Insulated Gate Bipolar Transistor Power Research Articles

Degradation mapping in high power IGBT modules using four-point probing

An electrical four-point probing approach is used to estimate local degradation in high power insulated gate bipolar transistor modules subjected to power cycling. By measuring electrical parameters of selected units and components the possibility of mapping the degradation is demonstrated. The development of failures is put in accordance with physical phenomena and materials fatigue. These results are directly usable for reliability purposes with a focus on geometry optimization and enhanced lifetime prediction methods.

Multiobjective Design Optimization of IGBT Power Modules Considering Power Cycling and Thermal Cycling

Insulated-gate bipolar transistor (IGBT) power modules find widespread use in numerous power conversion applications where their reliability is of significant concern. Standard IGBT modules are fabricated for general-purpose applications while little has been designed for bespoke applications. However, conventional design of IGBTs can be improved by the multiobjective optimization technique. This paper proposes a novel design method to consider die-attachment solder failures induced by short power cycling and baseplate solder fatigue induced by the thermal cycling which are among major failure mechanisms of IGBTs. Thermal resistance is calculated analytically and the plastic work design is obtained with a high-fidelity finite-element model, which has been validated experimentally. The objective of minimizing the plastic work and constrain functions is formulated by the surrogate model. The nondominated sorting genetic algorithm-II is used to search for the Pareto-optimal solutions and the best design. The result of this combination generates an effective approach to optimize the physical structure of power electronic modules, taking account of historical environmental and operational conditions in the field.

Dynamic Characterization of Parallel-Connected High-Power IGBT Modules

In high-power converter design, insulated gate bipolar transistor (IGBT) modules are often operated in parallel to reach high output currents. Evaluating the electrical and thermal behavior of the parallel IGBTs is crucial for the design and reliable operation of converter systems. This paper investigates the static and dynamic characterization of parallel IGBTs and the influence of the electrical parameters on the IGBT behavior. Si-based IGBT power modules with voltage rating of 4.5 kV and current rating of 1 kA are used for the experimental evaluation of module parallel connections. Parallel-connected modules have been driven by several commercial IGBT gate units at various dc-link voltages and current levels and with different temperatures. The tested IGBT gate units show good current sharing performance between the two parallel modules. Other important influencing factors such as busbar design layout, stray inductance variation, and gate driving are also investigated for parallel connections of IGBT modules. Finally, the switching energy of the parallel modules is extracted for IGBTs and diodes under different conditions.

Temperature mapping by μ-Raman spectroscopy over cross-section area of power diode in forward biased conditions

It has been demonstrated that high power devices like power diodes and IGBTs (Insulated Gate Bipolar Transistors) could remain functional after cross section. This has opened a field of possibilities for the characterization of distribution of physical quantities over vertical cross-sections of power semiconductor devices. In this paper, we used the Raman spectroscopy technique to perform the mapping of temperature distribution over the cross section area of a forward biased power PIN diode. As the mechanical stresses lead to shift the Raman peak, for accurate measurements in strained structures, it is necessary to deconvolute the influence of stress and temperature on Raman shift to measure temperature. Another solution consists in measuring the Full Width at Half Maximum (FWHM) of the silicon related Raman peak. This parameter depends only on the temperature and the crystalline quality of material. By this way, it is possible to measure the temperature accurately without any artifact due to the stress. Using this method, we have measured the temperature distribution over a vertical cross section of a power diode in forward bias conditions and strained by its packaging. The residual stress in the chip cross section was also estimated at room temperature in order to validate the FWHM choice for temperature calibration.

Reliability enhancement by integrated liquid cooling in power IGBT modules for hybrid and electric vehicles

Insulated Gate Bipolar Transistor (IGBT) modules in power train system of Hybrid and Electric Vehicles (HEV/EV) are working in harsh environment and high reliability and long lifetime are required. In this work, reliability enhancement by integrated liquid cooling structure in HEV/EV IGBT module is investigated. The thermal resistance of junction to heat sink can be reduced more than 50% by direct liquid cooling as eliminating thermal grease layer, so both active and passive temperature swings decrease significantly which will enhance module reliability and lifetime. The lifetime of modules with conventional and integrated liquid cooling structures are estimated under mission of standard driving cycles. We found that lifetime is prolonged obviously by direct cooling pin–fin base plate, and the compact module also makes the application power system simple and reliable.

