# US 8,786,450 B2 · Method for identifying dirt and/or dew on components of a voltage intermediate circuit converter

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- Number: US 8,786,450 B2
- Document ID: US8786450B2
- Status: Granted
- Kind: B2
- Application number: 13/320,326
- Filed: 2010-01-29
- Published: 2012-05-03
- Granted: 2014-07-22
- Earliest claimed: 2009-05-14
- Assignees: Siemens Aktiengesellschaft
- Applicants: Christian Dietrich; Werner Fischer; Jörg Hassel; Marc Hiller; Carsten Probol; Rainer Sommer
- Inventors: Christian Dietrich; Werner Fischer; Jörg Hassel; Marc Hiller; Carsten Probol; Rainer Sommer
- Web page: https://patentgrep.com/patent/US8786450B2

## CPC

- H02M 1/32: Means for protecting converters other than automatic disconnection
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)

## Abstract

The invention relates to a method for identifying dirt and/or dew on components of a voltage intermediate circuit converter. According to the invention, the temporal curve of a partial discharge pulsed current is detected at least during a precharging process of an intermediate circuit capacitor of the voltage intermediate circuit converter comprising at least one capacitor, wherein a frequency spectrum is calculated from said current pulse, and wherein depending of the result, a dirt warning and/or a dew warning is activated. Thus, the degree of dirt and/or dew of said voltage intermediate circuit converter can be determined at least during a charging process of an intermediate circuit capacitor of a voltage intermediate circuit converter, thereby preventing a breakdown including the consequences thereof.

## Claims

### Claim 1

A method for identifying contamination and/or condensation on components of a voltage intermediate circuit converter, comprising the steps of:
pre-charging an intermediate circuit capacitor of the voltage intermediate circuit converter, which comprises at least one capacitor, with a stepwise increasing voltage,
measuring a temporal curve of a partial discharge pulsed current at each voltage step of the stepwise increasing voltage,
computing a frequency spectrum for said pulsed current, and
activating, depending on the computed frequency spectrum, at least one of a contamination warning and a condensation warning.

### Claim 2 (depends on 1)

The method of claim 1, wherein the temporal curve of the partial discharge pulsed current is measured during operation of the converter following pre-charging.

### Claim 3 (depends on 1)

The method of claim 1, wherein the temporal curve of the partial discharge pulsed current is measured when an intermediate circuit voltage of the voltage intermediate circuit converter is at at least 60% or more of a nominal intermediate circuit voltage of the voltage intermediate circuit converter.

### Claim 4 (depends on 1)

The method of claim 1, wherein the pre-charging process is terminated, depending on the computed frequency spectrum.