Solid-state Pulsed Power Modulator Research Articles

Solid State Pulsed Power Modulator With High Repetition Rate and Short Pulse Width for High-Speed Pulsed Lasers

This paper 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 which 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.

Compact High-Voltage Pulse Discharging Switch With IGBT Stack and Simple Gate Drive Circuit

High-voltage switches composed of semiconductor switching components generally require a series stacked configuration, owing to limitations from the device voltage rating. In this configuration, isolated and synchronized gate signals should be applied to each of the switching devices for reliable operation. In this study, a high-voltage switch composed of a series stack of 12 semiconductor switches and a simple and low-cost gate drive circuit for the series stacked switch were designed. The proposed design can be applied to a low-power solid-state pulsed power modulator (SSPPM) without needing auxiliary circuits for the synchronized and isolated gate signal, by using a gate transformer with a single high-voltage cable loop on the primary side. Furthermore, the secondary side of the gate transformer has a simple circuit composed of two Zener diodes, a resistor, and a small storage capacitor. An insulated-gate bipolar transistor (IGBT) stack with 12 switches of 1200 V and 40 A rating each and a gate drive circuit were accordingly developed and proved to operate with a maximum pulse voltage and current of 10 kV and 100 A, respectively. The high-voltage switch with the IGBT-stack-based configuration was also verified to have compact dimensions of 10 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times$</tex-math> </inline-formula> 10 cm.

반도체 스위치 기반 고전압 펄스전원 연구 동향

This paper describes the research trends of the high voltage pulsed power modulator based on semiconductor switch. The research on the solid-state pulsed power modulator technology can be classified into three topics that were performed for introducing the topology of pulsed power modulator to overcome the ratings of semiconductor device, increasing the rated power with long pulse width and low voltage droop, minimizing rising/falling time with short pulse width. This paper provides a brief overview of these three research topics and introduces the developed pulsed power modulator in Korea Electrotechnoloy Institute(KERI).

MOSFET Gate Driver Circuit Design for High Repetitive (200 kHz) High Voltage (10 kV) Solid-State Pulsed-Power Modulator

Solid-state pulsed-power modulators can effectively generate high repetition rate pulses, which are required in applications where the process rate depends on the repetition rate, e.g., plasma source ion implantation and deposition, plasma immersion ion milling, and diamond-like carbon coating. In this article, a solid-state pulsed-power modulator for generating high repetitive pulses is developed. Active pull-down circuits and designed metal-oxide-semiconductor field-effect transistor (MOSFET) gate drivers are applied to the modulator without increasing its size. The drivers enable a fast rise, fall time, and minimize pulsewidth, which are effective for high-repetition-rate pulse applications. The developed modulator exhibits a maximum output pulse voltage of ±10 kV, maximum output pulse current of 50 A, pulsewidth between 200 ns and 10 us, maximum pulse repetition rate of 200 kHz, and average output power of 10 kW. The operation principle of the designed MOSFET gate driver is analyzed in detail. Experimental results show that the modulator operates stably at a high repetition rate of 10 kV and 200 kHz and the feasibility of this proposed circuit for high repetition rate operation are verified.

고반복 펄스 전원용 게이트 드라이버 회로 설계

In this paper, a new gate driver circuit is proposed to drive high voltage SiC MOSFET(Metal-Oxide-Semiconductor Field-Effect Transistor) of a solid-state pulsed power modulator. This gate driver circuit is designed to output pulses with repetition rates of several hundred kpps, and 1200V SiC MOSFETs are used as the main switch. In addition, a compact discharge structure was considered so that the volume of the modulator generating an average output of 10 kW could be designed to be within 26 liters, and thus a compact discharge structure based on an integrated gate driver of a discharge switch and a pull-down switch was implemented. In the experiment, synchronous stability was confirmed through gate synchronous driving tests of 12 discharge switches and pull-down switches, respectively. Based on this, a high repetition pulse output of 10 kV 150 kpps was finally performed, and the reliable operation of the proposed new gate driver and discharge circuit was verified.

Solid-State Pulsed Power Modulator for 9.3 GHz 1.7 MW X-Band Magnetron

This article describes a modification and an experiment conducted on a solid-state pulsed power modulator (SSPPM) for medical linear particle accelerator (LINAC) applications. Depending on the operating condition of the magnetron, an existing design of an insulated-gate bipolar transistor (IGBT)-based modulator is modified, from a positive pulse generator to a negative pulse generator. The design of the gate driver circuit of the pulse discharging IGBTs is also slightly changed to secure reliability against the arc condition. The developed modulator has the following maximum output-pulse voltage of -40 kV, pulse current of -100 A, pulsewidth of 5 μs, and pulse repetition rate of 250 Hz. By adapting the proposed design to the pulsed power modulator for driving the magnetron, high peak and average power densities of 43 kW/L and 48.9 W/L, respectively, can be achieved. The experimental results from various tests conducted using a resistor load, including a rated operation and an arc protection, verify the robustness and utility of the developed SSPPM for medical LINAC applications. An experiment using a 9.3-GHz 1.7-MW X-band magnetron is also conducted. The developed modulator achieved a successful arc protection operation for the arc generated in the waveguide during the magnetron drive test.

