Insulated Gate Bipolar Transistor Switching Research Articles

Renewable energy utilization method: A novel Insulated Gate Bipolar Transistor switching losses prediction model

Power module Insulated Gate Bipolar Transistor switching losses include switch-on losses and switch-off losses, the switching losses can generate a great deal of heat which causes a larger temperature rise. It will seriously affect the safe and reliable operation of the device, but how to obtain accurate switching losses quickly and conveniently needs to be solved. The goal of this study is to accurately predict the switching losses of Insulated Gate Bipolar Transistor. Firstly a dynamic characteristics test was carried out, the dynamic voltage and current waveforms under different test conditions were obtained. Based on the data, the influence which the circuit operating environment parameters have on switching losses was analyzed. Secondly, for the defect of switching losses in small sample modeling, a novel switching losses prediction model based on the support vector machine optimized by the improved chicken swarm optimization algorithm was established. This novel model is modified on the basis of the chicken swarm optimization algorithm. The dynamic inertia weight and the part of learning from optimal individuals were introduced to the location updating formula of chicks, so that the chicks could forage flexibly and jump from the local optimal solutions. Finally, the novel model was used to predict the switching losses. To further verify the accuracy and effectiveness of the novel model, the true switching losses were compared respectively with the predicted results of the novel model and the other two models. The result showed that the novel model had a higher convergence precision and prediction precision. Compared with the other two models, the average relative error of switching losses prediction from the novel model is at least reduced by 1.2607%. The novel model contributes to the accurate prediction of the switching losses. It also has an important guiding significance for the improvement of renewable energy utilization and the system reliability.

Wideband modeling and transient analysis of sub-module in modular multilevel converter

PurposeThis paper aims to establish the wideband model of a sub-module in a modular multilevel converter (MMC) and analyze the switch transients of the sub-module.Design/methodology/approachThe paper builds an MMC sub-module test circuit and conducts dynamic tests both with and without the bypass thyristor. Then, it builds the wideband model of the MMC sub-module and extracts the model parameters. Finally, based on the wideband model, it simulates the switch transients and analyzes the oscillation mechanism.FindingsThe dynamic testing shows the bypass thyristor will add oscillations during switch transients, especially during the turn-on process. The thyristor acts like a small capacitor and reduces the total capacitor in the turn-on circuit loop, thus causing under-damped oscillations.Originality/valueThis paper found that the bypass thyristor will influence the MMC sub-module switch transients under certain circumstances. This paper proposes a partial inductance extraction procedure for the MMC sub-module and builds a wideband model of the sub-module. The wideband model is used to analyze and explain the switch transients, and can be further used for insulated gate bipolar transistor switch oscillation inhibition and sub-module design optimization.

A pulse-burst laser system for Thomson scattering on NSTX-U

A pulse-burst laser system has been built for Thomson scattering on NSTX-U, and is currently being integrated into the NSTX-U Thomson scattering diagnostic system. The laser will be operated in three distinct modes. The base mode is continuous 30 Hz rep rate, and is the standard operating mode of the laser. The base mode will be interrupted to produce a “slow burst” (specified 1 kHz rep rate for 50 ms) or a “fast burst” (specified 10 kHz rep rate for 5 ms). The combination of base mode→ interruption→ burst mode is new and has not been implemented on any previous pulse-burst laser system. Laser pulsing is halted for a set period (∼ 1 minute) following a burst to allow the YAG rods to cool; this type of operation is called a heat-capacity laser. The laser is Nd:YAG operated at 1064 nm, q-switched to produce ⩾ 1.5 J pulses with ∼ 20 ns FWHM. It is flashlamp pumped, with dual-rod oscillator (9 mm) and dual-rod amplifier (12 mm). Variable pulsewidth drive of the flashlamps is accomplished by IGBT (insulated gate bipolar transistor) switching of electrolytic capacitor banks. Direct control of the laser Pockels cell drive enables optimal pulse energy extraction. The laser system has demonstrated compliance with all specifications, and is capable of exceeding design specifications by significant margins, e.g., higher rep rates for longer burst periods. Burst operation of this laser system will be used to capture fast time evolution of the electron temperature and density profiles during events such as ELMs, the L-H transition, and various MHD modes.

