Fuzzy Sliding Mode Control for Photovoltaic System

ABSTRACT

In this study, a fuzzy sliding mode control (FSMC) based maximum power point tracking strategy has been applied for photovoltaic (PV) system. The key idea of the proposed technique is to combine the performances of the fuzzy logic and the sliding mode control in order to improve the generated power for a given set of climatic conditions.

Different from traditional sliding mode control, the developed FSMC integrates two parts. The first part uses a fuzzy logic controller with two inputs and 25 rules as an equivalent controller while the second part is designed for an online adjusting of the switching controller’s gain using a fuzzy tuner with one input and one output.

Simulation results showed the effectiveness of the proposed approach achieving maximum power point. The fuzzy sliding mode (FSM) controller takes less time to track the maximum power point, reduced the oscillation around the operating point and also removed the chattering phenomena that could lead to decrease the efficiency of the photovoltaic system.

KEYWORDS

  1. DC-DC converter
  2. Fuzzy sliding mode control
  3. photovoltaic system
  4. MPPT
  5. Solar energy

SOFTWARE: MATLAB/SIMULINK

 CONCLUSION

In this paper, a fuzzy sliding mode controller based MPPT technique was developed and tested. The proposed controller is designed by combining the fuzzy logic and sliding mode control to guarantee the stability and the tracking performance and also to avoid the drawbacks of the traditional SM and FL controllers.

A Matlab/Simulink based simulation of a stand-alone PV system under varying climatic conditions and two levels of load was carried out to validate the proposed controller.

Simulation results demonstrate that the designed FSMC-MPPT exhibits good responses as it successfully and accurately achieved the maximum power point with a significantly higher performance than the P&O, SM and FLC strategies. The proposed approach provides a feasible approach to control PV power systems.

REFERENCES

[1] Dounis, A.I., Kofinas, P., Alafodimos, C., &Tseles, D. (2013). Adaptive fuzzy gain scheduling PID controller for maximum power point tracking of photovoltaic system. Renewable energy, 60, 202-214.

[2] Bhatnagar, P., & Nema, R.K. (2013). Maximum power point tracking control techniques: State-of-the-art in photovoltaic applications. Renewable and Sustainable Energy Reviews, 23, 224-241.

[3] Farhat, M., Barambones, O., & Sbita, L. (2015). Efficiency optimization of a DSP-based standalone PV system using a stable single input fuzzy logic controller. Renewable and Sustainable Energy Reviews, 49, 907-920.

[4] Kalashani, Mostafa Barzegar et Farsadi, Murtaza. New Structure for Photovoltaic Systems with Maximum Power Point Tracking Ability. International Journal of Power Electronics and Drive Systems, 2014, vol. 4, no 4, p. 489.

[5] Liu, F., Kang, Y., Zhang, Y., & Duan, S. (2008, June). Comparison of P&O and hill climbing MPPT methods for grid-connected PV converter. In Industrial Electronics and Applications, 2008. ICIEA 2008. 3rd IEEE Conference on (pp. 804-807). IEEE.

Direct Torque Control using Switching Table forInduction Motor Fed by Quasi Z-Source Inverter

ABSTRACT:

 Z-source inverters eliminate the need for front-end DC-DC boost converters in applications with limited DC voltage such as solar PV, fuel cell. Quasi Z-source inverters offer advantages over Z-source inverter, such as continuous source current and lower component ratings. In this paper, switching table based Direct Torque Control (DTC) of induction motor fed by quasi Z-Source Inverter (qZSI) is presented. In the proposed technique, dc link voltage is boosted by incorporating shoot through state into the switching table. This simplifies the implementation of DTC using qZSI. An additional DC link voltage hysteresis controller is included along with torque and flux hysteresis controllers used in conventional DTC. The results validate the boost capability of qZSI and torque response of the DTC.

