Turn-off Time Research Articles

IGBTレグとMOSFETレグを備えたオールメタル対応誘導加熱システム用フルブリッジ・ハーフブリッジ切り替えインバータ

An induction heating system is proposed as a new circuit topology for induction heating cookers that can be used with all metals. This system has the mechanism to drive an IGBT and a MOSFET in parallel that switch the inverter between full-bridge or modified half-bridge configuration according to the cookware material. When cookware made of a low-resistivity material such as copper or aluminum is heated, the inverter is switched to the half-bridge configuration, which turns off the IGBT leg earlier than the MOSFET leg. When cookware made of a high-resistivity material such as iron or magnetic stainless steel is heated, the inverter is switched to the full-bridge configuration. We confirmed a turn-off timing for the IGBT where the loss of the switching element in the parallel drive was minimized by an experiment. The proposed inverter effectively improved the electricity conversion efficiency for all metals pan heating with the utilized IGBT and MOSFET legs.

A liquid crystal cell with double-side protrusion electrodes for fast response and low-voltage operation

ABSTRACTWe propose a homogeneously aligned liquid crystal (LC) cell with double-side protrusion electrodes for fast response and low-voltage operation. In the proposed device, both the bottom and top substrates have pixel electrodes to generate the fringe electric field. Because the penetration depth of the electric field is increased owing to the protrusion electrodes, the operating voltage is very low and the turn-on time is dramatically reduced compared with the conventional in-plane switching (IPS) mode. Moreover, LC molecules anchored strongly to the penetrated protrusion electrodes on both substrates exert a strong restoring force, resulting in a fast turn-off time. We found that the total response time of the LC cell with the proposed structure is three times faster than that of the conventional IPS mode.

An insulated gate bipolar transistor with surface n-type barrier**Project supported by the National High Technology Research and Development Program of China (No. 2014AA052601) and the National Natural Science Foundation of China (No. 51277060).

This letter proposes a novel IGBT structure with an n-type barrier (NB-IGBT) formed on the silicon surface to enhance the conductivity modulation effect with a relatively simple fabrication process. TCAD simulation indicates that the NB-IGBT offers a current density 49% higher and turn-off losses 25% lower than a conventional field-stop IGBT (FS-IGBT) with a similar breakdown voltage, turn-off time and avalanche energy. Furthermore, the NB-IGBT exhibits extremely large transconductance, which is favorable to turn-on and turn-off. Therefore, the proposed IGBT offers an attractive option for high-voltage and large-power electronics applications.

Voltage regulation of a matrix converter with balanced and unbalanced three-phase loads

This paper addresses the design, simulation and experimental validation of a voltage control for a three-phase to three-phase Matrix Converterworking under balanced and unbalanced resistive loads. The converter is based on bidirectional switches and space vector pulse width modulationis used to control their turn-on and turn-off times. Tracking and repetitive controls are designed and implemented; having this last one a majorimpact on the performance of the output voltage regulation for balanced or unbalanced loads. The experimental control setup is comprised of afield programmable gate array board, a digital signal processor and a graphics interface board.All Rights Reserved © 2015 Universidad Nacional Autonoma de Mexico, Centro de Ciencias Aplicadas y Desarrollo Tecnologico. This is anopen access item distributed under the Creative Commons CC License BY-NC-ND 4.0.

An Insulated-Gate Bipolar Transistor With a Collector Trench Electron Extraction Channel

This letter proposes a novel collector trench insulated-gate bipolar transistor (IGBT) with an electron extraction channel formed on the collector side to enhance the electron extraction effect with a backside lithography process. TCAD simulation indicates that the new IGBT structure offers a turnoff fall time 74% lower than a conventional field-stop IGBT with a similar breakdown voltage, leakage current, threshold voltage, and forward current density, providing a new option for power electronic applications.

The Conduction Characteristics of a 700 V Lateral Insulated-Gate Bipolar Transistor in a Junction Isolation Technology

This letter presents the conduction characteristics of a 700 V n-type lateral insulated-gate bipolar transistor with quasi-vertical diffused metal-oxide-semiconductor (QVDMOS) field effect transistor fabricated with junction isolation technology. To improve the substrate leakage, a p-type buried layer (PBL) is inserted between the n-type drift region and the n-type buried layer. Measured results show that this structure successfully reduces the substrate current and ensures high breakdown voltage. Furthermore, due to the use of the QVDMOS cathode, an additional current path enables a reduction in the forward voltage drop. This letter shows that the PBL not only improves the dc properties of the device but also yields a shorter turn-OFF time.

