A Semi-modular-based and SiC-based Smart Transformer

Transcription

1 A Semi-modular-based and SiC-based Smart Transformer Prof. Marco Liserre Chair of Power Electronics Christian-Albrechts-Universität zu Kiel Kaiserstraße Kiel

2 Chair of Power Electronics at CAU Prof. Dr.-Ing. Marco Liserre (Lehrstuhlinhaber) Prof. Dr.-Ing. Friedrich W. Fuchs (Pens.) Dr.-Ing. Markus Andresen, Dr.-Ing. Rongwu Zhu, Dr.-Ing. Giovanni De Carne Prof. Costas Vournas, NTUA, Griechland (Lehrauftrag + Gastprofessor), Prof. Hossein Immanini, University of Tehran, Iran, Nimrod Vazquez Nava, Instituto Tecnologico de Celaya, Mexico 3 Sekretärinnen + 2 Labortechniker 20 wissenschaftliche Mitarbeiter + Studentische Hilfskräfte (HiWis) Abschlussarbeiten Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 1

3 Chair of Power Electronics at CAU Head of the Chair: Prof. Dr. Ing. Marco Liserre - Associate Prof. at Politecnico di Bari, Italy - Professor Reliable Power Electronics at Aalborg University, Denmark - Professor and Head of Power Electronics Chair at Christian-Albrechts-Universität zu Kiel, September 2013 Listed in ISI-Thomson report World s Most Influential Minds Active in international scientific organization (IEEE Fellow, journals, Vice-President, conf. organization) EU ERC Consolidator Grant (only one in EU in the field of power sys.) Created or contributed to the creation of several scientific laboratories Dr.-Ing. Rongwu Zhu Senior People of the Chair Dr.-Ing. Markus Andresen Dr.-Ing. Giovanni De Carne PhD in University of Aalborg Several Projects in Wind Power System 13 Journal articles PhD from CAU Kiel Visiting scholar at University of Wisconsin, Madison (USA), Journal articles PhD from CAU Kiel Visiting scholar at Georgiatech (USA), Journal articles Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 2

4 Chair of Power Electronics People Funding Cooperation with 20 companies 60 articles every year (20 in journals) 50 (Year) 2 Mill Euro (Year) Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 3

5 Chair of Power Electronics Competence in PE Wide-Band-Gap Semiconductors Isolated DC/DC-Converter Control of Inverters Multilevel Modular Converters Lifetime and Reliability Applications Electric Vehicles, Electrical Drives, Aerospace Electrical Vehicles, Active Grid, Aerospace Industrial Drives, Active Grid, HVDC, Power Quality, Wind Energy, Electrical Vehicle, Aerospace Wind Energy, Active Grid, HVDC Wind Energy, Industrial Drives, Active Grid, HVDC, Aerospace Chair of Power Electronics Marco Liserre 4

6 Grid Integration of inverters in PSCAD Features: Test of inverter in realistic grid conditions in one of the seven inverters RTDS with 2 racks Power Amplifier voltage or current controlled 7 inverters controlled through Dspace Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 5

7 Thermal Analysis of power converters Setup for Thermal Characterization of power electronic Converters (TC-PEC) High speed IR Camera with positioning system, AC & DC Voltage Sources, Electronic loads, Oscilloscope, Power Analyzer, Synchronization & Control system IR-camera with positioning system for junction temperature measurement in modular power converters. Chair of Power Electronics Marco Liserre 6

8 Medium-Voltage (MV) Laboratory Planned Contruction Work in Building (Stand Oktober 2015). Planned test for the MV Lab Chair of Power Electronics Marco Liserre 7

9 Table of Contents Smart Transformer in the electric grid Semi-modular topologies Comparison between MMC and CHB Comparison between DAB and QAB Results of the actual prototype Reliability/Maintenance challenge of the Smart Transformer Smart Transformer and Solid State Transformer tailored for the grid Chair of Power Electronics Marco Liserre 8

