Abstract: With wide-spread application of power electronic converters in high power systems, there has been a growing interest in system reliability analysis and fault-tolerant capabilities. This paper presents a comprehensive review of conventional fault-tolerant techniques regarding power electronic converters in case of power semiconductor device failures. These techniques can be classified into four categories based on the type of hardware redundancy unit: switch-level, leg-level, module-level, and system-level. Also, various fault-tolerant methods are assessed according to cost, complexity, performance, etc. The intent of this review is to provide a detailed picture regarding the current landscape of research in power electronic fault-handling mechanisms.

Abstract: Many power switching devices are used in hybrid vehicles (HVs) and electric vehicles (EVs). To improve the efficiency of HVs and EVs, better performance characteristics than those of Si power devices, for example, lower on-resistance, higher speed, higher operation temperature, are required for the power devices. GaN power devices are promising candidates for satisfying the requirements. A lateral GaN power device with a blocking voltage of 600 V and a vertical GaN power device with a blocking voltage of 1200 V are suitable for medium power applications for sub systems and high-power applications for the drive of main motors, respectively. Power device applications in HVs and EVs and the current status of the GaN power device are presented. The reliability of the GaN power device is also discussed.

Abstract: Electric drive systems, which include electric machines and power electronics, are a key enabling technology for advanced vehicle propulsion systems that reduce the petroleum dependence of the ground transportation sector. To have significant effect, electric drive technologies must be economical in terms of cost, weight, and size while meeting performance and reliability expectations. This paper will provide details of the design, analysis, and testing of an advanced interior permanent magnet (PM) machine that was developed to meet the FreedomCAR 2020 specifications. The 12-slot/10-pole machine has segmented stator structure equipped with fractional-slot nonoverlapping concentrated windings. The rotor has a novel spoke structure/assembly. Several prototypes with different thermal management schemes have been built and tested. This paper will cover the test results for all these prototypes and highlight the tradeoffs between the various schemes. Due to the high machine frequency (~1.2 kHz at the top speed), detailed analysis of various loss components and ways to reduce them will be presented. In addition, due to the high coolant inlet temperature and the fact that the machine is designed to continuously operate at 180 °C, detailed PM demagnetization analysis will be presented. The key novelty in this paper is the advanced rotor structure and the thermal management schemes.

Abstract: This paper proposes a stochastic framework for optimal sizing and reliability analysis of a hybrid power system including the renewable resources and energy storage system. Uncertainties of wind power, photovoltaic (PV) power, and load are stochastically modeled using autoregressive moving average (ARMA). A pattern search-based optimization method is used in conjunction with a sequential Monte Carlo simulation (SMCS) to minimize the system cost and satisfy the reliability requirements. The SMCS simulates the chronological behavior of the system and calculates the reliability indices from a series of simulated experiments. Load shifting strategies are proposed to provide some flexibility and reduce the mismatch between the renewable generation and heating ventilation and air conditioning loads in a hybrid power system. Different percentages of load shifting and their potential impacts on the hybrid power system reliability/cost analysis are evaluated. Using a compromise-solution method, the best compromise between the reliability and cost is realized for the hybrid power system.

Abstract: Power electronic systems play an increasingly important role in providing high-efficiency power conversion for adjustable-speed drives, power-quality correction, renewable-energy systems, energy-storage systems, and electric vehicles. However, they are often presented with demanding operating environments that challenge the reliability aspects of power electronic techniques. For example, increasingly thermally stressful environments are seen in applications such as electric vehicles, where ambient temperatures under the hood exceed 150 °C, while some wind turbine applications can place large temperature cycling conditions on the system. On the other hand, safety requirements in the aerospace and automotive industries place rigorous demands on reliability.

Abstract: Fused deposition modeling (FDM) is one of the most widely used additive manufacturing processes for fabricating prototypes and functional parts in common engineering plastics. The process is based on the extrusion of heated feedstock plastic filaments through a nozzle tip to deposit layers onto a platform to build parts layer by layer directly from a digital model of the part. The simplicity, reliability, and affordability of the FDM process have made the additive manufacturing technology widely recognized and adopted by industry, academia, and consumers. The FDM process has also been widely used by research and development sectors to improve the process, develop new materials, and apply the FDM systems in a wide range of engineering applications. This chapter describes an overview of the basic process, materials, and capabilities of the Stratasys FDM technology, and also presents a comprehensive review of research and development work undertaken using the FDM process since its inception over the past two decades.

