A Unified Control and Power Management Schemefor PV-Battery-Based Hybrid Microgrids for BothGrid-Connected and Islanded Modes

ABSTRACT:  

Battery storage is usually employed in Photovoltaic (PV) system to mitigate the power fluctuations due to the characteristics of PV panels and solar irradiance. Control schemes for PV-battery systems must be able to stabilize the bus voltages as well as to control the power flows flexibly. This paper proposes a comprehensive control and power management system (CAPMS) for PV-battery-based hybrid microgrids with both AC and DC buses, for both grid-connected and islanded modes. The proposed CAPMS is successful in regulating the DC and AC bus voltages and frequency stably, controlling the voltage and power of each unit flexibly, and balancing the power flows in the systems automatically under different operating circumstances, regardless of disturbances from switching operating modes, fluctuations of irradiance and temperature, and change of loads. Both simulation and experimental case studies are carried out to verify the performance of the proposed method.

KEYWORDS:

  1. Solar PV System
  2. Battery
  3. Control and Power Management System
  4. Distributed Energy Resource
  5. Microgrid
  6. Power Electronics
  7. dSPACE

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. The proposed control and power management system (CAPMS) for PV-battery-based hybrid microgrids.

 EXPECTED SIMULATION RESULTS:

Fig.. 2.. (Gb)rid-connected mode Case A-1: (a) power flows and (b) voltage

values of the PV-battery system.

Fig. 3. Grid-connected mode Case A-2: power flows of the PV-battery system.

Fig. 4. Grid-connected mode Case A-3-1: PV array in power-reference mode.

Fig. 5. Grid-connected mode Case A-3-2: DC bus and PV array voltages

during transitions between MPPT and power-reference modes.

Fig. 6. Grid-connected mode Case A-4: the PV-battery system is receiving

power from the grid after 2.2 s.

Fig. 7. Grid-connected mode Case A-5: Reactive power control of the

inverter.

Fig. 8. Grid-connected mode Case A-6: transition from grid-connected to

islanded mode.

Fig. 9. Islanded mode Case B-1: power flows of the PV-battery system with

changing loads.

Fig. 10. Islanded mode Case B-2: battery power changes with PV generation.

Fig. 11. Islanded mode Case B-3: bus voltage control of the PV-battery

system.

Fig. 12. Islanded mode Case B-4: (a) unsynchronized and (b) synchronized

AC bus voltages (displaying phase-a) when closing the breaker at the PCC.

CONCLUSION:

 This paper proposes a control and power management system (CAPMS) for hybrid PV-battery systems with both DC and AC buses and loads, in both grid-connected and islanded modes. The presented CAPMS is able to manage the power flows in the converters of all units flexibly and effectively, and ultimately to realize the power balance between the hybrid microgrid system and the grid. Furthermore, CAPMS ensures a reliable power supply to the system when PV power fluctuates due to unstable irradiance or when the PV array is shut down due to faults. DC and AC buses are under full control by the CAPMS in both grid-connected and islanded modes, providing a stable voltage environment for electrical loads even during transitions between these two modes. This also allows additional loads to access the system without extra converters, reducing operation and control costs. Numerous simulation and experimental case studies are carried out in Section IV that verifies the satisfactory performance of the proposed CAPMS.

REFERENCES:

[1] T. A. Nguyen, X. Qiu, J. D. G. II, M. L. Crow, and A. C. Elmore, “Performance characterization for photovoltaic-vanadium redox battery microgrid systems,” IEEE Trans. Sustain. Energy, vol. 5, no. 4, pp. 1379–1388, Oct 2014.

[2] S. Kolesnik and A. Kuperman, “On the equivalence of major variable step- size MPPT algorithms,” IEEE J. Photovolt., vol. 6, no. 2, pp. 590– 594, March 2016.

[3] H. A. Sher, A. F. Murtaza, A. Noman, K. E. Addoweesh, K. Al-Haddad, and M. Chiaberge, “A new sensorless hybrid MPPT algorithm based on fractional short-circuit current measurement and P&O MPPT,” IEEE Trans. Sustain. Energy, vol. 6, no. 4, pp. 1426–1434, Oct 2015.

[4] Y. Riffonneau, S. Bacha, F. Barruel, and S. Ploix, “Optimal power flow management for grid connected PV systems wi0th batteries,” IEEE Trans. Sustain. Energy, vol. 2, no. 3, pp. 309–320, July 2011.

[5] H. Kim, B. Parkhideh, T. D. Bongers, and H. Gao, “Reconfigurable solar converter: A single-stage power conversion PV-battery system,” IEEE Trans. Power Electron., vol. 28, no. 8, pp. 3788–3797, Aug 2013.

