SWITCHED-MODE POWER SUPPLY FOR POWERING A FREQUENCY CONVERTER

• US 20160315546A1
• Filed: 04/05/2016
• Published: 10/27/2016
• Est. Priority Date: 04/23/2015
• Status: Active Grant

• Current Assignee: Dr. Johannes Heidenhain GmbH
• Original Assignee: Dr. Johannes Heidenhain GmbH
• Inventors: Heinrich, Simon, von Le Suire, Christian
• Granted Patent: US 9,923,452 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02M 1/0006 Arrangements for supplying an adequate voltage to the control circuit of converters
• CPC Class Codes: H02M 1/36 Means for starting or stopping converters
• CPC Class Codes: H02M 3/3353 having at least two simultaneously operating switches on the input side, e.g. "double forward" or "double (switched) flyback" converter

Abstract

A switched-mode power supply for supplying an operating voltage to a frequency converter includes a supply capacitor configured to supply the operating voltage to a control device for generating control signals for semiconductor switches of the switched-mode power supply. The supply capacitor is chargeable through a start-up circuit from a DC link of the frequency converter. The start-up circuit includes a current regulator that is configured to control a total current from the DC link to the start-up circuit.

Claims

1. A switched-mode power supply for supplying an operating voltage to a frequency-converter, the switched-mode power supply comprising a supply capacitor configured to supply the operating voltage to a control device for generating control signals for semiconductor switches of the switched-mode power supply, the supply capacitor being chargeable through a start-up circuit from a DC link of the frequency converter, the start-up circuit including a current regulator that is configured to control a total current from the DC link to the start-up circuit.

2. The switched-mode power supply as recited in claim 1, wherein the current regulator is configured to maintain the total current constant, and wherein a valve of the current regulator that controls the total current is configured to act only on a first partial current which, together with a second partial current, makes up the total current.

3. The switched-mode power supply as recited in claim 2, wherein the second partial current includes a leakage current of the control de vice and a charging current of the supply capacitor.

4. The switched-mode power supply as recited in claim 1, further comprising two DC link capacitors connected in series in the DC link and configured to provide a mid-potential between an upper and a lower potential of the DC link, the supply capacitor being connected, at each of its two terminals, to a respective one of the upper and lower potentials of the DC link through a respective high-resistance resistor chain so that the start-up circuit and the control device are at the mid-potential.

5. The switched-mode power supply as recited in claim 4, wherein the control device is galvanically isolated from the semiconductor switches by gate driver transformers.

6. The switched-mode power supply as recited in claim 4, wherein a first terminal of a primary winding is connected to the mid-potential, and a second terminal of the primary winding is switchable between the upper and lower potentials of the DC link by means of the semiconductor switches.

7. The switched-mode power supply as recited in claim 1, further comprising, on a secondary side, a secondary winding and a self-supply winding whose rectified output voltages are buffered by a respective first and second buffer capacitor and fed to a voltage regulator which allows the control device to be supplied with the operating voltage during operation of the switched-mode power supply.

8. The switched-mode power supply as recited in claim 7, wherein the first buffer capacitor of the secondary winding has a capacitance that is a factor of at least 1,000 higher than that of the second buffer capacitor of the self-supply winding.

9. The switched-mode power supply as recited in claim 8, wherein the first buffer capacitor is isolated by a diode from the second buffer capacitor.