Presentation of Dissertation Phase-I On

1. MODELLING OF MODULAR STRUCTURE OF MULTILEVEL CAPACITOR CLAMPED DC-DC CONVERTER FOR BIDIRECTIONAL POWER FLOW CONTROL Presentation of Dissertation Phase-I On Prepared By: Mr. Kelvin Manavar ME Electrical (SEM-III) Enrolment No. 130030745004 Atmiya Inst. of Tech. & Science Rajkot Guided By: Prof. Nitin Adroja Assistant Professor Dept. of Electrical Engineering Atmiya Inst. of Tech.& Science Rajkot SUBMITTED TO: GUJARAT TECHNOLOGICAL UNIVERSITY

2. FLOW OF PRESENTATION • Introduction • Literature Review • Problem Definition • Features of Modular multilevel capacitor clamped dc to dc converter (MMCCC). • Principle of Operation for MMCCC • Simulation & Results • Conclusion • Future work • References

3. INTRODUCTION • Bidirectional DC to DC converters are generally used in various applications like Hybrid automotive systems[1], DC drive[2], Solar applications[3]etc. • The modularity in power electronic circuits is becoming a very important issue in power electronics research. • Power electronic circuits are not usually modular. • Using modularity, it is possible to simplify the analysis of many power electronic circuits and increase efficiency. • The purpose of this dissertation work is to introduce some modularity in power electronic dc-dc converter.

4. LITERATURE REVIEW [1] F. H. Khan and L. M. Tolbert, “A 5-kW multilevel DC–DC converter for future hybrid electric and fuel cell automotive applications” • The modular structure of the MMCCC topology gives high reliability, fault bypassing capability, flexible conversion ratio that gives bi-directional power management for automotive applications. Also it has better component utilization compared to the well known flying capacitor dc-dc converter. • In automotive applications where high ambient temperature (~200°C) is present, Buck-Boost converter with bulky inductors can suffer from limited space issue and become bulky as well as limited efficiency at partial loads and full efficiency at full loads.

5. [2] W. S. Harris and K. D. T. Ngo, “Operation and Design of a Switched- Capacitor DC-DC Converter with improved Power Rating” Series-Parallel SC converter [5] Advantages: • Inductor free operation. • only two switching states. • Efficiency >90%. Disadvantages: • Difficulty to change conversion ratio. • Voltage stress on transistors are different. • Bidirectional power flow control is not possible. • Lack of Redundancy. • Incapable to tolerant fault in circuit. • So, Non-Modular structure. Fig 1. Three level series parallel SC converter

6. [3] Marek S. Makowski, and Dragan Maksimovic, “Performance Limits of Switched- Capacitor DC-DC Converters” Advantages: • High conversion ratio can be achieved • with few components. Fig 2. Fibonacci converter with amplification of factor 5. Disadvantages: • The multiplication factor of this converter follows the Fibonacci series. So it is • not possible to make the output voltage 2 or 4 times of the input voltage. • Incapability of transferring power in both directions. Power can only be • delivered from low voltage side to high voltage side.

7. [4] F. Zhang, L. Du, F. Z. Peng, and Zhaoming Qian, “A New Design Method for High Efficiency DC-DC Converters with Flying Capacitor Technology” Advantages: • Eliminate voltage stress issue. All transistors • experience same voltage stress. • Efficiency > 96%. • Capable bidirectional power flow. Disadvantages: • Conversion ratio can not be changed. • If number of level increases then voltage stress • increases. • The incapability to withstand any fault in the • converter. • No redundancy can be incorporated in the • circuit. • No bi-directional power management. Fig 3. Three level FCMDC

8. For an N-level converter, the ON time for any transistor shrinks to (1/N)th of the total time period, and the effective switching frequency is N times of the original switching frequency. • This increased effective switching will introduce high frequency noise at the output dc voltage. For these reasons this circuit cannot be operated at high frequency Switching Scheme of FCMDC

9. PROBLEM DEFINITION • Classical dc-dc converters like buck, boost, buck-boost.[1] • These are not very efficient at higher temperatures. • Transistors used in those circuits experience high voltage stresses. • These are not used at high frequency operations and do not have modular structure. • Above problem can be solved by using dc to dc converters based on capacitive energy transfer like series parallel converter, flying capacitor multilevel dc to dc converter and Fibonacci converter. [4,5,6] • Among three types of converter have some problems like • Those do not have true bidirectional power flow control • not having redundancy and fault tolerant capability.

