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关键词： Temperature measurement   Insulated gate bipolar transistors   Junctions   Voltage measurement   Estimation   Current measurement   Logic gates   Fault diagnosis   insulated gate bipolar transistor (IGBT)   junction temperature estimation   Miller voltage plateau  

摘要： Junction temperature monitoring and fault diagnosis of power semiconductor devices can provide critical information to ensure the reliable operation of power electronic systems. In this article, an online condition monitoring method for insulated gate bipolar transistors (IGBTs), which is not affected by the collector current, is proposed based on the Miller voltage plateau of the conduction process. The relationship between the Miller voltage plateau and the junction temperature is analyzed, and an analytical model of the Miller voltage against junction temperature is established. By using this model and the conducting-state characteristics of the device, a reverse current phase measuring strategy is proposed to decouple the influence of the collector current on the junction temperature estimation, and an online measurement circuit of the Miller voltage is designed. In addition, the characteristics of the trigger voltage under different faults are analyzed to recognize fault types. The experimental results show that the proposed method has high sensitivity and good linearity. It is proven that the proposed measurement strategy is independent of the collector current, which can accurately distinguish the fault forms of IGBTs.

关键词： IGBT   insulating material   poly(imide-siloxane)   crosslinking   thermal property  

摘要： Insulated gate bipolar transistor (IGBT) is an important power device for the conversion, control, and transmission of semiconductor power, and is used in various industrial fields. The IGBT module currently uses silicone gel as an insulating layer. Since higher power density and more severe temperature applications have become the trend according to the development of electronic device industry, insulating materials with improved heat resistance and insulation performances should be developed. In this study, we intended to synthesize a new insulating material with enhanced thermal stability and reduced thermal conductivity. Poly(imide-siloxane) (PIS) was prepared and crosslinked through a hydrosilylation reaction to obtain a semi-solid Crosslinked PIS. Thermal decomposition temperature, thermal conductivity, optical transparency, dielectric constant, and rheological property of the Crosslinked PIS were investigated and compared to those of a commercial silicone gel. The Crosslinked PIS showed high thermal stability and low thermal conductivity, along with other desirable properties, and so could be useful as an IGBT-insulating material.

关键词： automotive   electric drive   IGBT   inverter   MOSFET   power electronics   power semiconductors   wide-bandgap materials  

摘要： In the automotive industry, the design and implementation of power converters and especially inverters, are at a turning point. Silicon (Si) IGBTs are at present the most widely used power semiconductors in most commercial vehicles. However, this trend is beginning to change with the appearance of wide-bandgap (WBG) devices, particularly silicon carbide (SiC) and gallium nitride (GaN). It is therefore advisable to review their main features and advantages, to update the degree of their market penetration, and to identify the most commonly used alternatives in automotive inverters. In this paper, the aim is therefore to summarize the most relevant characteristics of power inverters, reviewing and providing a global overview of the most outstanding aspects (packages, semiconductor internal structure, stack-ups, thermal considerations, etc.) of Si, SiC, and GaN power semiconductor technologies, and the degree of their use in electric vehicle powertrains. In addition, the paper also points out the trends that semiconductor technology and next-generation inverters will be likely to follow, especially when future prospects point to the use of "800 V" battery systems and increased switching frequencies. The internal structure and the characteristics of the power modules are disaggregated, highlighting their thermal and electrical characteristics. In addition, aspects relating to reliability are considered, at both the discrete device and power module level, as well as more general issues that involve the entire propulsion system, such as common-mode voltage.

关键词： IGBT modules   Particle filter   Improved state -space model   Long short-term memory   Fault prediction  

摘要： Insulated Gate Bipolar Transistor (IGBT) modules, being widely applied in many fields, are prone to aging and even fail under high voltage or temperature operation, so it is necessary to conduct IGBT modules fault pre-diction to avoid critical failures. Particle filter (PF) has strong applicability in IGBT modules fault prediction due to the fact that hidden state of IGBT modules can be evaluated from observed measurements containing noises. Nevertheless, the analytic form of state transition equation for PF is insufficient to represent nonlinear charac-teristics of complex systems, and the degradation process of IGBT modules in practical engineering does not conform to Markov property. Hence, a novel fault prediction method for IGBT modules based on improved particle filter is proposed in this paper, which has an improved nonlinear characteristics representation of state -space model. Specifically, long short-term memory (LSTM) model and curve fitting function are utilized to construct the state transition equation and the measurement equation, respectively. The IGBT accelerated aging test data published by NASA PCoE research center are used to verify the proposed fault prediction method, and the comparison studies show effectiveness and superiority of the proposed method in the IGBT modules fault prediction.

关键词： Capacitors   Switching frequency   Insulated gate bipolar transistors   Voltage control   Stress   Thermal stresses   Indexes   Conduction loss   insertion index   loss balancing   modular multilevel converter (MMC)  

摘要： Modular multilevel converter (MMC) is the state-of-the-art converter topology in HVdc transmission applications. The reliability and lifetime of MMCs are strongly dependent on the health of the internal power semiconductors. The operating loss of power semiconductors, which is one of the dominant factors affecting component aging, is not uniformly distributed between the top and bottom switches in the same submodule (SM) due to the dc bias in the arm current. Such loss imbalance leads to differences in lifetime of semiconductors and reduces the reliability of SM. Especially under inverter conditions, the bottom insulated gate bipolar transistor (IGBT) in SM is subjected to a severe thermal stress and has a relatively high failure rate for the thermal vulnerability of IGBT. To extend the lifetime and improve the reliability, this article proposes a component-level loss balancing method. It is achieved by insertion index modification based on a feed-forward gain controller. The proposed method can improve the loss distribution among the top and bottom semiconductors without side effects on ac and dc outputs. Its effectiveness and feasibility are validated through simulation and experimental results.

