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 pulse width. Design and implementation of 1.8kV PPMs with repetition rate of 1MHz and rising/falling time below 6ns are presented. Also, important issues for the practical use of the SiC-based PPM are discussed. Experiments results from the developed PPMs are shown to verify the proposed works.

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 mosfet s 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.

This article describes the development of an 80-kW high-voltage power supply (HVPS) to drive an X-ray tube. Since the developed HVPS is based on an LCC resonant converter with a symmetrical bipolar voltage multiplier (SBVM), it shows many superior features such as soft switching capability and low voltage imbalance among stages. In addition, the proposed circuit has high power density because a series resonant capacitor is removed by using a method converting the SBVM into capacitors and the full-wave rectifier. Furthermore, a suggested transformer achieves high insulation performance and effective winding area utilization by applying half of the output voltage to the core. The detailed design based on the fundamental harmonic approximation is presented for the practical use of the LCC resonant converter with the SBVM in high voltage and high power applications. Also, some significant issues in the implementation are addressed. The performance of the developed HVPS is verified by simulations and experimental results.

In this article, we proposed a bidirectional dual active bridge (DAB) converter adopting a boost-up function. The proposed converter can be implemented by adding only one capacitor to the high voltage side without additional active components. By utilizing the boost-up function, the proposed converter can achieve higher output power than the conventional DAB converter under the same leakage inductance condition. In comparison with the resonant converter in addressing the output power limitation, the proposed converter can reduce the switching and conduction losses due to the low turn- off and circulating currents, and complex control is not required to drive the synchronous rectifier. Furthermore, the direction of the output power can be easily changed with a simple control circuit. Experimental results from the proposed converter with a 3 kW rated power, 28-V low-side voltage, and 600-V high-side voltage are demonstrated to verify the proposed works.

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.

This article proposes a modular pulsed power modulator (PPM) with a short pulse width and high repetition rate for pulsed lasers. The presented PPM is based on the modular structure to use semiconductor switches with low voltage ratings since these switches have fast switching speed, which is an essential requirement to generate short pulses. In addition, to make a short gate signal which is also needed to generate short pulses, a gate driver circuit that applies positive and negative voltages asymmetrically is proposed. Moreover, a heatsink structure to minimize the parasitic capacitances is presented for the high repetition rate. Furthermore, a dc–dc converter for the modular PPM is developed, which connects transformers in parallel at the primary side to achieve voltage balance without any compensation circuit. Experimental results from a 5 kV PPM with the pulse width below 20 ns and repetition rate of 1 MHz are presented to verify the proposed works.