KEYWORDS:

  1. DTC
  2. QZSI
  3. DC-DC Converter
  4. DC Link Voltage
  5. Hysteresis Controller

 SOFTWARE: MATLAB/SIMULINK

 CONCLUSION:

 In this paper, direct torque control of induction motor fed by qZSI is presented. Dynamic torque response for step change obtained is 3 ms, which is needed for high performance applications. qZSI provides a single stage solution for drives with variable input DC voItage, instead of DC-DC converter cascaded with 3-leg inverter bridge. This paper presents a solution for drives with lesser DC input voItage availability and also requiring very fast torque response. The results shows that by introducing shoot through state in switching table of direct torque control, DC link voItage in qZSI is boosted. The DC link voItage hysteresis controller uses the input and capacitor voItage for controlling DC link voItage. If there is any disturbance in input voItage, the reference for capacitor voItage will be changed accordingly to maintain the DC link voItage.

REFERENCES:

 [I] 1. Takahashi and Y. Ohmori, “High-performance direct torque control of an induction motor, ” IEEE Trans. Ind. Appl., vol. 25, no. 2, pp. 257-264, 1989.

[2] B.-S. Lee and R. Krishnan, “Adaptive stator resistance compensator for high performance direct torque controlled induction motor drives, ” in Industry Applications Conference, 1998. Thirty-Third lAS Annual Meeting. The 1998 IEEE, vol. I, Oct 1998, pp. 423-430 voLl.

[3] G. Buja and M. Kazmierkowski, “Direct torque control of pwm inverter-fed ac motors-a survey, ” IEEE Trans. Ind. Electron., vol. 51, no. 4, pp. 744-757, Aug 2004.

[4] F. Z. Peng, “Z-source inverter, ” IEEE Trans. Ind. Appl., vol. 39, no. 2, pp. 504-510, Mar 2003.

[5] F. Z. Peng, A. Joseph, J. Wang, M. Shen, L. Chen, Z. Pan, E. Ortiz-Rivera, and Y. Huang, “Z-source inverter for motor drives, ” IEEE Trans. Power Electron., vol. 20, no. 4, pp. 857-863, July2005.

Improved MPPT method to increase accuracy and speed in photovoltaic systems under variable atmospheric conditions

ABSTRACT:

The changes in temperature and radiation cause visible fluctuations in the output power produced by the photovoltaic (PV) panels. It is essential to keep the output voltage of the PV panel at the maximum power point (MPP) under varying temperature and radiation conditions. In this study, a maximum power point tracking (MPPT) method has been developed which is based on mainly two parts: the first part is adapting calculation block for the reference voltage point of MPPT and the second one is Fuzzy Logic Controller (FLC) block to adjust the duty cycle of PWM applied switch (Mosfet) of the DC-DC converter. In order to evaluate the robustness of the proposed method, Matlab/Simulink program has been used to compare with the traditional methods which are Perturb & Observe (P&O), Incremental Conductance (Inc. Cond.) and FLC methods under variable atmospheric conditions. When the test results are observed, it is clearly obtained that the proposed MPPT method provides an increase in the tracking capability of MPP and at the same time reduced steady state oscillations. The accuracy of the proposed method is between 99.5% and 99.9%. In addition, the time to capture MPP is 0.021 sec. It is about four times faster than P&O and five times faster than for Inc. Cond. and, furthermore, the proposed method has been compared with the conventional FLC method and it has been observed that the proposed method is faster about 28% and also its efficiency is about 1% better than FLC method.

KEYWORDS:

  1. PV
  2. MPPT methods
  3. FLC based MPPT
  4. DC-DC converter

SOFTWARE: MATLAB/SIMULINK

 CONCLUSION:

This study proposes a novel MPPT method and the detailed performance comparison with commonly used methods such as P&O, Incremental conductance and FLC techniques is achieved. Under sudden change in atmospheric operating conditions, the proposed MPPT method performs better performance than other methods to determine MPP. The efficiency of proposed MPPT method is between 99.5% and 99.9%, while P&O is between 91% and 98%, Inc. Cond. Is between 96% and 99% and FLC is between 98.8% and 99.4% for all case studies. The proposed MPPT method has achieved the lowest oscillation rate at the MPP compared to commonly used methods. This brings the method to the forefront in terms of efficiency. The duration of the proposed MPPT technique to reach a steady state has been measured as 0.021 sec. It is about four times faster than P&O and five times faster than for Inc. Cond. and, furthermore, the proposed method has been compared with the conventional FLC method and it has been observed that the proposed method is faster about 28% than FLC method this means the speed of proposed MPPT technique is the best. At the same time, the amount of oscillation is very low compared to conventional methods. The accuracy of the algorithm is high (%99.9 in many study cases) and also the proposed method is easy to implement in the system.

REFERENCES:

[1] Luo HY, Wen HQ, Li XS, Jiang L, Hu YH. Synchronous buck converter based low cost and high-efficiency sub-module DMPPT PV system under partial shading conditions. Energy Convers Manage 2016;126:473–87.

[2] Babaa SE, Armstrong M, Pickert V. Overview of maximum power point tracking control methods for PV systems. J Power Energy Eng 2014;2:59–72.

[3] Dolara AFR, Leva S. Energy comparison of seven MPPT techniques for PV systems. J Electromagn Anal Appl 2009;3:152–62.

[4] Ngan MS, Tan CW. A study of maximum power point tracking algorithms for standalone photovoltaic systems. Applied Power Electronics Colloquium (IAPEC): IEEE. 2011. p. 22–7.

[5] Liu JZ, Meng HM, Hu Y, Lin ZW, Wang W. A novel MPPT method for enhancing energy conversion efficiency taking power smoothing into account. Energy Convers Manage 2015;101:738–48.

Power Quality Analysis and Enhancement of Grid Connected Solar Energy System

ABSTRACT:

In recent years, renewable energy resources are utilized to meet the growing energy demand. The  integration of renewable energy resources with the grid incorporates power electronic converters for conversion of energy. These power electronic converters introduce power quality issues such as a harmonics, voltage regulation etc. Hence, to improve the power quality issues, this work proposes a new control strategy for a grid interconnected solar system. In this proposed work, a maximum power point tracking (MPPT) scheme has been used to obtain maximum power from the solar system and DC/DC converter is implemented to maintain a constant DC voltage. An active filtering method is utilized to improve the power quality of the grid connected solar system. The proposed system is validated through dynamic simulation using MATLAB/Simulink Power system toolbox and results are delivered to validate the effectiveness of the work.

KEYWORDS:

  1. Power Quality
  2. Active Power Filter
  3. Fuzzy Controller
  4. Harmonics Compensation

 SOFTWARE: MATLAB/SIMULINK

CONCLUSION:

This work has presented a novel control of an existing grid interfacing inverter to improve the quality of power at PCC. It has been proved that the grid-interfacing inverter can be effectively utilized for power conditioning without affecting its normal operation of real power transfer. This approach eliminates the need for additional power conditioning equipment to improve the quality of power. Extensive MATLAB/Simulink simulation results have validated the proposed approach and have shown that the grid-interfacing inverter can be utilized as a multi-function device.

REFERENCES:

[1] Akagi, H. (2006) Modern Active Filters and Traditional Passive Filters. Bulletin of the Polish Academy of Sciences Technical Sciences, 54, 255-269.

[2] Kazem, H.A. (2013) Harmonic Mitigation Techniques Applied to Power Distribution Networks. Advances in Power Electronics. http://dx.doi.org/10.1155/2013/591680

[3] Ravindra, S., Veera Reddy, V.C., Sivanagaraju, S. and Gireesh Kumar, D. (2012) Design of Shunt Active Power Filter to Eliminate the Harmonic Currents and to Compensate the Reactive Power under Distorted and or Imbalanced Source Voltages in Steady State. International Journal of Engineering Trends and Technology, 3, 1-6.

[4] Kumar, A. and Singh, J. (2013 Harmonic Mitigation and Power Quality Improvement Using Shunt Active Power Filter. International Journal of Electrical, Electronics and Mechanical Control, 2, 13 p.

