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- Fault tolerance capability and semiconductor's hold-off voltage of solid-state bipolar Marx modulatorsPublication . Canacsinh, Hiren; Silva, Fernando; Luis RedondoTwo solid-state bipolar Marx modulators are analyzed and compared regarding hold-off semiconductor voltages and open-fault tolerance capability. Normal and abnormal operating conditions are considered, such as switch synchronization mismatches, failures, and open faults. Ten-stage laboratory prototypes of two bipolar Marx modulators have been assembled using 1200-V insulated gate bipolar transistors and matching diodes, to operate at 500-V dc input voltage. Outputs are 4-kV bipolar pulses, 1% duty ratio, into resistive loads, and 1-kHz frequency. Lack of synchronization and open-fault tests confirm that only topologies with redundant switches can operate without semiconductors being subjected to double hold-off voltages while presenting current paths to clear faults.
- Solid-state bipolar Marx modulators and generation of complementary pulses recovering the energy of the magnetizing inductancesPublication . Canacsinh, Hiren; Redondo, Luis; Silva, José FernandoA new methodology to reset an inductive load during the operation of solid-state bipolar Marx modulators is analyzed. In fact, after applying a positive (or negative) pulse to an inductive load, the reset of the magnetizing energy is evaluated considering the application of a voltage amplitude ranging from one to all capacitors voltage after each pulse: i) immediately after the pulse; ii) with a delay after the pulse. These reset alternatives make it possible to produce several current waveforms that can be used to produce magnetic fields used today in magnetic therapy. Four-stage laboratory prototypes of two bipolar Marx modulators have been assembled using 1200 V insulated gate bipolar transistors (IGBTs) and matching diodes, to operate at 1 kV dc input voltage. Outputs are 4-kV bipolar pulses, 0.5% duty ratio, into inductive load and 1 kHz frequency.
- Rise-time improvement in bipolar pulse solid-state Marx modulatorsPublication . Canacsinh, Hiren; Silva, Fernando; Luis RedondoThis paper presents the effect of stray capacitances in bipolar (negative and/or positive) pulses generated by the two different topologies of the solid-state Marx modulators. According to the analysis, the stray capacitances influence the energy transfer from the Marx modulator capacitors to the load affecting the bipolar (negative and/or positive) pulse rise time. This paper deals with the structure design to reduce the influence of the stray capacitance and to improve the pulse rise time of these bipolar solid-state Marx modulators. A four-stage laboratory prototype of the two topologies has been assembled using 1200-V insulated gate bipolar transistors and diodes, operating with 1000-V dc input voltage and 1-kHz frequency, producing 4-kV bipolar pulses, with 5-mu s pulse duration and 120-ns rise time, into a resistive load.
- Solid-state Marx based two-switch voltage modulator for the On-Line Isotope Mass Separator accelerator at the European Organization for Nuclear ResearchPublication . Luis Redondo; Silva, José Fernando; Canacsinh, Hiren; Ferrão, N.; Mendes, C.; Soares, R.; Schipper, J.; Fowler, A.A new circuit topology is proposed to replace the actual pulse transformer and thyratron based resonant modulator that supplies the 60 kV target potential for the ion acceleration of the On-Line Isotope Mass Separator accelerator, the stability of which is critical for the mass resolution downstream separator, at the European Organization for Nuclear Research. The improved modulator uses two solid-state switches working together, each one based on the Marx generator concept, operating as series and parallel switches, reducing the stress on the series stacked semiconductors, and also as auxiliary pulse generator in order to fulfill the target requirements. Preliminary results of a 10 kV prototype, using 1200 V insulated gate bipolar transistors and capacitors in the solid-state Marx circuits, ten stages each, with an electrical equivalent circuit of the target, are presented, demonstrating both the improved voltage stability and pulse flexibility potential wanted for this new modulator.
