Stability analysis of controlled rectifiers

A new approach to the experimental investigation of the steady-state stability of controlled rectifiers based on the measurement of the angle between sequential ignitions of the valves is discussed. The statistical treatment of the experimental data shows a special dependence on the deviation of the firing impulses and the amplifier gain factor. Such dependence provides a physical definition for the rectifier stability and its boundaries. The experimental investigation of the increasing of the impulse deviation with an increase of the gain factor has shown that the physical reason for such deviation change and rectifier instability is an increase of a varying component in the control voltage of the firing system input. Analyzing the data about the well-known forms of the rectifier´s instability-harmonic, ripple, and low-frequency-it can be concluded that the physical reason for the stability loss is the same: increase of alternating component in the firing control voltage. In conclusion, a new classification of rectifier instability forms is discussed.