lego-mimo architecture - princeton university
TRANSCRIPT
LEGO-MIMO Architecture:
A Universal Multi-Input Multi-Output (MIMO) Power Converter
with Linear Extendable Group Operated (LEGO) Power Bricks
Yenan Chen, Ping Wang, Youssef Elasser, and Minjie Chen
Princeton University
MIMO Applications
2
• Large number of modular cells
• MPPT, power balancing, SOC monitoring
• Multiple energy sources/loads
• Energy routing
MIMO Architectures
3
DC-Coupled MIMO☺ Decoupled controlMultiple conversion stages Low efficiency
AC-Coupled MIMO☺ Single-core multi-winding transformer☺ Fewer conversion stages☺ High efficiency Coupled power flow
Energy Router
AC-Coupled MIMO: Previous Work
4
+
-
• 50V-5V 10-Port converter for data center[2]
• 400V-48V-15V-5V 4-Port converter for DC power distribution in smart home[1]
• 12-Port converter for submodule capacitor balancing in 3-Phase MMC inverter[3]
❑Large number of ports with single magnetic core
❑Cover wide voltage & current range
LEGO-MIMO Concept
Linear
Extendable
Group
Operated
5
LEGO Power Brick (Active-Bridge)
LEGO-MIMO Converter
❑ Identical active-bridge unit: LEGO toy bricks
❑ Series/parallel connecting for wide voltage/current range
❑Modular design, reconfiguration
Power Rating of LEGO Bricks
6
Device selection area
• Traditional converterPmax = Vmax Imax >> Po
• 2 LEGO bricks• Vmax - 0.5Imax
• 0.5Vmax - Imax
Pmax = 2 0.5Vmax 0.5Imax
• N LEGO bricks• Pmax Po
Group Operated Control
7
Group Control Strategy
❑ LEGO bricks in the same group (port): same gate driver
❑ Plug-and-play, simpler controller, fewer sensors
LEGO Power Brick (Active-Bridge)Linear
Extendable
Group
Operated
Reduced Order Control Model
8
𝑉𝑊1
⋮𝑉𝑊𝑛
= 𝑗𝜔𝑴𝑾𝟐𝑾
𝐼𝑊1
⋮𝐼𝑊𝑛
Series Parallel
N bricks and M ports: N M
𝑉𝑃1⋮
𝑉𝑃𝑚
=𝑄𝑉11 ⋯ 𝑄𝑉1𝑛⋮ ⋱ ⋮
𝑄𝑉𝑚1 ⋯ 𝑄𝑉𝑚𝑛 𝑚×𝑛
𝑉𝑊1
⋮𝑉𝑊𝑛
𝐼𝑊1
⋮𝐼𝑊𝑛
=𝑄𝐶11 ⋯ 𝑄𝐶1𝑛⋮ ⋱ ⋮
𝑄𝐶𝑛1 ⋯ 𝑄𝐶𝑛𝑚 𝑛×𝑚
𝐼𝑃1⋮𝐼𝑃𝑚
𝑉𝑃1⋮
𝑉𝑃𝑚
= 𝑗𝜔𝑸𝑽𝑴𝑾𝟐𝑾𝑸𝑪
𝐼𝑃1⋮𝐼𝑃𝑚
Impedance matrix simplification
Voltage conversion
Current conversion
𝐼𝑃𝑋 = 𝐼𝑊ℎ = 𝐼𝑊𝑖 = 𝐼𝑊𝑗
𝑉𝑃𝑋 = 𝑉𝑊ℎ + 𝑉𝑊𝑖 + 𝑉𝑊𝑗
𝐼𝑃𝑌 = 𝐼𝑊𝑘 + 𝐼𝑊𝑙 + 𝐼𝑊𝑚
𝑉𝑃𝑌 = 𝑉𝑊𝑘 = 𝑉𝑊𝑙 = 𝑉𝑊𝑚
ො𝑣𝑃1ො𝑣𝑃2⋮
ො𝑣𝑃𝑚
= 𝑮𝑷𝒊
Ƹ𝑖𝑃1Ƹ𝑖𝑃2⋮Ƹ𝑖𝑃𝑚
+ 𝑮𝑷𝝓
𝜙𝑃1𝜙𝑃2⋮𝜙𝑃𝑚
• M × M transfer matrix
• For port P/V regulation
𝑃𝑖 =𝑁𝑖𝑉𝑖2𝜋2𝑓𝑠
𝑗≠𝑖
𝑁𝑗𝑉𝑗 Φ𝑖 −Φ𝑗 𝜋 − Φ𝑖 −Φ𝑗
𝑁𝑖2𝑁𝑗
2𝐿𝑖𝑗 + 𝑁𝑗2𝐿𝑖 + 𝑁𝑖
2𝐿𝑗Brick power:
DC
AC
DC
AC
AC
DC
AC
DC
DC
AC
DC
AC
AC
DC
AC
DC
DC
AC
DC
AC
AC
DC
AC
DC
Control Methods
9
• Phase-shift • Time-sharing • HybridΦ1
Φ2
Φ3
Φ4
𝐷1
𝐷2
𝐷3
𝐷4 Φ𝑖 𝑎𝑛𝑑 𝐷𝑖
IL1
IL2
IL3
IL4
IL1
IL2
IL3
IL4
IL1
IL2
IL3
IL4
LEGO-MIMO Design Example
10
❑ 1 magnetic core❑ Air-cooling ❑ No heatsink
• HV PCB (1 HV brick)• VH = 72V, NH = 8• Pmax = 200W, fs = 200kHz• GaN GS1004B/100V
• LV PCB (2 LV bricks)• VL = 9V, NL = 1• Pmax = 2100W, fs = 200kHz• DrMOS SIC632/24V
Multi-Winding Transformer Design
11
• HV windings as primary side, LV windings as secondary side• Current excitation: Ip = 4A, Is = 16A
PCB copper current density Magnetic field strength and core flux density
• Thermal measurement: HV input, LV output• P = 80W, Ta = 20C, no air-cooling
Interleaved structure:• Lower B and H• Smaller ac resistance (56% of non-interleaved
structure)
Port Configuration