- Hybrid Sepic-Ćuk DC-DC Converter Associated to a SRM Drive for a Solar PV Powered Water Pumping SystemPublication . Cordeiro, Armando; Chaves, Miguel; Canacsinh, Hiren; Luís, Ricardo; Fernao Pires, Vitor; Foito, Daniel; Pires, A. J.; Martins, JoaoThe present paper describes a solar photovoltaic (SPV) powered water pumping system employing a switched reluctance motor (SRM) and a merged Sepic-Ćuk DC-DC converter. The proposed solution was designed to use efficiently the available solar energy in order to supply water pumping systems. Solutions of this kind assume a special importance in the current scenario of natural and renewable resources optimization. The proposed DC-DC converter operates in continuous conduction mode (CCM), which combined with a maximum power point tracking (MPPT) controller, helps to optimize the power of the solar photovoltaic panel (SPV). The proposed DC-DC topology is characterized by high voltage static gain when compared with the classical boost topology and reduced voltage stress across the power switch and diodes. Several simulation and experimental results are presented in order to confirm the characteristics of the proposed solution for water pumping systems.
- Modeling MARX Generators for maximum pulse repetition rate estimationPublication . Rocha, Luis Lamy; Canacsinh, Hiren; Silva, J. Fernando; Redondo, Luis; Luciano, T.This paper presents a generalized n stage dynamic model for unipolar semiconductor based Marx generators. The model is tailored for the capacitors charging mode to enable the estimation of the maximum pulse repetition rate of the n stage generator. T The maximum pulse repetition rate for the n stage Marx generator can be calculated as a function of the number n of stages, and of the voltage decay allowed in each capacitor (usually less than 10%). Furthermore, given a needed pulse repetition rate the model can estimate the optimum number of stages (n) so that the working voltage of each stage can be selected. Simulation results for a ten-stage (n=10) positive output Marx generators are presented and discussed.
- Marx-Type solid-state bipolar modulator topologies: Performance comparisonPublication . Canacsinh, Hiren; Luis Redondo; Silva, José FernandoThe operation of generalized Marx-type solid-state bipolar modulators is discussed and compared with simplified Marx-derived circuits, to evaluate their capability to deal with various load conditions. A comparative analysis on the number of switches per cell, fiber optic trigger count, losses, and switch hold-off voltages has been made. A circuit topology is obtained as a compromise in terms of operating performance, trigger simplicity, and switching losses. A five-stage laboratory prototype of this circuit has been assembled using 1200 V insulated gate bipolar transistors (IGBTs) and diodes, operating with 1000 V dc input voltage and 1 kHz frequency, giving 5 kV bipolar pulses, with 2.5 mu s pulse width and 5 mu s relaxation time into resistive, capacitive, and inductive loads.
- Wireless home automation system for multifunctional devices incorporating Internet of Things (IoT)Publication . Pedro, Bruno; Barata, Filipe; Canacsinh, HirenHome automation systems have been increasing in quantity and quality, throughout the world. The scientific community has been spending its resources to improve these systems, regarding their capabilities, accessibility and price. In this article, a low cost, home automation system, in the form of an experimental prototype is presented, focused in wireless communication and IoT (Internet of Things) structures. The result of the work developed was a capable prototype, adaptable to conventional electrical installations, with smart management capabilities regarding actuators of electric loads and sensor information utilization.
- Modeling of a solid-state bipolar blumlein generator for N stagesPublication . Mendes, João Paulo M.; Luis Redondo; Canacsinh, Hiren; Rossi, Jose O.This paper models an n-stage stacked Blumlein generator for bipolar pulses for various load conditions. Calculation of the voltage amplitudes in time domain at the load and between stages is described for an n-stage generator. For this, the reflection and transmission coefficients are mathematically modeled where impedance discontinuity occurs (i.e., at the junctions between two transmission lines). The mathematical model developed is assessed by comparing simulation results to experimental data from a two-stage Blumlein solid-state prototype.
- New Technique for Uniform Voltage Sharing in Series Stacked SemiconductorsPublication . Luis Redondo; Canacsinh, Hiren; Silva, José FernandoThis paper describes the operation of a solid-state series stacked topology used as a serial and parallel switch in pulsed power applications. The proposed circuit, developed from the Marx generator concept, balances the voltage stress on each series stacked semiconductor, distributing the total voltage evenly. Experimental results from a 10 kV laboratory series stacked switch, using 1200 V semiconductors in a ten stages solid-state series stacked circuit, are reported and discussed, considering resistive, capacitive and inductive type loads for high and low duty factor voltage pulse operation.
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