This document discusses closed loop control of a cascaded input dual active bridge converter for transferring power from a DC source like solar panels or batteries to the grid. It describes the topology of the cascaded bridge converter and how it can reduce transformer size and cost while improving efficiency. It also discusses using a walking capacitor to prevent flux walking in the transformer and controlling the DC bus voltage. Finally, it covers synchronizing the converter to the grid using current control techniques and simulating current injection into the grid.

1. Closed loop control of cascaded input
dual active bridge converter
Presented By: -
Perwez Alam
M.Tech 3rd Semester
17PEE030
UNDER THE GUIDANCE OF :
Asst. Prof. ANINDITA JAMATIA
Dept. of Electrical Engineering
( NIT Agartala)

2. Contents
• Description about project
• Power Transfer
• Dc bus voltage control
• Grid integration
• Conclusion
• References

3. Final Project….
Source may be..
• Solar Array
• Battery Storage
• Fuel cell
DC Bus
Transformer size reduction
Cost reduction
 weight reduction
 low noise without compromising efficiency
Reliability
Highly efficient

4. Cascade input Bridge
Optimized value of alpha and beta has chosen such that
maximum fundamental voltage appear across Vcas
Voltage equation for cascaded bridge
𝑉
𝑠 𝑡 = 𝑉
𝑜 𝑆11 𝑡 − 𝑆13 𝑡 + 𝑆21 𝑡 − 𝑆23(𝑡)

5. Sec. Bridge
𝑉
𝑠 𝑡 = 𝑉
𝑜 𝑆31 𝑡 − 𝑆33(𝑡)

6. Walking capacitor
 It is used in series with transformer winding to avoid
the flux walking phenomenon
 This will result in a non-zero average value across the
primary winding of transformer causing the flux to
walk away and saturate the core
 This will ensure that the primary winding will always
have zero average voltage across it, and hence flus
walking phenomenon is absent

7. Power transfer by phase shift

8. Leakage inductor voltage and current waveform for Ig=3 amp
Leakage inductor voltage and current waveform for Ig=5 amp

9. Power flow equation
-2000
-1500
-1000
-500
0
500
1000
1500
2000
-100-90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100
Power Transfer VS Phase Shift
Assuming lossless power conversion
α=21𝑜 & β= 68𝑜

10. Dc Bus Voltage Control
𝐺𝑣𝑠−∅ 𝑠 =
𝑛𝑉
𝜔𝐿
2 −
4∅
𝜋
𝑅𝑒𝑞
1+𝐶𝑜𝑅𝑒𝑞𝑠
𝐻𝐶(𝑠) = 𝐾𝑝 +
𝐾𝑖
𝑠

11. Bode Plot for Dc bus voltage controller
𝐾𝑝=.1744, 𝐾𝑖=8.722

13. Grid Synchronization
Advantages-
• PV grid integration is possible
• Power can be transfer from battery
storage
• Consumer can use net-wattmeter in
solar roof-top
Note-
Grid injected current THD should be less
then 5%

14. Single phase inverter selection
• Why Bipolar inverter….control is
easy.
• SPWM technique used for Pulse
generation

15. Grid synchronization technique..
• About current injection
to grid
• Dq axis grid current
control
• Selection of pi controller
• Bode plotting
• Decoupled control

16. Current controller design
𝐺𝑖𝑛𝑣 𝑠 =
𝐺
1 + 𝑠𝑇𝑑
𝐺𝑝𝑙𝑎𝑛𝑡 𝑠 =
1
𝑠𝐿𝑖 + 𝑅𝑖
𝐻𝑐 𝑠 = 𝐾𝑝 +
𝐾𝑖
𝑠
𝐿𝑖= 30mH
𝑅𝑖= 0.05 ohm
G=
𝑉𝑑𝑐
𝑉𝑐
= 360
𝐾𝑝= 20
𝐾𝑖= 1400
𝐺𝑠𝑦𝑠(s) =
𝐺
(𝑠𝐿𝑖+𝑅𝑖)(1+𝑠𝑇𝑑)
𝐺𝑐_𝑠𝑦𝑠(s) =
𝐺(𝑠𝐾𝑝+𝐾𝑖)
𝑠(𝑠𝐿𝑖+𝑅𝑖)(1+𝑠𝑇𝑑)

17. Bode plot for current controller
𝐺𝑠𝑦𝑠(s) =
𝐺
(𝑠𝐿𝑖+𝑅𝑖)(1+𝑠𝑇𝑑)
𝐺𝑐_𝑠𝑦𝑠(s) =
𝐺(𝑠𝐾𝑝+𝐾𝑖)
𝑠(𝑠𝐿𝑖+𝑅𝑖)(1+𝑠𝑇𝑑)

18. Current injection….
• Online control of grid injection current
• Possible ways
• Distinguish between battery and solar system
• Flow charts

21. Grid current increase to 5amp
Grid current= 3amp

22. conclusion
• DC Bus voltage control (simulation)
• Grid integration (simulation)

23. References..
• H. Xiao and S. Xie, “A ZVS bidirectional dc-dc converter with phase shift plus PWM control scheme, ” IEEE Trans. Power Electron., vol. 23, no. 2, pp. 813–823,
Mar. 2008.
• C. Mi,H. Bai, C.Wang, and S.Gargies, “Operation, design and control of dual H-bridge-based isolated bidirectional dc-dc converter,” IET Power Electron., vol. 1,
no. 4, pp. 507–517, Apr. 2008.
• Amit Kumar Jain, Rajapandian Ayyanar,” PWM Control of Dual Active Bridge: Comprehensive Analysis and Experimental Verification”, IEEE transactions on
power electronics, VOL. 26, NO. 4, april 2011.
• R. T. Naayagi, Andrew J. Forsyth and R. Shuttleworth, “High-Power Bidirectional DC–DC Converter for Aerospace Applications”, IEEE transactions on power
electronics, vol. 27, no. 11, November 2012
• Aditi Chatterjee, Kanungo Barada Mohanty,” Current control strategies for single phase grid integrated inverters for photovoltaic applications-a review ”
Renewable and Sustainable Energy Reviews 92 (2018) 1364-0321.
• S. Samerchur, S. Premrudeepreechacharn, Y. Kumsuwun, and K. Higuchi, “Power Control of Single-Phase Voltage Source Inverter for Grid-Connected
Photovoltaic Systems,.” IEEE transactions on power electronic 978-1-61284-788-7/11

24. Quarries….?

25. Thank You