IGBT Losses Research Articles

An improved CB-DPWM strategy with NP voltage balance and switching loss reduction for 3-L NPC converter

Abstract The three-level (3-L) neutral-point-clamped (NPC) converter has found widespread applications in various fields, due to its simple structure, low failure rate and high efficiency. However, the 3-L NPC converter suffers the issue of unbalanced neutral-point (NP) voltage due to the divided two dc-side capacitors. The large NP voltage ripple and offset Based on the detailed analysis of the effects of vectors and clamping patterns on the NP voltage, a discontinuous optimized modulation method for NPC grid-connected inverter with both low switching loss and ability to balance NP voltage is presented. By measuring NP voltage and utilizing the property that superfluous clamping patterns have opposing effects on the NP voltage, the modulation method adjusts the NP voltage with the injection of various zero sequence voltages (ZSV) into the original sinusoidal waves. The results of this study demonstrate that the CB-DPWM can control the NP voltage balanced and decrease switching loss compared to conventional DPWM and SVPWM strategies. Moreover, the CB-DPWM strategy does not need to identify sectors and subsectors or calculate dwelling times. This modulation strategy effectively suppresses low-frequency fluctuations and deviations of the NP voltage with the injection of a simple ZSV, and improves the power quality of the output voltages and currents. Compared to the traditional SVPWM scheme, the suggested CB-DPWM has a 27 % lower overall IGBT loss. Moreover, this method is implemented through carrier waves, which is simpler than modulation schemes based on space vector, greatly shortens the program running time, and is conducive to engineering implementation.

IGBT Gate Boost Drive Technology for Promoting the Overload Capacity of Traction Converter.

Under certain circumstances, a high-speed railway may require constant acceleration or emergency braking, in which case the inverter may experience short-term overload conditions and the current passing through the IGBT will go beyond the rated design tolerance. Under overload conditions, the IGBT loss will increase instantly, raising the power semiconductor device's junction temperature in the process. This research examines the boosting-gate-voltage-driven IGBT control technology. It increases the gate drive voltage and the IGBT current capacity and decreases the conduction voltage drop of IGBT under short-term overload conditions, reducing the instantaneous loss and temperature rise undulation of IGBT. The working characteristics of IGBT devices are studied, and the influence of gate drive voltage on device loss and temperature rise fluctuations is analyzed. Based on the emergency acceleration and brake conditions of the actual train operation, the short-term overload characteristics of the inverter are analyzed. The optimization analysis of the boosting gate voltage under emergency conditions is carried out, and the IGBT drive circuit with gate voltage pumping function is designed. The effectiveness of the driving circuit is verified through PSpice simulation and actual switching characteristic test. According to the analysis of experimental data, it can be verified that increasing the gate voltage technology can reduce IGBT losses.

Integrated simulation of electromechanical and thermal dynamics of voltage source converters

This paper proposes a simplified yet accurate enough thermal model of Voltage Source Converters (VSC), aimed at circumventing the high computational cost of existing models, which prevents their use in electromechanical simulations. The proposed model reduces to a simple first-order system for thermal dynamics plus two quadratic equations separately modeling the IGBT and diode power losses. In addition, a methodology is provided to derive the proposed VSC thermal model parameters from manufacturer data. The proposed model is tested for two types of devices, both in steady and transient states. The results show that the reduced-order thermal model produces accurate results at a low computational cost, making it especially suitable for the co-simulation of thermal and electrical dynamic phenomena.

Multi-Level Synthesis Gate Voltage Active Control Technology for Optimizing IGBT Switching Characteristics

