Nouveaux mécanismes de commutation pour des structures dédiées aux convertisseurs de puissance de haute efficacité et interrupteurs du futur

Nowadays, the scarcity of cheap energy sources requires a particular effort in optimizing the performance of all conversions. The electric power vector is particulary expected to grow in importance, in conjunction with the development of renewable energy sources. Research in the field of power electronics considers several aspects, including conversion topologies, command strategy as well as the structure and performance of power switches. This work focusses on the power component and the study of dedicated power converting structures. One goal is the use of active switches to replace elements with spontaneous behaviors presenting dissipative phenomena, in order to attempt to reduce switching and conduction losses. Indeed, several works introduce bidirectional monolithic switches adopting new structures, and predict high efficiency components in the near future. On the other hand, the emergence of components without spontaneous properties leads to a redefinition of switching mechanisms in power converters in order to enable the replacement of diodes by active devices. One aspect of this work is the investigation of a close control system including the detection of zero-crossings based on the measurement of both voltage and current in bidirectional switches. A voltage-current representation for the exploitation of experimental results is provided in order to allow for comparison with theoretical behaviors. Several material and internal structure types of components are compared in terms of switching performances. The concept of automatic switching was recently introduced to describe mechanisms based on the detection of non-compliant situations in the switching cell, namely the short-circuit of a voltage source and the opening of a current source. The proposal of applying a new control strategy allows to compensate for the absence of spontaneous extinction. Where sources of a classic switching cell are in a situation of energy exchange or isolation, a third state appears in which source values (converter input/output currents and voltages) are subject to fast changes. The use of passive elements becomes compulsory in order to allow a limitation in the theoretical infinite variations of source values. An intelligent close control system allowing a bidirectional component to switch its state on the basis of measurements of both current and voltage was designed and implemented. An automatic diode with synthesized spontaneous switching functions was studied and experimented for the validation of the proposed self-switching mechanisms model including passive circuits. The use of bidirectional switches allows the extension of conventional converter topologies to new modes of operation. This work presents the modification of a current converter topology traditionally implemented with thyristors, to allow for compensation of reactive power. The spontaneous extinction of thyristors is replaced by a controlled extinction which becomes independent of the polarity of source values. However, the forced opening of the input line inductors current path requires to be absorbed by an input filter whose study is proposed in this work.

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