High Performance Mine Transient Electromagnetic System and Applications

This thesis introduces structures and main key technologies of high performance transient electromagnetic system of mine. Such system applies sectional transmitting coil with damping absorption circuit to shorten turn-off time, thus achieving linear falling edge of transmitter current; inspects the turn-off time and current falling edge to enrich essential data of primary field; uses programmable and variable receiving coil to provide different selection modes to solve influence of transient process; and also takes advantages of the pre-amplification and programmable amplification circuit and variable settings of sample period to solve the accurate collection problem for different period signals in secondary field. It provides detection layout and result of application examples proving good test effect and superior system performance.

MULTI-WAVELENGTH LIGHT CURVE MODEL OF THE ONE YEAR RECURRENCE PERIOD NOVA M31N 2008-12a

We present a theoretical light curve model of the recurrent nova M31N 2008-12a, the current record holder for the shortest recurrence period (1 yr). We combined interior structures calculated using a Henyey-type evolution code with optically thick wind solutions of hydrogen-rich envelopes, which give the proper mass-loss rates, photospheric temperatures, and luminosities. The light curve model is calculated for a 1.38 M_sun white dwarf (WD) with an accretion rate of 1.6 \times 10^{-7} M_sun yr^{-1}. This model shows a very high effective temperature (log T_ph (K) \geq 4.97) and a very small wind mass-loss rate (\dot M_wind \leq 9.3 \times 10^{-6} M_sun yr^{-1}) even at the maximum expansion of the photosphere. These properties are consistent with the faint optical peak of M31N 2008-12a because the brightness of the free-free emission is proportional to the square of the mass-loss rate. The model well reproduces the short supersoft X-ray turn-on time of 6 days and turnoff time of 18 days after the outburst. The ejecta mass of our model is calculated to be 6.3 \times 10^{-8} M_sun, corresponding to 37% of the accreted mass. The growth rate of the WD is 0.63 times the mass accretion rate, making it a progenitor for a Type Ia supernova. Our light curve model predicts a bright supersoft X-ray phase one or two days before the optical peak. We encourage detection of this X-ray flash in future outbursts.

A Novel Silicon-on-Insulator Lateral Insulated-Gate Bipolar Transistor With Dual Trenches for Three-Phase Single Chip Inverter ICs

A silicon-on-insulator lateral insulated gate bipolar transistor with dual trenches located under the high voltage interconnection (HVI), which can be used in 500 V three-phase single chip inverter ICs, is proposed in this letter for the first time. Using the dual trenches to sustain the electric potential from the collector region, the electric field crowding induced by HVI at the silicon surface can be alleviated. The influence of HVI can be shielded completely by adjusting the position and spacing of the trenches. The experimental results show that the breakdown voltage of the proposed structure is 550 V and its latch-up voltage ( $\text{V}_{\mathrm {\mathbf {LP}}})\vphantom {\big ({}}$ at gate-emitter voltage of 15 V ( $\text{V}_{\mathrm {\mathbf {GE}}} = 15$ V) is higher than 500 V. The current density ( $\text{J}_{\mathrm {\mathbf {C}}})$ is 129 A/cm $^{\mathrm {\mathbf {2}}}$ when $\text{V}_{\mathrm {\mathbf {GE}}} = 5$ V and collector-emitter voltage ( $\text{V}_{\mathrm {\mathbf {CE}}})$ is 3 V. The turn OFF time ( $\text{t}_{\mathrm {\mathbf {OFF}}})$ is 132 ns at turn OFF current density of 84 A/cm $^{\mathrm {\mathbf {2}}}$ .

Comparison of Turn-Off Strategies for SiC Thyristors

Three different turn-off strategies are presented for 6.5 kV class SiC Thyristors. A cathode current of 62 A (284 A/cm2) is successfully turned off by applying a reverse bias of ≈ 30 V to the cathode of a SiC Thyristor. The minimum turn-off time (tq) for the Thyristor using this forced commutation technique is investigated as a function of cathode current density, reverse gate current and the dV/dt of the re-applied forward (blocking) bias. The Anode Switched Thyristor (AST) turn-off mode is demonstrated at a maximum cathode voltage of 3600 V and 14.5 A (199 A/cm2) of cathode current. A cathode current of 5.5 A (75 A/cm2) is successfully turned off by the gate turn off (GTO) or hard turn-off mode at different temperatures up to 200°C. The high-level lifetime (tHL) in the thick p-layer is extracted from the hard turn-off waveforms.

