Research on the control system of cascaded multilevel STATCOM for unbalanced load compensation

For the unbalanced load, a control system of cascaded multilevel STATCOM for 50Hz fundamental frequency modulation + unbalanced load compensation is presented in this paper. The two levels admittance compensation method using ip-iq method + symmetrical components is proposed, the first level of which using ip-iq method is used to filter the harmonics, the last level of which using symmetrical components is to compensate for admittance calculation. The STATCOM system of linear PID controller combined with the method of the admittance compensation calculation has a faster system response speed and higher system robustness. Simulation results verified the effectiveness and feasibility of the imbalance compensation scheme for STATCOM control system.