10 Table of Contents Smart Transformer in the electric grid Semi-modular topologies Comparison between MMC and CHB Comparison between DAB and QAB Results of the actual prototype Reliability/Maintenance challenge of the Smart Transformer Smart Transformer and Solid State Transformer tailored for the grid Chair of Power Electronics Marco Liserre 9

11 What is the Smart Transformer? The Smart Transformer is: a power electronics based transformer a power system management node a link to different ac or dc infrastructures a possible storage-integration technology a link to other energy sources (gas, heat, hydrogen) a support for the EV infrastructure The Smart Transformer relieves the demand on single renewable sources and increases the capacity of electrical lines Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 10

12 Impact of the Smart Transformer Harbours Charging stations Wind/PV systems Data centers centralized peak decentralize d peak massive investments to modernize the electric grid: Line miles 70 s - Higher mobility of people - Electric vehicles charging infrastructure - Renewables Energies - Booming of internet -> large data centres Smart Infrastructures are also lighter infrastructures Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 11

13 Power electronics based transformer in traction application Traditional solution LF transformer (16 2/3 Hz) very bulky and heavy Low efficiency: 90 ~ 92 % Around 7tons Main concern: Reduce volume and weight Efficiency improvement Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 12

14 Power electronics based transformer in distribution application The Smart Transformer Main requirements Replace the traditional LF distribution tranformer HF/MF isolation Provide additional functionalities Functionalities Voltage sag and harmonics compensation Load voltage regulation Disturbance Rejection Power Factor Correction VAR Compensation and Active filtering Overload and short-circuit protection Chair of Power Electronics Marco Liserre 13

15 Smart Transformer in the electric grid The Smart Transformer features shall be: LV and MV DC-links available Advanced control of all the three-stages The system should be able to work even with faulty modules During partial loading conditions it should be able to fully use its rating for other services Chair of Power Electronics Marco Liserre 14

16 Smart Transformer in the electric grid Smart Transformer Voltage support (steady state and LVRT) Reactive power compensation at HV/MV substation Power quality improvements Islanding control (high DG in LV) Integration of EV-charging stations Integration of storage for dispatching Reverse Power Flow limitation Impedance identification Load identification Reverse Power Flow limitation ST overload control Soft-load reduction Damping ofharmonics and resonances LV-side power quality Chair of Power Electronics Marco Liserre 15

17 Challenges of the DC-DC Stage DC-DC Stage: The most challenge stage Isolation Efficiency Cost Deserves more attention High voltage Isolation High Input voltage High output current Galvanic Isolation in Medium/High frequency Power flow control dc link control Dc breacker feature (short circuit current proctection) Chair of Power Electronics Marco Liserre 16

18 Implementation: DC-DC Stage Operate at high frequency and high power Most challenging converter: high voltage in the MV side and current in the LV side. Dual-Active-Bridge (DAB) Series-Resonant Converter (SRC) Multicell converter Less number of HF transformer Operates similarly to eh DAB converter Easy to control (degree of freedom) Efficiency: ~ 97% Open loop operation (no control / less sensors) Efficiency: ~ 98% Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 17

19 DC-DC Stage: Implementation Concept Non-Modular Vs Modular Fewer number of components High Voltage WBG devices Simple control/communication system Low voltage/current rating semiconductors Scalability in voltage/power Fault tolerance capability Reduced dv/dt and di/dt Chair of Power Electronics Marco Liserre 18

20 Challenges of the DC-DC Stage DC-DC Stage: Building Block Converter High Voltage Isolation Bidirectional power flow Galvanic Isolation in Medium/High frequency Power flow control dc link control Dc breacker feature (short circuit current proctection) Efficiency Chair of Power Electronics Marco Liserre 19

21 Review on high efficiency dc-dc converter Relevant converters: Phase-shift Full-Bridge Series-Resonant Converter Dual-Active-Bridge Multiple-Active-Bridge Chair of Power Electronics Marco Liserre 20

22 Series-Resonant Converter Target: Efficiency Reliability Accurate losses modeling Automatic design - (optimum parameter selection) Wideband gap devices Fault tolerant topology Lifetime devices considerations Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 21