10. Proposed solution • By introducing modular structure in power electronic dc to dc converter above problems can be overcome.

11. Features of Modular circuit • Conversion ratio can be changed. • Bidirectional power flow control. • Hot swap feature. • Advantage to stack multiple modules to increase power rating. • High operating efficiency greater than 95%. • Improved voltage regulation. • Control strategy is very easy.

12. BLOCK DIAGRAM POWER FLOW (DOWN CONVERSION) POWER FLOW (UP CONVERSION) Fig 4. Block diagram of MMCCC for bidirectional power flow control

13. Fig. 5 Unique modular block (three transistor cell) of MMCCC . [1]

14. PRINCIPLE OF OPERATION FOR MMCCC • Three transistor cells can be considered as the foundation of the new topology. • Proposed multilevel modular capacitor clamped dc-dc converter (MMCCC) having a CR of 5, which means the high side voltage VHV isfive times of the low side voltage VLV. [1] • 5-level design means during up conversion output voltage is 5 times of input voltage and during down conversion output voltage is (1/5)th times of input voltage. • Conversion ratio (CR) depends on the number of modules used in the circuit. • The present design has 4 modules that produce a CR of 5. • Thus for an N-level converter, N-1 modules are required in the circuit.[7]

15. Figure 6 five level MMCCC for down conversion with four modular blocks. [7]

16. Switching Scheme: Fig. 7 Switching Scheme[7]

17. Operational diagram for 5 level MMCCC

18. Wave forms for node voltages

19. Capacitor charge-Discharge operation

21. Fig 8. Simplified operational diagram for MMCCC. [7]

22. Prototype specifications

23. SIMULATION & RESULTS Fig 9. Simulation Diagram

24. Down conversion

25. Up Conversion

26. Bi-directional power flow Down conversion Up conversion No Conversion

27. Voltage stress across switches 2 V LV

28. V LV

29. V LV

30. RESULTS:- Down conversion Mode

31. Up conversion Mode

32. CONCLUSION • MMCCC topology is verified through simulations. Stability performance is also proved for MMCCC. It gives steady average voltage over a complete cycle and bidirectional power flow control is also done.

33. FUTURE WORK • Simulation for Multiple load & source integration in MMCCC for bidirectional power flow management will be done in P-Sim. • Doing mathematical analysis.

34. REFERENCES F. H. Khan and L. M. Tolbert, “A 5-kW multilevel DC–DC converter for future hybrid electric and fuel cell automotive applications”, in Conf. Rec. IEEE IAS Annu. Meeting, 2007, pp. 628–635. Manu Jain, M. Daniele, and Praveen K. Jain, “A bi-directional dc to dc converter topology for Low power applications”, IEEE Transactions on power electronics, vol. 15, no. 4, July 2000. Suresh Kumar Reddy. G and V. Swarupa, “Extended phase shift control of isolated Bidirectional dc-dc converter for Renewable energy sources connected to Micro grid”, IJAREEIE, Vol. 2, Issue. 8, August 2013.

35. 4. W. S. Harris and K. D. T. Ngo, “Operation and Design of a Switched-Capacitor DC-DC Converter with improved Power Rating”, IEEE/APEC, pp. 192-198, Feb. 1994. • Marek S. Makowski, and Dragan Maksimovic, “Performance Limits of Switched- Capacitor DC-DC Converters” IEEE/PESC, vol. 2, pp. 1215-1221, June 1995. • F. Zhang, L. Du, F. Z. Peng, and Zhaoming Qian, “A New Design Method for High Efficiency DC-DC Converters with Flying Capacitor Technology” IEEE/APEC, pp. 92-96, March 2006. • F. H. Khan and L. M. Tolbert, “A multilevel modular capacitor clamped DC–DCconverter” IEEE Trans. Ind. Appl., vol. 43, no. 6, pp. 1628–1638, Nov. 2007.

36. Thank You…