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The evolution of laser medical devices for benign prostatic hyperplasia (BPH) treatment aims to enhance vaporization, coagulation, or tissue removal. In this study, we aim to evaluate the effectiveness and safety of the innovative application of insulated-gate bipolar transistor (IGBT) xenon lamp-pulsed drive technology holmium laser in endoscopic prostate enucleation operations using canine models. Six canines were used as an experimental unit, the breed of the canine unit used was beagle. Each canine served as its own control to minimize the number of experimental units. Endoscopic enucleation, performed by a single surgeon, involved enucleating the left hemi-prostate, leaving the right hem-prostate untouched to serve as the control. Throughout the study period, all canines maintained good health. No adverse events were observed in all six canines. Postoperatively, there were no indications of redness, swelling, or other adverse effects at the surgical sites. No abnormalities were observed in the appearance and morphology of major organs. The prostate and bladder, removed for further pathological evaluation, exhibited no abnormalities in size, color, or texture. No abnormalities or inflammation were observed, and the tissues were free of adhesions, indicating successful healing. In conclusion, our comparison of preoperative and postoperative parameters in canines suggests that the IGBT pulsed laser, at a power setting of 100 W, demonstrates characteristics of safety, efficacy, minimal tissue damage, and no major postoperative complications. This study establishes a theoretical foundation for future applications in human settings, encouraging further exploration of the IGBT holmium laser's potential in clinical practice. [ABSTRACT FROM AUTHOR]

High voltage direct current (HVDC) systems provide important advantages; among them the ability to transmit enormous amounts of electrical power over great distances at low cost. As a result, planners of power systems consider it as a viable choice for power transmission and interconnection of asynchronous networks. Depending on HVDC grids, continental/super grids have been recently constructed to promote global economic development. The study described in the paper focuses on the behavior of a voltage sourced converter (VSC) based HVDC transmission system comprising three arms-neutral point clamped (NPC) converters interconnecting two asynchronous alternating current (AC) networks. In addition, the system components, and the vector control strategy of active/reactive powers and direct current (DC) bus voltage are simulated in MATLAB/Simulink under varying situations by adjusting the controller's settings. The study records and analyzes AC/DC voltages and active/reactive powers at two converter stations under varying power and voltage conditions. The results of the study provide key performance indicators, such as settling time (tsett), steady state error (SSE), overshot/undershoot (OS%/US%), and correlation factor (CF), which demonstrate the robustness of the system's control. [ABSTRACT FROM AUTHOR]

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Currently, residual useful life (RUL) prediction models for insulated-gate bipolar transistors (IGBT) do not focus on the multi-modal characteristics caused by the pulse-width modulation (PWM). To fill this gap, the Markovian stochastic process is proposed to model the mode transition process, due to the memoryless properties of the grid operation. For the estimation of the mode transition probabilities, transfer learning is utilized between different control signals. With the continuous mode switching, fractional Weibull motion (fWm) of multiple modes is established to model the stochasticity of the multi-modal IGBT degradation. The drift and diffusion coefficients are adaptively updated in the proposed RUL prediction model. In the case study, two sets of the real thermal-accelerated IGBT aging data are used. Different degradation modes are extracted from the meta degradation data, and then fused to be a complex health indicator (CHI) via a multi-sensor fusion algorithm. The RUL prediction model based on the fWm of multiple modes can reach a maximum relative prediction error of 2.96% and a mean relative prediction error of 1.78%. The proposed RUL prediction model with better accuracy can reduce the losses of the power grid caused by the unexpected IGBT failures. [ABSTRACT FROM AUTHOR]

In recent years Au-Sn solid–liquid interdiffusion (SLID) has become a widely known bonding method to deliver promising die attaching techniques for high-temperature operating electronic vehicles. Insulated-gate bipolar transistor (IGBT) chips were assembled on direct bonded copper substrates by utilizing a Ni/Au-20Sn/Ni system based on SLID. Our previous research investigated the intermetallic compounds formed after isothermal aging. Electron microscopic instrumentation was employed to determine the interfacial reactions between AuSn and nickel (Ni). After total consumption of AuSn at the rim sites of (Ni, Au)3Sn2 grains, an increased concentration of Ni was identified. Prolongation of aging time at 240°C helped in precipitation of Ni3Sn at the interface of (Ni, Au)3Sn2 and Ni. This current research has theorized the mechanism of the intermetallic compounds formed at the rim sites of the Au-Sn System. From the results, the Au-Sn eutectic system attained in this article is ideal to assemble an IGBT for high-temperature devices using SLID. [ABSTRACT FROM AUTHOR]

