Unbalance Suppression Strategy Based on PQR Theory for Distribution Network

Aiming at the power quality problem of microgrid, this paper proposes an unbalance compensation method based on pqr theory. By comparing the theoretical degrees of freedom of instantaneous power in abc coordinate system, $\alpha\beta r$ coordinate system, $ dq\theta$ coordinate system and pqr coordinate system, it is proved that the control flexibility based on pqr theory is better. Considering the influence of non-ideal operating conditions, a pqr coordinate correction method based on a second-order generalized integrator is proposed. The proposed control strategy can improve the unbalance suppression capability, thereby improving the power quality of the system.