Rotating transformation and resonant control based feedback control strategy for dynamic voltage restorer system

Dynamic voltage restorer (DVR) has been demonstrated to be a very effective mechanism to deal with key voltage-quality disturbances. Although the dynamic response requirement for voltage sag could be satisfied by a feedforward control strategy, the voltage-quality requirement and zero-error tracking need an advanced feedback control strategy. This paper proposes a d-q transformation and proportional-resonant (PR) control based feedback control strategy for DVR system. Through d-q transformation, the fundamental component is transformed into DC signal; the 6k±1^th harmonic components are transformed into 6kth signals. Compared with the similar control strategy in stationary frame, the control system would only need two proportional-integral (PI) controllers for fundamental voltage control and two PR controller for each order harmonics in rotating frame. So the proposed control system is significantly simplified, open-loop and close-loop control system analysis provide a way for parameters design. The simulation on MATLAB Simulink demonstrates the validity and superiority of proposed control strategy.