Nowadays, the hybrid high-voltage direct current (HVDC) system consisting of line commutated converter (LCC) and modular multilevel converter (MMC) has become the most competitive candidate in multi-infeed power systems. Owing to the limitation of insulated-gate bipolar transistor's withstand voltage, the DC voltage rating of MMC is not compatible with the LCC valve. To increase the DC voltage level, the number of sub-modules of each arm should be increased drastically, leading to many technical problems in communication design, optical fibre instalment, cooler system design and so on. To overcome the above problems, a hybrid HVDC system consisting of LCC and cascaded hybrid MMC valves is proposed to realise ultra-HVDC transmission. It can switch two operating modes (single valve/double valve) according to the conditions so that the system can maintain a certain power transmission when one of the valves quit operation during faults or maintenances. Meanwhile, by implementing the hybrid MMC, the system can ride through DC faults. The design of the topology and controllers, the DC fault ride-through strategy and the online switching strategy for MMCs will be presented in this study. Finally, the performance during DC faults and online switching is verified by extensive simulations. [ABSTRACT FROM AUTHOR]

A reverse conducting (RC) insulated‐gate bipolar transistor (IGBT) with p‐poly trench‐collectors is proposed. A narrow n‐drift region between two p‐poly trench‐collectors is formed as a self‐controlled electron path to the collector contact. Owing to the built‐in potential between the p‐poly and n‐drift regions, the narrow n‐drift region is depleted to offer a high‐resistance electron path at forward bias, which helps to suppress snapback. At reverse bias, holes accumulate at the n‐drift/trench‐collector interface and then the potential difference between the p‐poly and n‐drift regions mainly drops at the thin oxide layer. Thus, the narrow n‐drift becomes undepleted to offer a low‐resistance electron path, and the RC diode can be turned on. Simulation results show that the proposed RC‐IGBT is able to suppress snapback with a much smaller cell width and obtain a 21% lower turn‐off loss compared to the conventional RC‐IGBT. [ABSTRACT FROM AUTHOR]

This study presents a finite‐control‐set model predictive current control (FCS‐MPCC) with phase shift compensation for a cost‐effective voltage source inverter. Firstly, the FCS‐MPCC algorithm uses the discrete‐time model of the inverter to predict the coming value of the load current. In addition, a cost function is defined to evaluate all possible voltage vectors from the inverter, where the cost function is selected. Moreover, a pulse computation module is developed to obtain the final switching signals for insulated‐gate bipolar transistors. In addition, the problem of current distortion caused by phase shift is solved by employing a time interval compensation factor. Furthermore, a comparison between the hysteresis control, pulse‐width modulation control, and proposed predictive control is presented in terms of the steady‐state and dynamic performances. Both simulation and experiment are conducted, which confirm the validity of the proposed control scheme of FCS‐MPCC. [ABSTRACT FROM AUTHOR]

This paper proposes an algorithm for fault tolerance of three-phase, inverter-fed, speed-sensor-less control of a three-phase induction motor drive system. The fault tolerance of the inverter when one switch is open or one leg of six-switch inverter is lost is considered. The control of the drive system is based on indirect rotor field-oriented control theory. Also, the speed estimator is based on model reference adaptive system (using stator current and rotor flux as state variables for estimating the speed). The fault-tolerant algorithm is able to adaptively change over from a six-switch inverter to a four-switch inverter topology when a fault occurs; also, it makes a smooth transition of the motor speed, torque, and current when changing over from a faulty condition to a new healthy status, which is four-switch three-phase inverter (FSTPI) topology; thus, the six-switch three-phase inverter (SSTPI) topology (pre-fault status) is almost retained for the medium-power range of induction motor applications. The proposed algorithm is simulated by using the MATLAB/SIMULINK package. Also, the proposed control system is tested experimentally using a digital signal processor (DSP1104). The obtained results from the simulation model and experimental system demonstrate the performance enhancement and good validity of the fault-tolerance control for the speed-sensor-less induction motor drive system. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

This paper proposes a novel packaging method for insulated-gate bipolar transistor (IGBT) modules based on the concepts of P-cell and N-cell. The novel packaging reduces the stray inductance in the current commutation path in a phase-leg module and hence improves the switching behavior. A P-cell- and N-cell-based module and a conventional module are designed. Using finite-element-analysis-based Ansys Q3D Extractor, electromagnetic simulations are conducted to extract the stray inductance from the two modules. Two prototype phase-leg modules based on the two different designs are fabricated. The parasitics are measured using a precision impedance analyzer. Finally, a double pulse tester based-switching characterization is performed to illustrate the effect of stray inductance reduction in the proposed packaging design. The experimental results show the reduction in overshoot voltage with the proposed layout. [ABSTRACT FROM AUTHOR]

The design of a 200-A, all-SiC power-module-based on bipolar junction transistor devices is described, and the impact of the module is assessed on the performance of a 50-kW dc-dc converter for electric vehicle applications, particularly the overall weight and efficiency. Using a hard-switching dual-interleaved topology, which has proven high efficiency and high-power density capability, the operation of a 50-kW, 75-kHz all-SiC converter is compared with that of an insulated-gate bipolar transistor-based silicon converter, switching at 25 kHz, each providing 600-V output. The results show that the total losses are reduced by almost 40%, whilst the overall weight is reduced by 27%, achieving a power density of 10.5 kW/kg. Experimental results of the SiC converter operating at 220-600 V, 52.8 kW are provided, showing an efficiency of 97%. [ABSTRACT FROM AUTHOR]