Design of a Novel SiC MOSFET Structure for EV Inverter Efficiency Improvement

Inverters for electric vehicle motor drive systems are essential in converting the battery's direct current into alternating current. Si(Silicon) IGBT that is commonly used in inverter modules have large Vce,sat and turn-off time due to p+ drain and tail current. Therefore, inverter modules consist of Si IGBT with relatively low efficiency. If we can use MOSFETs instead of IGBT in inverter modules, it is possible to achieve high efficiency because of short turn-off time and high operating frequency. Yet also has a problem; Si MOSFETs has large on-resistance compared to Si IGBTs. In this study, SiC(Silicon Carbide) was used to make MOSFETs instead of Si. Futhermore, an accumulation channel concept is adapted to a SiC trench MOSFET, namely Trench ACCUFET. Compared with conventional SiC trench MOSFETs, the novel SiC trench ACCUFET structure has not only lower on-resistance but also high breakdown voltage as shown by the simulation results. We fabricated the Trench ACCUFET for verification, and described improvements that is to be made.

The Theoretical Analysis and Optimization of the Fuel Injection Drive Circuit for Diesel Engine

In order to achieve different response indifferent moment of fuel Injection Solenoid, a driving mode of Peak&Hold is generally applied to electronic control fuel injection system of the diesel engine. The theoretical analysis of high speed response and duplicate supply drive circuit based on the energy recovery is made, and a theoretical guidance for optimization design is presented. According to an electronic unit pump developed by ourselves, the optimization design of drive circuit for the fuel injection system is done. The results showed that during the process of injection, the time of current of solenoid valve form 0 to 20A is 224, and the turn-off time is 120which is a little longer than that of the high speed circuit based on the avalanche. And the turn-off time is met the requirement of control precision. With many advantages, such as energy saving and heat reducing, the high speed response and duplicate supply drive circuit based on the energy recovery will become a good choice in electronic control fuel injection system.

The electro-optics of nematic liquid crystals stabilized by physical networks

A new composite material based on the 5CB nematic stabilized by a physical network formed by 12-hydroxyoctadecane acid has been prepared. The electro-optical properties of the material—the dependence of the transmittance and the turn-on and turn-off times on the voltage—have been studied. Two turn-on and turn-off times have been found. It has been found that the gelling agent (acid) strongly violates the orientation of the liquid crystal to form two systems of its regions. One has a planar orientation; the other, an inclined orientation. The effective sizes of these regions are different and significantly smaller than the thickness of the cell.

Junction Temperature Extraction Approach with Turn-off Delay Time for High-voltage High-Power IGBT Modules

Thermo-sensitive electrical parameter (TSEP) approaches are widely employed in the junction temperature extraction and prediction of power semiconductor devices. In this paper, the turn-off delay time is explored as an indicator of a TSEP to extract the junction temperature from high-power insulated gate bipolar transistor (IGBT) modules. The parasitic inductor L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eE</sub> between the Kelvin and power emitter terminals of an IGBT module is utilized to extract the turn-off delay time. Furthermore, the monotonic dependence between the junction temperature and turn-off delay time is investigated. The beginning and end point of the turn-off delay time can be determined by monitoring the induced voltage v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eE</sub> across the inductor L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eE</sub> . A dynamic switching characteristic test platform for high-power IGBT modules is used to experimentally verify the theoretical analysis. The experimental results show that the dependency between IGBT junction temperature and turn-off delay time is near linear. It is established that the turn-off delay time is a viable TSEP with good linearity, fixed sensitivity, and offers nondestruction on-line IGBT junction temperature extraction.

Simulation and Analysis of Static and Dynamic Performance of Normally-off TIVJFET Using Sentaurus TCAD

2D numerical simulation of normally-off 4H-SiC Trenched and Implanted VJFET is performed using Sentaurus TCAD simulator. Transport equations and different physical models are employed for exploring the device characteristics. Dynamic and static characteristics are simulated under various channel widths (0.81-0.93μm, step 0.03μm). At a channel width of 0.93μm, forward drain current of 5.77 A is observed which corresponds to specific on-state resistance of 0.328 mΩ.cm2. The device is capable of blocking voltage up to 850V with leakage current of the order of 10-7 A. The switching times and energy losses are extracted from switching waveforms. The turn-on and turn-off times of 3 and 9ns are recorded at RT. Furthermore, the turn-on energy of 1.8μJ and turn-off energy of 5.4μJ are also calculated at RT.