Abstract: Reliability of power converters and lifetime prediction has been a major topic of research in the last few decades, especially for traction applications. The main failures in high power semiconductors are caused by thermomechanical fatigue. Power cycling and temperature cycling are the two most common thermal acceleration tests used in assessing reliability. The objective of this paper is to study the various power cycling tests found in the literature and to develop generalized steps in planning application specific power cycling tests. A comparison of different tests based on the failures, duration, test circuits, and monitored electrical parameters is presented.

Abstract: Electric power industry is experiencing a movement from the existing conventional electric grid to a more reliable, efficient and secure smart grid. In order to achieve these goals, components such as energy storage will be included, and potentially in large scale. Many feasible applications of energy storage in power systems have been investigated. The major benefits of energy storage include electric energy time-shift, frequency regulation and transmission congestion relief. In this paper, we focus on the reliability improvement of the bulk power system brought by the utilization of energy storage in the local distribution systems integrated with renewable energy generation. An intelligent operation strategy for energy storage which improves reliability considering the renewable energy integration is presented. The smart grid communication and control network is utilized to implement the proposed energy storage operation. A bulk power system reliability evaluation framework is proposed to study the reliability impact brought by the energy storage integration and operation. A detailed case study and sensitivity analysis is performed to demonstrate the effectiveness of the presented operation strategy and evaluation framework, and to provide valuable insights on the power system reliability impact derived from the energy storage integration.

Abstract: The real-time junction temperature monitoring of a high-power insulated-gate bipolar transistor (IGBT) module is important to increase the overall reliability of power converters for industrial applications. This article proposes a new method to measure the on-state collector-emitter voltage of a high-power IGBT module during converter operation, which may play a vital role in improving the reliability of the power converters. The measured voltage is used to estimate the module average junction temperature of the high and low-voltage side of a half-bridge IGBT separately in every fundamental cycle of the current by calibrating them at load current. The measurement is very accurate and also measures the voltage at the middle of a pulse-width modulation (PWM) switching. A major objective is that this method is designed to be implemented in real applications. The performance of this technique is measured in a wind power converter at a low fundamental frequency. To illustrate more, the test method as well as the performance of the measurement circuit are also presented. This measurement is also useful to indicate failure mechanisms such as bond wire lift-off and solder layer degradation. The measurements of and rise in the junction temperature after five million cycles of normal operation of the converter are also presented.

Abstract: Semiconductor Memories provides in-depth coverage in the areas of design for testing, fault tolerance, failure modes and mechanisms, and screening and qualification methods including.* Memory cell structures and fabrication technologies.* Application-specific memories and architectures.* Memory design, fault modeling and test algorithms, limitations, and trade-offs.* Space environment, radiation hardening process and design techniques, and radiation testing.* Memory stacks and multichip modules for gigabyte storage.

Abstract: SRAM Physical Unclonable Function (PUF) makes use of efficient silicon fabrication process where duplication of exact replica devices is difficult. One of the major issues with SRAM-PUF is the reliability and uniformity of the start-up pattern with environmental fluctuations. This paper presents a technique for improving uniformity (distribution of 1's & 0's) and reliability (variations in power-up patterns) of SRAM-PUF utilizing aging effects (mainly NBTI). The proposed technique maintains the uniformity of SRAM-PUF by controlling the polarity of the aging in SRAM arrays. The reliability is controlled by further injecting aging to the SRAM arrays after achieving target uniformity.

Abstract: The impact of self-heating effect (SHE) on device reliability characterization, such as BTI, HCI, and TDDB, is extensively examined in this work. Self-heating effect and its impact on device level reliability mechanisms is carefully studied, and an empirical model for layout dependent SHE is established. Since the recovery effect during NBTI characterization is found sensitive to self-heating, either changing V T shift as index or adopting μs-delay measurement system is proposed to get rid of SHE influence. In common HCI stress condition, the high drain stress bias usually leads to high power or self-heating, which may dramatically under-estimate the lifetime extracted. The stress condition V g = 0.6~0.8V d is suggested to meet the reasonable operation power and self-heating induced temperature rising. Similarly, drain-bias dependent TDDB characteristics are also under-estimated due to the existence of SHE and need careful calibration to project the lifetime at common usage bias.