Compared with the conducting and blocking steady-state processes, the voltage and current stress of IGBT become very higher in the turning-on and turning-off transient processes, and the instantaneous power loss increases significantly. The switching transient conditions greatly affect the reliability and stability of IGBT device and power converter. During the IGBT turning on process, the reverse recovery of the symmetrical bridge arm anti paralleled diode can cause additional turn-on loss and current peak overshoot. The gate voltage active control technology can effectively suppress current spike and reduce turn-on loss in the period from the initial opening time to Miller platform. The multilevel synthesis technology can adjust the gate voltage waveform and produce depression or bulge in the normal driving voltage waveform for a certain time. In this paper, the sensitive parameters of gate voltage active control, which affect the current overshoot, and turn-on loss of IGBT are studied based on the theoretical calculation and mathematical model. A multi-level synthesis gate voltage active control technology is proposed according to the principle of gate voltage active control. The relationship among the acting voltage amplitude, execution time, current peak and switching loss is studied. Considering the actual application conditions, the optimized active control scheme of gate voltage is designed. Finally, the switching characteristics test is carried out, the results verify that the proposed control technology can effectively reduce the current overshoot and turn-on loss in comparison with the conventional schemes.

A new series‐connected 36‐pulse rectifier with hybrid DC‐reinjection method for high power output

AbstractIn this study, a new 36‐pulse rectifier with a hybrid DC‐reinjection circuit is proposed. It multiplies the AC‐side input voltage steps from 12 to 36 using a hybrid auxiliary circuit for voltage and current modulation. Both the AC and DC side harmonics of the rectifier system are efficiently suppressed when combined with filter capacitors at DC side. Only 2 more diodes and an IGBT are used in the proposed approach for constituting the injection circuit. The cascaded structure of rectifier bridges allows for significant voltage gain, making it appropriate for high power output rectification applications. The proposed 12‐pulse rectifier's phase shifting structure and 36‐pulse rectifier's operational theory are introduced. The injection transformer's turn ratio and the IGBT's conduction angle are both designed to have the lowest possible harmonic distortion of the voltage at AC side. Analyses are done on the rectifier's impedance matching feature and energy loss of IGBT. The operating performance of the rectifier is assessed when the active switch fails. With the help of a 1.8 kW prototype and a HIL system based on Starsim, the theoretical portion is confirmed. The results of the simulation and experiments support the effectiveness of the hybrid voltage harmonic injection method studied.

Optimization of DC-Link Capacitance Based on the Power Loss Modeling of IGBT for Inverters Under Swing Bus Operation

The power density and reliability of the inverter can be improved with reduced DC-link capacitance by swing bus operation, etc. With insufficient DC-link capacitance, a double line frequency voltage ripple will be superimposed on the DC link, but how this voltage ripple affects the power loss of the IGBT in the inverter system has been seldom discussed. This paper analyzes the influence of voltage fluctuations on the power loss of IGBT and establishes the characteristic database of IGBTs under different operating voltages and currents using a dynamic test chamber. A switching profile-based power loss model has been proposed to evaluate the power loss of IGBT in the single-phase inverter under different DC link voltage ripples. All the theoretical analysis has been verified by a 6-kW inverter platform under swing bus operation (SBO).

МОДЕЛИРОВАНИЕ ЗАМКНУТОЙ СИСТЕМЫ ЭЛЕКТРОПРИВОДА ПОСТОЯННОГО ТОКА С ШИРОТНО-ИМПУЛЬСНЫМ ПРЕОБРАЗОВАТЕЛЕМ

This article investigates the regulation of the angular speed of an electric drive (ED) with a pulse-width converter (PWC) and a direct current motor (DC motor) of independent excitation (NV) when controlled in a closed-loop system. A proportional-integral (PI) -regulator was used as a regulator of the angular velocity. To analyze the processes in the closed-loop SHIP-DPT system, the methods of simulation are used. The principle of operation of an electric drive with control from a PWM is described. Developed and modeled EP circuits with PWM in the Matlab environment using blocks from the Simulink / SimPowerSystem library. A model block has been modeled that calculates the static and dynamic power losses of the PWP IGBT. To calculate the static and dynamic losses, the method of approximating the loss graphs was used. The obtained mathematical dependences describe quite accurately the graphs of the power losses of the IGBT transistor. It is shown that when using a PI-controller, the angular speed of the electric drive is set according to a given speed reference signal.

