Comparison Of Anti-Windup Alternatives For Parallel Controllers

Parallel controller structures are broadly used for controlling electrical variables in distorted grids and other applications such as electric drives. Each controller in the structure ideally regulates a single harmonic component. In the event of controller output saturation, some anti-windup strategy must be implemented to ensure a correct operation of the controller and a fast and smooth transition from saturated to non-saturated state. The anti-windup techniques proposed for single controller structures can be applied to parallel structures. However, two options exist: 1) Consider the controllers in the parallel structure as independent units during saturation; 2) Consider the parallel controller structure as a whole. The first one is broadly used while the second one has been recently proposed. This paper analyzes the implementation differences and the performance of both solutions in different scenarios: grid-forming and grid-feeding applications.