12
• System maximum power: 500W
Input operation range Output operation range
• Experiment Setup
Power Distribution
13
Measured power of the 9V, 18V and 36V ports with same Φ
Interleaved structure:
• Balanced power distribution
• Able to be linearly extended
• P9V ≠ P18V
• P9V + P18V ≠ P36V
• P9V P18V
• P9V + P18V P36V
Input Output
Efficiency with Different Winding Structures
14
Winding currents in the HV bricks, Po = 300W
Input Output
Interleaved structure:
• Lower current peak
• Higher efficiency
Efficiency with Different Port Structures
15
Winding currents in the LV bricks with interleaved structure, Po = 300W
• 96.7% @ 288V - 9V /300W
• Voltage slightly unbalanced among
series bricks
• Tradeoff: cost vs. efficiency
Thermal Measurement
16
• LV Group 1: 9V-18V-36V output• P = 500W, Ta = 23C • Airflow = 21.9 CFM
❑ Hottest components: HV inductors and LV DrMOS❑ Natural distribution of heat❑ No heatsink
Design Guideline
For equal power distribution
• Interleaving the input bricks (windings)
and output bricks (windings)
• Using bricks with similar linkage
inductance Lij for the same port
17
input output
Summary
• LEGO-MIMO: Linear Extendable Group Operated Multi-Input Multi-Output
• Applicable to wide operation range multiport dc-dc applications
– Battery balancer, energy router, PV MPPT
• Design example: 500W 12-Brick MIMO dc-dc converter
• Wide operation range: 72V/8A-288V/2A input, 9V/56A-72V/7A output
• Multi-winding single-core transformer design
• 96.7% peak efficiency @ 288V-9V/250W
• Natural heat distribution
18
References
1. Y. Chen, P. Wang, H. Li and M. Chen, "Power Flow Control in Multi-Active-Bridge Converters: Theories and Applications," 2019 IEEE Applied Power Electronics Conference and Exposition (APEC), Anaheim, CA, USA, 2019, pp. 1500-1507.
2. P. Wang, Y. Chen, Y. Elasser and M. Chen, "Small Signal Model for Very-Large-Scale Multi-Active-Bridge Differential Power Processing (MAB-DPP) Architecture," 2019 20th Workshop on Control and Modeling for Power Electronics (COMPEL), Toronto, ON, Canada, 2019, pp. 1-8.
3. Y. Chen, Y. Elasser, P. Wang, J. Baek and M. Chen, "Turbo-MMC: Minimizing the Submodule Capacitor Size in Modular Multilevel Converters with a Matrix Charge Balancer," 2019 20th Workshop on Control and Modeling for Power Electronics (COMPEL), Toronto, ON, Canada, 2019, pp. 1-8.
4. R. W. Erickson and D. Maksimovic, “A multiple-winding magnetics model having directly measurable parameters," PESC 98 Record. 29th Annual IEEE Power Electronics Specialists Conference (Cat. No.98CH36196), Fukuoka, 1998, pp. 1472-1478 vol.2.
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Control Model for Multi-Active-Bridge
20
• N-Brick multi-active-bridge converter • Cantilever model for an N-winding transformer[4]
𝑃𝑖 =𝑁𝑖𝑉𝑖2𝜋2𝑓𝑠
𝑗≠𝑖
𝑁𝑗𝑉𝑗 Φ𝑖 −Φ𝑗 𝜋 − Φ𝑖 −Φ𝑗
𝑁𝑖2𝑁𝑗
2𝐿𝑖𝑗 + 𝑁𝑗2𝐿𝑖 + 𝑁𝑖
2𝐿𝑗Average power of Brick i:
Small signal model[1][2]: ො𝑣1ො𝑣2⋮
ො𝑣𝑛
= 𝑮𝒊
Ƹ𝑖1Ƹ𝑖2⋮Ƹ𝑖𝑛
+ 𝑮𝝓
𝜙1𝜙2⋮𝜙𝑛
• Gi and G: n × n transfer matrix
• For independent P/V regulation
Prototype Parameters
21
• System maximum power: 500W