[5] Gligor, A. (2009) Design and Simulation of a Shunt Active Filter in Application for Control of Harmonic Levels. Acta Universitatis Sapientiae, Electrical and Mechanical Engineering, 53-63.

A Novel Design of Hybrid Energy Storage System for Electric Vehicles

ABSTRACT:  

In order to provide long distance capacity and secure the minimization of a cost function for electric vehicles, a new hybrid energy storage system for electric vehicle is create in this paper. For the hybrid energy storage system, the paper suggest an optimal control algorithm create using a Li-ion battery power dynamic limitation rule-based control based on the SOC of the super-capacitor. At the same time, the magnetic integration technology adding a second-order Bessel low-pass filter is introduced to DC-DC converters of electric vehicles. As a result, the size of battery is reduced, and the power quality of the hybrid energy storage system is increase. Finally, the efficiency of the proposed method is confirm by simulation and experiment.

KEYWORDS:
  1. Hybrid energy storage system
  2. Integrated magnetic structure
  3. Electric vehicles
  4. DC-DC converter
  5. Power dynamic limitation

 SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

Fig.1 Topology of the hybrid energy storage system

EXPECTED SIMULATION RESULTS:

(a) Power command and actual power

 

(b) Power of the super-capacitor and Li-ion battery

Fig.2 Simulation results of the proposed HESS

  • (a) Battery current

(b) Super-capacitor current

(c) Load current

  • (d) Load voltage

Fig.3 Simulation results of the proposed HESS applied on electric vehicles

 

CONCLUSION:

 In this paper, a new hybrid energy storage system for electric vehicles is create based on a Li-ion battery power dynamic limitation rule-based HESS energy management and a new bi-directional DC/DC converter. The system is compared to traditional hybrid energy storage system, showing it has significant advantage of reduced volume and weight. Moreover, the ripple of output current is reduced and the life of battery is improved.

REFERENCES:

[1] Zhikang Shuai, Chao Shen, Xin Yin, Xuan Liu, John Shen, “Fault analysis of inverter-interfaced distributed generators with different control schemes,” IEEE Transactions on Power Delivery, DOI: 10. 1109/TPWRD. 2017. 2717388.

[2] Zhikang Shuai, Yingyun Sun, Z. John Shen, Wei Tian, Chunming Tu, Yan Li, Xin Yin, “Microgrid stability: classification and a  review,” Renewable and Sustainable Energy Reviews, vol.58, pp. 167-179, Feb. 2016.

[3] N. R. Tummuru, M. K. Mishra, and S. Srinivas, “Dynamic energy management of renewable grid integrated hybrid  energy storage system, ” IEEE Trans. Ind. Electron., vol. 62, no. 12, pp. 7728-7737, Dec. 2015.

[4] T. Mesbahi, N. Rizoug, F. Khenfri, P. Bartholomeus, and P. Le Moigne, “Dynamical modelling and emulation of Li-ion batteries- supercapacitors hybrid power supply for electric vehicle applications, ” IET Electr. Syst. Transp., vol.7, no.2, pp. 161-169, Nov. 2016.

[5] A. Santucci, A. Sorniotti, and C. Lekakou, “Power split strategies for hybrid energy storage systems for vehicular applications, ” J. Power Sources, vol. 258, no.14, pp. 395-407,  2014.

Varying Phase Angle Control In Isolated Bidirectional DC–DC Converter For Integrating Battery Storage And Solar PV System In Standalone Mode

ABSTRACT:

This study proposes a varying phase angle control (VPAC) in isolated bidirectional dc–dc converter (IBDC) for integrating battery storage unit to a DC link in a standalone solar photovoltaic (PV) system. The IBDC is capable of power transfer using high step up/down ratio between DC link and battery.  VPAC control proposed in this study effectively manage the power flow control between the battery storage unit and the solar PV fed DC link by continuously varying the phase angle between high voltage and low voltage (LV) bridge voltage of the IBDC.