Energy Management and Control System for Laboratory Scale Microgrid based Wind-PV-Battery

ABSTRACT:  

This paper proposes an energy management and control system for laboratory scale microgrid based on hybrid energy resources such as wind, solar and battery. Power converters and control algorithms have been used along with dedicated energy resources for the efficient operation of the microgrid. The control algorithms are developed to provide power compatibility and energy management between different resources in the microgrid. It provides stable operation of the control in all microgrid subsystems under various power generation and load conditions. The proposed microgrid, based on hybrid energy resources, operates in autonomous mode and has an open architecture platform for testing multiple different control configurations. Real-time control system has been used to operate and validate the hybrid resources in the microgrid experimentally. The proposed laboratory scale microgrid can be used as a benchmark for future research in smart grid applications.

KEYWORDS:

  1. Wind energy
  2. Solar energy
  3. Conversion
  4. Storage
  5. Hybrid system
  6. Control
  7. Energy management

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 Fig. 1. Components of the laboratory scale experimental microgrid

 EXPECTED SIMULATION RESULTS:

Fig. 2. Wind turbine-generator speed

Fig. 3. PV module current

 

Fig. 4. DC-link voltage

Fig. 5. Battery current

Fig. 6. Power at different locations in the microgrid (variable wind power)

Fig. 7. Battery state of charge

Fig. 8. Load Voltage

Fig. 9. Power at different locations in the microgrid (variable wind power)

Fig. 10. Battery current

Fig. 11. Battery state of charge

Fig. 12. DC-bus voltage

Fig. 13. Load Voltage

CONCLUSION:

 A laboratory scale experimental microgrid of distributed renewable energy sources with battery storage and energy management and control system is developed in this paper. The experimental setup is flexible and allows testing difference power electronics interfaces and combinations. The control software is open source in order to implement different control strategies. This tool contributes to the enhancement of education and research the field of renewable energy and distributed energy systems.

REFERENCES:

[1] A. Bari, J. Jiang, W. Saad and A. Jaekel, “Challenges in the Smart Grid Applications: An Overview,” Int. J. of Distributed Sensor Networks, pp.1–12, 2014.

[2] M. B. Shadmand and R. S. Balog, “Multi-objective optimization and design of photovoltaic-wind hybrid system for community smart DC microgrid,” IEEE Trans. Smart Grid, vol. 5, no. 5, pp. 2635–2643, Sep. 2014.

[3] M. J. Hossain, H. R. Pota, M. A. Mahmud and M. Aldeen, “Robust control for power Sharing in microgrids with low-inertia wind and PV generators,” IEEE Trans. Sustain. Energy, vol. 6, no. 3, pp. 1067–1077, Jul. 2015.

[4] Zaheeruddin and M. Manas, “Renewable energy management through microgrid central controller design: an approach to integrate solar, wind and biomass with battery,” Energy Reports, vol. 1, pp.156–163, 2015.

[5] A. Tani, M. B. Camara and B. Dakyo, “Energy management in the decentralized generation systems based on renewable energy—ultracapacitors and battery to compensate the wind/load power fluctuations,” IEEE Trans. Ind. Appl., vol. 51, no. 2, pp. 1817–1827, 2015.

 

Control Strategy of Photovoltaic Generation Inverter Grid-Connected Operating and Harmonic Elimination Hybrid System

ABSTRACT:  

This paper proposes a three-phase three-wire photovoltaic generation inverter grid-connected operating and harmonic elimination hybrid system. The hybrid system mainly consists of photovoltaic array battery, photovoltaic output filter, three-phase voltage-type inverter, inverter output filter and passive filters. Based on working principle and working characteristics of the proposed hybrid system, the composite control strategy about active power, reactive power  and harmonic suppression is proposed. The composite control strategy mainly consists of a single closed-loop control slip of active power and reactive power, double closed-loop control slip of harmonics. Simulation results show the correctly of this paper’s contents, the hybrid system have an effective to improve power factor, supply active power for loads and suppress harmonics of micro-grid.

KEYWORDS:

  1. Micro grid
  2. Harmonic restraint
  3. Active power control
  4. Reactive power control
  5. Photovoltaic generation

 SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

  • Figure 1. Structure of novel hybrid system.

 EXPECTED SIMULATION RESULTS:

 (a) Current dynamic waveform of load and grid side

 

(b) Current spectrum waveform of load and grid side

(c) Voltage and current dynamic waveform of grid side

(d) Voltage waveform of the DC capacitor

Figure 2. Simulation results when photovoltaic generation is connected.

(a) Current dynamic waveform of load and grid side

(b) Current spectrum waveform of load and grid side

(c) Voltage and current dynamic waveform of grid side

(d) Voltage waveform of the DC capacitor

Figure 3. Simulation results when photovoltaic generation is not connected.

