Frequency converter
AssigneeSemikron Elektronik GmbH & Co. KG
InventorDejan Schreiber
Life of this patent
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Abstract
The invention relates to a frequency converter for an energy flow from a three-phase network to a consumer for medium and high output voltages, with variable frequency, current and voltage outputs, fed from secondary windings of a transformer with one or more cells per output phase (R, S, T). For each output phase, each identical cell has a diode input rectifier circuit, an active harmonic filter, an intermediate-circuit capacitance, and a three-point DC/AC converter on the output side.
Claims6
A Frequency converter for converting energy flow from a three-phase network to a three-phase consumer supply at variable frequency, current and voltage outputs, comprising:
- at least one cell per phase of said three-phase consumer supply;
- all of said cells being identical;
- each of said cells includes:
- a diode input rectifier circuit;
- an active harmonic filter;
- an intermediate-circuit capacitance;
- a three-point DC/AC converter on an output side;
- said DC/AC converter comprising NPC diodes;
- said active harmonic filter includes at least two input inductors, at least two series-connected controllable switches and at least two diodes for receiving sinusoidal line current input and for generating a controllable intermediate-circuit voltage for said intermediate-circuit capacitance;
- said intermediate-circuit capacitance has two series-connected capacitor groups;
- and
- a neutral lead of a star circuit formed from said secondary windings is connected to a central point of said series-connected controllable switches, a center point of said series-connected capacitor groups and said NPC diodes of said three-point DC/AC converter.
A Frequency converter for an energy flow from a three-phase network to a consumer with variable frequency, current and voltage outputs, comprising:
- an input transformer;
- means for feeding said energy to secondary windings of said transformer;
- at least three identical cells connected to said secondary winding of each phase of said three-phase network;
- said cell comprising:
- a diode input rectifier circuit;
- an active harmonic filter;
- an intermediate-circuit capacitance;
- a DC/AC converter on an output side;
- wherein an output of said DC/AC converter for said at least three identical cells for each phase are serially interconnected, and said serially connected DC/AC converter outputs for each phase are connected to a common star point:
- said active harmonic filter includes:
- an input inductor;
- at least one controllable switch;
- at least one diode for receiving a sinusoidal line current input and for generating a controllable intermediate-circuit voltage for said intermediate-circuit capacitance.
Dependencies are inferred from the claim text.