Design and Experimental Testing of a Resonant DC–DC Converter for Solid-State Transformers

In the solid-state transformer (SST) concept, the key task of voltage adaptation and isolation is performed by a high-power dc–dc converter, which is operated in the medium-frequency range, hence enabling a reduction in size and weight of the converter's reactive components. This dc–dc converter presents the main challenge in the implementation of the SST concept, given its operation at medium frequency together with the direct connection to medium voltage. This combination demands the utilization of dc–dc converter topologies that are able to operate in the soft-switching mode, whereby, given that typically insulated-gate bipolar transistor switches are used as power devices, zero-current switching modulation schemes become highly attractive and often mandatory in order to achieve the targeted efficiency goals. This paper describes in detail the analysis and design of a 166-kW/20-kHz dc–dc converter of the series-resonant type, which results to be particularly interesting for high-power applications, given its tight input-to-output transfer characteristics and its capability to ensure soft-switching transitions of all semiconductor devices. The main focus of this paper is to describe in detail the practical implementation of the aforementioned resonant dc–dc converter, where its main components, i.e., the medium- and low-voltage-side power bridges and the medium-frequency transformer, are described independently. The assembled prototype is presented together with the implemented testing strategy and the final experimental results.

Current limiting soft starter for three phase induction motor drive system using PWM AC chopper

This study presents a new current-limiting soft-starter for a three-phase induction motor drive system using pulse width modulation (PWM) AC chopper. A novel configuration of three-phase PWM AC chopper using only four insulated gate bipolar transistors (IGBTs) is also proposed. The proposed control strategy does not require zero crossing detection circuits, which employed in thyristorised soft starters. It requires only one current sensor. The duty ratio of the chopper IGBTs is obtained from the closed-loop current control in order to limit the motor starting current at a preset value. Only two complementary gate pulses are obtained from the control circuit to control the four IGBT switches. The proposed control strategy is characterised by a simple control loop; thus, a low-cost processor can be used due to the low-computation burden. The superiority of the proposed strategy is proved theoretically and confirmed experimentally. The experimental work is developed using a laboratory prototype system composed of DSP-DS1104 digital control board and 1.5 HP induction motor. The proposed starter offers a smooth start-up for the motor speed, torque ripple minimisation, less number of semiconductor switches, less switching and conduction losses, less harmonics and improved input power factor.

Investigation of the trade‐off between switching losses and EMI generation in Gaussian S‐shaping for high‐power IGBT switching transients by active voltage control

Over three decades of development effort has brought insulated gate bipolar transistor (IGBT) technology to a high-level of maturity. IGBT converters have been widely used in industry. However, the high-speed switching transient of the IGBT-freewheel diode chopper cell causes high-level electromagnetic interference (EMI). Electromagnetic compatibility requirements are normally taken into account by utilising costly EMI filters or shielding on the load and supply side. The risk of this traditional method is to incur a delay in commercialising the converters since identification of the failure causes, modifications, and successfully re-testing are required. A promising alternative is to constrain the EMI at source by introducing active voltage control technique and shaping the IGBT switching transient into a sophisticated ‘S’-shape. Previously, IGBT switching waveforms have been successfully shaped into an advanced Gaussian ‘S’-shape with the EMI greatly reduced. In this study, the authors further investigated the trade-off between EMI generation and switching losses in such an S-shaping method. The investigation was carried out in an accurate physical IGBT/diode model that is able to accurately simulate the device switching transient. From the results, it can be seen that by using the Gaussian S-shaping method the trade-off between EMI and switching losses could be much improved.

