Multi-objective coordination control of distributed power flow controller

In this paper, distributed power flow controller (DPFC) constraints are analyzed. The energy balance relationship between fundamental wave and third harmonic in series and shunt-side converter is deduced. A proportional integral (PI) controller of the DPFC is constructed. The PI controller uses the voltage amplitude and phase angle injected into the system in the series side, along with the modulation ratio of the three-phase converter on the shunt side as the control variables. A multiobjective coordinated control equation is proposed, which factors the constraints of the energy balance between series and shunt side, device capacity limit, safe operation limit, fundamental component, as well as third harmonic component of the injection voltage at the series side. The equation minimizes the variance between the actual value of the control target and its given value to ensure that the DC capacitor voltage, both in the series and shunt side, is stable at target value. Simulations are conducted to verify correctness and effectiveness of the proposed control method.