Circuit arrangement for driving the switching element of a delta-connected isolating transformer

摘要

It is intended to specify a circuit arrangement for driving the switching element (V1) of a delta-connected isolating transformer, whose transformer (T1) has a diode (D1, D2) in the secondary load circuit both on the high-voltage side and at the neutral point, when the current (i2) in the load circuit becomes zero, which circuit arrangement operates without any delay and at the same time, nevertheless, provides potential isolation between a zero-current detecting element in the load circuit and the control circuit for the switching element (V1). For this purpose, the neutral point diode (D2) is supplemented towards the load by a further diode (D2') which is polarised in the same direction and is bridged by a series circuit comprising a non-active resistor (R2) and the primary winding of a transformer (T2). The secondary winding of the transformer (T2) is connected to a storage element (S1) which is connected to the control input of the switching element (V1). <IMAGE>