Multi-phase AC/AC Step-down Converter for Distribution Systems

• US 20150229227A1
• Filed: 02/07/2014
• Published: 08/13/2015
• Est. Priority Date: 02/07/2014
• Status: Active Grant

• Current Assignee: ABB Schweiz AG (ABB Limited)
• Original Assignee: ABB Technology AG (ABB Limited)
• Inventors: Aeloiza, Eddy C., Burgos, Rolando P.
• Granted Patent: US 9,800,167 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02M 5/04 by static converters controlling transformers, reactors or choke coils, e.g. by tap changing H02P13/00
• CPC Class Codes: H02M 5/293 using semiconductor devices only

Abstract

A step-down AC/AC converter for use in an electric distribution system includes at least one chopper circuit for each one of a plurality of phases of the AC power, each chopper circuit including a four-quadrant switch coupled in series between primary and secondary sides of the chopper circuit and a current-bidirectional two-quadrant switch coupled between the secondary side of the chopper circuit and a common node. Each current-bidirectional two-quadrant switch is oriented in the same direction, with respect to the secondary side of the corresponding chopper circuit and the common node. The converter further includes a control circuit configured to pulse-width-modulate control inputs of the switches, to convert a first multiphase AC voltage at the primary sides of the chopper circuits to a second multiphase AC voltage at the secondary sides of the chopper circuits, the second multiphase AC voltage being lower in voltage than the first multiphase AC voltage.

Claims

1. A step-down converter for converting multi-phase alternating current (AC) power, the step-down converter comprising:

at least one chopper circuit for each one of a plurality of phases of the AC power, each chopper circuit comprising a four-quadrant switch coupled in series between primary and secondary sides of the chopper circuit, each chopper circuit further comprising a current-bidirectional two-quadrant switch having a first end coupled to the secondary side of the chopper circuit, wherein a second end of each of the current-bidirectional two-quadrant switches is coupled to a common node and wherein each of the current-bidirectional two-quadrant switches is oriented in the same direction, with respect to the secondary side of the corresponding chopper circuit and the common node; and

a control circuit connected to the chopper circuits and configured to pulse-width-modulate control inputs of the four-quadrant switches and the current-bidirectional two-quadrant switches, to convert a first multiphase AC voltage at the primary sides of the chopper circuits to a second multiphase AC voltage at the secondary sides of the chopper circuits, the second multiphase AC voltage being lower in voltage than the first multiphase AC voltage and having an equal frequency.

2. The step-down converter of claim 1, wherein the four-quadrant switch in each chopper circuit comprises a first pair of integrated-gate bipolar transistor (IGBT) devices including antiparallel freewheeling diodes and connected in a back-to-back configuration.

3. The step-down converter of claim 2, wherein the four-quadrant switch in each chopper circuit comprises a second pair of IGBT devices connected in a back-to-back configuration and coupled in series with the first pair of IGBT devices, each of the second pair comprising an antiparallel freewheeling diode.

4. The step-down converter of claim 1, wherein each of the current-bidirectional two-quadrant switches consists of a single integrated-gate bipolar transistor (IGBT) device including an antiparallel freewheeling diode.

5. The step-down converter of claim 1, wherein each of the current-bidirectional two-quadrant switches consists of two or more integrated-gate bipolar transistor (IGBT) devices including antiparallel freewheeling diodes, wherein the two or more IGBT devices are connected in series and oriented in the same direction with respect to the secondary side of the corresponding chopper side and the common node.

6. The step-down converter of claim 1, wherein the step-down converter comprises at least two chopper circuits for each phase, the at least two chopper circuits being connected in parallel with respect to their primary and secondary sides.

7. A step-down converter for converting multi-phase alternating current (AC) power, the step-down converter comprising at least two converter stages connected in cascade, wherein each of the at least two converter stages comprises:

at least one chopper circuit for each one of a plurality of phases of the AC power, each chopper circuit comprising a four-quadrant switch coupled in series between primary and secondary sides of the chopper circuit, each chopper circuit further comprising a current-bidirectional two-quadrant switch having a first end coupled to the secondary side of the chopper circuit, wherein a second end of each of the current-bidirectional two-quadrant switches is coupled to a common node and wherein each of the current-bidirectional two-quadrant switches is oriented in the same direction, with respect to the secondary side of the corresponding chopper circuit and the common node; and

a control circuit connected to the chopper circuits and configured to pulse-width-modulate control inputs of the four-quadrant switches and the current-bidirectional two-quadrant switches, to convert a first multiphase AC voltage at the primary sides of the chopper circuits to a second multiphase AC voltage at the secondary sides of the chopper circuits, the second multiphase AC voltage being lower in voltage than the first multiphase AC voltage.