The effect of electro-thermal parameters on IGBT junction temperature with the aging of module

This paper presents the effect of the change of electro-thermal parameters on IGBT junction temperature with module aging. Five IGBT modules are subjected to advance power thermal cycling, and IGBT I–V characterization, switching loss, and transient thermal impedance curve are measured every 1000 power thermal cycles. Then, electro-thermal models of IGBT module under power thermal cycles were built by change electro-thermal parameters, and the influence of various parameters of the electro-thermal model on the junction temperature was researched respectively. Experimental results demonstrate that IGBT collector-emitter voltage, switching loss and thermal resistance increase more quickly with the aging process of module. Simulation results indicate that the variations of electro-thermal parameters have crucial influences on the IGBT junction temperature. After 6000 power thermal cycles, the IGBT steady state junction temperature mean and variation are increased 1.97 K and 0.1656 K over its initial value, respectively. The relative temperature rise is 38.10% and relative temperature variation is 15.08% after 6000 power thermal cycles. The rise in switching loss increases both the steady state junction temperature mean and variation. The change of thermal impedance has great influence on the steady state junction temperature mean, but has little effect on steady state junction temperature variation.     

Thermal lifetime estimation method of IGBT module considering solder fatigue damage feedback loop

The accurate thermal damage assessment and lifetime estimation are essential for ensuring the safety and reliability of semiconductor power devices. This study presents a thermal fatigue feedback loop method for evaluating the lifetime of an Insulated Gate Bipolar Transistor (IGBT) module considering the accumulated effect of solder layer fatigue. First, a three-dimension (3D) finite element method (FEM) model for an IGBT module is established and, combined with the accelerated aging experiments resulting in that the accumulated thermal resistance increment could not be neglected when conducting thermal network modeling and lifetime consumption assessment. Then, the Cauer thermal network is improved for establishing the fatigue feedback loop model, which takes the influence of accumulated solder layer fatigue into account when estimating the power module lifetime. The effectively of this method is validated by experimental results and resisting models. Finally, the lifetime consumption of the IGBT module utilized in a practical wind energy conversion system, is investigated by using the multi-scale feedback loop method. It is found that the Miner model would exaggerate the lifetime of power modules and, the lifetime consumption under low frequency thermal loading is faster than that under a fundamental frequency condition.     

Reliability and lifetime evaluation of different wire bonding technologies for high power IGBT modules

IGBT modules for power transmission, industrial and traction applications are operated under severe working conditions and in harsh environments. Therefore, a consequent design, focused on quality, performance and reliability is essential in order to satisfy the high customer requirements. One of the main failure mechanisms encountered in high power IGBT modules subjected to thermal cycles is wire bond lift-off, which is due to the large thermal expansion coefficient mismatch between the aluminum wires and the silicon chips. The paper describes various bonding technologies using different wire materials directly bonded onto chip metallisation as well as the ABB solution where the wire is bonded on a thin molybdenum strain buffer soldered onto the chip. We assess in the present paper the potential of these technologies to enhance module reliability and lifetime through a power cycling test. Failure analysis results are presented and the failure mechanisms related to each technology are explained in detail.     

基于CAN总线的智能型温湿度采集系统设计

设计一种基于CAN总线的智能型温湿度数据在线采集系统。该系统主要由两大模块构成：现场数据采集模块和USB～CAN转换接口模块。现场数据的采集是以AT89S52单片机为核心控制单元,外接温度传感器AD590和湿度传感器HM1500,通过CAN总线控制器SJA1000将数据发送到CAN总线上;USB—CAN转换接口模块是以ATmega 162芯片为控制单元,外接FT245BM USB通信芯片及SJA1000控制器,实现USB—CAN接口转换。整个系统的终端设备为监控PC机,用户软件采用VC^＋＋语言编写,可以实现现场状态监控、上下限报警和中断接收数据管理等功能。     

