A Novel High-Gain Soft-Switching DC-DC Converter With Improved P&O MPPT for Photovoltaic Applications

ABSTRACT:

This paper proposes a novel high voltage gain structure of DC-DC converter with soft-switching ability for photovoltaic (PV) applications. A small size coupled inductor with one magnet core is utilized to improve the voltage conversion ratio in the proposed converter. The converter has one active MOSFET with low conducting resistance (RDS􀀀ON ), which in turn reduces the conduction losses and complexity of the control section. Due to the low input current ripple, the lifetime of the input PV panel is increased, and the maximum power point (MPP) of the PV panel can be easily tracked. The MOSFET's zero-voltage and zero-current switching and diodes are the other countenance of the proposed converter, which improve its efficiency. Additionally, an improved Perturb and Observe MPP tracking (IP&O MPPT) algorithm is introduced to boost the extracted power of the input PV sources. To validate the performance of this converter, the operation modes principle, steady-state and efficiency survey, and comparison results with other same family converters are carried out. Finally, an experiential prototype is built with 20 V input, 200 V output, power rate of 200W, and 50 kHz operating frequency to validate the mathematical analysis and effectiveness of the proposed structure. The efficiency of the proposed converter was estimated by over 95% at various power levels.

KEYWORDS:

1.      Perturb and observe algorithm

2.      Dc-dc converter

3.      Photovoltaic

4.      MPPT

5.      Zero current switching

6.      High efficiency

SOFTWARE: MATLAB/SIMULINK

SCHEMATIC DIAGRAM:

 

 

Figure 1. Schematic Diagram Of The Non-Isolated High Step-Up Dc-Dc Converter For Pv Applications.

 

Figure 2. Structure Of The Proposed High Step-Up Dc-Dc Converter For Pv Systems.

 

EXPECTED SIMULATION RESULTS:

Figure 3. Simulation Result Of The Capacitor Voltages.

 

Figure 4. Simulation Result Of The Capacitor Voltages Of The Proposed Converter, (A) Vo-Vin, (B) Iin.

 

Figure 5. Simulation Result Of The Capacitor Voltages Proposed, (A) Vd1-Id1, (B) Vd2-Id2, (C) Vdo-Ido And (D) Vsw -Isw:

CONCLUSION:

This paper proposed a novel structure of non-isolated DC-DC converter with high voltage gain and soft-switching capability for PV applications. The presented converter benefits from 1) high voltage gain, 2) low input current ripple, 3) high efficiency, 4) simple structure, 5) peak voltage throughout the semiconductor components and 6) low components count. In the presented non-isolated DC-DC converter, a small size and cost coupled inductor with one magnet core is used to increase the voltage conversion ratio. The suggested topology has only one active MOSFET with lower conducting resistance (RDS􀀀ON ), which can decrease the control section's conduction losses and complexity. Due to the low input current ripple, the lifetime of the input PV panel is increased and the MPP of the PV panel can be easily tracked. Soft switching conditions include ZVS and ZCS of power MOSFET, and diodes are the other features of the proposed converter which improve efficiency. Additionally, an improved P&O MPPT algorithm is suggested to increase the extracted power from the input PV sources. In the rest of this paper, to verify the performance of the suggested converter, the operation modes principle, steady-state and efficiency calculation, and comparison results with other similar converters are provided. The outcomes of this study proved the theoretical analysis and the efficiency of higher than 95% at different power levels.

REFERENCES:

[1] M. Mostafa, H. M. Abdullah, and M. A. Mohamed, ``Modeling and experimental investigation of solar stills for enhancing water desalination process,'' IEEE Access, vol. 8, pp. 219457_219472, 2020.

[2] M. A. Mohamed, A. A. Z. Diab, and H. Rezk, ``Partial shading mitigation of PV systems via different meta-heuristic techniques,'' Renew. Energy, vol. 130, pp. 1159_1175, Jan. 2019.

[3] A. M. Eltamaly, Y. Sayed Mohamed, A.-H. M. El-Sayed, M. A. Mohamed, and A. Nasr A. Elghaffar, ``Power quality and reliability considerations of photovoltaic distributed generation,'' Technol. Econ. Smart Grids Sustain.z Energy, vol. 5, no. 1, pp. 1_21, Dec. 2020.

[4] S. Mishra, K. Bhargava, and D. Deb, ``Numerical simulation of potential induced degradation (PID) in different thin-_lm solar cells using SCAPS- 1D,'' Sol. Energy, vol. 188, pp. 353_360, Aug. 2019.