Sparse AC/AC Modular Multilevel Converter

A new bidirectional multilevel converter topology called the sparse modular multilevel converter suitable for high power ac/ac applications is presented. The proposed topology has fewer insulated-gate bipolar transistor switches and capacitors compared with conventional approaches. Moreover, a salient feature of the proposed topology is that more than half of the switches are operating in soft switching conditions, which considerably decreases the switching losses of the converter. The theoretical calculations and simulation results are provided to verify the feasibility of the proposed topology.

Mitigation Emission Strategy Based on Resonances from a Power Inverter System in Electric Vehicles

Large dv/dt and di/dt outputs of power devices in the DC-fed motor power inverter can generate conducted and/or radiated emissions through parasitics that interfere with low voltage electric systems in electric vehicles (EVs) and nearby vehicles. The electromagnetic interference (EMI) filters, ferrite chokes, and shielding added in the product process based on the “black box” approach can reduce the emission levels in a specific frequency range. However, these countermeasures may also introduce an unexpected increase in EMI noises in other frequency ranges due to added capacitances and inductances in filters resonating with elements of the power inverter, and even increase the weight and dimension of the power inverter system in EVs with limited space. In order to predict the interaction between the mitigation techniques and power inverter geometry, an accurate model of the system is needed. A power inverter system was modeled based on series of two-port network measurements to study the impact of EMI generated by power devices on radiated emission of AC cables. Parallel resonances within the circuit can cause peaks in the S21 (transmission coefficient between the phase-node-to-chassis voltage and the center-conductor-to-shield voltage of the AC cable connecting to the motor) and Z11 (input impedance at Port 1 between the Insulated gate bipolar transistor (IGBT) phase node and chassis) at those resonance frequencies and result in enlarged noise voltage peaks at Port 1. The magnitude of S21 between two ports was reduced to decrease the amount of energy coupled from the noise source between the phase node and chassis to the end of the AC cable by lowering the corresponding quality factor. The equivalent circuits were built by analyzing current-following paths at three critical resonance frequencies. Interference voltage peaks can be suppressed by mitigating the resonances. The capacitances and inductances generating the parallel resonances and responsible elements were determined by the calculation through the equivalent circuits. A combination of mitigation strategies including adding common-mode (CM) ferrite chokes through the Y-caps and the AC bus bar was designed to mitigate the resonances at 6 MHz, 11 MHz, and 26 MHz related to the CM conducted emission by IGBT switching and the radiated emission of the AC cable. The values of Z11 decreased respectively by 15 dB at 6 MHz, 0.4 dB at 11 MHz, and 11.5 dB at 26 MHz and the values of S21 decreased respectively by 8.6 dB at 6 MHz, 7 dB at 11 MHz, and 6.3 dB at 26 MHz. An equivalent model of the power inverter system for real-time simulation in time domain was built to validate the mitigation strategy in simulation software PSPICE.

A Single-Phase Cell-Based Asymmetrical Cascaded Multilevel Inverter

A single-phase asymmetrical cascaded multilevel inverter is introduced with the goal of increasing power quality with the reduction of power in insulated-gate bipolar transistor (IGBT) switches. In the present work, the proposed inverter topology is analyzed and generalized with respect to different proposed algorithms for choosing different voltage source values. To prove the advantages of the proposed inverter, a case study involving a 17-level inverter is conducted. The simulation and experimental results with reduced THD are also presented and compared with the MATLAB/SIMULINK simulation results. Finally, the proposed topology is compared with different multilevel inverter topologies available in the literature in terms of the number of IGBT switches required with respect to the number of levels generated in the output of inverter topologies.