23 Series-Resonant Converter Overview of basic dc-dc topologies suitable to be used as a building block of the ST dc-dc stage Influence on efficiency: Wideband-gap devices plays an important role Design: correct parameters selection CAU Kiel dc-dc converter Max Eff = 98.61% Eff (@P max ) = 98.1% Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 22

24 Series-Resonant Converter Fault Tolerant Series-Resonant Converter Regulated output voltage Chair of Power Electronics Marco Liserre 23

25 Quadruple Active Bridge Overview of basic dc-dc topologies suitable to be used as a building block of the ST dc-dc stage Influence on efficiency: Wideband-gap devices plays an important role Design: correct parameters selection CAU Kiel dc-dc converter Max Eff = 97.5% (SiC) Highest efficiency of a MAB converter Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 24

26 DC/DC for the Smart Transformer Dual/Quad Active Bridge Serie Resonant Converter DAB controlability Voltage and current sensors simplicity LVDC link control VSI Chair of Power Electronics Marco Liserre 25

27 DC/DC for the Smart Transformer Dual/Quab Active Bridge DAB controls the LVDC link Serie Resonant Converter CHB controls the MVDC link and, consequenlty the LVDC link Chair of Power Electronics Marco Liserre 26

28 Electric Car Charging Station Problem The needed charging power is increasing and the peak charging power is challenging the electric grid Solution DC distribution for higher efficiency Load Control to smooth effect of the charging Chair of Power Electronics Marco Liserre 27

29 Datacenter Problem In 2016, the average cost of an unplanned outage per minute was nearly $9,000 per incident and the most expensive cost of an unplanned outage was higher than $17,000 per minute. The requested reliability for this application is % Solution Connectivity among several busses Higher reliability Chair of Power Electronics Marco Liserre 28

30 Aerospace Problem The military standard (MIL-STD-704F) has rigorous requirements on the reliability and uninterrupted operation of the aerospace power supply system. According to NPRD-95, the failure rate of the inverter is per million hours and the failure probability is in 1000 hours. Solution Higher Safety because of more connectivity Lower Volume and Weight because of less magnetic component In cooperation with Prof. G. Buticchi, Nottingham electrification center, Ninbo China Chair of Power Electronics Marco Liserre 29

31 Table of Contents Smart Transformer in the electric grid Semi-modular topologies Comparison between MMC and CHB Comparison between DAB and QAB Results of the actual prototype Reliability/Maintenance challenge of the Smart Transformer Smart Transformer and Solid State Transformer tailored for the grid Chair of Power Electronics Marco Liserre 30

32 Semi-modular topologies Modulation level Cell level Converter level System level Different modular levels can be freely combined Chair of Power Electronics Marco Liserre 31

33 Semi-modular topologies Concept of semi-modular Basic Module Modular Architecture: Basic modules are used as building blocks for the entire ST Semi-Modular Architecture: The building block is composed by several cells and a central (unreplaceable) element. In this case: Multiwinding transformer Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 32

34 Semi-modular topologies Asymmetrical vs. Symmetrical Possible configurations Generic Asymmetrical MV side: 3 cell LV side: 1 cell Symmetrical MV side: 2 cell LV side: 2 cell Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 33

35 Semi-modular topologies 1. DAB-Based Standard / Benchmark 9 MV cells 9 Units 2. Assymetrical QAB 9 MV cells 3 Units Same voltage MV side 3. Symetrical QAB (V) 10 MV cells 5 Units Same voltage MV side Less power per unit 4. Symetrical QAB (P) 6 MV cells 6 Units 1. DAB-Based 2. Assymetric QAB 3. Symetric QAB 4. Symetric QAB Same power rating / unit (V) (P) less MV cells Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 34

36 Table of Contents Smart Transformer in the electric grid Semi-modular topologies Comparison between MMC and CHB Comparison between DAB and QAB Results of the actual prototype Reliability/Maintenance challenge of the Smart Transformer Smart Transformer and Solid State Transformer tailored for the grid Chair of Power Electronics Marco Liserre 35