Solid-State Pulsed Power Modulator With Fast Rising/Falling Time and High Repetition Rate for Pockels Cell Drivers

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 ( MOSFET s) 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.

Gate Driving Circuit With Active Pull-Down Function for a Solid-State Pulsed Power Modulator

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.

Simplified Design of a Solid State Pulsed Power Modulator based on Power Cell Structure

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 μ s, 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.

Robust Design of a Solid-State Pulsed Power Modulator Based on Modular Stacking Structure

This paper describes the design of a robust high-voltage solid-state pulsed power modulator (SSPPM), which requires reliable series stacking and driving of a number of semiconductor switches. For voltage balancing against overvoltage during both at transient and at steady-state, the power-cell-based modular stacking structure consists of an energy storage capacitor, bypass diode, and switching device (such as an insulated-gate bipolar transistor or a metal-oxide-semiconductor field-effect transistor (mosfet)). In addition to the reliable voltage balancing of each switching device, the modular power cell stacking structure provides a fault-tolerant design by allowing individual protection circuit for each switching device. In this paper, the inclusion of a compensating third winding is proposed. This compensating third winding solves the voltage unbalance issue, which results from difference of leakage inductance of separate located transformer core, using magnetic flux compensation. A protection method using this compensating winding is also suggested to detect abnormal occurrences in each power cell under operating conditions. Additionally, an arc current protection circuit to ensure continuous operation of the SSPPM is designed. Through simulation and experimental results of tests on the SSPPM with the structure outlined earlier, it is verified that the proposed design can be used effectively, as it exhibits both robustness and reliability.

Design and Comparison of Capacitor Chargers for Solid-State Pulsed Power Modulator

This paper describes the design, implementation, and comparison of high-voltage capacitor chargers for a solid-state pulsed power modulator (SSPPM). The three different converter topologies are a series resonant converter operating at a discontinuous conduction mode with switching frequency control (SRC_DCM_SFC), a series resonant converter operating at a continuous conduction mode with phase shifted pulse width modulation control (SRC_CCM_PSPWMC), and a series-parallel resonant converter operating at the CCM with SFC (SPRC_CCM_SFC). On the basis of these converter topologies, 10-kWaverage high-voltage capacitor chargers are designed for the three types of SSPPMs, which have the following maximum output specifications: 1) SRC_DCM_SFC: 60 kV, 300 A, 3 kpps, and 50 μs; 2) SRC_CCM_PSPWMC: 10 kV, 50 A, 50 kpps, and 10 μs; and 3) SPRC_CCM_SFC: 40 kV, 150 A, 7 kpps, and 10 μs. Although the pulse output specifications are different, it is worth comparing the resonant inverter topologies and the control methods from the viewpoint of the losses, control characteristics, and merits and demerits of the high-voltage capacitor chargers. From the analysis and investigation of the three resonant inverters, the design procedure, including the determination of the resonant tank parameters, is provided, which considers the design of the high-voltage capacitor charger. PSPICE simulation is used to elucidate the effects of the resonant tank structure and its parameters, and the resonant current waveform and losses of the Insulated Gate Bipolar Transistor are compared. Finally, experiments for each charger are performed under various load conditions, and the comparison results of the three capacitor chargers, including the conduction and switching losses, control characteristics, and overall efficiency, are discussed in this paper.

Stray parameters in a novel solid state pulsed power modulator

In many pulsed power applications, high voltage and high frequency square pulses are needed. Traditional Marx type modulators based on solid-state switches often couldn't meet the requirements, especially on frequency and waveform. To solve the problems, a novel solid-state pulsed power modulator based on charging and driving by magnetic ring transformers is introduced in this paper. In order to obtain pulses with steep voltage edges on various kinds of loads, half bridges formed by MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) switches are used in the modulator. The usage of magnetic rings makes the stray capacitance become one of the most important aspects to distort the output voltage waveforms. The effect of stray parameters on output waveforms is analyzed in detail in this paper. According to the analysis, this paper deals with a design of the pulsed power modulator with isolated recharge for dielectric barrier discharge (DBD) research, In order to design much more suitable pulse modulators, some methods are described to reduce the influence of the stray parameters.

Design of a High-Efficiency 40-kV, 150-A, 3-kHz Solid-State Pulsed Power Modulator

This paper deals with the detailed design of a pulsed power modulator using insulated gate bipolar transistor (IGBT) switches for industrial applications. Output specifications of the proposed modulator are as follows: variable output pulse voltage 1~40 kV; pulse width 0.5~5 μs ; maximum pulse repetition rates 3 kHz, and average output power of 13 kW. The proposed pulsed power modulator consists of a high-voltage capacitor charger based on a high-efficiency resonant inverter and pulse generator part including a series of connected 24 pieces power cells. To verify the proposed design, PSpice modeling was performed. Finally, experimental results proved the reliability and robustness of the proposed solid-state pulsed power modulator.

