Control of a Small Wind Turbine in the High Wind Speed Region

ABSTRACT:

This paper proposes another delicate slowing down control methodology for network associated little wind turbines working in the high and high wind speed conditions. The proposed strategy is driven by the evaluated flow/torque points of confinement of the electrical machine as well as the power converter, rather than the appraised intensity of the associated load, which is the restricting variable in different techniques. The created technique furthermore manages the issue of framework startup keeping the generator from quickening to a wild working point under a high wind speed circumstance. This is practiced utilizing just voltage and current sensors, not being required direct estimations of the breeze speed nor the generator speed. The proposed strategy is connected to a little wind turbine framework comprising of a perpetual magnet synchronous generator and a basic power converter topology. Reproduction and test results are incorporated to exhibit the execution of the proposed technique. The paper additionally demonstrates the impediments of utilizing the stator back-emf to gauge the rotor speed in changeless magnet synchronous generators associated with a rectifier, because of noteworthy d-pivot current at high load.

 CIRCUIT DIAGRAM:

Fig. 1. Schematic representation of the wind energy generation system: a) Wind turbine, generator and power converter; b) Block diagram of the boost converter control system; c) Block diagram of the H-bridge converter control system.

EXPECTED SIMULATION RESULTS:

 

Fig. 2. Simulation result showing the behavior of the proposed method under increasing wind conditions (10 m/s, 17 m/s from 10 s, and 33 m/s from 13s): a) rectifier voltage command (v_ r ), rectifier voltage (vr) and minimum rectifier voltage command (v_ r min); b) boost current (ib), filtered boost current (~i b), current limit (ilimit) and MPPT current target (imppt); c) turbine torque (Tt) and generator torque (Tg); d) mechanical rotor speed (!rm).

 Fig. 3. Simulation result showing the behavior of the proposed method under decreasing wind conditions (30 m/s, 21 m/s from 4.5 s, and 8.5 m/s from 7s): a) rectifier voltage command (v_ r ), rectifier voltage (vr) and minimum rectifier voltage command (v_ r min); b) boost current (ib), filtered boost current (~I b), current limit (ilimit) and MPPT current target (imppt); c) turbine torque (Tt) and generator torque (Tg); d) mechanical rotor speed (!rm).

Fig. 4. Experimental results showing the behavior of the propose method under increasing wind conditions (10 m/s, 17 m/s from 10 s, and 33 m/s from 13 s): a) rectifier voltage command (v_ r ), rectifier voltage (vr) and minimum rectifier voltage command (vr min); b) boost current (ib), filtered boost current (~I b), current limit (ilimit) and MPPT current target (imppt); c) mechanical rotor speed (!rm).

 Fig. 5. Experimental results showing the behavior of the propose method under decreasing wind conditions (30 m/s, 21 m/s from 4.5 s, and 8.5 m/s from 9 s): a) rectifier voltage command (v_ r ), rectifier voltage (vr) and minimum rectifier voltage command (vr min); b) boost current (ib),filtered boost current (~I b), current limit (ilimit) and MPPT current target (imppt); c) mechanical rotor speed (!rm).

CONCLUSION:

The activity of little wind turbines for local or private venture use is driven by two variables: cost and practically unsupervised task. Extraordinarily essential is the turbine activity and insurance under high wind speeds, where the turbine torque can surpass the appraised torque of the generator. This paper proposes a delicate slow down strategy to diminish the turbine torque if a high wind speed emerges and, as a special element, the technique can early distinguish a high wind condition at startup keeping the turbine/generator running at low rotor speed maintaining a strategic distance from progressive begin and stop cycles. The proposed strategy utilizes just voltage and current sensors commonly found in little turbines making it a reasonable arrangement. Both reenactment and trial results show the legitimacy of the proposed ideas. This paper additionally demonstrates that generally utilized machine and rectifier models accepting solidarity control factor don’t give precise estimations of the generator speed in stacked conditions, regardless of whether the resistive and inductive voltage drop are decoupled, because of the noteworthy flow of d-pivot current if a PMSG is utilized. This paper proposes utilizing a pre-dispatched look-into table whose inputs are both the rectifier yield voltage and the lift current.

