An expected lifetime of converters is of great importance for optimal decision-making in the planning of modern Power Electronic (PE) systems. Hence, the lifetime management of power electronic systems has attracted a lot of attention in academia and industry. This paper is a guideline for managing the lifetime of power converters. Analyzing the different kinds of failures, failure modes and their corresponding mechanisms are investigated in the first section along with the failure data needed as input parameters of the assessment. In the second section, lifetime prediction in two aspects of component-level and system level is discussed and all the possible techniques to achieve them are investigated and compared. All the steps required to predict the lifetime in the component-level including electrothermal modeling, cycle counting, lifetime model, damage accumulation, parameter estimation, and lifetime distribution are described and then system level methods consisting of reliability block diagrams, fault-tree analysis, and Markov chains are examined and compared. The last section contains the roadmap of the lifetime extension including the reliable design and condition monitoring.

High voltage gain DC-DC boost converters are used widely in grid-connected applications through integration with the Renewable Energy Sources (RESs). Photovoltaic (PV) arrays or Fuel Cells (FCs) generate a limited value of the DC voltages and then for high power and high voltage applications, at the first stage, these voltages should be increased. This study presents a high gain, single-switched, and efficient DC-DC boost converter using the switched-capacitor and switched-inductor cells. These blocks easily can enhance the voltage and present an input current with the less values of the ripples. This will be done through replacing the location of the input inductors and by applying a switched-inductor block. Magnetizing in parallel and demagnetizing in series for the inductors present the smaller input current stresses. A single switch is used for the proposed boost converter that directly decreases the complexity of the control circuit for obtaining a fixed DC voltage at the output side for flexible input voltages or loads. More voltages will be presented by the used switched-capacitor cell simply by adding several diodes and capacitors. A deep and detailed mathematical analysis will be presented for continuous (CCM) and discontinuous conduction modes (DCM) and a 200 W laboratory-scaled prototype is presented. The results of the hardware tests confirm the correctness of the theoretical analysis and simulation results.

In this article, an optimal structure for a high step-up nonisolated dc–dc converter is proposed. In this topology, the required high voltage gain can be obtained with a low number of elements. Furthermore, by implementing an auxiliary circuit, zero-voltage switching condition for the switches is provided, input current ripple has been reduced to almost zero, and all of the power diodes turn off and on under zero-current conditions. In the proposed structure, to regulate voltage gain, the extendable number of diode–capacitor voltage multiplier (DCVM) stages are combined with a coupled inductor. The voltage stresses across the semiconductors can be regulated by the number of the DCVM stages and the turns ratio of the coupled inductor. Thus, it provides two degrees of freedom for the designer to use low-rated semiconductors, which increases the converter efficiency. In this article, the performance of the proposed converter, in terms of voltage stress, voltage gain, and efficiency, has been analyzed, and a comprehensive comparison between the presented topology and other similar topologies presented. Finally, to verify the performance of the proposed topology, a 500 W (40 V/400 V) laboratory prototype has been developed and tested. The experimental results confirm its superiority and suitability.

The reliability of power electronic converters is a major concern in industrial applications because of using prone-to-failure elements such as high-power semiconductor devices and electronic capacitors. Hence, designing fault-tolerant inverters has been of great interest among researchers in both academia and industry over the last decade. Among the three stages of fault management, compensating the fault is the most important and challenging part. The techniques for fault compensation can be classified into three groups: hardware redundancy methods which use extra switches, legs, or modules to replace the faulty parts directly or indirectly, switching states redundancy methods which are about omitting and replacing the impossible switching states, and unbalance compensation including the techniques to compensate for the unbalances in the system caused by a fault. In this paper, an overview of fault-tolerant inverters is presented. A classification of fault-tolerant inverters is demonstrated and major cases in each of its categories are explained.

A new dual-coupled inductor (CI) single-switch high step-up DC-DC topology featuring high-power density is proposed in this study. Various capacitive power transfer methods, as well as inductive power transfer techniques, are utilized to act as a more efficient power interface between the input and the load. Three ports in the output terminal are employed to distribute the overall output voltage, diminish the voltage ripple in high-voltage gain ratios, and decrease the voltage stress on the port component. In the proposed converter, (i) the voltage gain is high in lower duty cycles of the switching; (ii) the stored energy of magnetizing and leakage inductances are recycled in both Cls; (iii) the switch voltage spikes are alleviated; (iv) the operation is done with no circulating current; (v) low-size passive components are presented; (vi) high-power density is obtained, and the voltage range is widened, and (vii) a simple PWM utilizing a wide control range is provided. In this study, the steady-state operation is analyzed under both continuous conduction mode (CCM) and discontinuous conduction mode (DCM), and the performance of the converter is evaluated using comparisons with similar works. In addition, the experimental results have been provided to justify the feasibility of the design.

Increasingly, dc microgrids are attracting attention because of their universality, high efficiency, and potential application market. To enhance the fault protection of dc systems, solid-state circuit breakers (SSCBs) have been developed to perform fast protection. However, there are still challenges including decoupling of the source and load during operation, using the switches of the main path, MOV's reliability, and charged capacitors before reclosing. In this article, three bidirectional dc SSCBs are proposed that address the aforementioned issues using a third switch to bypass the fault current, eliminating the snubber from the power line, not using the main path switches, and placing a snubber that provides a discharged capacitor before reclosing. These also provide the structure extra reliability and increased voltage utilization rate of the switches. These features increase both device and human safety. The working principle and operating modes of these SSCBs along with the equations for calculation of crucial time intervals, voltages, and currents and the design procedure are provided, and the experimental results demonstrate the proper performance of the topology and validate the findings.