Siemens Ag Osterreich

Siemens Aktiengesellschaft

Wilhelm Reischer

Heinz Pichorner

Franz Wöhrer

Walter Kolzer

Leo Karl

Vladislav Damec

A protective circuit (SCH) for a line-commutated thyristor bridge (B, B'), which is designed for feeding energy of a power circuit connected to the bridge and also for feedback from this circuit, and which is connected between the thyristor bridge and the power circuit. In a series branch of the protective circuit, there is at least one IGBT transistor (GTGT), which is biased in the feedback direction with an inverse-parallel diode (DDD), and which can be deactivated for the appearance of a tipping recognition signal (s, U), which is supplied by a control circuit (AST) associated with the transistor.

Protective circuit for a network-controlled thyristor bridge

Current transformer arrangement for three-wire three-phase systems to

In a circuit arrangement for an alternating control a PI controller comprises a first operational amplifier having an output connected via a resistor to the non-inverting input of a second operational amplifier wired as an impedance transformer. The output of the second operational amplifier is fed back via an RC stage to the inverting input of the first operational amplifier. The output of a second controller is connected via a decoupling diode to a junction between the decoupling resistor and the non-inverting input of the second operational amplifier. Positive as well as negative signals can occur at the output of the first operational amplifier, and discontinuities in control during a switch over between the two controllers are avoided.

Circuit arrangement for an alternating control

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Vienna, Austria

Wilhelm Reischer