Bidirektionaler AC/DC-Netzkoppler Bidirectional isolating AC/DC converter for coupling DC grids with the AC mains based on a modular approach

Transcription

1 IISB JAHRESTAGUNG & CLUSTER-SEMINAR NIEDERSPANNUNGS-GLEICHSTROMNETZE Bidirektionaler AC/DC-Netzkoppler Bidirectional isolating AC/DC converter for coupling DC grids with the AC mains based on a modular approach Stefan Zeltner, Stefan Endres, Jens Schmenger stefan.zeltner@iisb.fraunhofer.de Fraunhofer Institute for Integrated Systems and Device Technology IISB Schottkystrasse Erlangen Germany Tel , Fax Page 1

2 Content Introduction Future high voltage DC grid within buildings AC/DC in future DC micro grids Control of complex power electronic systems High power density systems State of art central control approach Proposed solution Decentralized control approach Using intelligent power units Advantages of proposed solution 3.7 kw bidirectional isolating AC/DC realized with IPUs Application DC Micro Grid Control System for optimized usage of renewable energy in buildings Summary Page 2

3 Introduction Future high voltage DC grid within buildings Page 3 Bidirectional isolating AC/DC converters are used in smart micro or nano grids for a safe coupling of the DC grid with the AC mains.

4 Introduction AC/DC in future DC micro grids Topology example: Page 4 Bidirectional isolating AC/DC converter is a complex power electronic system. totem pole bridgeless PFC with smoothing transformer bidirectional isolating resonant converter

5 Introduction Control of complex power electronic systems Microcontroller (FPGA, DSP ) Gate Drive Circuit? G D ON: +15 V S OFF: -5 V 12x! 400 V Isolation barrier Transfer of energy for gate drive and data transfer necessary! 0 V e.g kv/us Page 5

6 PCB for power switches PCB for passive components Introduction High power density systems PCB for control logic PCB for gate-driver Different devices need different joining technologies. Power switches passive components Goal for high power density systems: no air between devices Examples for state of art high power density systems. Page 6

7 Introduction State of art central control approach Page 7

8 Proposed solution Decentralized control approach Page 8

9 Proposed solution Using intelligent power units Gate drive unit with uc Intelligent gate drive unit Integration of power module and passive devices Intelligent power unit (IPU) Change position of safe isolation barrier Introducing 2-wire connection Plug&Play IPU for modular system designs Page 9

10 Advantages of proposed solution Page 10 Only 2-wires to control and supply complete IPU (e.g. with 4/6/8 power switches) Precise timing of different IPUs possible by synchronized 2-wire interfaces Safe galvanic isolation by single magnetic core Insulation voltage only defined by design of a single transformer Reduced requirements to drive high side switches (only functional safety requirements) Lowest possible coupling capacity (very high common-mode transient immunity proofed by tests)

11 3.7 kw bidirectional isolating AC/DC realized with IPUs IPUs The isolating AC/DC is realized with 3 nearly identical IPUs. Page 11 and with 3 more plug&play IPUs 3 additional DC/DC converters integrated. Battery Rack

12 3.7 kw bidirectional isolating AC/DC realized with IPUs Efficiency Measurements Page 12 eta sum 93% (with low cost Si IGBT solution)

13 3.7 kw bidirectional isolating AC/DC realized with IPUs EMI Filter optimization with smoothing transformer without smoothing transformer Page 13

14 Application DC Micro Grid Control System for optimized usage of renewable energy in buildings Page 14

15 Summary Problem to control complex power electronic systems, i.e. with a lot a active switches (e.g. bidirectional, isolating AC/DC converter) was shown. Problem can be solved by using a decentralized control approach based on novel intelligent power units (IPUs) with a 2-wire interface for integrated power and signal transfer. Proof of concept: shown on the example of a 3.7 kw bidirectional isolating AC/DC converter realized with three IPUs. AC/DC integrated in all-in-one DC micro grid control system. Page 15

16 Thank you for your attention Fraunhofer IISB Your Partner in Power Electronics Page 16