A Novel Sensorless Controller for Three-Phase Power Converters

This paper address the estimation problem in power converters using nonlinear observers. In general, most of the schemes used to control the power converters are based on measurements of all voltages and currents involved. In this paper we present the design of dynamical systems called observers or estimators which allows to reduce the number of measurements, Ie, sensors, and still implement the controller algorithm. Using such observers makes it possible to reduce the number of sensors and thus reduce costs or even increase reliability if these soft sensors are used as backups for security purposes. In this light, we propose two nonlinear observers based on the sliding mode theory for two particular cases. In the first case, the observer allows us to eliminate the use of the DC-link voltage. In the second case, we show that it Is possible to eliminate the AC-mains sensors with such observers. Finally, the performance of these soft sensors is investigated by simulations in a control-loop which is based on the popular dead-beat space vector modulation technique