Comparative analysis of PI decoupling control strategies with or without feed-forward in SRF for three-phase power supply

In synchronous rotating frame (SRF), the mathematical mode of a three-phase PWM VSI with LC filter is complex, and the dq components have cross coupling terms. In order to obtain good dynamic and static performance, the controller structure should be inherently based on the system’s mathematical model, which means that the decoupling control strategy with feed-forward should be adopted. But this control strategy is complex, and the control performance depends on fast data sampling, process, and much more sensors. Whereas in the case of not very faster transient response is required, the decoupling control strategy without feed-forward may be a better choice due to simple control and less sensors. After deducing the mathematical mode of a three-phase PWM VSI with LC filter, the comparative analysis of PI decoupling control strategies with or without feed-ward in SRF is implemented on a digital signal processor system and experimentally tested on an 80-kVA prototype unit.