An adaptive direct power control for three-phase pwm rectifier in the unbalanced case

In this paper, a model based controller is proposed that directly controls the instantaneous active and reactive power of a PWM rectifier in the unbalanced case. Instrumental for our developments is the expression of the source voltage in terms of both sequences, positive and negative, which allows a more complete description of the model. The controller incorporates an adaptation mechanism to cope with the system uncertainties. It is shown that regulation of instantaneous powers is possible at the expenses of deformation of the line current. It is shown that the balanced case can be recovered by simply neglecting the source voltage negative sequence and thus it is a special case of the proposed scheme. However, the use of the balanced case DPC controller, i.e., neglecting the negative sequence, in an unbalanced voltage situation may produce a quite deteriorated performance. Numerical tests are provided to illustrate the merits of the proposed solution.