Abstract: Reliability of electronic systems for operating in all types of environments has become a necessity. The progressive miniaturization in electronics, packaging of a large number of active devices per unit area of the component due to higher integration levels, higher power density per unit area, need for low- cost and reliable products, and the wide range of applications in specialized commercial, avionics, underground oil exploration, automotive, and other high temperature environments besides the normal commercial applications demands a high degree of reliable operation of the electronics under harsh environmental conditions. In such situations, reliability has to be built into the system by design, choice of suitable components, packaging and cooling techniques. This paper discusses the effect of temperature on the reliability of components used in typical electronic systems. Various models based on the temperature principle are discussed with illustrative examples for reliability calculations.Further, it is shown that by using the principle of cause - effect relationship, suitable methods can be applied to minimize failures of electronic components due to thermal stresses.

Abstract: In this paper, we present reliability and stability data based on a large body of data accumulated from high volume production of SiC power MOSFETs. The SiC MOSFETs (Gen2, C2M) showed excellent body diode and threshold voltage stability after 1000 hours of accelerated stressing tests. Results from next generation SiC power MOSFET development efforts are also presented. A significant reduction in specific on-resistance was demonstrated, and a wide range of blocking voltages, from 900 V to 15 kV, has also been demonstrated.

Abstract: In general, power converters are operated in closed-loop systems, and any characteristic variations in one component will simultaneously alter the operating point of other components, resulting in a shift in overall reliability profile. This interdependence makes the reliability of a converter a complex function of time and operating conditions; therefore, the application may demand periodic replacement of converters to avoid downtime and maintenance cost. By knowing the present state of health and the remaining life of a power converter, it is possible to reduce the maintenance cost for expensive high-power converters. This paper presents a reliability analysis for a boost converter, although this method could be used to any power converter being operated using closed-loop controls. Through the conducted study, it is revealed that the reliability of a boost converter having control loops degrades with time, and this paper presents a method to calculate time-varying reliability of a boost converter as a function of characteristic variations in different components in the circuit. In addition, the effects of operating and ambient conditions have been included in the reliability model as well. It was found that any increase in the ON-state resistance of the MOSFET or equivalent series resistance of the output capacitor decreases the overall reliability of the converter. However, any variation in the capacitance has a more complex impact on the converter's reliability. This paper is a step forward to the power-converter reliability analysis because the cumulative effect of multiple degraded components has been considered in the reliability model.

Abstract: Relationships between Power System Dynamic Equilibrium, Load-Flow, and Operating Point Stability.- Fast Assessment of the Distance to Stability.- Accuracy Testing and Real-Time Implementation of Dimo's Stability Analysis Technique.- Emergency Monitoring and Corrective Control of Voltage Instability.- On-Line Voltage Security Assessment.- Critical Issues for Successful On-Line Security Assessment.- The Case for Using Wide-Area Control Techniques to Improve the Reliability of the Electric Power Grid.- Preventive and Emergency Control of Power Systems.- Sensitivity Analysis of Dynamic Stability Indicators in Power Systems.- Model Predictive Control of Electric Power Systems under Emergency Conditions.- The Role of Power System Visualization in Enhancing Power System Security.- Comprehensive approach to Real-Time Stability.- Transient Stability in Real-Time Implementations.

Abstract: Lifetime of power electronics modules can be extended with passive methods (condition monitoring) and active ones. This paper intends to give an overview in the second category, namely active thermal control or lifetime control, offering a critical comparison based on a comprehensive reference list. Mission profiles are compared to evaluate the potential of the controllers.

