Nonlinear dynamics and switching time bifurcations of a thyristor controlled reactor circuit

We study a thyristor controlled reactor circuit used for static VAR control of utility electric power systems. The circuit exhibits switching times which jump or bifurcate as fold or transcritical bifurcations. We study the nonlinear dynamics of the circuit using a Poincare map and demonstrate that the Poincare map has discontinuities and is not invertible. The circuit has multiple attractors, moreover, the basin boundary separating the basins of attraction intersects with the Poincare map discontinuities. These novel properties illustrate some of the basic features of dynamical systems theory for thyristor switching circuits.