigger circuit for a high-power gas switch. By incorporating a flyback circuit in a high-power gas switch, it is possible to generate a high step-up ratio and high-voltage pulse by using a transformer. Furthermore, simple trigger circuit having the minimum possible number of components (transformer and switch) can be realized. When an inductor is used as an energy storage element, energy is stored as a current source, and thus, the element can operate reliably when low impedance exists between the trigger node of the switch after triggering. According to the fundamental operating principle of a flyback circuit, the proposed trigger circuit is designed considering the maximum trigger voltage and energy required for a high-power gas switch. To verify the proposed design procedure and feasibility of the trigger circuit, a compact trigger circuit (7.5 kV, 1.3 mJ/pulse) is simulated using the PSpice program and implemented. Based on this compact circuit, a trigger circuit (20 kV, 100 mJ/pulse) for a triggered vacuum switch (TVS) is developed, and the tests with an actual TVS (3.3 kJ) are carried out. [ABSTRACT FROM AUTHOR]

This paper describes a bipolar pulsed power supply for strategic mineral exploration. Depending on the operating conditions, the bipolar pulsed power supply is capable of delivering the required high voltage and low current or low voltage and high current when operated, respectively, in either the grounded dipole mode or the loop mode. Based on a 500-V 12.5-A unit module, series and parallel connections of four modules are configured to satisfy both the grounded dipole mode (2000 V) and the loop mode (50 A), respectively. A unit module comprising an LCC resonant converter and a full-bridge-based bipolar pulse-switching unit is designed. In order to achieve high power density, the leakage inductance of the transformer is used as a resonant inductor in place of an external inductor. Accordingly, the resonant tank parameters are designed to give the resonant current a trapezoidal shape to reduce conduction loss and provide high efficiency. In addition, a simple gate-driving algorithm that uses the repetitive short pulse to cover the frequency range from dc to 8 kHz is proposed to allow the compact design of a minimized gate transformer. In this paper, the detailed design of the resonant circuit and the transformer of a unit module is described, and the operation is verified through simulation and experimental results. Finally, the developed LCC resonant converter achieves the maximum efficiency of 95%, the maximum power factor of 0.96, and a high power density of 806.5 W/L. [ABSTRACT FROM AUTHOR]

In this paper, the detailed design of an ion pump power supply is presented. The ion pump power supply was designed based on an LCC resonant topology with high switching frequency to take advantage of a smaller transformer for isolation. Because the proposed ion pump power supply has a 7-kV, 50-mA specification, high-voltage insulation is required. In order to secure insulation reliability, the power supply was designed with eight separate transformers that share primary turns. The spacing between the primary turns and secondary turns allows for increases in the leakage inductance and parasitic capacitance of the transformer. A compact design can be achieved using the parasitic component generated by the proposed design as the resonant parameters of the LCC resonant converter. In addition, based on a trapezoidal approximation of the LCC resonant converter, the resonant parameters are designed to have trapezoidal shapes of the resonant current in order to reduce conduction loss. Finally, the results of the experiment indicate that the developed ion pump power supply can be used effectively in high-voltage and low-current applications. [ABSTRACT FROM AUTHOR]