CPES Initiative on Sustainable Buildings and Nanogrids

Transcription

1 Center for Power Electronics Systems Bradley Department of Electrical and Computer Engineerung College of Engineering Virginia Tech, Blacksburg, Virginia, USA CPES Initiative on Sustainable Buildings and Nanogrids Igor Cvetkovic, Dushan Boroyevich, Fred C. Lee, Paolo Mattavelli, Dong Dong, Wei Zhang, Li Jiang, Pengju Kong, Bo Zhou presentation to 2 APEC: Special Presentation Session on Power Electronics and Alternative Energy

2 DC-based Nanogrid System HYDRO NUCLEAR HVAC TRANSMISSION HYDRO NUCLEAR COMBUSTION COMBUSTION AC DISTRIBUTION Smart Power Meter HOUSEHOLD LOADS μc ac-nanogrid microgrid PHEV dc-nanogrid

3 Sustainable Buildings 2 Objective Apply power electronics to future residential and commercial buildings to enable major improvements in energy efficiency and sustainability while minimizing cost and maximizing reliability.

4 Solar PV Mini-Consortium for Renewable Energy and Nanogrids (REN) Entertainment and Data Systems Smart Appliances and Lighting Wind Turbine PV System Work Scope Plug-in Hybrid Electric Vehicles / Battery Storage Wind Power Energy Management for the Nanogrid AC Nanogrid DC Nanogrid Plug-in Hybrid with Bidirectional Converter Electric Energy Management Hub Grid Connection with Bidirectional Converter Heating, Ventilation, and Air Conditioning Current Principal Plus Members in this area: Solid State Lighting Research Sponsors Industry Consortium College of Engineering ICTAS 3

5 Mini-Consortium Power Management Consortium (PMC) (998 present) Work Scope: Devices and Magnetics Modeling and control (analog & digital) 3D integration High performance VRM/POL converters DC/DC converters and Bus converters EMI and PFC Power architecture and management 4

6 Mini-Consortium for High Density Integration (HDI) Work Scope: High-Temperature Integration Technologies Components Module-Level Integration System-Level Integration Current Principal Plus Members in this area: Research Sponsors Industry Consortium 5

7 Sustainable Building Design Initiative Renewable Energy DC Nanogrid Objectives DC-based power architecture (bus structure) Decoupled dynamics from grid Islanded operation Bidirectional power conversion Zero-net annual energy cost Dispatchable generation / consumption Droop-based Continuous Power Sharing and Automatic Prioritized Energy Use Optimization μc GRID ECC SOLAR ARRAY DC bus 36 4 V WIND TURBINE ENERGY STORAGE PLUG-IN HYBRID Challenges Power management Wireless communication Integrated protection Breakerless system Grounding, EMI, & power quality Safety μc 48 V μc Consumer el.: TV, Computer... μc M Appliances: Washer, Dryer... μc Appliances: Stove/Range... Safe, Efficient, Convenient, Aesthetic, and Enjoyable Appliances and Ambient LED light 6

8 Voltage Levels in the DC-Nanogrid System High power appliances: Wide input voltage range V to 24 V AC (Japan to Europe) Rectified max = 34 V DC PFC output V DC Chosen is 38 V as the nominal voltage of the bus Low power consumer electronics: Low, safe touch voltage < 5 V DC 5 V, 9 V, 24 V, 48 V Chosen is 48 V as the nominal voltage for the low voltage local distribution Standard - Standard - 7

9 Sustainable Building Design Initiative Energy Control Center Bi-directional Grid Interface Converter 36-4 V DC Bus with droop regulation and short-circuit current limiting V DC L DC C DC C LINK L AC C AC L AC2 V AC Two-stage converter using low-cost 3Φ motor-drive IPM 24 V, 6 Hz, Φ Grid with dispatchable active & reactive power and short-circuit current limiting Features Large dc-link voltage variation Small dc-link capacitor Soft-start on both sides High performance PLL Fast dc voltage & ac current control Full EMI compliance on both sides Small CM voltage on both sides Prototype of kw high power density bi-directional grid interface converter 8