Abstract: This paper discusses the modeling and application of thermoelectric cooling (TEC) in power electronics circuits. To investigate the benefits and challenges of using TEC, a temperature-dependent thermoelectric model which includes both power electronics circuits and TEC device is presented. With this model, both steady-state and small signal analyses can be carried out, and this paper is more focused on the steady-state part. For the steady-state analysis, the results have identified the allowed operation range which could be used as guidelines for system design. Also, with TEC device, the case temperature and junction temperature of power electronics switches can be dynamically controlled. Therefore, the switches' thermal cycling problem could be alleviated, and the switch lifetime and overall system reliability will be improved. Both simulation and experimental results are presented in this paper to verify the analysis.

Abstract: The reliability prediction of hybrid electric vehicles (HEVs) is of paramount importance for planning, design, control, and operation management of vehicles, since it can provide an objective criterion for comparative evaluation of various configurations and topologies and can be used as an effective tool to improve the design and control of the overall system. This paper presents a mission-profile-dependent simulation model based on MATLAB for quantitatively assessing the reliability of the electric drivetrain of HEVs. This model takes into consideration the variable driving scenarios, dormant mode, electrical stresses, and thermal stresses. Therefore, more reliable and accurate prediction of system reliability has been achieved. The methodology is explained in detail, and the results of reliability assessment based on a series HEV are presented. Based on reliability analysis, two control strategies are proposed to increase the mean time to failure of HEV powertrains: 1) variable dc-link voltage control and 2) hybrid discontinuous pulsewidth modulation scheme. These novel control schemes reduce the power losses and thermal stresses of power converters, and consequently, enhance system reliability. Numerical simulation results verify the benefits of two proposed control strategies in terms of power losses and reliability.

Abstract: A new method for junction temperature measurement of power semiconductor switches is presented. The measurement exploits the temperature dependent resistance of the temperature sensitive electrical parameter (TSEP): the internal gate resistance. This dependence can be observed during the normal switching transitions of an IGBT or MOSFET, and as a result the presented method uses the integral of the gate voltage during the turn-on delay. A measurement circuit can be integrated into a gate driver with no modification to converter or gate driver operation and holds significant advantages over other TSEP based measurement methods, primarily being: an absence of any dependence on operating conditions such as load current, and the potential to achieve higher sensitivity (20mV/C or more) than alternative TSEPs.

Abstract: GaN and SiC have been widely investigated for future power switching systems with high efficiencies. So far, prototypes of working transistors using these wide bandgap materials have demonstrated the superior performances suggesting the great potential. Remaining tasks for the commercialization include finding niche applications as entry ones with the well-established reliability. In this paper, recent progress of the GaN and SiC power devices developed at Panasonic is reviewed. After reviewing the reliability issues in the conventional transistors, normally-off GaN Gate Injection Transistors (GITs) and SiC Diode-integrated MOSFET (DioMOS) free from the degradations are presented. These state-of-the-art GaN and SiC devices are very promising for practical applications.

Abstract: The demand for highly scalable and low power memory has led to research in emerging technologies and devices. Among these devices, memristors has attracted increased attention as being a promising storage device. However, due to its nano-scale size it faces various types of reliability issues. In this study, we have reviewed the memristive mechanisms and reliability concerns existing in memristor memory design. Then, we have simulated the ionic drift memristor model in presence of the process variability. Next, by considering a normal distribution for the resistive distribution of memristors in LRS and HRS state we have shown the instabilities and probability of failure in read and write procedure of memristive memories, and highlighted the requisite and motivation for the reliability aware memristive circuit design.

Abstract: With the continuously increasing demand for energy and the limited supply of fossil fuels, renewable power sources are becoming ever more important. Knowing that future energy demand will grow, manufacturers are increasing the size of new wind turbines (WTs) in order to reduce the cost of energy production. The reliability of the components has a large impact on the overall cost of a WT, and press-pack (PP) insulated gate bipolar transistors (IGBTs) could be a good solution for future multi-megawatt WTs because of advantages like high power density and reliability. When used in power converters, PP IGBTs are stacked together with other components in a clamping mechanism in order to ensure electrical and thermal contact. Incorrect mechanical clamping of PP IGBTs has a negative impact on their reliability and consequently on the reliability of the WT. In this study the impact of mechanical clamping conditions on the static thermal distribution among chips in PP IGBTs is investigated.