Solar PV system is include with the maximum power point tracking using DC–DC converter. In order to control the voltage across the AC load a voltage source inverter is used. The study also presents the design form of the IBDC converter for the application considered. The performance of the proposed power flow control design has been studied through PSCAD/EMTDC simulation and validated using LPC 2148 ARM processor.

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Fig. 1 Block diagram for proposed standalone system

(a) Generalised block diagram, (b) Mode 1 operation, (c) Mode 2 operation, (d) Mode 3 operation

EXPECTED SIMULATION RESULTS:

 

 Fig. 2 Simulation results of IBDC

(a) Battery current during change in mode 1 to mode 2, (b) Battery current during change in mode 2 to mode 1, (c) Solar PV power, load power and battery power during change in mode 1 to mode 2, (d) Solar PV power, load power and battery power during change in mode 2 to mode 1

 CONCLUSION: 

The proposed variable phase angle control of IBDC converter balances the power flow between the solar PV system, battery storage unit and AC load in all the modes.  VPAC algorithm ensures that the, (i) solar PV system delivers maximum demanded power corresponding to the load and battery gets charged/ discharged through the available excess/short power.

Governing mathematical formulation of problem reveals the need of average battery current on phase angle between the voltages of LV and HV side of the IBDC converter and hence provides a strategy to control the power flow.

Analysis presented can be used to method the passive components and switches of the IBDC. From the obtained results, the performance of the proposed VPAC has been established with smooth transition of power flow between the PV fed DC link and the battery through the IBDC converter. The maximum power is essence from the solar PV and AC load voltage is controlled in all the modes.

REFERENCES:

[1] Bull, S.R.: ‘Renewable energy today and tomorrow’, Proc. IEEE, 2001, 89, (8), pp. 1216–1226

[2] Solodovnik, E.V., Liu, S., Dougal, R.A.: ‘Power controller design for maximum power tracking in solar installations’, IEEE Trans. Power Electron., 2004, 19, (5), pp. 1295–1304

[3] Kuo, Y.-C., Liang, T.-J., Chen, J.-F.: ‘Novel maximum-power-point tracking controller for photovoltaic energy conversion system’, IEEE Trans. Ind. Electron., 2001, 48, (3), pp. 594–601

[4] Koutroulis, E., Kalaitzakis, K., Voulgaris, N.C.: ‘Development of a microcontroller-based, photovoltaic maximum power point tracking control system’, IEEE Trans. Power Electron., 2001, 16, (1), pp. 46–54

Direct Torque Control using Switching Table for Induction Motor Fed by Quasi Z-Source Inverter

ABSTRACT:

 Z-source inverters eliminate the need for front-end DC-DC boost converters in applications with limited DC voltage such as solar PV, fuel cell. Quasi Z-source inverters offer advantages over Z-source inverter, such as continuous source current and lower component ratings. In this paper, switching table based Direct Torque Control (DTC) of induction motor fed by quasi Z-Source Inverter (qZSI) is presented.

In the proposed technique, dc link voltage is boosted by incorporating shoot through state into the switching table. This simplifies the implementation of DTC using qZSI. An additional DC link voltage hysteresis controller is included along with torque and flux hysteresis controllers used in conventional DTC. The results validate the boost capability of qZSI and torque response of the DTC.

KEYWORDS:

  1. DTC
  2. QZSI
  3. DC-DC Converter
  4. DC Link Voltage
  5. Hysteresis Controller

 SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

 

Fig. 1: Block Diagram for DTC using qZSI

EXPECTED SIMULATION RESULTS:

 Fig.2: Torque vs. Time

Fig. 3: Stator Phase ‘a’ Current

Fig. 4: Speed vs. Time

Fig. 5: DC Link Voltage

Fig. 6: Capacitor Voltage, VC1

 CONCLUSION:

 In this paper, direct torque control of induction motor fed by qZSI is presented. Dynamic torque response for step change obtained is 3 ms, which is needed for high performance applications. qZSI provides a single stage solution for drives with variable input DC voItage, instead of DC-DC converter cascaded with 3-leg inverter bridge.