CONCLUSION:

 Aiming at the shortages and problems of active power, reactive power and harmonic control technology in microgrid, a three-phase three-wire photovoltaic generation inverter grid-connected operating and harmonic elimination hybrid system is proposed in this paper. The principle and control strategy of the proposed hybrid system are studied. Through the research of this paper, the following conclusions can be drawn:

(1) The compensation of active, reactive power and the real-time dynamic control of harmonics can be realized through the proposed hybrid system.

(2) Based on the working principle of the proposed hybrid system at different time, the hybrid control method of active power, reactive power and harmonic suppression is proposed. The proposed control strategy is simple and easy to be implied in engineering.

(3) Simulation results show the correctly of this paper’s contents, at the same time, the proposed control method can also be applied to other similar systems in this paper.

REFERENCES:

[1] Ding Ming, Wang Min.Distributed generation technology. Electric Power Automation Equioment, vol. 24, no.7, pp. 31–36, July 2004.

[2] Liang Youwei , Hu Zhijian , Chen Yunping. A survey of distributed generation and it s application in power system. Power System Technology, vol. 27, no.12, pp. 71-75, December 2003.

[3] Wang Chengshan, Xiao Chaoxia, Wang Shouxiang. Synthetical Control and Analysis of Microgrid. Automation of Electric Power Systems, vol. 32, no.7, pp. 98-103, April 2008.

[4] Liu Yang-hua1,Wu Zheng-qiu,Lin Shun-jiang. Research on Unbalanced Three-phase Power Flow Calculation Method in Islanding Micro Grid. Journal of Hunan University(Natural Sciences) , vol. 36, no.7, pp. 36-40, July 2009.

[5] Xie Qing Hua, Simulation Study on Micro-grid Connection/Isolation Operation Containing Multi-Micro-sources. Shanxi Electric Power,vol. 37, no.8, pp. 10-13, August 2009.

Performance Investigation of Shunt Hybrid Active Power Filter With A Synchronous Reference Frame BasedController

ABSTRACT:  

This paper presents a novel synchronous reference frame based (SRF) control strategy for shunt hybrid active power filter (SHAPF). The control strategy includes a direct current control (DCC) and an indirect current control (ICC) strategy. SHAPF can achieve harmonic compensation and dynamic reactive power compensation with the proposed controller. In this proposed method, as distinct from studies in literature, dynamic reactive power compensation and dc link voltage control is realized with ICC and harmonic current compensation is realized with DCC. Also, the proposed controller provides a variable SHAPF dc link voltage which is adjusted according to the reactive power compensation requirements in order to decrease the switching losses of converter and achieve power savings. The performance of proposed controller is verified with experimental results.

KEYWORDS:

  1. Active Power Filter (APF)
  2. Harmonics
  3. Reactive Power Compensation
  4. Direct Current Control
  5. Indirect Current Control

 SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

Fig. 1. Power Circuit Diagram of SHAPF

 EXPECTED SIMULATION RESULTS:

(a)

(b)

Fig.2. Reactive Power Trend (a) and Current Harmonic Spec. (b) of Case I

(a)

(b)

Fig.3. Reactive Power Trend (a) and Current Harmonic Spec. (b) of Case II

CONCLUSION:

 This paper presents a SRF based controller approach for SHAPF. In proposed control method, DCC strategy is preferred for harmonic compensation control to maintain superior dynamic and steady state performance on the compensation of low order harmonics. ICC strategy is used for the reactive power compensation controller and the dc link voltage controller to simplify the controller and provide a successful performance without being affected by dynamic changes in active and reactive current components. Additionally, the dc link voltage is determined with adaptive to the reactive power demand of load by the proposed control method. By the help of this ability, the switching losses of SHAPF is decreased by keeping only required voltage level on dc link. The proposed control method is applied on the laboratory prototype of SHAPF. The steady state and dynamic performance of controller is verified with the experimental results.

REFERENCES:

[1] H. Fujita and H. Akagi, “A practical approach to harmonic compensation in power systems-series connection of passive and active filters,” IEEE Trans. Ind. Appl., vol. 27, no. 6, pp. 1020–1025, 1991.

[2] H. Akagi, “Active and hybrid filters for power conditioning,” ISIE’2000. Proc. 2000 IEEE Int. Symp. Ind. Electron. (Cat. No.00TH8543), vol. 1, 2000.

[3] H. Fujita, T. Yamasaki, and H. Akagi, “A hybrid active filter for damping of harmonic resonance in industrial power systems,” IEEE Trans. Power Electron., vol. 15, no. 2, pp. 215–222, Mar. 2000.

