1. 1 ANNEXURE PROJECT TITLE : A Novel Power Management Control Strategy for Renewable Energy Power System SUBMITTED BY : N.SAHUL HAMEED V.DINESH BABO P.PURSOTHAMAN REVIEW NUMBER : 02 REVIEW DATE :

2. Overview Introduction Objective Proposed Topology Operational Principles(two stages) Matlab/PSIM Simulation Results Describe Project Build and tests Experimental Test results Conclusion

3. Introduction and Scope Comparing single-stage grid-connected photovoltaic (PV) system with power quality improvement, in this project, a high-capacity single phase grid-connected PV system based on wide range conversion converter + inverter is proposed, which not only allows a wide range of input voltage, but also compensates unbalance current of the local load comparing in the case of three-phase three-wire PV system. This project explains the control principle of each power stage of the system and the simplified cost effective control strategy of combination of PV grid-connected generation in detail. then the Simulation and Experimental results of the proposed system represents the features of the proposed system.

4. Introduction and Scope Conversion from low-voltage dc to high-voltage ac for grid- tie applications were proposed to deal with specific issues such as high efficiency, low cost, and safety. The aim of this article is to introduce and discuss the main features of these relatively new circuit topologies that deal with these practical design issues. The aim of this article is to introduce and discuss the main features of these relatively new circuit topologies that deal with these practical design issues

5. Grid Tie converter system For low-voltage dc energy sources, a power conditioning system (PCS) is needed to convert the energy sources to a higher-voltage dc before making it to ac for grid tie applications. Solar photovoltaic (PV) and fuel cells are perhaps the most well- known and prospective energy sources with low-voltage dc output. A thermoelectric generator, a battery, and an ultra capacitor are also examples of such low-voltage dc energy sources. Recently, numerous circuit topologies for the power conversion from low- voltage dc to high-voltage ac for grid-tie applications were proposed to deal with specific issues such as high efficiency, low cost, and safety.

6. 6 INTRODUCTION : PV SYSTEM  The PV power system can be classified into two types: stand- alone PV system and grid-connected PV system.  In remote or isolated regions where power grid can not extend to, stand-alone PV schemes have found a fairly wide application to meet the need for small but essential electric load.

8. Functional block diagram

9. Grid-connected /Stand alone PV system with power quality comprehensive compensator

10. Power flow of the system with nonlinear load

11. Proposed System The system aims transferring the photovoltaic (PV) power to the ac load and paralleled with the utility. The dc-dc converter is used to boost the PV voltage to a level higher than the peak of the voltage utility such that the inverter can provide the ac voltage without requiring the transformer. The dc-dc converter is also responsible for tracking the maximum power point of the PV modules to fully utilize the PV power. The shortage of load power from the PV module is supplemented by the utility. On the contrary, the excessive power from the PV module to the load can be fed to the utility. The balance of power flow is controlled through the inverter. The inverter also is used to act always as an active power filter to compensate the load harmonics and reactive power such that the input power factor is unity

12. 12 INTRODUCTION-wide Range conversion Converter  New technologies are emerging that require a wide range voltage conversion such as integrated circuits with voltage of power supply of 3.3 V and 1.5 V, automotive systems, aeronautical systems and telecommunications systems, solid state lighting systems.  The above requirements can be satisfied using conventional PWM converters by: operating at extremely low or high duty ratios with the corresponding limitations on the finite commutation times of the switching devices, or using a step-down or step-up transformer with the corresponding difficulties in switching surges and operating frequencies.

13. 13 INTRODUCTION Continued…  In theory, larger conversion ratios can be obtained by properly adjusting the modulating control signal of the converter. In practice, the maximum and the minimum attainable conversion ratios for the conventional converters are limited by the characteristics of the switching devices.  A scheme that provides larger conversion ratios without an isolation transformer is a cascade connection. This scheme is a multistage approach that consists of various converters connected in cascade.  One of the major advantages of these converters is a high gain; however, a major drawback is that the total efficiency may be low if the number of stages is high

14. 14 OBJECTIVE  In this project, quadratic boost buck converter (boost 2 -buck) is derived from the quadratic converters is proposed. This topology presents non-pulsating input and output current.  It has operations equivalent to a cascade converter consisting of two boost converter and one buck converter, but with the advantage of using single active switch.

