Distributed generation (DG) is deeply changing the existing distribution networks which become very sophisticated and complex incorporating both active and passive equipment. The simplification of their management can be obtained assuming a structure with small networks, namely, microgrids, reproducing, in a smaller scale, the structure of large networks including production, transmission, and distribution of the electrical energy. Power converters in distributed generation systems carry on some different ancillary functions as, for example, grid synchronization, islanding detection, fault ride through, and so on. In view of an optimal utilization of the generated electrical power, fault tolerant operation is to be considered as a suitable ancillary function for the next future. This paper presents a complete modeling of fault tolerant inverters able to simulate the main fault type occurrence and a control algorithm for fault tolerant converters suitable for microgrids. After the model description, formulated in terms of healthy device and leg binary variables, and the illustration of the fault tolerant control strategy, the paper shows how the control preserves power quality when the converter works in the linear range. The effectiveness of the proposed approach and control is shown through computer simulations and experimental results. 1. Introduction The exponential penetration of distributed generation (DG) is leading to enormous changes in the conception of the electrical system management. Involved networks are no longer to be regarded as passive components but integrate a growing number of functions such as load management, demand side management, and generation curtailment. Both standalone and grid connected microgrids, locally reproducing the structure of the whole generation and distribution system, may be a viable solution to enhance DG benefits, reducing at the same time the drawbacks of DG itself. All the future hypothetical scenarios will lead to great transformations in the design of power systems, with interesting implications in different fields of research [1–5]. Some problems which arise immediately are the presence of bidirectional power flow, the need for a different design of the power lines and transformers, the unwanted islanding conditions, a different protection philosophy, and the possibility of a fault tolerant operation to increase the level of continuity. This paper considers fault tolerant operation as a possible ancillary function. This additional function may be important in autonomous microgrid that cannot benefit from
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