Study of Bonding Wire Failure Effects on External Measurable Signals of IGBT Module

The relationship between bonding wire liftoff and terminal voltage in insulated gate bipolar transistor (IGBT) power module is studied. Bonding wire liftoff failure is one of the most dominant limiting factors to the reliability behavior of IGBT power module. In this paper, in order to monitor this type of fault, the effects of the typical degradations are considered. The parasitic inductance and gate equivalent capacitance of IGBT module change due to bonding wire liftoff, which have different impacts on the external characteristics. So, two aspects of IGBT module terminal characteristics are investigated to identify any measurable signature used for monitoring bond wire liftoff failures: 1) gate-emitter voltage during turn-on process and 2) collector-emitter voltage during turn-off process. This paper aims to provide useful information for further development in monitoring the health of IGBT module.

Power electronics design and application for the energy recovery controller of a battery electric vehicle

To realise the driving and regenerative braking of a battery electric vehicle, the hardware circuit and the software flowchart are designed based on digital signal processor (DSP) in detail. The power electronics design and application for the energy recovery controller is presented. The snubber circuit of large power insulated gate bipolar transistor is given with emphasis. The control targets are analysed for the driving and regenerative braking, in which the motor current is defined as the target for the former and the constant regenerative braking current control strategy for the latter, respectively. Both the indoor experiments and the outside experiments are carried out to validate the feasibility, stability and reliability of the energy recovery controller based on DSP and power electronics.

Investigation of the prediction model of IGBT junction temperature based on the rate of voltage change

Based on semiconductor physics and the essential structure of insulated gate bipolar transistor (IGBT), the model of dV_{CE}/\d t is established through reasonable simplification and theoretical derivation. The influencing factors and temperature characteristics of dV_{CE}/\d t are studied in depth. It is concluded that dV_{CE}/\d t increases linearity with the increase of voltage or current, and decreases with the increase of junction temperature also linearly. On the basis of the model for dV_{CE}/\d t, the prediction model of junction temperature is established. Results of simulations and experiments verify the correctness and accuracy of the models. It is significant in theory and practical application for realizing IGBT junction temperature monitoring on-line and improving the reliability of IGBT module and power electronic equipment.

Adaptive Acquisition of Power IGBT Transients With Discrimination Circuit

The frequency spectrum of the power insulated gate bipolar transistor (IGBT) circuit originates mostly from high gradient switching and low rate conduction components. High gradient transients are captured with direct probes. Switching losses are represented with 3-D surfaces acquired with Delaunay triangulation processing. Interpolation functions are introduced, allowing the prediction of the switching loss in the entire 3-D space. A chopper circuit is introduced for the acquisition of the IGBT low rate transients in the conductive stage of operation. A Zener discriminator enhances the measurement accuracy by two orders of magnitude. The experimental results are presented for a half-bridge converter. Measurement uncertainties are acquired with dc and impulse calibration apparatuses.

Novel High-Efficiency Three-Level Stacked-Neutral-Point-Clamped Grid-Tied Inverter

In recent years, high photovoltaic array voltage up to 1000 V and transformerless grid-tied inverter have been increasingly researched and applied to elevate the inverter and the dc power collection efficiency. With the same reasons, a three-level neutral point clamped (3L-NPC) inverter featuring low power device voltage stress and low leakage current becomes increasingly attractive. In this paper, the operation and the features of a novel grid-tied 3L-NPC are presented. The proposed topology is a derivative of the three-level stacked neutral point clamped (3L-SNPC) structure. However, compared with the conventional 3L-SNPC and its pulse width modulation (PWM) strategy, the new topology with novel PWM strategy features completely inactive intrinsic body diodes. Furthermore, only two outer power devices are working with switching frequency, while the other four Insulated Gate Bipolar Transistors (IGBTs) are actually with the grid frequency. Therefore, the relatively high switching frequency is selected to reduce the inverter output filter inductance. A hybrid CoolMosfet and IGBT power module configuration is also proposed based on the new PWM strategy. The calculation shows that the total power device losses are reduced. The experimental results are illustrated in this paper to confirm the operation of the proposed topology and controller.