Development of a 20 kV damped oscillating voltage generator

This study describes the design and development of a 20 kV rated damped oscillating voltage (DOV) generator that can detect the partial discharge (PD) condition in 6/10 kV power cables. A complete system using a novel high-voltage switch consisting of a series of connected insulated gate bipolar transistors (IGBTs) is designed and tested. The switch consists of ten identical IGBT switch units, a multiple output isolated power supply system and a trigger unit. Physically, it is a 60 cm diameter fan-shaped printed circuit board. To coordinate the various tested objects and to comply with the IEC 60060-3 standards, an air-core inductor is calculated to precisely fit the most general application conditions using the magnetic vector potentials method. A laboratory prototype is assembled and tested. Waveforms illustrating the performance of the IGBT switch and the output of the DOV are presented. Finally, an application-oriented test demonstrates that the scheme can successfully complete the PD test and PD location test for a cable sample.

Experimental characterisation and performance evaluation of a coaxial current transformer for measurement of insulated gate bipolar transistor switching current

Measurement of device current during switching characterisation of an insulated gate bipolar transistor (IGBT) requires a current sensor with low insertion impedance and high bandwidth. This study presents an experimental procedure for evaluating the performance of a coaxial current transformer (CCT), designed for the above purpose. A prototype CCT, which can be mounted directly on a power terminal of a 1200 V/50 A half-bridge IGBT module, is characterised experimentally. The measured characteristics include insertion impedance, gain and phase of the CCT at different frequencies. The bounds of linearity within which the CCT can operate without saturation are determined theoretically, and are also verified experimentally. The experimental study on linearity of the CCT requires a high-amplitude current source. A proportional-resonant (PR) controller-based current-controlled half-bridge inverter is developed for this purpose. A systematic procedure for selection of PR controller parameters is also reported in this study. This set-up is helpful to determine the limit of linearity and also to measure the frequency response of the CCT at realistic amplitudes of current in the low-frequency range.

Conducted noise analysis and protection of 45 kJ/s, ±50 kV capacitor charging power supply when interfaced with repetitive Marx based pulse power system.

Pulse power systems with highly dynamic loads like klystron, backward wave oscillator (BWO), and magnetron generate highly dynamic noise. This noise leads to frequent failure of controlled switches in the inverter stage of charging power supply. Designing a reliable and compatible power supply for pulse power applications is always a tricky job when charging rate is in multiples of 10 kJ/s. A ±50 kV and 45 kJ/s capacitor charging power supply based on 4th order LCLC resonant topology has been developed for a 10 Hz repetitive Marx based system. Conditions for load independent constant current and zero current switching (ZCS) are derived mathematically. Noise generated at load end due to dynamic load is tackled effectively and reduction in magnitude noise voltage is achieved by providing shielding between primary and secondary of high voltage high frequency transformer and with LCLC low pass filter. Shielding scales down the ratio between coupling capacitance (Cc) and the collector-emitter capacitance of insulated gate bi-polar transistor switch, which in turn reduces the common mode noise voltage magnitude. The proposed 4th order LCLC resonant network acts as a low pass filter for differential mode noise in the reverse direction (from load to source). Power supply has been tested repeatedly with 5 Hz repetition rate with repetitive Marx based system connected with BWO load working fine without failure of single switch in the inverter stage.

Design Considerations of a 15-kV SiC IGBT-Based Medium-Voltage High-Frequency Isolated DC–DC Converter

A dual active bridge (DAB) is a zero-voltage switching (ZVS) high-power isolated dc–dc converter. The development of a 15-kV SiC insulated-gate bipolar transistor switching device has enabled a noncascaded medium voltage (MV) isolated dc–dc DAB converter. It offers simple control compared to a cascaded topology. However, a compact-size high frequency (HF) DAB transformer has significant parasitic capacitances for such voltage. Under high voltage and high $dV/dT$ switching, the parasitics cause electromagnetic interference and switching loss. They also pose additional challenges for ZVS. The device capacitance and slowing of $dV/dT$ play a major role in deadtime selection. Both the deadtime and transformer parasitics affect the ZVS operation of the DAB. Thus, for the MV-DAB design, the switching characteristics of the devices and MV HF transformer parasitics have to be closely coupled. For the ZVS mode, the current vector needs to be between converter voltage vectors with a certain phase angle defined by deadtime, parasitics, and desired converter duty ratio. This paper addresses the practical design challenges for an MV-DAB application.

