Reducing Astable Relay Power Consumption by the Use of a Constant-Current Buck Converter

Conference: PCIM Europe 2018 - International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management
06/05/2018 - 06/07/2018 at Nürnberg, Deutschland

Proceedings: PCIM Europe 2018

Pages: 7Language: englishTyp: PDF

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Heidinger, Michael; Simon, Christoph; Denk, Fabian; Kling, Rainer; Heering, Wolfgang (Karlsruhe Institute of Technology (KIT), Germany)

Relays are essential components for the safety of power converters. Photovoltaic AC inverters require two astable relays per line wire, resulting in eight relays on the AC side. As the race for efficiency continues, not only in solar converters, reducing every watt of loss becomes mandatory. Relays require a high power at turn on, whereas in on-state, a reduced drive current is sufficient. This paper compares the linear constant current relay driver, the constant current buck converter and the voltage buck converter and shows a power consumption reduction by 87%. For one specific relay, the turn-on-behavior is analyzed and a calculation method for the power on timing is shown.