10 Sustainable Building Design Initiative Wind Turbine Conventional structure: Two-stage power conversion AC-DC and DC-AC Sensor Power Supply Control and drive Feature Ability to regulate output voltage in stand-alone (islanded) operation Generator AC Grid SW2 AC-DC converter SW DC-AC converter New structure: AC-DC converter for the Nanogrid System Vertical-axis Cleanfield Energy Wind Turbine Power Supply Control and drive Generator DC Bus SW4 AC-DC converter SW3 9

11 Sustainable Building Design Initiative Plug-in Hybrid Electric Vehicle Demonstrated V2G technology in an AC Nanogrid System Dispatchable Active & Reactive power Future plans: High Power Density Bidirectional DC-DC Converter Conventional structure: Two stage bidirectional power conversion DC-DC and DC-AC AC Grid DC Nanogrid

12 Sustainable Building Design Initiative Battery Management System SAFT Lithium Ion Battery System External CAN Bus + Dissipative BM C Battery Management Module I Bat.. GEM # GEM #2 GEM #3 Non-dissipative GEM #4 Internal CAN Bus (Voltage, Current, Temperature) GEM #5 GEM #6 I Bat..

13 Sustainable Building Design Initiative Photovoltaic Management System I s I s2 I s3 I s V s 2 nd stage converter Non-inverting Buck-boost I pv V bus Droop mode MPPT mode P s DC bus 36V 4V Current limit mode I pv I I limit =A o I sc =5.4A MPP (35.2V,4.83A) V oc =43.8V 3 I pv I o V pv Vo V pv Solarmagic Power optimizer MPPT range V limit =4V V o Smart PV panel Peak power tracking at the panel level Peak power tracking at the system level 2% more efficient than the centralized MPPT system 2

14 Sustainable Building Design Initiative Solid State Lighting 3 2-stage MC 3 LED Driver Schematic of proposed multi-channel constant current source LLC resonant topology Multiple outputs current source DC block cap balance the current of two strings f s Scalable for multiple LED strings

15 Integration of Technology into the Home Environment - Synergy of power electronics and interior design Ceiling-based plug-and-play DC system Design by: Kitchen School of architecture + design, Virginia Tech PC lab Hallway Conference room Source: Source: Integration of existing technology Source: 4

16 Static (V-I) Characteristics of the System Components (dc-bus signaling technique*) PLUG-IN HYBRID I g I s I w I b I p DC bus 36 4V Converter rating Converter rating Actual MPPT Converter rating Actual MPPT Converter rating Operating range Operating range [*] J. Bryan, R. Duke, and S. Round, "Decentralized generator scheduling in a nanogrid using DC bus signaling," in Power Engineering Society General Meeting, 24. IEEE, 24, pp Vol.. 5

17 6 Static Operation of the DC-Nanogrid System GRID μc I g I s I w I b I p I L LOAD I w +II w s +I I w g s +I I g bs w +I I g b p = s = I L I g I p I s I s I g I wb I b I I sw I g II ss I g I w

18 Optimization of the DC-nanogrid Operation Grid interface converter Battery converter 4 V [V] B A B 37 A 36 I g B I g A I g I b A I b B 7

19 Power Socket/Plug for the High Voltage 8 Disconnect (PE) (-) (+) dc-outlet dc-plug + - (-) (+) An equivalent circuit of the system above: Isolation and control Disconnecting point - simulation results - ideal disconnect - high di/dt r c L c C E r c2 L c2 vb i C s v v CE v 2 i 2 D s C L R L L L

20 Building the Non-linear Static and Linear Dynamic Model 9 Load regulation static curve Non-linear static model AC-sweep point Linear dynamic model