[5] M. A. Mohamed, H. M. Abdullah, A. S. Al-Sumaiti, M. A. El-Meligy, M. Sharaf, and A. T. Soliman, ``Towards energy management negotiation between distributed AC/DC networks,'' IEEE Access, vol. 8, pp. 215438_215456, 2020.

A Non-Inverting High Gain DC-DC Converter With Continuous Input Current

ABSTRACT:

High gain DC-DC converters are increasingly being used in solar PV and other renewable generation systems. Satisfactory steady-state and dynamic performance, along with higher efficiency, is a pre-requirement for selecting the converter for these applications. In this paper, a non-inverting high gain DC-DC boost converter has been proposed. The proposed converter has only one switch with continuous input current and reduced voltage stress across switching devices. The operating range of the duty cycle is wider, and it obtains a higher gain at a lower value of the duty cycle. Moreover, the converter has higher efficiency at a lower duty cycle while drawing a continuous input current. The continuous input current is a desirable feature of the dc-dc converter making it suitable for solar photovoltaic applications. The converter's operation has been discussed in detail and extended to include the real circuit parameters for a practical performance evaluation. The proposed converter has been compared with other similar recently proposed converters on various performance parameters. The loss analysis for the proposed converter has also been carried out. Finally, the simulation has been validated with results from the experimental prototype.

KEYWORDS:

1.      Continuous conduction mode

2.      Duty cycle

3.      High gain

4.      DC-DC boost converter

5.      Voltage stress

SOFTWARE: MATLAB/SIMULINK

SCHEMATIC DIAGRAM:

Figure 1. (A) Conventional Quadratic Boost Converter (Cqbc) (B) Proposed Converter In [26] (C) Proposed Converter.

EXPECTED SIMULATION RESULTS:

Figure 2. Simulated Waveforms Of Il1 And Il2 And Vgs1 At D D 0.3.

Figure 3. Simulated Waveforms Of V0 And Vin At D D 0.3 With Vgs1.

 

Figure 4. Simulated Waveforms Of Input Current Iin At D D 0.3.

 

Figure 5. Simulated Waveforms Of Vc1, Vc3 And Vc4 At D D 0.3.

 

Figure 6. Simulated Waveforms Of Vd5, Vs1 And Vgs1 At D D 0.3.

 

CONCLUSION:

A new non-inverting DC-DC boost converter is proposed in this paper. The proposed converter has high gain and utilizes only one switch to operate the converter, and therefore, control is easy. The voltage stress on the switch and diodes is low, and therefore low voltage-rated switch can be chosen which increases the efficiency and reduces the cost. The converter has draws continuous input current and thus the need for an input filter does not arise. Hence, it can be used in microgrid applications as the voltage of the converter at a low duty ratio is high compared to the conventional boost converter and other high gain converters. To verify the analysis practically, a 200W hardware prototype has been prepared for the converter. The peak of the efficiency of the proposed converter is observed to be greater than 95% but the efficiency decreases at high output power on account of losses. Thus, the proposed converter is suitable for medium power range suitably up to 300W. The merits of the converter make it suitable to be used in solar PV applications, automobiles, fuel cells and electric vehicles.

REFERENCES:

[1] D. Habumugisha, S. Chowdhury, and S. P. Chowdhury, ``A DC_DC interleaved forward converter to step-up DC voltage for DC microgrid applications,'' in Proc. IEEE Power Energy Soc. Gen. Meeting, Vancouver, BC, Canada, Jul. 2013, pp. 1_5, doi: 10.1109/PESMG.2013.6672501.

[2] P. K. Maroti, M. S. B. Ranjana, and D. K. Prabhakar, ``A novel high gain switched inductor multilevel buck-boost DC_DC converter for solar applications,'' in Proc. IEEE 2nd Int. Conf. Electr. Energy Syst. (ICEES), Chennai, India, Jan. 2014, pp. 152_156, doi: 10.1109/ICEES.2014. 6924159.

[3] A. Sarikhani, B. Allahverdinejad, and M. Hamzeh, ``A nonisolated buckboost DC_DC converter with continuous input current for photovoltaic applications,'' IEEE J. Emerg. Sel. Topics Power Electron., vol. 9, no. 1, pp. 804_811, Feb. 2021, doi: 10.1109/JESTPE.2020.2985844.

[4] F. L. Tofoli, D. D. C. Pereira, W. J. de Paula, and D. D. S. Oliveira, Jr., ``Survey on non-isolated high-voltage step-up DC_DC topologies based on the boost converter,'' IET Power Electron., vol. 8, no. 10, pp. 2044_2057, Oct. 2015, doi: 10.1049/iet-pel.2014.0605.