Investigation of pre-bending substrate design in packaging assembly of an IGBT power module

Serious warpage and a high level of thermal stress or strain resulting from the heavy coefficients of the thermal extension mismatch between direct bonded copper (DBC) and a copper-base plate are obviously introduced into module structures in the packaging of the power modules of an insulated gate bipolar transistor (IGBT) during multi-temperature cycles of assembly. The aforementioned phenomenon is unfavorable in maintaining the long-term reliability of an IGBT power module because failure modes such as burn-out of connected wires among IGBT chips and growth of cracks in the soldered materials between the DBC and base plate could occur. A pre-bending substrate with a curve opposite the warp direction is proposed in this paper to eliminate warping as well as to achieve suitable co-planarity. The proposed design is found to be effective via finite element method-based simulation validated by experimental measurements. A thick base plate is also recommended to reduce warping of the entire packaging structure based on the predictive results of parametric analyses of the thickness of the Al2O3 and copper-base plates.

Nickel–Tin Transient Liquid Phase Bonding Toward High-Temperature Operational Power Electronics in Electrified Vehicles

This paper presents the concept, fabrication, and evaluation for quality and reliability of nickel-tin transient liquid phase (Ni-Sn TLP) bonding that provides high reliability for high-temperature operational power electronics in electrified vehicles. The need for automotive power electronics to operate at high-temperature presents significant challenges in terms of packaging and bonding technology used. TLP bonding is one attachment approach that addresses these challenges and facilitates high remelting temperatures while allowing processing to occur at relatively low temperatures and pressures. In particular, the Ni-Sn TLP bonding process exhibits a number of desirable characteristics for power electronics, including popularity in conventional power electronics, low cost, and uniform and homogeneous alloy formation. The work herein presents Ni-Sn TLP bonding (ready for high-temperature operation) as applied to silicon power devices of relatively large size (12 mm × 9 mm). The quality and reliability of the developed bonding process was characterized using material, optical, and electrical analysis. Analysis indicates that the resulting bondline is uniformly composed of Ni <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> alloy throughout the bond area. This bonding approach has exhibited excellent reliability for bonded devices after thermal cycling from -40°C to 200°C. Electrical properties of the bonded insulated gate bipolar transistor power devices demonstrated that Ni-Sn TLP bonding exhibits electrical performance comparable with conventional solder and is reliable at high-temperature operation.

A low-frequency high-power arbitrary-shape voltage pulse generator

A circuit diagram and design of the arbitrary-shape bipolar voltage pulse generator with amplitudes up to 800 V and a peak output on a matched load of 400 kW are described. The generator is based on car rechargeable batteries and power insulated-gate bipolar transistors (IGBTs). Results of the experiments aimed at producing high-power harmonic signals with frequencies of 50 Hz and 1 kHz are presented.

Hybrid Solid- and Liquid-Cooling Solution for Isothermalization of Insulated Gate Bipolar Transistor Power Electronic Devices

Rapid increases in the power ratings and continuing miniaturization of power electronic devices have pushed chip heat fluxes well beyond the range of conventional thermal management techniques. The heat flux of power electronic devices for hybrid electric vehicles is currently at the level of 100-200 W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and is projected to increase to 500 W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> in next generation vehicles. Such high heat fluxes lead to higher and less uniform insulated gate bipolar transistor (IGBT) chip temperature and significantly degrade the device performance and system reliability. Maintaining the maximum temperature below a specified limit, while isothermalizing the surface temperature of the chip, has become a critical issue for thermal management of power electronics. In this paper, a hybrid solid- and liquid-cooling system design, which combines cold plate liquid cooling and TE solid-state cooling, is proposed for thermal management of a 10 × 10 mm IGBT chip. The liquid-cooling cold plate is used for global cooling of the entire IGBT module while the embedded thin-film TE cooler (TEC) is employed for isothermalization of the individual IGBT chip. A detailed package-level 3-D thermal model is developed to explore the potential application of this cooling concept, with the primary attention focused on isothermalization and temperature reduction of IGBT chip associated with variations in TEC sizes, TE materials, applied current on TEC, cooling system designs, working fluid temperature, cold plate cooling capacity, and IGBT chip heat flux. The results demonstrate that the hybrid solid and liquid cooling is a very promising thermal management solution that can eliminate more than 90% of the temperature nonuniformity on the IGBT chip.