This paper presents a solution for drives with lesser DC input voItage availability and also requiring very fast torque response. The results shows that by introducing shoot through state in switching table of direct torque control, DC link voItage in qZSI is boosted. The DC link voItage hysteresis controller uses the input and capacitor voItage for controlling DC link voItage. If there is any disturbance in input voItage, the reference for capacitor voItage will be changed accordingly to maintain the DC link voItage.

REFERENCES:

 [I] 1. Takahashi and Y. Ohmori, “High-performance direct torque control of an induction motor, ” IEEE Trans. Ind. Appl., vol. 25, no. 2, pp. 257-264, 1989.

[2] B.-S. Lee and R. Krishnan, “Adaptive stator resistance compensator for high performance direct torque controlled induction motor drives, ” in Industry Applications Conference, 1998. Thirty-Third lAS Annual Meeting. The 1998 IEEE, vol. I, Oct 1998, pp. 423-430 voLl.

[3] G. Buja and M. Kazmierkowski, “Direct torque control of pwm inverter-fed ac motors-a survey, ” IEEE Trans. Ind. Electron., vol. 51, no. 4, pp. 744-757, Aug 2004.

[4] F. Z. Peng, “Z-source inverter, ” IEEE Trans. Ind. Appl., vol. 39, no. 2, pp. 504-510, Mar 2003.

[5] F. Z. Peng, A. Joseph, J. Wang, M. Shen, L. Chen, Z. Pan, E. Ortiz-Rivera, and Y. Huang, “Z-source inverter for motor drives, ” IEEE Trans. Power Electron., vol. 20, no. 4, pp. 857-863, July2005.

A DSP Based Digital Control Strategy for ZVS Bidirectional Buck+Boost Converter

ABSTRACT:

 The non-isolated and bidirectional DC-DC converters are the most famous topology for low or medium power of the hybrid electric vehicle (HEV) or fuel cell vehicle (FCV) applications. These type of converters have the benefit of simple circuit topology, and bidirectional flows, zero-voltage switching (ZVS), and high efficiency, and high power density.

The turned-on ZVS for all MOSFETs is reach by the negative offset of the inductor current at the beginning and the end of each switching duration. To do this, the converter want a involved switching method which is chosen to be implemented by the digital signal processing (DSP) . This paper now the digital implementation of the switching design to provide the ZVS condition for such converter. A 5kW prototype is implement to verify the capability of such control scheme.

KEYWORDS:

  1. DC-DC converter
  2. Bidirectional converter
  3. Digital control
  4. Phase shift control

 SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

Fig1. Bidirectional dc dc converter

EXPECTED SIMULATION RESULTS:

 Fig. 2. Inductor current waveforms of (a) boost mode and (b) buck mode

Fig. 3. ZVS turn on of switch S1

Fig. 4. Overall efficiency of both boost and buck operating modes

 CONCLUSION:

 A DSP located digital control method because the bidirectional DC-DC converter is prepared in this paper. The new control method produce a negative inductor current at the beginning of each pulse period that, in conjunction with just the parasitic MOSFET output capacitances but no additional element, admit ZVS with the full voltage and load range.

The DSP chip TMS320F28035 from Texas tool is employed to do this control algorithm. The experimental results not only show the ZVS because four switches but also produce an excellent overall efficiency at least 96% at the power range.

REFERENCES:

 [1] S. S. Williamson, S. M. Lukic, and A. Emadi, “Comprehensive drive train efficiency analysis of hybrid electric and fuel cell vehicles based on motor controller efficiency modeling,” IEEE Trans. Power Electron., vol. 21, no. 3, pp. 730-740, May 2006.

[2] K. Wang, C. Y. Lin, L. Zhu, D. Qu, F. C. Lee, and J. Lai, “Bidirectional dc to dc converters for fuel cell systems,” in Conf. Rec. 1998 IEEE Workshop Power Electronics in Transportation, pp. 47-51.

