Voltage converter apparatus having output regulating means

Claim 1

In a voltage converter system including (a) switching circuit means including a pair of switching devices (Tr1, Tr2) connected with a unidirectional voltage source, each of said switching devices including a control terminal and being alternately operable between conducting and non-conducting conditions; (b) converter transformer means (T1) for cyclically operating said switching devices between opposite conducting and non-conducting conditions, respectively, said converter transformer means including a pair of switching windings (T1a, T1b) connected with the control terminals of said switching devices, respectively said converter transformer means also including a load winding (Tlc); and (c) load circuit means for connecting said load winding with a pair of output terminals (13) adapted for connection with a load, whereby a periodically inverted voltage is produced across said load winding, said load circuit means including a load current path in which said load winding is connected in series, whereby the reflected load current flowing in said load current path and said load winding induces a corresponding voltage in that switching winding which is associated with the switching device that is conductive at a given time; the improvement which comprises regulating means for maintaining the output voltage appearing across said output terminals at a regulated value, said regulating means including (d) means in said load circuit means defining an inductance in series with said load winding, whereby owing to the rate of change characteristic of said inductance defining means, a variation in the reflected load current flowing through said load winding produces a corresponding change in the leading portion of the inductance current waveform, thereby to produce an opposite variation in the trailing waveform portion and in the complementary output voltage appearing across said output terminals; and (e) means for varying the switching operation of said switching devices, said converter transformer means further including a control winding (T1d) magnetically coupled with said switching and load windings, said switching operation varying means including (1) drive pulse generating means (Tr3, Tr4) for supplying drive pulses to said control winding to induce voltages in said switching windings for operating said switching devices between their conductive and non-conductive conditions, respectively; and (2) short circuit means (Tr8, Tr9) for short circuiting said control winding to control the instants of switching of said switching devices.