Patent ID: 8060349

Claim:
A method for controlling current, in an electric power system based on passivity-based control theory, to regulate a load bus voltage with a static synchronous compensator (STATCOM) controller designed using a STATCOM model, comprising: constructing a STATCOM model with a viewpoint of energy balancing as a circuit model constructed in Euler-Lagrange (EL) dynamic frame, wherein the model also considers the dynamic response of a changeable load, and is used to determine a control command for fast adjustment of a load characteristic in an electric power system using a STATCOM controller wherein the STATCOM model is given by DÅ¼âˆ’M{dot over (w)}+Rz+J ( u ) zâˆ’R 1 w+J 1 ( u ) w=Îµ, where z = [ i sd i sq V dc ] , â¢ w = [ i Ld i Lq 0 ] , â¢ M = [ L 0 0 0 L 0 0 0 0 ] , â¢ J 1 â¡ ( u ) = [ 0 - Ï‰ â¢ â¢ L 0 Ï‰ â¢ â¢ L 0 0 - 1.5 â¢ u d - 1.5 â¢ u q 0 ] , â¢ R 1 = [ R 0 0 0 R 0 0 0 0 ] , L=the Lagrangian term of the STATCOM EL model, D,M =the Rayleigh disruptive term of the STATCOM EL model, R,R l =the dissipation term of the STATCOM EL model, J,J l =the interconnection term of the STATCOM EL model, Ï‰=dÎ¸/dt=the angular speed of the ac system, Î¸=the angle of the STATCOM bus voltage, Îµ=the external force term of the STATCOM EL model, i sd ,i sq =the d-q axis current through a loss resistor ( 114 ) and a loss inductor ( 115 ) under the direct-quadrature rotating frame, i Ld ,i Lq =the d-q axis current through the changeable load under the direct-quadrature rotating frame, V dc =the DC side voltage across a coupling capacitor ( 113 ) and the loss resistor, u d ,u q =the d-q axis control input of converter ( 106 ); designing a STATCOM controller for controlling current in said electric power system on the basis of passivity-based control using said STATCOM model and technologies of energy shaping and damping injection and using controlled current to regulate a load bus voltage; wherein said damping injection changes the STATCOM model to DÅ¼*âˆ’M{dot over (w)}+Rz*+J(u)z*âˆ’R 1 w+J 1 (u)wâˆ’R m {tilde over (z)}=Îµ, where R m = [ R m â¢ â¢ 1 0 0 0 R m â¢ â¢ 2 0 0 0 R m â¢ â¢ 3 - 1 ] , and wherein the energy shaping error signal is defined as {tilde over (z)}=zâˆ’z*=[i sd âˆ’i* sd i sq âˆ’i* sq V dc âˆ’V* dc ] T ; and controlling current in said electric power system on the basis of passivity-based control to regulate the load bus voltage with the STATCOM controller.