37 Comparison between MMC and CHB The Comparison is carried out for different blocking voltages and different grid voltages Chair of Power Electronics Marco Liserre 36

38 Comparison between MMC and CHB Chair of Power Electronics Marco Liserre 37

39 Comparison between MMC and CHB Chair of Power Electronics Marco Liserre 38

40 Optimal design of the CHB+DC/DC Chair of Power Electronics Marco Liserre 39

41 Optimal design of the CHB+DC/DC Chair of Power Electronics Marco Liserre 40

42 Optimal design of the CHB+DC/DC Chair of Power Electronics Marco Liserre 41

43 Optimal design of the CHB+DC/DC Chair of Power Electronics Marco Liserre 42

44 Optimal design of the CHB+DC/DC Chair of Power Electronics Marco Liserre 43

45 Table of Contents Smart Transformer in the electric grid Semi-modular topologies Comparison between MMC and CHB Comparison between DAB and QAB Results of the actual prototype Reliability/Maintenance challenge of the Smart Transformer Smart Transformer and Solid State Transformer tailored for the grid Chair of Power Electronics Marco Liserre 44

46 Comparison between DAB and QAB Comparative analysis: considering different semiconductor technologies 1. Design consideration Semiconductors / Capacitors / Heatsink Magnetics (wire losses and cost) Auxillaries (gate driver, power supply, communication) 2. Specifications 3. Design algorithm Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 45

47 Comparison between DAB and QAB Comparative analysis results of performance (losses/kw) and cost 1. DAB-Based 2. Assymetrical QAB 3. Symetrical QAB (V) 4. Symetrical QAB (P) Standard / Benchmark 9 MV cells 9 Units 9 MV cells 3 Units Same voltage MV side 10 MV cells 5 Units Same voltage MV side 6 MV cells 6 Units Same power rating per unit Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 46

48 Comparison between DAB and QAB But why QAB and NOT DAB? Around 20% of cost reduction when AQAB is adopted Chair of Power Electronics Marco Liserre 47

49 Comparison between DAB and QAB But why QAB and NOT DAB? Around 20% of cost reduction when AQAB is adopted Reduced number of: Auxilar components (GDU, APS and control) Semiconductors on LV side Less semiconductor on the LV side, but with higher current rating. Few impact on the cost Chair of Power Electronics Marco Liserre 48

50 Comparison between DAB and QAB But why QAB and NOT DAB? DAB and QAB have similar efficiencies (only 5% of difference in favor of the QAB) SiC offers 10% of losses reduction, but increase the cost in around 40% Chair of Power Electronics Marco Liserre 49

51 Optimal QAB design Chair of Power Electronics Marco Liserre 50

52 Table of Contents Smart Transformer in the electric grid Semi-modular topologies Comparison between MMC and QAB Comparison between DAB and QAB Results of the actual prototype Reliability/Maintenance challenge of the Smart Transformer Smart Transformer and Solid State Transformer tailored for the grid Chair of Power Electronics Marco Liserre 51

53 Results of the actual prototype Semi-modular 3 stage architecture <Semi-modular architecture> Specification: Three-phase system MVAC: 2.6 kvrms (line-to-line) LVDC: 800 Vdc Power: 100 kva (33 kva x 3) Features: Power stage: MVAC-MVDC-LVDC - MV stage: CHB - DC-DC stage: QAB Available funcionalities - Bidrectional power flow - VAr and voltage compensation in both MV/LVAC - LVDC connectivity Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 52

54 Results of the actual prototype <Developed scaled prototype> <QAB (top) and CHB (bottom)> Chair of Power Electronics Marco Liserre 53

55 Results of the actual prototype Efficiency measurement: QAB and the whole prototype (QAB+CHB) <QAB efficiency> <Whole prototype efficiency> Chair of Power Electronics Marco Liserre 54

56 New Topology: interphase use of QAB Combining them... Same unit circuit, but NEW configuration Chair of Power Electronics Marco Liserre 55

57 New Topology: interphase use of QAB Power delivered to dc-buses is always balanced Multi dc-buses easly possible Easy maintenance Chair of Power Electronics Marco Liserre 56