Switching Time Delay Optimization for “SiC+Si” Hybrid Device in a Phase-Leg Configuration

Compared to SiC MOSFET, the switching loss of Si IGBT is much higher due to its slow switching speed and tail current. Si IGBT/SiC MOSFET hybrid switch device can reach to optimal performance with low static and dynamic loss, which can improve the current capacity of SiC devices and reduce the power loss of Si IGBT based converters. With the separated gate control signals, the switching moments of the two devices can be controlled independently to ensure Si IGBT under zero-voltage switching (ZVS) conditions. This measurement tends to reduce the switching loss of Si IGBT. However, the switching time delay between these two devices has significant impacts on its power loss. In this paper, the switching time delay optimization method is proposed to minimize the power loss of the hybrid switch. The static and dynamic characteristics of Si IGBT/SiC MOSFET hybrid-paralleled switch are studied, and a generalized power loss model for hybrid switch is developed. The influence of switching time delay on the characteristics of hybrid switch is analyzed and verified through double pulse tests in a phase-leg configuration. The experimental results show that the optimal turn-on delay time is that the two devices turn on at the same time and the turn-on loss can be reduced by about 73% compared with the solely Si IGBT and by about 52% compared with the solely SiC MOSFET. While the optimal turn-off sequence is that the Si IGBT turns off ahead of the SiC MOSFET. Under the proposed optimal turn-off delay time of the hybrid switch, the turn-off loss is reduced by about 61.4%. This optimization strategy is used in a Buck converter to verify the superiority of the SiC/Si hybrid switch and the optimal switching sequence. Simulation results show that the optimal switching sequence is consistent with theoretical analysis, and the efficiency is improved by 2.5% compared with Buck converter using solely Si IGBT.

An Optimized Zero-Current, Zero-Voltage, and Three-Level DC–DC Converter

In this article, an optimized zero-voltage and zero-current pulsewidth modulation converter is proposed by investigating conventional converters widely used in dc grids. In this presented model, instead of using three-phase power switches, single-power switches are employed since single-power MOSFETs and IGBTs have lower switching loss and simpler drive circuit than the other module series. Therefore, the converter size and its power loss will decrease compared with the models with three-phase components. In addition, soft switching is utilized in the proposed converter to decrease the total power loss and increase efficiency accordingly. Also, for optimum use of zero-voltage switching (ZVS) and zero-current switching (ZCS), a new combination of IGBT and MOSFET is presented in the converter's circuit. Considering low turn-off loss for IGBT and low capacitive loss for MOSFET, IGBT and MOSFET are taken for ZVS switching and ZCS switching, respectively. In addition, a simple stabilizer circuit is added to the output part to improve the operation of the output filter since the filter plays an essential role in dc-dc converters. Finally, simulation of the proposed model is implemented in the PLECS software, and the results confirm the proper application of ZVS and ZCS, converter high efficiency, and high stability at the output voltage.

Performance comparison of switching losses of SiC DMOS vs Si IGBT

Silicon Carbide Double Diffused Metal Oxide Semiconductor (SiC-DMOS), having a more comprehensive bandgap, fast switching and low power losses, has been rapidly developed and applied. This paper elaborates a detailed analysis of switching losses by comparing Si IGBT and SiC DMOS under the same voltage parameters and identical conditions. The switch’s characteristics are evaluated and contrasted in various gate resistances. In addition, a gate driver is designed to calculate the switching losses of IGBT and SiC DMOS at different frequencies. Then they are respectively used in the buck converter. The experimental platform is built to test and validate that the SiC DMOS buck converter achieves faster dynamic performance and higher efficiency than Si IGBT.

Review of Si IGBT and SiC MOSFET based on hybrid switch

SiC Hybrid switch (HyS) combines low conduction loss of Si IGBT and low switching loss of SiC MOSFET, and the cost is closer to that of Si IGBT. The promising high performances of HyS will bring considerable achievement in terms of enhancing power density of a converter system. By reviewing the gate drive pattern, gate drive hardware, current sharing, module design, converter design, and cost, this paper introduces state-of-the-art SiC HyS.

