Converter circuit arrangement having a DC intermediate circuit

• US 6,288,915 B1
• Filed: 08/11/2000
• Issued: 09/11/2001
• Est. Priority Date: 12/23/1997
• Status: Expired due to Term

• Current Assignee: ABB Schweiz AG (ABB Limited)
• Original Assignee: Asea Brown Boveri AG (ABB Limited)
• Inventors: Stulz, Christian, Stemmler, Christoph
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Vu, Bao Q.
• Application Number:
  US09/581,942
• Time in Patent Office: 396 Days
• Field of Search: 63/34, 63/35, 63/37, 63/40, 63/44, 63/47, 63/48
• US Class Current: 363/34
• CPC Class Codes: H02M 1/12 Arrangements for reducing harmonics from ac input or output

Abstract

A converter circuit arrangement having a DC intermediate circuit (3) includes a transformer (8) having at least two windings (9 and 10). This transformer (8) is connected in the intermediate circuit (3) such that the undesirable, unbalanced current components lead to magnetization of the transformer core and are thus reduced. A grounded LC filter (Lf, Cf) is connected upstream of the load (6) and produces a sinusoidal voltage across the load (6). In consequence, the circuit can be used with any desired rotating-field machines, and thus also for retrofitting existing systems.

Claims

1. A converter circuit arrangement comprising:

(a) a first converter which is connected to a voltage supply network by conductors;

(b) a second converter which is connected to a load by conductors;

(c) a DC intermediate circuit having a positive path and having a negative path, via which intermediate circuit the first converter is connected to the second converter;

(d) a transformer having at least first, second and third windings which are magnetically coupled to one another,

one of the first and second windings being inserted into each one of the conductors between the voltage supply network and the first converter, or

the first winding being inserted into the positive path and the second winding being inserted into the negative path of the intermediate circuit, or

one of the first and second windings being inserted into each one of the conductors between the second converter and the load,

the third winding being magnetically coupled to the first and second windings and being terminated by an attenuating resistor; and

(e) a grounded LC filter having filter inductances and filter capacitors, the grounded LC filter being connected between the load and the second converter, wherein the filter inductances are inserted in the conductors between the second converter and the load and the filter capacitances are inserted between a) the conductors between the second converter and the load and b) a common ground.

2. The converter circuit arrangement as claimed in claim 1, wherein the windings of the transformer are oriented in parallel, so that a current flowing in one winding in the direction of the load produces the same transformer magnetization direction as a current flowing in another winding in the direction of the load.

3. The converter circuit arrangement as claimed in claim 1, wherein the second converter has a three-point inverter topology, and a neutral point is formed by two internediate-circuit capacitors which are connected in series between the positive path and the negative path.