A Novel Feedback/Feedforward Control Strategy for Three-Phase Voltage-Source Converters

In this paper a novel control strategy for voltage source converters (VSCs) is introduced. The proposed strategy consists of a nonlinear feedback controller based on feedback linearization plus a feedforward compensation of the load current. In our proposal an energy function and a quadrature current are considered as outputs, such that zero dynamics is avoided. In this way, a full linearization is obtained via nonlinear transformation and feedback. In order to improve the performance of the whole system and to diminish the output capacitor size an estimate of the load current is feed forwarded. The estimate is calculated by using a nonlinear reduced order observer. Simulation results are presented in order to validate the proposal. These results include performance in presence of parameters uncertainties and noisy measurements. In addition, a comparison with other controllers introduced by other researchers is carried on.