Loss Analysis of Propulsion System on an Electric Railway

Electric Railway (KRL) is a train that is based on eletrification system. The electrification system in the KRL supplies electrical energy to the train locomotive and several other carriage units, so the train can run. Electrical energy can be either AC or DC source. There are two electrical systems to support the performance of KRL, propulsion system and auxiliary system. The propulsion system is a driving system and than the auxiliary system is the system that handles the electrical load on KRL. In this research, discuss about the loss of propulsion system on KRL LAA Electric DC, AC Traction Motor. The propulsion system consists of several components, such as pantograph, circuit breaker, capacitor filter, IGBT VVVF inverters and AC traction motors. The component has different losses and different efficiencies. There are five test conditions for AC traction voltage inputs of 160.5V, 321V, 493.9V, 635V and 645V. By calculating using equations, from the five test conditions it can be seen that the propulsion system has the lowest power loss with the highest efficiency at the input voltage of AC 635V traction motors, which obtained the power loss of inverter VVVF IGBT 41.996kW with the efficiency 90.67% and the power loss of AC traction motor 18.219kW with the efficiency 91.45%.

The IGBT Losses Analysis and Calculation of Inverter for Two-seat Electric Aircraft Application

This paper presented a parabola interpolation method to calculate the inverter IGBT losses, diode conduction losses, switching losses, total losses and efficiency. The method used parabola interpolation to fit the losses characteristic curves instead of linear approximation. A test platform for the two-seat electric aircraft inverter was set up, and the efficiency was tested. The efficiency was 95.13% at the current of 68.31 A and 93.42% at the current of 97.41 A. The errors between calculation and tested results were 3.3% and 3.9%, respectively. The errors both in the range of 4% verified a good agreement with experimental values and affirmed the accuracy of the parabola interpolation method.

A Novel Power Converter Topology for Electrostatic Precipitators

In this paper, we introduced an improved transformer-based parallel-resonant converter, suitable for high voltage, high power dc loads. The resonant capacitors are connected in parallel with diodes of the high voltage rectifier, thus restraining d v /d t stress in high voltage circuits. The LC tank resonant frequency is well beyond the switching frequency, reducing in this way the VA rating of LC components. With rated load, the output current of the IGBT bridge is equal to zero at switching instants, and the switching losses are very low. Proposed subresonant circuit requires lower primary current for the given output power and it has reduced IGBT losses. Experimental setup delivers 79 kW with an efficiency of 96.78%. The paper explains the switching states of the devised topology, and provides the guidelines for designing the power transformer, the LC tank and controls. Analytical prediction of the performance curves is verified both in laboratory and by the field tests with an electrostatic precipitator plant.

Transient Turn-ON Characteristics of the Fin p-Body IGBT

In this paper, the transient turn-ON performance of the 1200 V-class fin p-body insulated gate bipolar transistor (Fin-p IGBT) is numerically analyzed and experimentally characterized. Analysis shows that the gate self-charging effect at the turn-ON transient of the device can effectively be suppressed due to its unique structural features of wide trenches and spacer gates. As a result, the Fin-p IGBT demonstrates excellent controllability on the turn-ON dV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CE</sub> /dt of the IGBT, and hence the reverse-recovery dV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">KA</sub> /dt of the free-wheeling diode. Compared with conventional floating p-body IGBTs, the Fin-p IGBT can achieve a significant reduction (up to 82%) in the reverse-recovery dV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">KA</sub> /dt, which is of great merit in suppressing the electromagnetic interference noise. Moreover, the turn-ON energy loss of the Fin-p IGBT can be reduced by 53% compared with that of the conventional one at the same reverse-recovery dV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">KA</sub> /dt of 10 kV/μs.

120kW급 IGBT 인버터의 열 응답 특성 실시간 모델

Abstract >> As the power electronics system increases the frequency, the power loss and thermal management are paid more attention. This research presents a real time model of dissipation power with junction temperature response for 120kw IGBT inverter which is applied to the thermal management of high power IGBT inverter.Since the computational time is critical for real time simulation, look-up tables of IGBT module characteristiccurve are implemented. The power loss from IGBT provides a clue to calculate the temperature of each module of IGBT. In this study, temperature of each layer in IGBT is predicted by lumped capacitance analysis of layerswith convective heat transfer. The power loss and temperature of layers in IGBT is then communicated due to mutual dependence. In the dynamic model, PWM pulses are employed to calculation real time IGBT and diode power loss. Under Matlab/Simulink ® environment, the dynamic model is validated with experiment. Results showedthat the dynamic response of power loss is closely coupled with effective thermal management. The convective heat transfer is enough to achieve proper thermal management under guideline temperature.

