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.

Reactive Power Control of Permanent-Magnet Synchronous Wind Generator With Matrix Converter

 ABSTRACT:

In this paper, the reactive power control of a variable speed permanent-magnet synchronous wind generator with a matrix converter at the grid side is improved. A generalized modulation technique based on singular value decomposition of the modulation matrix is used to model different modulation techniques and investigate their corresponding input reactive power capability. Based on this modulation technique, a new control method is proposed for the matrix converter which uses active and reactive parts of the generator current to increase the control capability of the grid-side reactive current compared to conventional modulation methods. A new control structure is also proposed which can control the matrix converter and generator reactive current to improve the grid-side maximum achievable reactive power for all wind speeds and power conditions. Simulation results prove the performance of the proposed system for different generator output powers.

KEYWORDS:

  1. Matrix converter
  2. Permanent-magnet synchronous generator (PMSG)
  3. Reactive power control
  4. Singular value decomposition (SVD) modulation
  5. Variable-speed wind generator

 SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Fig. 1. Simplified control block diagram of a PMSG.

EXPECTED SIMULATION RESULTS:

Fig. 2. Generator-side active and reactive power and the maximum grid side

reactive power versus generator shaft speed  ɷm for different strategies.

Fig. 3. Matrix converter grid-side reactive power and the generator direct axis current (Igd) , terminal voltage and losses for ɷm = 1 rad/s.

Fig. 4. Matrix converter grid-side reactive power and the generator direct axis

Current (Igd) , terminal voltage, and losses for ɷm = 4.5 rad/s.

 CONCLUSION:

In this paper, a new control strategy is proposed to increase the maximum achievable grid-side reactive power of a matrix converter-fed PMS wind generator. Different methods for controlling a matrix converter input reactive power are investigated. It is shown that in some modulation methods, the grid-side reactive current is made from the reactive part of the generator-side current. In other modulation techniques, the grid-side reactive current is made from the active part of the generator-side current. In the proposed method, which is based on a generalized SVD modulation method, the grid-side reactive current is made from both active and reactive parts of the generator-side current. In existing strategies, a decrease in the generator speed and output active and reactive power, will decrease the grid-side reactive power capability. A new control structure is proposed which uses the free capacity of the generator reactive power to increase the maximum achievable grid-side reactive power. Simulation results for a case study show an increase in the grid side reactive power at all wind speeds if the proposed method is employed.

 REFERENCES:

[1] P. W.Wheeler, J. Rodríguez, J. C. Clare, L. Empringham, and A.Weinstein, “Matrix converters: A technology review,” IEEE Trans. Ind. Electron., vol. 49, no. 2, pp. 276–288, Apr. 2002.

[2] L. Zhang, C. Watthanasarn, and W. Shepherd, “Application of a matrix converter for the power control of a variable-speed wind-turbine driving a doubly-fed induction generator,” Proc. IEEE IECON, vol. 2, pp. 906–911, Nov. 1997.

[3] L. Zhang and C.Watthanasarn, “A matrix converter excited doubly-fed induction machine as a wind power generator,” in Proc. Inst. Eng. Technol. Power Electron. Variable Speed Drives Conf., Sep. 21–23, 1998, pp. 532–537.

[4] R. CárdenasI, R. Penal, P. Wheeler, J. Clare, and R. Blasco-Gimenez, “Control of a grid-connected variable speed wecs based on an induction generator fed by a matrix converter,” Proc. Inst. Eng. Technol. PEMD, pp. 55–59, 2008.

[5] S. M. Barakati, M. Kazerani, S. Member, and X. Chen, “A new wind turbine generation system based on matrix converter,” in Proc. IEEE Power Eng. Soc. Gen. Meeting, Jun. 12–16, 2005, vol. 3, pp. 2083–2089.

Analysis and Design of Three-Level, 24-Pulse Double Bridge Voltage Source Converter Based HVDC System for Active and Reactive Power Control

ABSTRACT

This paper manages the investigation, plan and control of a three-level 24-beat Voltage Source Converter (VSC) based High Voltage Direct Current (HVDC) framework. A three dimension VSC working at essential recurrence exchanging (FFS) is proposed with 24-heartbeat VSC structure to enhance the power quality and decrease the converter exchanging misfortunes for high influence applications. The structure of three-level VSC converter and framework parameters, for example, air conditioning inductor and dc capacitor is displayed for the proposed VSC based HVDC framework. It comprises of two converter stations encouraged from two diverse air conditioning frameworks. The dynamic power is exchanged between the stations in any case. The receptive power is autonomously controlled in every converter station. The three-level VSC is worked at advanced dead edge (β). A planned control calculation for both the rectifier and an inverter stations for bidirectional dynamic power stream is created dependent on FFS and neighborhood responsive power age. This outcomes in a significant decrease in exchanging misfortunes and maintaining a strategic distance from the responsive influence plant. Recreation is conveyed to confirm the execution of the proposed control calculation of the VSC based HVDC framework for bidirectional dynamic power stream and their autonomous receptive power control.

 BLOCK DIAGRAM:

image001

Fig. 1 Three-level 24-pulse double bridge VSC based HVDC system

 

EXPECTED SIMULATION RESULTS:

image002

Fig. 2a Performance of rectifier station during reactive power control of three level 24-pulse VSC HVDC system

image003

Fig. 2b Performance of Inverter station during reactive power control at rectifier station of three-level 24 pulse VSC HVDC system

image004

Fig. 2c Variation of (δ) and (α) values for rectifier and inverter Stations for reactive power variation of a three-level 24-pulse VSC HVDC system

image005

Fig. 3a Rectifier station during active power reversal of three-level 24-pulse VSC HVDC system

image006

Fig. 3b Inverter station during active power reversal of three-level 24-pulse VSC HVDC system

image007

Fig. 3c Variation of (δ) and (α) values during active power reversal of three level 24-pulse VSC HVDC system.

 CONCLUSION

Another three-level, 24-beat voltage source converter based HVDC framework working at essential recurrence exchanging has been planned and its model has been produced and it is effectively tried for the autonomous control of dynamic and receptive forces and satisfactory dimension consonant prerequisites. The responsive power has been controlled free of the dynamic power at the two conditions. The converter has been effectively worked in each of the four quadrants of dynamic and responsive forces with the proposed control. The inversion of the dynamic power stream has been actualized by switching the course of dc current without changing the extremity of dc voltage which is exceptionally troublesome in traditional HVDC frameworks. The power nature of the HVDC framework has additionally enhanced with three-level 24-beat converter task. The symphonious execution of this three-level, 24-beat VSC has been seen to an identical to two-level 48-beat voltage source converter.