15. PROPOSED HIGH VOLTAGE TRANSFORMERLESS DC-DC CONVERSION TOPOLOGY

17. Simulation Diagram: Schematic of Proposed High Step Up Converter

18. Simulation results of proposed converter

19. Circuit Description Circuit Description In proposed circuit, It has operations equivalent to a cascade converter consisting of two boost converter and one buck converter, but with the advantage of using single active switch. This topology presents non-pulsating input and output current. The schematic of the High step Up Boost converter is show in figure. The operation in continuous conduction mode in steady state consists of two states.

20. Design Formulas The voltage gain is given by,- (Discontinuous) The normalized inductor time constant is defined as: The voltage gain is given by(Continouous) conduction mode)

21. PROPOSED INVERTER (two stages)

22. Switching rules Either A+ or A– is closed, but never at the same time * Either B+ or B– is closed, but never at the same time * *same time closing would cause a short circuit from Vdc to ground (shoot-through) *To avoid dhoot-through when using real switches (i.e. there are turn-on and turn-off delays) a dead-time or blanking time is implemented Corresponding values of Va and Vb A+ closed, Va = Vdc A– closed, Va = 0 B+ closed, Vb = Vdc B– closed, Vb = 0 Bridge Inverter Basics – Creating AC from DC Vdc Load A+ B+ A– B– Va Vb Single-phase H-bridge (voltage source) inverter topology:

23. Corresponding values of Vab A+ closed and B– closed, Vab = Vdc A+ closed and B+ closed, Vab = 0 B+ closed and A– closed, Vab =–Vdc B– closed and A– closed, Vab = 0 The free wheeling diodes permit current to flow even if all switches are open These diodes also permit lagging currents to flow in inductive loads Vdc Load A+ B+ A– B– Va Vb BRIDGE INVERTER + Vdc − Utility interfacing Inverter Circuit

24. Corresponding values of Vab A+ closed and B– closed, Vab = Vdc A+ closed and B+ closed, Vab = 0 B+ closed and A– closed, Vab =–Vdc B– closed and A– closed, Vab = 0 The free wheeling diodes permit current to flow even if all switches are open These diodes also permit lagging currents to flow in inductive loads Vdc Load A+ B+ A– B– Va Vb BRIDGE INVERTER + 0 −

25. Corresponding values of Vab A+ closed and B– closed, Vab = Vdc A+ closed and B+ closed, Vab = 0 B+ closed and A– closed, Vab =–Vdc B– closed and A– closed, Vab = 0 The free wheeling diodes permit current to flow even if all switches are open These diodes also permit lagging currents to flow in inductive loads Vdc Load A+ B+ A– B– Va Vb BRIDGE INVERTER − Vdc +

26. Corresponding values of Vab A+ closed and B– closed, Vab = Vdc A+ closed and B+ closed, Vab = 0 B+ closed and A– closed, Vab =–Vdc B– closed and A– closed, Vab = 0 The free wheeling diodes permit current to flow even if all switches are open These diodes also permit lagging currents to flow in inductive loads Vdc Load A+ B+ A– B– Va Vb BRIDGE INVERTER + 0 −

27. Simulation Diagram of Proposed 12 volt Photovoltaic inverter feeding Non-linear load without feeding utility

28. Simulation results of Proposed 12 volt Photovoltaic inverter feeding Non-linear load without feeding utility

29. Experimental Prototype Design Details To demonstrate the feasibility of the discussed PV system, a prototype was designed and implemented. The specifications of the system shown in fig are shown below: Solar array: Number of PV Module: 1 Rated power: 20W; Rated voltage: 12V; Rated current: 1.5A; Dc-dc power converter: Input voltage : 12 volt-400vol maximum Output voltage: Maximum 500V; Switching frequency: 20 kHz; Switch used: IRFP450,

30. Contin.., Inductors: L1 = 100uH L2 = 100uH Capacitors: Co = 470uF Diodes: Do,D1, D2, D3 = BY399

31. Cont.., Inverter: Switches Used: MOSFETs IRP450 (500Volts, 15 Amp max) Switching frequency: 5 kHz; Filter inductance: 1.5 mH Filter capacitor : 170uF Output voltage: 12V-500Volt, 50Hz; Load: 500VA In the proposed system, a LC filter is connected with the PV array output to filter the high frequencies drained by the dc-dc converter, and a series LC filter is connected between the converters to support the second-order component (100Hz) resented in the input inverter current.

32. Advantages of Proposed circuit: when compared with a converter cascade, it is  cheaper,  less bulky and  used circuit control simpler.

33. Applications of Proposed circuit: Suitable for automotive systems, Aeronautical systems Telecommunications systems and, solid state lighting systems