Abb Patent Gmbh

Ascom Energy Systems Ag

Delta Energy Systems (switzerland) Ag

Johann W Kolar

Wilhelm Korb

An apparatus for converting a three-phase voltage system to a DC voltage is supported by an output capacitor and a star circuit. On the input side of filter capacitors is a controllable three-phase bridge and at a positive output of the bridge circuit, a current-stabilizing inductance is included, which, in conjunction with a step-up controller diode and a step-up controller transistor, forms a DC voltage/DC voltage step-up controller which is integrated in the converter structure. The phase arms of the three-phase bridge have an identical structure and their conductance state can be controlled by control switches. In order to produce an output voltage from the system which is below the mean value of the maximum output voltage of the bridge circuit, the step-up controller transistor remains in the switched-off state, and a voltage value which is above the maximum output voltage is formed.

Unidirectional three phase pulse controlled rectifier system with failed phase voltage operation

The invention relates to an apparatus for initial charging of the output capacitors of a three-phase three-point pulsed rectifier system. According to the invention, a thyristor is arranged in each phase between the input terminal and is connected in the current flow direction to the anode of the freewheeling diode, and an initial charging path is connected in parallel with this thyristor. The circuit for actuating the thyristor is activated after completion of the initial charging; the reference voltage is applied to the negative input of the comparator. When the potential profile which is present at the tap of the voltage divider at the input of the bridge path rises, the voltage at the positive comparator input slightly before the zero crossing of the mains voltage to positive values exceeds the reference voltage, thus initiating switching of the comparator output and/or actuation of the thyristor and, after the mean bridge branch input potential passes through zero, the actuation of the thyristor is suppressed once again. The thyristor is thus triggered only within that mains voltage half-cycle in which it is required for carrying the mains phase current.

Device and method for line-voltage dependent thyristor controlled pre-charging of output capacitors in a three-level pulse rectifier system

An apparatus for conversion of a three-phase voltage system into an electrically isolated DC voltage to be predetermined freely, and a method for controlling the same, include primary and secondary circuits. Each phase of the primary circuit has a series inductance connected to one input of a bidirectional, bipolar electronic switching apparatus. Second inputs of the switching apparatuses are directly connected. A positive primary voltage rail is fed through diodes, and a negative primary voltage rail is fed through other diodes. One winding end of a primary winding of a transformer is connected to a line connecting the second inputs of the switching apparatuses. A power transistor, which is connected to the positive primary voltage rail on the collector/drain side and has an antiparallel connected diode, is connected to another winding end of the primary winding. A further power transistor, which is connected to the negative primary voltage rail on the emitter/source side and has an antiparallel connected diode, branches off from the other winding end of the primary winding. A secondary winding of the transformer is connected to input terminals of a single-phase diode bridge having a capacitance disposed between output terminals and smoothing the output voltage as a full-wave bridge circuit.

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Vienna, Austria

Johann W Kolar