21 Two port network behavioral model + - v i 2 v 2 v G o i 2 H i Y i Z o i two-port network dc-dc converter = 2 2 ) ( ) ( ) ( ) ( i v s H s Y s Z s G i v i i o o x X x + = + = ) ( ) ( ) ( ) ( I V I i V v s H s Y s Z s G i v i i o o Small-signal model: Model containing DC operating point and the small-signal dynamics expanded with the DC operating point 2

22 Phase [ ] Magnitude.. -2 Modular Terminal Behavioral (MTB) Low-frequency Model of DC-DC Converter Current Back-gain H i (jω ) Frequency [rad/s] Black Box Modeling Example A commercial 6 W bus converter. i i Z i H o o i i o 48 V v i Y i v o 8 V G o v i Magnitude Phase [ ]. - Output Impedance Z o (jω ) Frequency [rad/s] Magnitude Phase [ ]. Input Admittance Y i (jω ) Frequency [rad/s] Measured frequency response functions Curve-fitted, reduced order transfer functions Magnitude Phase [ ].. -2 Audio Susceptibility G o (jω ) Frequency [rad/s] 2

23 Obtaining un-terminated from the terminated transfer functions 22 Setup : + - V o Z s Source Setup 2: i L i p v i i R i 2 Y i + - i 2 H i Z o v G o two-port network dc-dc converter Z + s + V v - o Y i - Source i 2 H i Z o v G o two-port network dc-dc converter v 2 i 2L i 2R i p v 2 Y L Load Y L Load I o I o Z G v 2 om ( s) =, Yim( s) = v om T gm ( s) = i2 v i v R v 2 ( s) =, Him( s) = i2 L v Trm( s) = i 2L i i 2L Go Yi = Z o TgmT H i rm T rm T rm T gm T gm G Y Z H om im om im

24 System-level Model Verification (Sample System) Grid Interface Converter V bus =V g2 I g2 DC/DC Bus conv. LOAD V g2, I g2 Impedance Interconnection Non-linear static model Solar Converter I s2 DC/DC Bus conv. 2 LOAD 2 V s2, I s2 V bus2 =V s2 Grid Interface Converter v bus =v g2 i g2 DC/DC Bus conv. LOAD Impedance Interconnection Linear dynamic model Solar Converter i s2 DC/DC Bus conv. 2 LOAD 2 v bus2 =v s2 23

25 System-level Model Verification (Sample System) Grid Interface Converter V bus =V g2 I g2 DC/DC Bus conv. LOAD Output current [A] V g2, I g2 Solar Converter I s2 Output voltage [V] Impedance Interconnection Non-linear static model DC/DC Bus conv. 2 LOAD 2 V s2, I s2 V bus2 =V s2 Output current [A] Grid Interface Converter v bus =v g2 i g2 Output voltage [V] Impedance Interconnection DC/DC Bus conv. Linear dynamic model LOAD Solar Converter i s2 DC/DC Bus conv. 2 LOAD 2 v bus2 =v s2 24

26 DC System Stability (example with low bus capacitance C b ) GRID SOLAR ARRAY Voltage [V] DC bus Z wire v g i g Z c Z wire v s i s Current [A] C b LOAD LOAD 2 Z S Z L C b Load Source Z S Z L Source Z S - -2 Load Z L k k Frequency [Hz] k 25

27 DC System Stability (value of C b has increased) GRID SOLAR ARRAY v g,v s Output voltage Grid interface converter Solar converter Time [s] DC bus Z wire v g i g Z c Z wire v s i s 5 5 Grid interface converter Solar converter Output current i g i s C b LOAD LOAD 2 Z S Z L C b Time [s] Impedance Magnitude [db] Load Source Z L Z S Impedance Phase [deg] - -2 Source Load Z L k k Frequency [Hz] Z S k 26

28 Thank You The work and contributions are by many CPES faculty, students, and Staff. Many global industrial and US government sponsors of CPES research are gratefully acknowledged. Center for Power Electronics Systems Bradley Department of Electrical and Computer Engineerung College of Engineering Virginia Tech, Blacksburg, Virginia, USA 27