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.

Analysis of Active and Reactive Power Control of a Stand-Alone PEM Fuel Cell Power Plant

ABSTRACT:

This paper presents analytical details of how active and reactive power output of a stand-alone proton-exchange-membrane (PE M) fuel cell power plant (F C PP) is controlled. This analysis is based on an integrated dynamic model of the entire power plant including the reformer. The validity of the analysis is verified when the model is used to predict the response of the power plant to: 1) computer-simulated step changes in the load active and reactive power demand and 2) actual active and reactive load profile of a single family residence. The response curves indicate the load-following characteristics of the model and the predicted changes in the analytical parameters predicated by the analysis.

 

KEYWORDS:

  1. Active power control
  2. Fuel cell
  3. Fuel cell model,
  4. PEM fuel cell
  5. Proton exchange membrane (PEM)
  6. Reactive power.

 

BLOCK DIAGRAM:

Fig. 1. FCPP, inverter and load connection diagram.

 

EXPECTED SIMULATION RESULTS:

Fig. 2 Load step changes.

Fig. 3. FCPP output current.

Fig. 4. AC output voltage.

Fig. 5. Active output power.

Fig. 6. Reactive output power.

Fig.7 Output voltage phase angle.

Fig. 8. Hydrogen flow rate.

Fig. 9. AC output power.

Fig. 10. Active power of residential load.

Fig. 11. Reactive power of residential load.

Fig. 12 FCPP active power output.

Fig. 13. FCPP reactive power output.

                                                                                                                     CONCLUSION:

This paper introduces an integrated dynamic model for a fuel cell power plant. The proposed dynamic model includes a fuel cell model, a gas reformer model, and a power conditioning unit block. The model introduces a scenario to control active and reactive power output from the fuel cell power plant. The analysis is based on traditional methods used for the control of active and reactive power output of a synchronous generator. To test the proposed model, its active and reactive power outputs are compared with variations in load demand of a single family residence. The results obtained show a fast response of the fuel cell power plant to load changes and the effectiveness of the proposed control technique for active and reactive power output.

 

REFERENCES:

[1] M. A. Laughton, “Fuel cells,” Power Eng. J., vol. 16, no. 1, pp. 37–47, Feb. 2002.

[2] S. Um et al., “Computational fluid dynamics modeling of proton exchange membrane fuel cell,” J. Power Electrochem. Soc., vol. 147, no. 12, pp. 4485–4493, 2000.

[3] D. Singh et al., “A two-dimension analysis of mass transport in proton exchange membrane fuel cells,” Int. J. Eng. Sci., vol. 37, pp. 431–452, 1999.

[4] J. C. Amphlett et al., “A model predicting transient response of proton exchange membrane fuel cells,” J. Power Sources, vol. 61, pp. 183–188, 1996.

[5] J. Padulles et al., “An integrated SOFC plant dynamic model for power systems simulation,” J. Power Sources, vol. 86, pp. 495–500, 2000.