To investigate the influential factors of power devices on the dead-time of inverters, the effects of voltage, current, and temperature on the switching time of the insulated-gate bipolar transistor (IGBT) were analyzed based on the semiconductor theory and the formula of dead-time. The regularity of the three factors with the IGBT switching time was given and therefore the dead-time was obtained. Experiment results using two-level half-bridge inverter unit shows that the dead-time increases approximately linearly with the voltage ascending and the temperature ascending, but decreases with the current ascending, following the composed rule of exponential and hyperbola. In addition, the occurrence of bridge shoot through is in accordance with the calculation of dead-time, which proves the accuracy of the theoretical analysis. Finally, the obtained conclusion can be important references for the accurate setup of dead-time and the optimization of dead-time compensation algorithm in electrical power converters in practical applications. [ABSTRACT FROM AUTHOR]

This study presents design and implementation of a dynamic electronic load controller (DELC) for voltage and frequency control of a three‐phase self‐excited induction generator (SEIG) driven by constant power unregulated small‐hydro turbine. This DELC is a combination of insulated‐gate bipolar transistor‐based voltage sourced converter (VSC) and variable frequency drive (VFD) which is connected across the DC link of VSC. The VFD operates in direct torque control mode and is coupled with a pumping system. The DELC is connected at point of common coupling in parallel with consumer loads. The VSC provides instantaneous control of the SEIG voltage through reactive power compensation. The VFD consumes the power in excess of consumer loads to maintain constant generator output power which in turn regulates the frequency. The excess generated power consumed by the VFD is used to pump water either to an overhead tank or for irrigation purposes. The performance of the proposed DELC of SEIG is demonstrated under various types of loads such as linear/non‐linear, balanced/unbalanced loads and so on. Test results recorded on a developed DELC of SEIG exhibit simultaneous voltage and frequency control capabilities of the DELC under varying loads. [ABSTRACT FROM AUTHOR]

Practical aspects of design of converters based on compound bipolar transistors are analyzed. The passage of a small reactive current through a compound bipolar transistor is analyzed using the example of a voltage inverter. A frequency converter with input protection is designed and loaded with an asynchronous motor at the output. [ABSTRACT FROM AUTHOR]

This paper presents a power loss estimation method for insulated-gate bipolar transistors (IGBTs) and diodes that operate under hysteresis switching. The method relies on datasheet information and three measurements in a phase leg: phase current, one IGBT switching gate signal, and the dc bus voltage across the phase leg. No parasitic models, thermal analysis, or slow simulations are required, and measurements can be provided from simulations or experiments. The method is validated for periodic pulsewidth modulation, then for aperiodic hysteresis switching. Results show that the proposed method is accurate while maintaining simplicity. It is promising for implementation in combined thermoelectric simulations and design optimization. [ABSTRACT FROM AUTHOR]

Power semiconductor devices are important for numerous applications with power conversion being an important one. Wide energy gap semiconductors and have properties that make them attractive for such applications. Among these properties are high thermal conductivity, high breakdown electric field, wide energy gap, low intrinsic carrier concentration, high thermal stability, high saturation velocity and chemical inertness. These lead to low on-resistance, high breakdown voltage, high frequencies, small volume, and small passive inductors and capacitors. These desirable properties are offset by the higher material costs and higher defect densities. Although wide energy gap devices have been in development for many years, only recently have they become available commercially. Their main competition is silicon power devices with breakdown voltages up to 8000 V and very high surge current capacity. However, silicon power devices are approaching their material limits and wide energy gap devices are beginning to have an impact in the power electronics space. has the advantage of substrates with diameters approaching 150 mm and the ability to grow thermal . has the heterojunction advantage, but no viable substrate technology. In fact, a large portion of production is used for substrates. material development has also benefited significantly from the development of optical devices, e.g., light-emitting diodes and lasers. [ABSTRACT FROM AUTHOR]

This paper presents a multicell converter topology composed of N single-phase power cells per phase and a multipulse power transformer. The topology achieves high-power-quality waveforms in three-phase applications under the presence of severe unbalanced ac mains. Moreover, the power cells are properly arranged in order to achieve high-performance ac supply current waveforms under asymmetrical loads. The configuration is based on single-phase power cells that feature a pulsewidth-modulation rectifier in order to achieve an overall unitary displacement power factor and a controlled dc-link voltage at the power-cell level. The configuration is implemented, and different experimental tests are performed where unbalance and distortion indexes are computed. [ABSTRACT FROM AUTHOR]

The analysis of a multicell topology that is implemented with single-phase nonregenerative cells under an unbalanced ac mains is presented. The study shows that the topology naturally compensates most of the voltage unbalance; for instance, for a 100% voltage unbalance in the ac mains, just 32% reaches the load. For critical applications, a feedforward control technique is proposed in order to compensate the remaining unbalance at the load side. The resulting topology, in combination with the proposed strategy, reduces near to zero the load fundamental voltage unbalance, while the input current unbalance and distortion are also improved. A theoretical analysis that is based on symmetrical components and the experimental results confirm the theoretical considerations. [ABSTRACT FROM AUTHOR]