关键词： IGBT   Online monitoring   Reliability   Reliability Temperature fluctuation  

摘要： The IGBT chip temperature is an important index affecting device reliability. Due to the existence of packaging, the temperature data of the IGBT chip is difficult to obtain directly. Because the large IGBT switching frequency, the temperature changes quickly. The chip junction temperature fluctuation is too difficult to measure. Based on the Cauer electrothermal coupling model, this paper deduces the calculation formula of the IGBT chip temperature fluctuation. Through the on-stage voltage, collector current, thermal resistance, thermal capacitance, on time and off time that can be directly monitored, the chip temperature fluctuation inside the package can be calculated. Then the accuracy of the calculation formula of temperature fluctuation is verified by experimental method, and the experimental results confirm the feasibility of this method. The chip temperature fluctuation monitored by this method is the premise for the lifetime prediction and reliability research of the IGBT, which plays a great role in the engineering field.

关键词： fault-tolerant control   modular multilevel matrix converter (M3C)   open-circuit failure   Fault detection  

摘要： The modular multilevel matrix converter (M3C) is a topology that can realize direct ac-to-ac power conversion. To increase the reliability of the M3C, submodule (SM) fault ride-through capability is required to avoid unscheduled shutdown caused by the failures of power components in its SMs, such as the open-circuit fault of insulated gate bipolar transistors. Although this kind of fault has been widely studied for the regular dc-ac modular multilevel converter (MMC), the existing fault diagnosis criteria and fault-tolerant control processes are not directly applicable to the M3C. To solve this problem, this article analyzes the behavior of the M3C under open-circuit faults and proposes a suitable fault detection criterion for the M3C by transferring the observation errors of circulating currents into specific values. Meanwhile, since the observers can only identify two types of faults but not accurately locate the faulty device in a full-bridge SM, a modified fault tolerance process is proposed. Moreover, this article proposes a method to obtain the actual maximum intrinsic errors (AMIEs) of the observers to determine fault diagnosis thresholds under different load conditions. A downscaled M3C prototype with 27 SMs is built, and experimental results are presented to validate the effectiveness of the proposed fault detection criterion, the fault-tolerant control process, and the AMIE-obtaining method.

关键词： Insulated gate bipolar transistor (IGBT)   Health state prediction   Unscented particle filter   Thermal resistance   Genetic algorithm  

摘要： Insulated gate bipolar transistor (IGBT), as the most critical and vulnerable power electronic component in the field of rail transportation, its reliability has become a research hotspot in recent years. To improve the safe and reliable operation of rail transportation and to reduce the maintenance cost by rationalizing system maintenance, it is critical to monitor the health of the traction converter IGBTs. This paper first reviews the failure mechanism of the IGBT, then analyzes the health state characterization parameters of the IGBT by the accelerated aging test, selects thermal resistance as the health state characterization parameter of the IGBT, and establishes the degradation model of the IGBT. On this basis, a health state prediction method of IGBT based on the genetic algorithm unscented particle filter (GA-UPF) is proposed. This method uses an unscented Kalman filter to generate important proposal density distribution for each particle, estimates, and updates the parameters of the degradation model, alleviates the particle degradation problem, and uses a genetic algorithm to solve the particle impoverishment problem introduced by the traditional resampling method, which improves the particle diversity and prediction accuracy. Mahalanobis distance is used to monitor the abnormal state of the thermal resistance. After the abnormal occurs, the value of the thermal resistance is predicted according to the degradation model and updated parameters. The degradation trend of the thermal resistance is predicted to reflect the health state of the IGBT. Experiments on IGBT degradation data show that the proposed method can provide higher health state prediction accuracy than the traditional particle filter method.

关键词： Inverter   IGBT   Fault diagnosis   Open-circuit   Wavelet packet analysis   VMD   Variance   Average  

摘要： It is critical to accurately detect IGBT (Insulated Gate Bipolar Transistor) switch faults in order to ensure the reliability and robustness of three-phase inverters. In this work, a new approach for the enhancement of the IGBTs open-circuit faults of a three-phase diagnosis inverter is proposed. This approach is based on an Enhanced version of the Variational Mode Decomposition algorithm (EVMD) combined with wavelet packet analysis (WPA) and scalar indicators such as the average and variance value. Firstly, the three-phase current signals are denoised using an improved version of the denoising technique based on a WPA. Secondly, the denoised current signals are decomposed by EVMD algorithm into Band Limited Intrinsic Mode Functions (BLIMFs). Thirdly, BLIMFs that have the highest correlation coefficients with current signals are selected as useful modes. Fourthly, the variance of the BLIMFs that have the highest correlation coefficient among those selected is calculated in order to detect the faulty phase and, consequently, the faulty arm. Finally, the average of the BLIMF that has the lowest correlation coefficient among those selected for the faulty phase is calculated to localize the fault position in either the upper or the lower IGBTs of the faulty arm. The proposed approach is applied to experimental signals and the results obtained show well the efficiency of the performance of the proposed approach in the diagnosis of open-circuit faults.

关键词： RC-IGBT   Single -event burnout   Snapback  

摘要： This paper proposes a reverse conducting insulated gate bipolar transistors (RC-IGBT) structure with a raised N -buffer layer (RNB-IGBT) to improve the single-event burnout (SEB) robustness. The electrical and radiation properties of the structure were verified by TCAD simulations. At the same snapback voltage of 0.22 V and the liner energy transfer (LET) of 60 MeVcm2/mg conditions, the SEB threshold of RNB-IGBT is improved by 52 % compared to that of conventional RC-IGBT. This result indicates that the raised N-buffer layer of the RNB-IGBT can effectively reduce impact ionization, so it can suppress excessive heat concentration and avoid induce SEB.