基于有限元仿真的IGBT混合模块的可靠性分析

集成化与微型化是当今电子信息产业发展的特点,其中电子元件的结温与热应力是影响其可靠性的重要因素。硅基IGBT和SiC基续流二极管组成的混合模块广泛应用于城市轨道交通等领域,其可靠性直接影响轨道交通车辆的运行性能。本文建立IGBT混合模块的仿真模型,随着各层材料厚度、焊料空洞大小和位置的变化,计算分析IGBT混合模块的温度与应变变化规律,对模块封装结构进行优化设计。将高热导率石墨烯应用在IGBT混合模块中,仿真分析应用位置不同对模块可靠性的影响,从而进一步优化混合模块的封装结构。通过仿真计算,优化后的IGBT混合模块可将最高结温降低近3℃,最大热应力下降超过30 MPa。     

Substrate-to-base solder joint reliability in high power IGBT modules

Acoustic microscope imaging proved to be an excellent tool to detect and quantify solder fatigue of the substrate to base interface of high power IGBT modules. This technique was used to establish the dependence of the thermal cycling capability on the temperature swing of the module base for a A1N/Cu system. Results from temperature cycling tests were combined with results from power cycling tests to predict the solder joint reliability over a wide range of temperature excursions.     

IGBT junction and coolant temperature estimation by thermal model

The capability of IGBT (Insulated Gate Bipolar Transistor) to handle heat is one of its main limitations of high power application. This paper aims to study an IGBT thermal model under flow cooling condition and estimate the IGBT module junction and coolant temperature. Firstly, this paper studies the IGBT module internal sandwich structure and calculates the thermal resistance and thermal capacitor for each layer using a 1D physical model. Then a Cauer electric model is built for the IGBT module to evaluate the thermal constant time of the model. The liquid cooling method is applied in this project for fast cooling and the thermal parameters are studied and measured since this cooling method involves both solid and liquid. In order to estimate the junction temperature, the sensing temperature from NTC (Negative temperature coefficient) resistor inside the module is used as reference temperature. The equivalent thermal models, also named Foster model, from both junction to NTC and NTC to coolant are built, respectively. With these thermal models, the junction and coolant temperature estimation methods are derived. For the purpose of making the estimation accurate, the thermal coupling effect is carefully studied. Finally, the thermal model is verified by inverter application with current steps sweeping; the estimated temperature is compared with thermal camera measurement result which demonstrates good accuracy of the thermal model. The estimated coolant temperature is also well matched with thermocouple measurement result.     

Failure criteria for long term Accelerated Power Cycling Test linked to electrical turn off SOA on IGBT module. A 4000 hours test on 1200A–3300V module with AlSiC base plate

With AlSiC base plate technology for big module, the reliability about thermal cycling due to railway traction is largely improved and the accelerated Power Cycling Test time is increased a lot to reach over 6 months. Then it appears that these failure indicators as; Rth increasing, Vce increasing, or Iges increasing, must be linked to the interface behavior (thermal and mechanical) and the full electrical capabilities of the device to switch on and switch off current and voltage in a converter.This paper discuss about test methodology and protocol of accelerated Power Cycling Test (PCT), including turn off Safe Operating Area (SOA) measurement before and after reliability tests in order to evaluate the influence of the parameters drift Vce, Rth, and gate leakage Iges.Mainly, PCT and SOA results are presented on 1200A-3300V IGBT module with AlSiC base plate materials after a 4000 hours test (376000 cycles) on very hard conditions. It is also shown the SOA capability on one IGBT module with gate leakage failure.     

Design optimization of an integrated liquid-cooled IGBT powermodule using CFD technique

This paper presents a novel approach to optimize pin array design of an integrated, liquid-cooled, insulated gate bipolar transistor (IGBT) power module. With the aid of a computational fluid dynamics (CFD) code, the fluid field and heat transfer inside the module were analyzed, and several design options on pin arrays were examined. For IGBT die circuitry, the uniformity of temperature distribution among dies is as critical as the magnitude of the die temperature. A noticeable variation in temperature among dies can accelerate the thermal runaway and reduce the reliability of the devices. With geometrically-optimized-pin designs located both upstream and downstream of the channel, a total power dissipation of 1200 W was achieved. The maximum junction temperature was maintained at 100°C and the maximum variation among dies was controlled within 1°C. The results from this study indicated that the device junction temperatures were not only reduced in magnitude but were equalized as well. In addition, the maximum power dissipation of the module was enhanced. Comparison with other direct- (pool boiling) and indirect- (cold plate) liquid cooling techniques was also discussed     