Online High-Power P-i-N Diode Chip Temperature Extraction and Prediction Method With Maximum Recovery Current <italic>di</italic>/<italic>dt</italic>

P-i-N diode chip temperature is a significant indicator when evaluating the reliability of high-power converters. The feasibility of state-of-the-art thermosensitive electrical parameter (TSEP) extraction strategies for a high-power module is investigated and the limitations of using forward voltage drop for high-power P-i-N diode TSEP are explored. In the widely employed half-bridge topology, by detailed analysis of the upper antiparallel diode reverse recovery process due to lower nonideal insulated-gate bipolar transistor switching behavior, the inherent monotonic relationship between the maximum recovery current rate di d /dt and chip temperature is disclosed. The maximum di d /dt during the recovery period is chosen as the better TSEP, which can accurately reflect P-i-N diode chip temperature variation. Fortunately, by monitoring the negative peak voltage on the parasitic inductor between the Kelvin and power emitters under different temperatures, the maximum recovery rate di d /dt can be readily determined. Consequently, additional passive components are not required for P-i-N diode chip temperature extraction, which is practical and cost-effective for high-power applications. Finally, a dynamic switching characteristics test platform based on a half-bridge topology is designed and adopted to experimentally verify the theoretical analysis. The experimental results show that the dependence between P-i-N diode chip temperature and the maximum recovery di d /dt is approximately linear. This leads to a 3-D lookup table that can be used to estimate online P-i-N diode chip temperature.

Accurate Analytical Modeling for Switching Energy of PiN Diodes Reverse Recovery

PiN diodes are known to significantly contribute to switching energy as a result of reverse-recovery charge during turn- off . At high switching rates, the overlap between the high peak reserve-recovery current and the high peak voltage overshoot contributes to significant switching energy. The peak reverse-recovery current depends on the temperature and switching rate, whereas the peak diode voltage overshoot depends additionally on the stray inductance. Furthermore, the slope of the diode turn- off current is constant at high insulated-gate bipolar transistor (IGBT) switching rates and varies for low IGBT switching rates. In this paper, an analytical model for calculating PiN diode switching energy at different switching rates and temperatures is presented and validated by ultrafast and standard recovery diodes with different current ratings. Measurements of current commutation in IGBT/PiN diode pairs have been made at different switching rates and temperatures and used to validate the model. It is shown here that there is an optimal switching rate to minimize switching energy. The model is able to correctly predict the switching rate and temperature dependence of the PiN diode switching energies for different devices.

Shaping High-Power IGBT Switching Transitions by Active Voltage Control for Reduced EMI Generation

High-performance power switching devices [insulated-gate bipolar transistors (IGBTs)] realize high-performance power converters. Unfortunately, with a high switching speed of the IGBT-freewheel diode chopper cell, the circuit becomes intrinsic sources of high-level electromagnetic interference (EMI). Therefore, costly EMI filters or shielding is normally demanded on the load and supply sides. An S-shaped voltage transient with a high-order time derivative eliminates the discontinuity in the switching transient and can suppress high-frequency spectrum of EMI emissions. More importantly, it provides an improved tradeoff between EMI generation and switching time, therefore switching losses. This promising tradeoff can be explored further for better high-frequency EMI suppression by using the infinitely differentiable characteristics of Gaussian S-shaped transients. However, current gate drive schemes cannot achieve the S shaping. In this paper, active voltage control is applied and improved successfully to define IGBT switching dynamics with a smoothed Gaussian waveform.

