Study On Direct Power Control For Static Var Generator System

Static var generator (SVG) is applied to not only compensating reactive power but also eliminating harmonic current pollution in the power system. By using space-vector pulse-width modulator (SVPWM) to instead of hysteresis comparators and the switching table, a direct power control with constant frequency is used in SVG.In the present thesis, a special attention is firstly paid to Principles of SVG operation, and different mathematical models of SVG in different coordinate systems are presented and implemented by Simulink software. Comparing with the conventional control schemes of SVG based on direct current control, a direct power control is applied to SVG. The method uses SVPWM to instead of hysteresis comparators of the traditional direct power control system, the utilization of SVPWM makes the switching frequency constant and enables it feasible to decreases the switching loss of system.The design method of controller is proposed, and a design method of the inductance of AC side based on steady-state and transient current tracking is presesnted, which can meet demands of SVG system. The proposed approaches are evaluated by the simulated results.