58 Table of Contents Smart Transformer in the electric grid Semi-modular topologies Comparison between MMC and CHB Comparison between DAB and QAB Results of the actual prototype Reliability/Maintenance challenge of the Smart Transformer Smart Transformer and Solid State Transformer tailored for the grid Chair of Power Electronics Marco Liserre 57

59 Lifetime target in various PE applications Applications Aircraft Automotive Industry motor drives Railway Wind turbines Photovoltaic plants The Different O&M program Typical design target of Lifetime 24 years (100,000 hours flight operation) 15 years (10,000 operating hours, 300,000 km) 5-20 years (40,000 hours in at full load) years (10 hours operation per day) 20 years (18-24 hours operation per day) years (12 hours per day) Applications from which companies participated in the study. Designed lifetime target for the different applications. Data source: KDEE Kassel, Chair of Power Electronics, Kiel, Investigation of reliability issues in power electronics, ECPE study, Chair of Power Electronics Marco Liserre 58

60 Solutions for high reliability from survey Which trends or approaches will improve the system reliability of power electronic converters in the future? Scale: Not beneficial 1 to very beneficial 6 Topologies & condition monitoring Please rank the following options to achieve high reliability for power electronic systems Highest priority 5 points to lowest priority 1 point Robust components & intelligent control Data source: KDEE Kassel, Chair of Power Electronics, Kiel, Investigation of reliability issues in power electronics, ECPE study, Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 59

61 Reliability challenge of modular systems: Modular power converters consist of several components, which can potentially fail: Capacitors (1 dc-link per H-bridge) Power semiconductors (8 per H-bridge) Drivers (1 per transistor) Modular power converters obtain redundancy on the building block level Redistribution of the stress (Power routing) A failure of a component can be delayed Principle of Power routing for three building blocks. Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 60

62 Power routing for maintenance schedule Components will fail and maintenance will be required Power routing can be utilized to control the wear out and schedule maintenance Power routing can be used to delay maintenance Chair of Power Electronics Marco Liserre 61

63 Reducing the variance of the time to the failure Slightly different temperatures of the devices affect different lifetimes: With similar loading, the lifetime will have a high variance With power routing the variance of the lifetime is significantly reduced The time to a 5% failure probability is increased and mean lifetime is also slightly increased Chair of Power Electronics Marco Liserre ml@tf.uni-kiel.de 62

64 Improving reliability of More Electric Aircraft with power routing Reliability is crucial in aircraft applications Penetration of onboard power electronics converters is increasing Thermal parameter variations and cooling system failures may result in unexpected failures while processing equal power Lifetime control provides better prognostic maintenance with lower early failure probability Chair of Power Electronics Marco Liserre 63

65 Unbreakable HEART Chair of Power Electronics Marco Liserre 64

66 Table of Contents Smart Transformer in the electric grid Semi-modular topologies Comparison between MMC and CHB Comparison between DAB and QAB Results of the actual prototype Reliability/Maintenance challenge of the Smart Transformer Smart Transformer and Solid State Transformer tailored for the grid Chair of Power Electronics Marco Liserre 65

67 Smart Transformer and Solid State Transformer tailored for the grid How to rate ST and SST? Chair of Power Electronics Marco Liserre 66

68 Smart Transformer and Solid State Transformer tailored for the grid How to rate ST and SST? Chair of Power Electronics Marco Liserre 67

69 Smart Transformer and Solid State Transformer tailored for the grid How to rate ST and SST? Chair of Power Electronics Marco Liserre 68

70 Join the PhD Course Feb 2019 Half time in Lab! Chair of Power Electronics Marco Liserre 69

71 Acknowledgement Thank you for the contribution of: Prof. Giampaolo Buticchi (University of Nottingham, Ningbo, China) Dr. Markus Andresen (CAU Kiel) Levy Costa (ABB Corporate Research Center, Switzerland) Vivek Raveendran (CAU Kiel) Chair of Power Electronics Marco Liserre 70