[4] S. Srianthumrong and H. Akagi, “Medium-voltage transformerless ac/dc power conversion system consisting of a diode rectifier and a shunt hybrid filter,” IEEE Trans. Ind. Appl., vol. 39, no. 3, pp. 874–882, May 2003.

[5] R. Inzunza and H. Akagi, “A 6.6-kV Transformerless Shunt Hybrid Active Filter for Installation on a Power Distribution System,” IEEE Trans. Power Electron., vol. 20, no. 4, pp. 893–900, Jul. 2005.

Hybrid Shunt Active Filter Offering Unity PowerFactor and Low THD at Line Side with Reduced Power Rating

ABSTRACT:  

This paper present analysis of hybrid active power filter with synchronous reference frame control algorithm. The proposed topology consist of active power filter and passive power filter are connected in shunt with the mains feeding a nonlinear load. The shunt passive power filter is tuned to eliminate most dominate 5th order load current harmonic. The shunt active power filter is used compensate all other higher order load current harmonics. This approach help toreduce the overall rating of shunt active power filter, and maintain unity power factor at line side with low THD, which makes system more economical for industrial usage. Detail design steps for 5th order tuned filter is also discussed and results are presented. The proposed shunt active power filter is also tested for dynamic loading condition. Hardware results for the verification of proposed control algorithm is also presented and discussed.

KEYWORDS:

  1. Hybrid Active Filter
  2. Passive Filter
  3. Total Harmonic Distortion
  4. Synchronous Reference Frame
  5. Unity Power Factor

 SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

Fig. 1: Main Power Circuit Diagram of HAPF

 EXPECTED SIMULATION RESULTS:

 

Fig. 2: Simulation Result ofSPPF (a) Phase-A Output Load Current

without Compensation (b) Phase-A Source Current with Compensation

(c) Phase-A 5th Order Harmonic Current

(d) Phase-A Source Voltage and Source Current

Fig. 3: FFT Curve ofSPPF (a) FFT of Output Load Current without

Compensation (b) FFT o f Source Current with Compensation

Fig. 4: Simulation Result of SAPF Under Fixed Load (a) Phase-A Output

Load Current without Compensation (b) Phase-A Source Current after

Compensation (c) D C Bus Voltage Across Capacitor (d) Phase-A Actual

Compensating Current (e) Phase-A Source Voltage and Source Current

Fig. 5: Simulation Result ofSAPF under Dynamic Load (a) Phase-A

Output Load Current without Compensation (b) Phase-A Source Current

after Compensation (c) Phase-A Actual Compensating Current (d) DC

Bus Voltage Across Capacitor

Fig. 6: Hysteresis Controller Results (a) Reference and Actual

Compensating Currents of Phase-A (b) Line-Line Voltage of lnverter

 

Fig.7: FFT Curve of Source Current after Compensation by using SAPF

  • under Fixed Load (b) under Dynamic Load

Fig. 8: Simulation Result ofHAPF(a) Phase-A Load Current without

Compensation,(b) Phase-A Source Current with Compensation,

(c) Phase-A Phase Voltage and Current, (d) DC Link Voltage oflnverter,

(e) Phase-A Actual Compensating Current

Fig. 9: Simulation Result ofHAPF (a) Three Phase Output Load

Current, (b) Three Phase Load Current, (c) Three Phase Source Current,

(d) FFT Curve of Source Current with Compensation

CONCLUSION:

 This paper analyze the performance and simulation of hybrid active power filter (HAPF). Through the simulation analysis, this paper verified the mitigation of harmonic, to achieve unity power factor with reduced rating of SAPF. Proposed control technique is able to give fast dynamic response during variable load condition, which demonstrate the robustness of controllers. The proposed topology is an effort to provide cost effective solution for harmonic elimination in various industrial application

REFERENCES:

[I] B. Singh, V. Verma, A. Chandra and K. AI-Haddad ” Hybrid filter for power quality improvement” IEEE proc. Gener. Transm. Distrib. , Volume:152, No.3 , May 2005.

[2] J. Arrillaga and N. R. Watson, Power System Harmonics, 2nd ed. Hoboken, NJ: Wiley, 2003

[3] B. Singh, K. AI-Haddad, and A. Chandra, ” A reviewof active filter for power quality improvement,” IEEE Trans. Ind. Electron. , Vol. 46, nO.5 pp. 960-971 , Oct.l999.

[4] H. Akagi, ” Active harmonic filters” Proc. IEEE, vol. 93, no. 12, pp.2128-2141 , Dec. 2005.

[5] K. K. Shyu, M. Yang, Y.M. Chen, and Y.F.Lin, “Model reference Adaptive control design for a shunt active po we filter systems,” TEEE Trans. Tnd. Electron., vol. 55, no. 1, pp. 97-106, Jan. 2008.