Modelling and Control of Power electronic Converters

Nowadays the power electronic converters are widely used in any technical product, device or machine. Their applications always lie on any kind of electrical power conditioning like, for example: AC/DC power conversion, DC/AC inversion to drive electrical machines or passive loads (UPS), DC/DC power conversion to feed electronic equipment, active filtering (attenuation of harmonics) of currents and voltages in electrical power distribution networks, reactive power compensation in electrical power distribution networks, and many others. Particularly, in recent years, there has been a proliferation of nonlinear loads in typical power distribution systems. This fact has reduced the power quality of electric power systems and has increased the power losses reducing, then, its operating sustainability. This fact has led to the proposal of more stringent requirements regarding power quality like those specifically collected in the standards IEC-61000-3-{2,4} and IEEE-519 on current harmonics produced by nonlinear loads. These requirements are leading to the development of active filters for power distribution networks and AC/DC power converters with near unity power factor for supply DC loads. Another area of research and development is the electrical power conditioning of new sources like windmills, fuel cells and small hydro-power stations with asynchronous or synchronous generators. In these cases is necessary to develop power converters to connect efficiently the power source to the network or, in the case of island operation, supply electrical power to the users with an acceptable level of quality. The wide range of applications has given a great number of topologies of power converters that need the development of accurate models and special control techniques to fully exploit their characteristics and to offer the best available performance.