Physics‐based insulated‐gate bipolar transistor model with input capacitance correction

Insulated-gate bipolar transistor (IGBT) terminal capacitances play an important role in IGBT switching transients. The terminal capacitance modelling is a difficult task because of their operating-point-dependent characteristics. In particular, the input capacitance needs careful treatment if accurate modelling is to be performed. Previously, for the planar gate IGBT, the Miller capacitance's voltage dependency is modelled by considering the depletion region growth pattern. For modern trench gate designs, however, there is no similar dynamic model available. Also, its current dependency needs to be accounted for. This study presents an improved IGBT physics-based model with input capacitance correction. By comparison of experimental and simulation results, the proposed model works well for different types of IGBTs (including the state-of-art trench-gate field-stop type) over a wide range of operating conditions and is convenient to implement.

FREQUENCY DETERMINATION OF HIGH-FREQUENCY LINK FOR PERCPECTIVE ELECTRIC ROLLING STOCK

Purpose. Total mileage of Ukrainian electric railways is distributed approximately equally between the areas of direct and alternating current. A double system of electric rolling stock is used to pass jointing places of different current kinds without train’s stop. Therefore introduction of such rolling stock of a new concept that is using an asynchronous traction drive is prospective for Ukrainian railways. Apart from advantages a rolling stock of similar concept has significant disadvantages, it is pulse energy consumption from the power supply, and it can affect the reliability of track automatic devices, and consequently, the train traffic safety. In addition the specific power of traction transformer is considerably inferior to the power density of other traction elements. The promising schemes using an intermediary link of increased frequency, which consist of a transformer and inverter, have been proposed for disadvantages amendments. The main task for the further introduction of prospective circuit is to determine the operating frequency for high frequency link. Methodology. The method of thermal parameters calculation of semiconductor devices has been used for determination switching transistors of maximum operating frequency. To obtain analytical expressions curves of energy, released during the IGBT (insulated-gate bipolar transistor) switching from its current load approximation method is used. Findings. The permissible frequency of lowfrequency link is determinated by load current of intermediate transformer. Operating frequency range of a link depending on load current has been determined. A comparative analysis of the switching characteristics of 65 class IGBT production by companies Infineon and ABB has been performed. Originality. The further determination method of the maximum operating frequency of intermediate link for circuit with high-frequency transformer has been developed. Practical value. The established operating frequency range of the highlevel link will develop further research of tractive circuit with highfrequency transformer use for double feed electric rolling stock with asynchronous tractive drive. It will evaluate the introduction effectiveness of similar configuration circuits.

A compact high-voltage pulse generator with opening insulated-gate bipolar transistor switch and a high pulse repetition rate

A small-size high-voltage (∼20 kV) microsecond pulse generator, which is based on a pulse transformer and loaded into a reactor with a pulse corona discharge, is described. Insulated-gate bipolar transistors (IGBTs) that form the switch are used in the low-voltage circuit of the generator. When the switch is open, voltage pulses with an amplitude of up to 1000 V are created across it and, hence, across the primary winding of the transformer. The pulse repetition rate of the generator is ∼20000 pulses/s.

Efficient voltage regulation scheme for three‐phase self‐excited induction generator feeding single‐phase load in remote locations

This study presents analysis, design and implementation of a microcontroller based electronic load controller (ELC) for efficient voltage regulation of a three-phase self-excited induction generator (SEIG) feeding single-phase loads in remote locations. The proposed ELC has an uncontrolled rectifier, a filtering capacitor, an insulated gate bipolar transistor switch and a series dump load. The pulse-width modulation (PWM) pulses with appropriate duty cycle are generated using the dsPIC30F6010 microcontroller. The duty ratio is determined based on the closed-loop control scheme which decides the amount of power diverted to the dump load. The proposed SEIG–ELC system demonstrates an effective power switching between the main load and the dump load thereby providing an efficient voltage regulation at the machine terminals. The controller is modelled in Matlab/Simulink and the simulated results are validated by experimental results.