GB1026074A - Improvements in or relating to alternating-current voltage regulating devices - Google Patents

Abstract

1,026,074. Controlled non-linear inductors. S. BROD. Feb. 28, 1964 [April 23, 1963], No. 15989/63. Heading H3B. [Also in Division G3] An A.C. voltage regulating circuit, Fig. 1, has its input terminals 10, 11 coupled to its output terminals 22, 23 through a tapped transformer 14 and controlled saturable reactors 19, 20, each reactor being controlled in accordance with the distribution of control current between the reactor control windings 39, 40 and having its main winding 17, 18 connected between a common terminal 21 and a respective voltage tap 15, 16 of the transformer, so that a range of output voltage values is available between the upper limiting voltage of tap 15 and the lower limiting voltage of tap 16. The transformer may be either double wound or an autotransformer as shown. The distribution of current between the control windings is determined by transistors 43, 44 arranged in a complementary conducting relationship, the limits of operation being transistor 44 fully conductive with transistor 43 cut-off and vice versa. Each transistor is shunted across a respective control winding, the upper limit of output voltage from tap 15 being obtained when transistor 43 is cut-off so that reactor 19 is fully saturated and reactor 20 unsaturated. Similarly, the lower voltage limit from tap 16 is reached when transistor 44 is cut-off. The rectified outputs of a tapped secondary winding 28 of a further transformer 24 provide the control winding and transistor currents. A further secondary winding 50 supplies a voltage stabilizing bridge network 55 comprising fixed resistors 56, 57, 60 and a Zener diode 59, the output from the bridge being taken between terminal 62 and an adjustment potentiometer 58 to control the conductivity of a transistor 48 in the base circuit of transistor 43, and hence the conductivity of the latter transistor. Each control winding is shunted by a rectifier 41, 42 to suppress induced voltages and the bridge network is shunted by a smoothing capacitor 61. In a modification, Fig. 2 (not shown), the reactors are connected on the input side of the transformer 14.