[5] S.-Y. Tseng and C.-Y. Hsu, ``Interleaved step-up converter with a singlecapacitor snubber for PV energy conversion applications,'' Int. J. Electr. Power Energy Syst., vol. 53, pp. 909_922, Dec. 2013.

A New Discrete Four Quadrant Control Technique for Grid-Connected Full-Bridge AC–DC Converters

ABSTRACT:

This paper presents a new control technique for grid-connected full-bridge AC–DC converters. The proposed control scheme is based on one-cycle control approach and enables the converter to process power in all four quadrants. In the proposed method, switching pulses are generated using a discrete control law with a superimposed fictitious reactive current term. This term enables seamless four-quadrant operation of the converter. Implementation of the discrete controller includes estimation of the current ripple based on measured values of the input current and voltages, sampled at the beginning of each switching cycle. The estimated current ripple is then used for a carrier-less implementation of the proposed control technique. A detailed controller stability analysis using Lyapunov theory is also presented. Theoretical analysis, simulation results, and experimental results show fast dynamic response for the grid current.

KEYWORDS:

1.      AC–DC Converters

2.      One-Cycle Control (OCC)

3.      Predictive-Digital Control

4.      Reactive Power Control

5.      Power Factor (PF)

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

 

 

Fig. 1. The circuit diagram of the full-bridge AC–DC converter with the proposed four-quadrant OCC technique.

 EXPECTED SIMULATION RESULTS:

 

Fig. 2. Simulation Results for operation of converter using conventional OCC technique at (a) Heavy load operation - showing stable operation, (b) Light load - showing saturated variables.

 

 

Fig.3. Simulation results for stable operation of converter with proposed scheme of reactive power control using one-cycle control.

 

Fig. 4. Simulation results for stable operation of converter using fictitious resistance at (a) Rectifier Mode - Heavy load operation, (b) Rectifier Mode - Medium load operation(same operating point as the one in Fig. 8(b)), (c) Rectifier Mode - No Load operation, (d) Inverter Mode - stable heavy load operation, and (e) Inverter Mode - unstable heavy load operation

 

Fig. 5. Simulation results for transient performance of converter with active power control using conventional fictitious current based OCC ((a) & (b)), and reactive power control using proposed fictitious reactive current based OCC ( (c), (d), (e) & (f)).

 

Fig. 6. Simulation results for comparing the transient performance of the proposed digital OCC with the conventional digital OCC. The conventional controller (b) takes longer time as compared to the proposed controller (a) to reach steady state after a reactive current transient is applied to the converter.

 

Fig. 7. Simulation results for grid voltage transient applied to converter with four quadrant power control.

 CONCLUSION:

A novel discrete current control technique based on one cycle control scheme has been proposed in this paper. Four quadrant power flow has been achieved using the proposed control technique. By using this strategy, a fast transient response is achieved for EV battery charger applications. The proposed OCC includes a novel carrier-less implementation method using current ripple estimation, which simplifies its digital implementation. In addition, a generalized stability analysis of OCC scheme has been performed using discrete Lyapunov stability theory to ascertain the limits of stable converter operation. The simulation and experimental results presented in this paper verified that the proposed control technique is suitable for the operation of a single-phase ACDC converter in all four quadrants.

REFERENCES:

[1] B. K. Bose, “Global energy scenario and impact of power electronics in 21st century,” IEEE Transactions on Industrial Electronics, vol. 60, no. 7, pp. 2638–2651, Jul. 2013.

[2] R. Doolan and G. Muntean, “Reducing carbon emissions by introducing electric vehicle enhanced dedicated bus lanes,” in IEEE Intelligent Vehicles Symposium Proceedings, Dearborn, MI, USA,, 2014, pp. 1011– 1016.

[3] M. Yilmaz and P. T. Krein, “Review of the impact of vehicle-to grid technologies on distribution systems and utility interfaces,” IEEE Transactions on Power Electronics, vol. 28, no. 12, p. 5673–5689, Dec. 2013.

[4] C. A. Hill, M. C. Such, D. Chen, J. Gonzalez, and W. M. Grady, “Battery energy storage for enabling integration of distributed solar power generation,” IEEE Transactions on Smart Grid, vol. 3, no. 2, pp. 850–857, Jun. 2012.

[5] B. Koushki, A. Safaee, P. Jain, and A. Bakhshai, “Review and comparison of bi-directional AC-DC converters with V2G capability for onboard EV and HEV,” in IEEE Transportation Electrification Conference and Expo (ITEC), Dearborn, MI, USA, 2014, pp. 1–6.