Improvement of Power System Stability by Using New Switching Technique in Bridge-type Fault Current Limiter

The bridge-type fault current limiter has the capability of controlling the fault current by controlling the DC reactor current. This fault current limiter is mainly composed of a diode bridge rectifier and a DC reactor. To achieve this capability, a resistor parallel with a semiconductor switch has been used in series with a DC reactor. For this fault current limiter, a control scheme is proposed that uses the DC reactor current as a control variable to improve transient stability of the model power system without measuring any parameters of system. In this article, an analytical and simulation study was conducted on a one-machine infinite-bus system including a bridge-type fault current limiter and the proposed control scheme. Simulation results show that by controlling the turn-on and turn-off times of the switch, i.e., the switching technique, the proposed fault current limiter can not only limit the fault current but also absorb the accelerating energy of the generator, thereby improving power system transient stability. The rotor velocity, maximum output power of the generator, and critical fault clearing time are studied in this article to evaluate the effects of the proposed fault current limiter on power system transient stability.

A snapback-free shorted-anode insulated gate bipolar transistor with an N-path structure

A snapback-free field stop shorted-anode insulated gate bipolar transistor (SA-IGBT) with an N-path structure is proposed for the first time in this paper. The N-path structure is partially surrounded by the floating P-layer (P-float) and oxide layer in the backside of the wafer, which provides a direct path to the N-collector for electronic current and achieves shorter turn-off time. As demonstrated in numerical simulations, compared with the conventional field stop SA-IGBT, the proposed N-path SA-IGBT is able to completely suppress the snapback effect without causing extra performance fluctuations as long as the doping concentration of the N-path is low enough, while it also has a better reverse conduction ability and a much softer reverse recovery property at the same time without causing any on state loss or turn off speed degradation.

On the Analysis and Design of Low-Loss Single-Pole Double-Throw W-Band Switches Utilizing Saturated SiGe HBTs

This paper describes the analysis and design of saturated silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) switches for millimeter-wave applications. A switch optimization procedure is developed based on detailed theoretical analysis and is then used to design multiple switch variants. The switches utilize IBM's 90-nm 9HP technology, which features SiGe HBTs with peak f T/ fmax of 300/350 GHz. Using a reverse-saturated configuration, a single-pole double-throw switch with a measured insertion loss of 1.05 dB and isolation of 22 dB is achieved at 94 GHz after de-embedding pad losses. The switch draws 5.2 mA from a 1.1-V supply, limiting power consumption to less than 6 mW. The switching speed is analyzed and the simulated turn-on and turn-off times are found to be less than 200 ps. A technique is also introduced to significantly increase the power-handling capabilities of saturated SiGe switches up to an input-referred 1-dB compression point of 22 dBm. Finally, the impact of RF stress on this novel configuration is investigated and initial measurements over a 48-h period show little performance degradation. These results demonstrate that SiGe-based switches may provide significant benefits to millimeter-wave systems.

Creation of cluster state of four ions in ion-trap system by individual addressing

The cluster state is a special, highly entangled quantum state that forms the universal resource, on which measurement-based quantum computation can be performed. In this study, a new scheme is presented for creating four-ions cluster state in ion-trap system. This scheme is based on resonant sideband excitation in which the population is transferred to target states by precise control of pulse area. Meanwhile, the scheme is consist of combination of elementary stages belonging to a universal set whereby cluster state has been created in five interaction stages by individually addressed ions with red- or blue-sideband resonance laser pulses. The paper studies the population transfer of the system by numerical solutions of the master equation, considering the effect of decoherence channels due to dissipation in the phonon modes. The presented scheme does not require control of the turn-off ratio and time delay among pulses.

Chip Technology Based on High Efficiency DC Power Supply

The switching power supply is the use of modern power electronics, by controlling the switching transistor turn-on and turn-off time ratio, maintaining a stable output voltage of the power supply. Switching power supply technology at the core, it is mainly divided into AC / DC and DC / DC two categories. Switching power supply eliminates bulky frequency transformers, replacing tens of kHz, MHz or even hundreds of kHz frequency transformer. Since the adjustment pipe work in the off state, and thus low power consumption and high efficiency.