应用于车载变流器的RC-IGBT工作特性

逆导型IGBT (RC-IGBT)是将IGBT功能与续流二极管功能集成在一个芯片上,实现了在相同封装体积下,可获得更大的功率密度,由于IGBT与二极管紧密的移相热耦合,在相同散热条件下,RC-IGBT允许的工作结温更高.同时,RC-IGBT的本征二极管还受到栅极电压控制,通过栅极电压控制策略,可以降低器件损耗,优化系统特性.介绍了RC-IGBT的基本工作原理和二极管退饱和控制特性,研究了RC-IGBT应用于变流器系统的损耗优化控制策略,分析了应用RC-IGBT的单相脉宽调制(PWM)整流器的工作特性与损耗特性.通过一个具体的应用工况运行仿真,分析对比了RC-IGBT和普通IGBT在PWM整流器应用中的损耗特性.结果显示,应用RC-IGBT后总体损耗有所降低,验证了RC-IGBT退饱和脉冲控制的有效性.     

Mutual and self-aging effects of power semiconductors on the thermal behaviour of DC-DC boost power converter

A shift from conventional to renewable resources has increased the importance of power exploitation via power converters. In this respect, estimating an accurate useful lifetime of power converters plays a major role for the manufacturers and users. This paper touches the issues related to the self and the mutual degradation effects of the power semiconductors such as IGBT and diode on each other in a conventional DC-DC boost converter. By IGBT and diode aging, junction-case thermal resistance, IGBT collector-emitter voltage and diode forward voltage have been increased leading to thermal operating point changes. These changes have a significant effect on the degradation and the useful lifetime of devices. It is shown that by either IGBT or diode aging due to the thermo-mechanical fatigue, an increase in the IGBT or diode junction temperature has been occurred. The results reveal the importance of mutual- and self-aging effects on the reliability assessment. An experimental validation has been also performed via a prototype setup of 200/400V 3000W DC-DC boost converter.     

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.     

TLM method for thermal investigation of IGBT modules in PWM mode

The insulated gate bipolar transistor (IGBT) is popularly used in high power, high frequency power-electronic applications such as motor control and inverters. These applications require well designed thermal management system to ensure the protection of IGBTs. Choice simulation tools for accurate prediction of device power dissipation and junction temperature become important in achieving optimised designs.In this paper, thermal analysis of a 1200 A, 3.3 kV IGBT module was investigated and analysed using the three-dimensional transmission line matrix (3D-TLM) method. The results show a three-dimensional visualisation of self-heating phenomena in the device. Since the comparison TLM results with the analytical solutions do not exist for this IGBT module, we use the MSC.NASTRAN tool to find the similar range of the temperatures. Results are compared.Typically, IGBT is used in a three-phase inverter leg where the control signals are generated via PWM scheme so, the prediction of the temperature rise is important in the pulse operation conditions for the IGBT device. A view of the dynamic thermal temperature rise is obtained with 100 W-step pulse dissipation applied at IGBT chips. The temperature rises are calculated using TLM method during the PWM load cycles. Simulations give clear indications of the importance of the spreader material and are helpful in selecting the proper one.TLM has been successful in modelling heat diffusion problems and has proven to be efficient in terms of stability and complex geometry. The three-dimensional results show that method has a considerable potential in power devices thermal analysis and design.     

Degradation behavior of 600 V–200 A IGBT modules under power cycling and high temperature environment conditions

One challenge for automotive hybrid traction application is the use of high power IGBT modules that can withstand high ambient temperatures, from 90 °C to 120 °C, for reliability purpose. The paper presents ageing tests of 600 V–200 A IGBT modules subjected to power cycling with 60 °C junction temperature swings at 90 °C ambient temperature. Failure modes are described and obtained results on the module characteristics are detailed. Especially, physical degradations are described not only at the package level, like solder attach delaminations, but also at the chip level, with a shift on electrical characteristics such as threshold voltage. Finally, numerical investigations are performed in order to assess the thermal and thermo-mechanical constraints on silicon dies during power cycling and also to estimate the effect of ambient temperature on the mechanical stresses.     