SiC Power Devices in a Soft Switching Converter, Including Aspects on Packaging

In many applications of power electronic converters efficiency and size are important figures of merit. Low losses in the power semiconductors and high frequency operation are important factors. The converters considered in this paper are off-line powered and in the power range of 50 – 150 kW with a high-voltage dc-output. The switching frequency is 20-40 kHz. With modern IGBTs an efficient operation (n> 95%) can be obtained when using soft-switching topologies. Fig 1(a) shows the schematic diagram of an SLR, series loaded resonant converter [1]. In Fig 1(b) typical waveforms of transformer current and voltage are depicted. In a recent paper, [2], frequency dependent IGBT losses are evaluated. Fig 2 shows the on-state voltage of an IGBT when conducting a sinusoidal current at different frequencies. At the higher frequency (30 kHz, Tr4) the increase of conduction losses is evident. Power switches made from SIC show excellent properties enabling; low conduction losses, high frequency operation and an ability to operate at high die temperatures [3]. Fig 3 (a) shows the on-state voltage of an unipolar SIC switch while Fig 3(b) shows the on-state voltage of a bipolar switch. Measurements have been performed up to 200 kHz without showing any high-frequency effects. High voltage SiC PiN diodes can replace several series connected Si diodes due to the higher critical field strength in SiC. This enables substantially reduced conduction losses in the output rectifier. In Fig 4 on-state voltages of 10 kV SiC and Si-diodes are shown, indicating a 50% reduction of losses.

Hybrid Si-IGBT/SiC Rectifier Co-Packs and SiC JBS Rectifiers Offering Superior Surge Current Capability and Reduced Power Losses

Novel device design and process innovations made at GeneSiC on SiC JBS rectifiers result in a significant increase in surge current capability with a 33% decrease in power dissipation at 10x rated current. On the 1200 V-class rectifiers, a clear signature of avalanche-limited breakdown with ultra-low leakage currents is observed at temperatures as high as 240 °C. Almost temperature independent Schottky barrier heights of 1.2 eV and ideality factors 2K2 (for 4H-SiC) is directly extracted from the forward I-V characteristics. When compared with an off-the-shelf all-Si IGBT power co-pack, GeneSiC’s GA100XCP12-227 co-pack offers 88% and 47% reduction at 125 °C in the IGBT and free-wheeling diode switching energy losses, respectively. This results in an overall switching loss reduction of about 28% as compared to its silicon counterpart.

Power Supply of Vertical Stability Coil in EAST

Power supply of vertical stability coil in EAST(Experimental Advanced Superconducting Tokamak) traces given signal from PCS(Plasma Control System), supplies excitation current of active feedback coils in vacuum chamber, then magnetic field will be product to restrain plasma vertical displacement in large elongate model. It is a kind of single phase inverter power supply with large capacity, which consists of HV switches, AC/DC converters, 24 3-level half bridges with diodes neutral point clamping IGBT modules in parallel, it can output large current with fast response ability. To decrease switching loss of IGBT, the technique of carrier wave phase-shift PWM is applied in IGBT modules, which can raise converter equal switch-frequency and improve output wave quality. The result of simulation and experiments show that scheme and control strategy are effective. The power supply has been under operation since 2006 in the EAST Tokamak.

Application of Phase-Shift PWM in EAST Fast Control Power Supply

EAST (Experimental Advanced Superconducting Tokamak) fast control power supply is a large capacity single phase inverter power supply, which traces displacement signal of plasma, and excites four fast-control coils in vacuum chamber to produce magnetic field that realizes plasma stabilization in large elongate model. To meet the requirement of large current and fast response, multi-inverters in parallel is presented. The technique of carrier wave Phase-shift PWM is applied to decrease switching loss of IGBT, raise equal switch-frequency of converter and improve performance of output wave. The system design scheme and control method are introduced, and the analysis of harmonic and simulation are carried out. The validity of proposed scheme and control strategy were confirmed by experiments, the power supply system can supply large current and has ability of fast response.