Active Power Filter with Model Based Predictive Current Control in natural and dq Frame

In this paper, a model based predictive current control scheme for active power filters is presented. The proposed method is based on common control schemes, but is only related with a low computational effort. For the predictive control, an inverse model of the voltage source inverter is used. For calculating the inverse model, a future value of the reference current is needed. In the steady state, the load current and thereby the reference current are periodic with the fundamental period, meaning that a future value is equal to a corresponding past value. Thus, this past value can be used. The proposed method is applied to a three-phase four-wire system with control in natural frame and to a three-phase three-wire system with control in the synchronous dq frame. With focus on the predictive control, the general advantages and disadvantages of the diffcrcnt setups arc discussed. Simulation and measurement results compensating the distortion current of a non-linear load are presented and the performance of both setups is compared.