[3] A. Emadi, S. S. Williamson, and A. Khaligh, “Power electronics intensive solutions for advanced electric, hybrid electric, and fuel cell vehicular power systems,” IEEE Trans. Power Electron., vol. 21, no. 3, pp. 567-577, May 2006.

[4] D. Patel Ankita, “Analysis of bidirectional Buck-Boost converter by using PWM control scheme,” ISSN: 2321-9939, Electronics and Communication, Marwadi Education Foundation Group of Institute, Rajkot, India.

[5] Texas Instruments, “Modeling of bidirectional Buck/Boost converter for digital control using C2000 microcontroller,” Application report SPRABX5, January 2015.

Grid to Vehicle and Vehicle to Grid Energy Transfer using Single-Phase Bidirectional AC-DC Converter and Bidirectional DC – DC converter

ABSTRACT:

 In this paper, a configuration of a single-phase bidirectional AC-DC converter and bidirectional DC-DC converter is proposed to transfer electrical power from the grid to an electrical vehicle (EV) and from an EV to the grid while keeping improved power factor of the grid. In first stage, a 230 V 50 Hz AC supply is converted in to 380V dc using a single-phase bidirectional AC-DC converter and in the second stage, a bidirectional buck–boost dc-dc converter is used to charge and discharge the battery of the PHEV (Plug-in Hybrid Electric Vehicle).

In discharging mode, it delivers energy back to the grid at 230V, 50 Hz. A battery with the charging power of 1.2 kW at 120V is used in PHEV. The buck-boost DC-DC converter is used in buck mode to charge and in a boost mode to discharge the battery. A proportional-integral (PI) controller is used to control the charging current and voltage. Simulated results validate the effectiveness of proposed algorithm and the feasibility of system.

KEYWORDS:
  1. Plug-in Hybrid Electric Vehicle (PHEV)
  2. Bidirectional AC-DC Converter
  3. DC-DC Converter
  4. Vehicle to grid (V2G)
  5. Electric drive vehicle (EDVs)

 SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

 Fig.1 Proposed configuration for V2G and G2V Energy transfer

 EXPECTED SIMULATION RESULTS:

 Fig.2 Charging and discharging of PHEV battery (Full profile)

               Fig.3 Charging and discharging of PHEV battery (in large view)

Fig.4. Discharging and Charging of PHEV battery demonstrating unity

Power factor operation

Fig.5 Waveform and harmonics spectrum of the discharging grid current

Fig.6 Waveform and harmonics spectrum of the Charging grid current

CONCLUSION:

The proposed converter has delivered the AC current to/and from the grid at unity power factor and at very low current harmonics which ultimately prolongs the life of the converter and the battery and minimizes the possibility of distorting the grid voltage. It also enables V2G interactions which could be utilized to improve the efficiency of the grid.

REFERENCES:

[1] Young-Joo Lee, Alireza Khaligh, and Ali Emadi, “Advanced Integrated Bidirectional AC/DC and DC/DC Converter for Plug-In Hybrid Electric Vehicles,” IEEE Trans. on Vehicular Tech. vol. 58, no. 8, pp. 3970-3980, Oct, 2009.

[2] Bhim Singh, Brij N. Singh, Ambrish Chandra, Kamal Al-Haddad, Ashish Pandey and Dwarka P. Kothari, “A review of single-phase improved power quality ac–dc converters,” IEEE Trans. Industrial Electronics, vol. 50, no. 5, pp. 962-981, Oct. 2003.

[3] M.C. Kisacikoglu, B. Ozpineci and L.M. Tolbert, “Examination of a PHEV bidirectional charger system for V2G reactive power compensation,” in Proc. of Twenty-Fifth Annual IEEE Applied Power Electronics Conference and Exposition (APEC), 2010, 21-25 Feb.2010, pp.458-465.

