US 11,705,715 B2
Method, electrical circuit arrangements and insulation monitoring devices for an interference-resistant insulation monitoring of an ungrounded power supply system having a converter
Dieter Hackl, Fernwald (DE)
Assigned to Bender Gmbh & Co. KG, Gruenberg (DE)
Filed by Bender Gmbh & Co. KG, Gruenberg (DE)
Filed on Jul. 10, 2018, as Appl. No. 16/30,918.
Claims priority of application No. 10 2017 211 845.8 (DE), filed on Jul. 11, 2017.
Prior Publication US 2019/0020187 A1, Jan. 17, 2019
Int. Cl. H02H 3/17 (2006.01); G01R 27/18 (2006.01)
CPC H02H 3/17 (2013.01) [G01R 27/18 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A method for an interference-resistant insulation monitoring of an ungrounded power supply system having a converter, comprising the method steps:
applying a measuring voltage between an active conductor of the power supply system and ground and detecting a measuring signal driven by the measuring voltage,
detecting a displacement voltage between an active conductor of the power supply system and ground on an input side of the converter,
filtering a switching-frequent signal portion, which is generated by the converter, from the detected displacement voltage,
evaluating the filtered, switching-frequent signal portion,
triggering a switching signal should the evaluation of the switching-frequent signal portion yield that the switching-frequent signal portion surmount a critical amplitude value.