Two-Phase Liquid Cooling for Thermal Management of IGBT Power Electronic Module

Recent trends including rapid increases in the power ratings and continued miniaturization of semiconductor devices have pushed the heat dissipation of power electronics well beyond the range of conventional thermal management solutions, making control of device temperature a critical issue in the thermal packaging of power electronics. Although evaporative cooling is capable of removing very high heat fluxes, two-phase cold plates have received little attention for cooling power electronics modules. In this work, device-level analytical modeling and system-level thermal simulation are used to examine and compare single-phase and two-phase cold plates for a specified inverter module, consisting of 12 pairs of silicon insulated gate bipolar transistor (IGBT) devices and diodes. For the conditions studied, an R134a-cooled, two-phase cold plate is found to substantially reduce the maximum IGBT temperature and spatial temperature variation, as well as reduce the pumping power and flow rate, in comparison to a conventional single-phase water-cooled cold plate. These results suggest that two-phase cold plates can be used to substantially improve the performance, reliability, and conversion efficiency of power electronics systems.

Real Time Simulation of Insulated Gate Bipolar Transistor

The voltage spike, current spike and power loss in switching process is important factors in reliability of insulated gate bipolar transistor (IGBT). The real time simulation of IGBT is studied in this paper, taking the basic cell of IGBT power electronic circuit as an example. The function model of IGBT for real time simulation is built by piecewise interpolation method, in which the parameters are get from the datasheet. The real time simulation of IGBT is realized in field programmable gate array (FPGA), and the results can reflect the key performances of switching process.

Reliability estimation with uncertainties consideration for high power IGBTs in 2.3 MW wind turbine converter system

This paper investigates the lifetime of high power IGBTs (insulated gate bipolar transistors) used in large wind turbine applications. Since the IGBTs are critical components in a wind turbine power converter, it is of great importance to assess their reliability in the design phase of the turbine. Minimum, maximum and average junction temperatures profiles for the grid side IGBTs are estimated at each wind speed input values. The selected failure mechanism is the crack propagation in solder joint under the silicon die. Based on junction temperature profiles and physics of failure model, the probabilistic and determinist damage models are presented with estimated fatigue lives. Reliably levels were assessed by means of First Order Reliability Method taking into account uncertainties.

Nonlinear resistive electric field control for power electronic modules

The trend towards increasing blocking voltage of high power Insulated Gate Bipolar Transistor (IGBT) modules is challenging for their electric insulation system. In particular, the electric field at the edges of the substrate metallization increases accordingly and can exceed the dielectric strength of the gel commonly used as encapsulation, leading to partial discharges or even breakdown of the insulation. This paper reports on the use of nonlinear resistive field grading to mitigate the electric field within power electronic modules. Finite element simulations show how the field enhancements can be significantly reduced by applying a functional coating with suitable nonlinear resistive characteristic. Coatings made of polyimide filled with ZnO microvaristors were manufactured and tested.

고내압 IGBT의 전기적 특성 향상에 관한 연구

Development of new efficient, high voltage switching devices with wide safe operating area and low on-state losses has received considerable attention in recent years. One of those structures with a very effective geometrical design is the trench gate Insulated Gate Bipolar Transistor(IGBT).power IGBT devices are optimized for high-voltage low-power design, decided to aim. Class 1,200 V NPT Planer IGBT, 1,200 V NPT Trench IGBT for class has been studied.

Transient Thermal Performance of IGBT Power Modules Attached by Low-Temperature Sintered Nanosilver

Recently, to accurately study the transient thermal behavior of power modules, a transient thermal measurement system was developed to investigate the transient thermal behavior of insulated-gate bipolar transistor (IGBT) modules attached by nanosilver paste and two kinds of lead-free solders. We found that the transient thermal impedance of IGBT modules attached by nanosilver paste was 9% lower than that of the modules using SAC305 and SN100C with 40-ms heating pulse. In addition, finite-element analysis is employed to simulate thermal performance of the IGBT devices. The simulation shows that the transient thermal impedance of IGBT modules attached by nanosilver paste was also lower than that of the modules using lead-free solders. A convenient way was introduced to well predict the transient thermal behavior of IGBT power module. The calculated results agreed well with the measured one. The interface thermal impedance of sintered nanosilver and SNC100C are calculated to be 0.011 ~ 0.031 K/W and 0.022 ~ 0.042 K/W, respectively.