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AC power cycling tests allow the most realistic reliability assessment by applying close to real stress to the device or module under test to meet functional safety standards, which is highly critical for traction applications. This paper presents a comprehensive guideline and shares critical know-how to develop a 120 KVA AC power cycling test setup for high-power Silicon Carbide (SiC) modules. As of today, traction applications can not generate an early warning signal for drivers to replace critical components on time. For this purpose, the suitable precursors for all dominant failure mechanisms are discussed, and the corresponding condition monitoring tools are proposed to monitor the device aging on power converters. These condition monitoring tools are integrated into the built-in desaturation protection circuit of the electric vehicle (EV) gate driver for low-cost, practical implementation. The on-resistance of all twelve switches is monitored online as a temperature-sensitive electrical parameter (TSEP) to measure the junction temperature of the devices. To avoid heavy processing load in the microcontroller, the out-of-order equivalent time sampling technique is developed for data sampling, which leads to a measurement error of less than 1.5%. In addition, the design considerations regarding common mode noise and aging effect on DESAT protection are investigated, and experimental findings are presented.

Interleaved converters are used in photovoltaic (PV) applications to handle high power conditions with high reliability. To improve the reliability of these converters, redundant switch configuration can be employed which reduce the failure rates of the power switches significantly. However, evaluation reliability of the interleaved converters equipped with redundant switch configurations may be complex. This paper aims to simplify the reliability Analysis of interleaved converters considering mission profile and redundant switch configuration. Different possible configurations of the studied converter are shown as Markov chain states in the proposed method, which simplify the reliability and failure rates Analysis. The effect of different parameters such as the converter power level, switch configuration type, and operation modes are derived and a better insight into the effectiveness of the switch configuration on improving the reliability is provided.

Fault detection and reconfiguration in fault-tolerant converters may complicated and necessitate using all-purpose microprocessors and high-speed sensors to guarantee the satisfactory performance of power converters. Therefore, providing fault-clearing feature without increasing the processing and sensing burdens and reducing the transition time between faulty to normal state are of great importance. This research proposes a new redundant-switch configuration to address the mentioned challenges. The proposed configuration uses one diode and two fuses to eliminate the faulty switch and replace the reserve one, spontaneously. Open-circuit fault in the proposed configuration is clarified instantly. Moreover, the short-circuit fault is dealt as an open-circuit fault by using a fuse. Thus, the fault-tolerant feature of the proposed switch configuration is achieved without using a complex, versatile and multifaceted fault managing unit. Resultant behaviors of the case studies are derived using MATLAB/SIMULINK. Also, steady-state thermal distribution of power switches which are implemented on a monolith heat sink, analyzed in COMSOL Multi-physics environment. Finally, the viability of the proposed configuration is demonstrated by a laboratory-scaled prototype.

In this paper, a non-isolated high step-up DC-DC converter has been proposed for renewable energy applications. The proposed structure converter has been derived from the fundamental Zeta converter, in both of which only a single switch is employed. The voltage gain ratio has considerably enhanced in this converter with the absence of using switched capacity. To magnify voltage gain of the converter, a coupled-inductor has adopted. Increase and decrease of gain by changing the ratio of coupled-inductor assist the duty cycle. The number of components is low in this structure. The operating principle and evaluation of the proposed converter, considering designing approaches for elements, are discussed in detail. To verify the feasibility of the proposed converter, simulation results have been provided and evaluated.

In this paper, a new dual function fault current limiter-dynamic voltage restorer (FCL-DVR) topology is proposed. The proposed structure, in addition to performing routine FCL tasks, can be used to improve the voltage quality of point of common coupling (PCC). A salient feature of this FCL-DVR is its reduced number of semiconductor switches and gate drive and control circuit components. Perhaps, variety structure of FCL-DVR have been proposed but most distinctive feature of proposed structure is lower power loss. The operation modes and the control strategy of the FCL have been presented and studied. In addition, the proposed structure has been compared with other structures to prove the efficiency of proposed structure. The simulation results as well as experimental outcomes from a laboratory scaled-down prototype are provided, which prove the efficiency and feasibility of the proposed structure.

Experience shows that semiconductor switches in power electronics systems are the most vulnerable components. One of the most common ways to solve this reliability challenge is component-level redundant design. There are four possible configurations for the redundant design in component-level. This paper presents a comparative reliability analysis between different component-level redundant designs for solid state fault current limiter (SSFCL). The aim of the proposed analysis is to determine the more reliable component-level redundant configuration. The mean time to failure (MTTF) is used as the reliability parameter. Considering both fault types (open circuit and short circuit), the MTTFs of different configurations are calculated. It is demonstrated that more reliable configuration depends on the junction temperature of the semiconductor switches in the steady state. That junction temperature is a function of i) ambient temperature, ii) power loss of the semiconductor switch and iii) thermal resistance of heat sink. Also, results sensitivity to each parameter is investigated. The results show that in different conditions, various configurations have higher reliability. The experimental results are presented to clarify the theory and feasibility of the proposed approaches. At last, levelized costs of different configurations are analyzed for a fair comparison.

Up to now, many modulation techniques have been proposed for neutral point clamped (NPC) inverters. In this paper, for the first time, a general methodology is applied to calculate and compare the failure analysis and reliability of NPC inverter with most commonly used control strategies. Also, the mean time to failure (MTTF) of NPC inverter is derived for different control strategies. It is demonstrated that the key feature of control strategies in determining the reliability of inverter is their loss distribution among the switches. The failure rate of components that is relevant to this study and junction temperature calculation is developed, then conduction losses and switching losses of switches for different control strategies are calculated. Finally, the most reliable control strategy is identified. Experimental results obtained have promptly justified the theoretical analysis and outlined procedure.

In this paper, a new fault tolerant dc-ac converter-fed induction motor drive is proposed to maintain motor as close as possible to its desired normal operation under open- and short-circuit switch failures. The operational principles for fault detection and isolation schemes are provided. Two control strategies including predictive control and voltage mode-controlled PWM with integral-double-lead controller for two stage of the converter are presented in conjunction with the elaborated discussion. The control strategy determines appropriate switching states for continuous operation of the drive after a fault. The proposed topology makes it possible to integrate the minimal redundant hardware and full tolerance capability which is an important advantage of the proposed topology. Moreover, the most important advantages of the proposed topology are a fast response in a fault condition and low cost of the converter in comparison with the evaluated topologies. A Joule-integral-based method for selecting an appropriate rating of applied fuses has been presented to provide a reliable fault-isolation operation. Also, a comparison with currently available fault-tolerant dc-ac converters is given to show the merits of the proposed topology. Finally, the experimental results are presented to verify the validity of the theoretical analysis and industrial feasibility of the proposed converter.

This paper proposes a new DC-AC converter with a less number of semiconductor switches and therefore gate drive and control circuit components. A salient feature of this inverter is its pure sinusoidal line-to-line voltages with no need for output filter. Also, the proposed inverter improves the voltage utilization factor of the input dc supply compared to four-switch three-phase inverter (first best topology in the literature from the number of switches point of view) and standard six-switch inverter with sine PWM. The proposed inverter is capable of operating with a wide range of output voltages from zero to the full value of the dc input voltage by appropriately altering instantaneous duty-cycle. For the first time to our knowledge, in this paper, a three-phase universal inverter with only three power-switch has been proposed. For the purpose of providing a good compromise between fast transient response and stability, a model predictive controller is proposed. All the design expressions have been derived. A comparison with other DC-AC converters is given to show the merits of the proposed converter. Finally, satisfactory circuit operation is confirmed by experimental results from a laboratory prototype.