A novel solid state pulsed power module for excimer laser

For effective excimer laser pumping high voltage pulses with a pulse duration of 100 ns and energies from a fraction of joules to some 10's of joules are necessary. This energy is deposited via a gas discharge into the laser vessel. The generation of these pulses has traditionally been achieved using thyratron circuits. The limited lifetime and repetition rates of thyratron circuits do not fulfill the requirements of a modern excimer lasers. The current state of the art is to use solid state circuits with insulated gate bipolar transistor (IGBT) switches, high voltage pulse transformer, and pulse compression networks. Due to the many stages, complexity is high and efficiency is moderate. To overcome this limitation a new solid state circuit for excimer laser pumping was developed. The circuit works without magnetic pulse compression. The switch is made by a stack of "off-the-shelf" metal oxide semiconductor field effect transistors (MOSFETs) and SiC diodes. In the presentation the general design and its calculation, diode and switch qualification and test results are presented. An additional emphasis is put on the voltage sharing within the stack and the gate control.

Ferrite core based pulse power modulator

This paper describes the experiments conducted for the development of a solid state pulse power modulator using low cost Mn-Zn ferrite cores. These ferrite cores although have restricted magnetic parameters, gave promising results for use in pulsed power systems. The experience gained has revealed that such low cost ferrite can be used in the development of pulse power modulators.

Compact and high repetitive pulsed power modulator based on semiconductor switches

This paper describes the design of a compact and highly repetitive pulsed power modulator based on semiconductor switches. Output specifications of the proposed modulator are as follows: variable output pulse voltage, 1-10 kV; width, 1-10 μs; pulse repetition rate (PRR), 1-50,000 pps; and average output power, 10 kW. The proposed solid-state pulsed power modulator has two main parts: an IGBT stack that hasa gate drive circuit for the pulse output with a variable pulse width and repetition rate, and a capacitor charger that has a controllable output voltage. To connect all the storage capacitors in a series for high voltage pulses, a simple and reliable IGBT stack structure was proposed based on the Marx generator. In addition, the gate driver circuit, which supplies power and signals to all the IGBTs simultaneously, was introduced. This providesa superior protection function against the arc and the short. To charge the storage capacitors, a novel 10 kW (10 kV, 1 A) high voltage capacitor charger with the combined advantage of a series-loaded resonant converter and a ZVS (zero-voltage-switching) full-bridge pulse width modulation (PWM) converter was proposed and designed especially for the solid-state pulsed power modulator. Theexperiment results verified that the proposed scheme and structure can be used effectively for a high voltage pulsed power modulator that requires variable voltage, repetition rate, and pulse width, depending on the process of the applications.

固体开关小能量准分子激光器的设计与实验研究

固体开关小能量准分子激光器的设计与实验研究

Development of solid state pulse power modulator using toroidal amorphous core

This paper discusses the experiments conducted for the development of 50 kV, 10 A, 10 mus duration, and rise time of 2 mus solid state pulse power modulator using toroidal amorphous steel core and low cost IGBT switches. The experiments revealed (i) the need for new design methodologies based on energy transfer between the electrical and magnetic systems and (ii) the success of low-cost switching circuit.

Parasitic resonance in a solid-state pulsed power modulator

A resonant structure, induced by parasitic capacitance and inductance, was studied in a solid state pulsed power modulator for an induction synchrotron. Parasitic capacitors form a resonant structure in a switching arm with a self-inductance of the modulator circuit. The resonance induces a ringing in an acceleration voltage, causing an extra force to particles in the longitudinal direction. This effect is serious around the transition energy, because a mismatch exists between the particle distribution before the transition and a bucket shape after the transition. It was found that the most promising way to avoid this situation is to reduce the self-inductance of the modulator circuit. By sufficient reduction, an output waveform without any serious deterioration of flatness has been achieved by a newly developed power modulator.

Performance characterization for an excimer laser solid-state pulsed power module (SSPPM) after 20B shots

An experiment has been designed to characterize a solid-state pulsed power module (SSPPM) during the initial manufacturing cycle and then repeat the same characterization measurements after the module has gone through several sequences of 10B shots of normal operation in an excimer laser. The goal of such an experiment is to determine what, if any, degradation occurs during these extended periods and to assist in the development of expected module lifetimes that can then be used to estimate the cost of operation of the overall excimer laser. Initial component and subassembly measurements include the capacitance and Q of energy storage capacitors; the inductance and Q of bias, charging, and energy recovery inductors; the B-H characteristics of magnetic cores; insulation breakdown strength; connection resistance; and the general physical appearance of the unit. Operational measurements also compare the efficiency of each pulse compression stage, the repeatability and accuracy of diagnostics, thermal management parameters, and the recovery and on-state characteristics of the silicon-controlled rectifiers (SCRs) and diodes. Each of these items is monitored before testing and after each sequence of 10B shots has been completed. Results of the experiment are described.