[4] M.C. Kisacikoglu, B. Ozpineci and L.M. Tolbert, “Effects of V2G reactive power compensation on the component selection in an EV or PHEV bidirectional charger,” in Proc. of Energy Conversion Congress and Exposition (ECCE), 2010 IEEE, 12-16 Sept. 2010, pp.870-876.

[5] W. Kempton and J. Tomic, “Vehicle-to-grid power fundamentals: Calculating capacity and net revenue,” J. Power Sources, vol. 144, no. 1, pp. 268–279, Jun. 2005.

Power management in PV-battery-hydro based standalone microgrid

ABSTRACT:

This work deals with the frequency regulation, voltage regulation, power management and load levelling of solar photovoltaic (PV)-battery-hydro based microgrid (MG). In this MG, the battery capacity is reduced as compared to a system, where the battery is directly connected to the DC bus of the voltage source converter (VSC). A bidirectional DC–DC converter connects the battery to the DC bus and it controls the charging and discharging current of the battery. It also regulates the DC bus voltage of VSC, frequency and voltage of MG. The proposed system manages the power flow of different sources like hydro and solar PV array. However, the load levelling is managed through the battery. The battery with VSC absorbs the sudden load changes, resulting in rapid regulation of DC link voltage, frequency and voltage of MG. Therefore, the system voltage and frequency regulation allows the active power balance along with the auxiliary services such as reactive power support, source current harmonics mitigation and voltage harmonics reduction at the point of common interconnection. The experimental results under various steady state and dynamic conditions, exhibit the excellent performance of the proposed system and validate the design and control of proposed MG.

 SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:
Fig. 1 Microgrid Topology and MPPT Control

(a) Proposed PV-battery-hydro MG

 EXPECTED SIMULATION RESULTS

 

 Fig. 2 Dynamic performance of PV-battery-hydro based MG following by solar irradiance change

(a) vsab, isc, iLc and ivscc, (b) Vdc, Ipv, Vb and Ib, (c) vsab, isa, iLa and ivsca, (d) Vdc, Ipv, Vb and Ib

 

Fig. 3 Dynamic performance of hydro-battery-PV based MG under load perturbation

(a) vsab, isc, Ipv and ivscc, (b) Vdc, Ipv, Vb and Ib, (c) vsab, isc, Ipv and ivscc, (d) Vdc, Ipv, and Vb

CONCLUSION:

In the proposed MG, an integration of hydro with the battery, compensates the intermittent nature of PV array. The proposed system uses the hydro, solar PV and battery energy to feed the voltage (Vdc), solar array current (Ipv), battery voltage (Vb) and battery current (Ib). When the load is increased, the load demand exceeds the hydro generated power, since SEIG operates in constant power mode condition. This system has the capability to adjust the dynamical power sharing among the different RES depending on the availability of renewable energy and load  demand. A bidirectional converter controller has been successful to maintain DC-link voltage and the battery charging and discharging currents. Experimental results have validated the design and  control of the proposed system and the feasibility of it for rural area electrification.

REFERENCES:

[1] Ellabban, O., Abu-Rub, H., Blaabjerg, F.: ‘Renewable energy resources: current status, future prospects and technology’, Renew. Sustain. Energy Rev.,2014, 39, pp. 748–764

[2] Bull, S.R.: ‘Renewable energy today and tomorrow’, Proc. IEEE, 2001, 89  (8), pp. 1216–1226

[3] Malik, S.M., Ai, X., Sun, Y., et al.: ‘Voltage and frequency control strategies of hybrid AC/DC microgrid: a review’, IET Renew. Power Gener., 2017, 11, (2), pp. 303–313

[4] Kusakana, K.: ‘Optimal scheduled power flow for distributed photovoltaic/ wind/diesel generators with battery storage system’, IET Renew. Power  Gener., 2015, 9, (8), pp. 916–924

[5] Askarzadeh, A.: ‘Solution for sizing a PV/diesel HPGS for isolated sites’, IET Renew. Power Gener., 2017, 11, (1), pp. 143–151