A Multifunctional Non-Isolated Dual Input-Dual Output Converter for Electric Vehicle Applications

ABSTRACT:

High voltage conversion dc/dc converters have perceived in various power electronics applications in recent times. In particular, the multi-port converter structures are the key solution in DC microgrid and electric vehicle applications. This paper focuses on a modified structure of non-isolated four-port (two input and two output ports) power electronic interfaces that can be utilized in electric vehicle (EV) applications. The main feature of this converter is its ability to accommodate energy resources with different voltage and current characteristics. The suggested topology can provide a buck and boost output simultaneously during its course of operation. The proposed four-port converter (FPC) is realized with reduced component count and simplified control strategy which makes the converter more reliable and cost-effective. Besides, this converter exhibits bidirectional power flow functionality making it suitable for charging the battery during regenerative braking of an electric vehicle. The steady-state and dynamic behavior of the converter are analyzed and a control scheme is presented to regulate the power flow between the diversified energy supplies. A small-signal model is extracted to design the proposed converter. The validity of the converter design and its performance behavior is verified using MATLAB simulation and experimental results under various operating states.

KEYWORDS:

1.      Multi-port converter

2.      Electric vehicle

3.      Bidirectional dc/dc converter

4.       Battery storage

5.      Regenerative charging

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 

  

Figure 1. Block Diagram Of (A) Conventional Converter (B) Proposed Integrated Four-Port Converter (Fpc) Interface In An Electric Vehicle System.

 EXPECTED SIMULATION RESULTS:

Figure 2. Experimental Results Of All The States: (I) State 1, (Ii) State 2, (Iii) State 3, (Iv) State 4, & (V) State 5.

 

 

Figure 2. (Continued.) Experimental Results Of All The States: (I) State 1, (Ii) State 2, (Iii) State 3, (Iv) State 4, & (V) State 5.

 

Figure 2. (Continued.) Experimental Results Of All The States: (I) State 1, (Ii) State 2, (Iii) State 3, (Iv) State 4, & (V) State 5.

 

Figure 3. Experimental Results With Change In Input Voltage Change In Duty Cycle And Load: (I) Change In Pv Voltage, Constant Battery Voltage, And Constant Duty Cycle, (Ii) Vo And Vo1, (Iii) Change Constant Duty Cycle, When Constant Pv Voltage And Battery Voltage, (Iv) Output Load Voltages.

Figure 3. (Continued.) Experimental Results With Change In Input Voltage Change In Duty Cycle And Load: (I) Change In Pv Voltage, Constant Battery Voltage, And Constant Duty Cycle, (Ii) Vo And Vo1, (Iii) Change Constant Duty Cycle, When Constant Pv Voltage And Battery Voltage, (Iv) Output Load Voltages.

 

CONCLUSION:

A single-stage four-port (FPC) buck-boost converter for hybridizing diversified energy resources for EV has been proposed in this paper. Compared to the existing buck-boost converter topologies in the literature, this converter has the advantages of a) producing buck, boost, buck-boost output even without the use of an additional transformer b) having bidirectional power flow capability with reduced component count c) handling multiple resources of different voltage and current capacity. Mathematical analysis has been carried out to illustrate the functionalities of the proposed converter. A simple control algorithm has been adopted to budget the power flow between the input sources. Finally, the operation of this converter has been verified through a low voltage prototype model. Experimental results validate the feasibility  of the proposed four-port buck-boost topology.

REFERENCES:

[1] H. Wu, Y. Xing, Y. Xia, and K. Sun, ``A family of non-isolated three-port converters for stand-alone renewable power system,'' IEEE Trans. Power Electron., vol. 1, no. 11, pp. 1030_1035, 2011.

[2] K. I. Hwu, K.W. Huang, and W. C. Tu, ``Step-up converter combining KY and buck-boost converters,'' Electron. Lett., vol. 47, no. 12, pp. 722_724, Jun. 2011.

[3] H. Xiao and S. Xie, ``Interleaving double-switch buck_boost converter,'' IET Power Electron., vol. 5, no. 6, pp. 899_908, Jul. 2012.

[4] H. Kang and H. Cha, ``A new nonisolated High-Voltage-Gain boost converter with inherent output voltage balancing,'' IEEE Trans. Ind. Electron., vol. 65, no. 3, pp. 2189_2198, Mar. 2018.

[5] T. Bang and J.-W. Park, ``Development of a ZVT-PWM buck cascaded buck_boost PFC converter of 2 kW with the widest range of input voltage,'' IEEE Trans. Ind. Electron., vol. 65, no. 3, pp. 2090_2099, Mar. 2018.