压接型IGBT器件单芯片子模组功率循环试验仿真

压接型绝缘栅双极型晶体管(IGBT)器件因具有双面散热、短路失效和易于串联等优点,正逐步应用到柔性直流输电等领域.但其在工作过程中的热学、力学特性与传统焊接式IGBT模块相比有很大差异,故存在不同的长期可靠性问题.基于有限元法建立了压接型IGBT器件单芯片子模组多物理场耦合仿真模型,研究了三种功率循环仿真条件下器件的热学和力学特性,并且在功率循环过程中利用金属弹塑性模型来模拟材料的瞬态特性.仿真结果表明,IGBT芯片发射极表面与发射极钼片相接触的边缘是应力集中区域,芯片发射极表面栅极缺口和四周边角处有明显的塑性变形.同时,将仿真结果与实际失效的IGBT芯片进行了对比,进一步验证了仿真模型的有效性和适用性.     

基于Msp430单片机的直流电子负载设计

以Msp430F169单片机为控制芯片,通过设计外围键盘液晶显示模块、A/D采集输入电路、D/A转换输出电路、多路电源输出模块和恒流源输出电路,配合系统软件设计,制作了一款可靠实用的直流电子负载。经实验测试,该直流电子负载可靠性好、测量精确度高、抗干扰能力强,具有较强的实用价值。     

Solar Energy System with Digital Controller for Grid Connected Systems

The solar photovoltaic (PV) module output voltage changes according to the variation of light intensity and temperature. This paper presents the implementation of an automatic digital controller of a DC-DC boost converter without batteries for a solar cell module by using a peripheral interface controller, which forms a closed loop, to control the ON-OFF period of the switching pulse. The output of DC-DC converter is maintained by automatically increasing or decreasing the pulse width. To produce the pulse width modulation (PWM), the microcontroller is programmed according to the required duty cycle for the power switch. The PWM ON period is increased with the decrease in the PV voltage and vice-versa. The input voltage to the inverter is maintained constantly and is converted into an AC signal by using the metal-oxide-semiconductor field effect transistor (MOSFET) H-bridge operated in the sinusoidal pulse width modulation mode by using a PIC (peripheral interface controller) microcontroller. The generated AC signal can be connected to the AC grid or to the AC load. The simulated results by using Proteus 8 and hardware implemented results verify the effectiveness of the proposed controller.     

新型不带铜底板IGBT功率模块的散热设计

随着16BT芯片功率密度的提高,在中小功率IGBT功率模块中,不带铜底板的IGBT模块已经成为模块封装发展的一个趋势。但是每一种新型结构的功率模块封装都有它的优缺点,新型的不带铜底板的功率模块,它的优点是体积小,重量轻,成本低;缺点是它的散热性能受导热硅脂性能和厚度的影响非常大。本文通过大量仿真及实验数据．详细描述了导热硅脂对不带铜底板模块散热性能的影响,并结合实验数据,介绍了Vincotech公司推出的预涂高性能导热硅脂服务对模块散热的改善效果。     

Modeling and Control of PV Charger System With SEPIC Converter

The photovoltaic (PV) stand-alone system requires a battery charger for energy storage. This paper presents the modeling and controller design of the PV charger system implemented with the single-ended primary inductance converter (SEPIC). The designed SEPIC employs the peak-current-mode control with the current command generated from the input PV voltage regulating loop, where the voltage command is determined by both the PV module maximum power point tracking (MPPT) control loop and the battery charging loop. The control objective is to balance the power flow from the PV module to the battery and the load such that the PV power is utilized effectively and the battery is charged with three charging stages. This paper gives a detailed modeling of the SEPIC with the PV module input and peak-current-mode control first. Accordingly, the PV voltage controller, as well as the adaptive MPPT controller, is designed. An 80-W prototype system is built. The effectiveness of the proposed methods is proved with some simulation and experimental results.     

PrimePACK^TM模块在风力发电系统中的可靠性考虑

本文介绍了PrimePACK^TM模块风力发电系统中的应用。PrimePACK作为英飞凌推出的新一代的大功率IGBT模块,采用了的全新的封装技术,以及芯片技术。这使得PrimePACK模块的可靠性大大提高。