A New Hybrid Power Conditioner for Suppressing Harmonics and Neutral-Line Current in Three-Phase Four-Wire Distribution Power Systems

ABSTRACT:

In this paper, a new hybrid power conditioner is proposed for suppressing harmonic currents and neutral-line current in three-phase four-wire distribution power systems. The proposed hybrid power conditioner is composed of a neutral-line current attenuator and a hybrid power filter. The hybrid power filter, configured by a three-phase power converter and a three-phase tuned power filter, is utilized to filter the nonzero-sequence harmonic currents in the three-phase four-wire distribution power system. The three-phase power converter is connected to the inductors of the three-phase tuned power filter in parallel, and its power rating can thus be reduced effectively. The tuned frequency of the three-phase tuned power filter is set at the fifth harmonic frequency. The neutral- line current suppressor is connected between the power capacitors of the three-phase tuned power filter and the neutral line to suppress the neutral-line current in the three-phase four-wire distribution power system. With the major fundamental voltage of the utility dropping across the power capacitors of the three-phase tuned power filter, the power rating of the neutral-line current suppressor can thus be reduced. Hence, the proposed hybrid power conditioner can effectively reduce the power rating of passive and active elements. A hardware prototype is developed to verify the performance of the proposed hybrid power conditioner. Experimental results show that the proposed hybrid power conditioner achieves expected performance.

 KEYWORDS:

  1. Harmonic
  2. Neutral-line current
  3. Power converter

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

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Fig. 1. Configuration of the advanced hybrid power filter.

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Fig. 2. System configuration of the proposed hybrid power conditioner.

EXPECTED SIMULATION RESULTS:

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 Fig. 3. Experimental results of the balanced three-phase load: (a) phase a load current, (b) phase b load current, (c) phase c load current, and (d) neutral line current of load.

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Fig. 4. Experimental results of the hybrid power conditioner under the balanced three-phase load: (a) phase a utility current, (b) phase b utility current, (c) phase c utility current, and (d) neutral line current of the utility.

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Fig. 5. Experimental results of the three-phase four-wire hybrid power conditioner under the transient of applying the neutral-line current attenuator: (a) phase a utility voltage, (b) phase a utility current, (c) phase a load current, and (d) neutral line current of the utility.

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Fig. 6. Experimental results of the unbalanced three-phase load, (a) phase a load current, (b) phase b load current, (c) phase c load current, and (d) neutral line current of the load.

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Fig. 7. Experimental results of the hybrid power conditioner under the unbalanced three-phase load: (a) phase a utility current, (b) phase b utility current, (c) phase c utility current, and (d) neutral line current of the utility.

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Fig. 8. Experimental results of the hybrid power conditioner under the transient of increasing load: (a) phase a utility voltage, (b) phase a utility current, (c) phase a load current, and (d) neutral line current of the utility.

 CONCLUSION:

Three-phase four-wire distribution power systems have been widely applied to low-voltage applications; however, they encounter serious problems of harmonic current pollution and large neutral-line current. In this paper, a new hybrid power conditioner, composed of a hybrid power filter and a neutral- line current attenuator, is proposed. In the proposed hybrid power conditioner, the power capacity of power converters in the hybrid power filter and neutral-line current attenuator can be effectively reduced, thus increasing its use in high-power applications and enhancing the operation efficiency. A prototype is developed and tested. Experimental results verify that the proposed hybrid power conditioner can suppress the harmonic currents and attenuate the neutral-line current effectively whether the loads are balanced or not. Hence, the proposed hybrid power conditioner is an effective solution to the problems of harmonic currents and neutral-line current in three-phase four-wire distribution power systems. Besides, the output current of the three-phase power converter is much smaller than the conventional hybrid power filter, and the power rating of the zig-zag transformer is smaller than the rating of the conventional neutral-line current attenuator.

REFERENCES:

[1] B. Singh, P. Jayaprakash, T. R. Somayajulu, and D. P. Kothari, “Reduced rating VSC with a zig-zag transformer for current compensation in a three-phase four-wire distribution system,” IEEE Trans. Power Del., vol. 24, no. 1, pp. 249–259, Jan. 2009.

[2] R. M. Ciric, L. F. Ochoa, A. Padilla-Feltrin, and H. Nouri, “Fault analysis in four-wire distribution networks,” Proc. Inst. Elect. Eng., Gen., Transm. Distrib., vol. 152, no. 6, pp. 977–982, 2005.

[3] J. C. Meza and A. H. Samra, “Zero-sequence harmonics current minimization using zero-blocking reactor and zig-zag transformer,” in Proc. IEEE DRPT, 2008, pp. 1758–1764.

[4] H. L. Jou, J. C.Wu,K.D.Wu,W. J. Chiang, andY. H. Chen, “Analysis of zig-zag transformer applying in the three-phase four-wire distribution power system,” IEEE Trans. Power Del., vol. 20, no. 2, pt. 1, pp. 1168–1178, Apr. 2005.

[5] S. Choi and M. Jang, “Analysis and control of a single-phase-inverterzigzag- transformer hybrid neutral-current suppressor in three-phase four-wire systems,” IEEE Trans. Ind. Electron., vol. 54, no. 4, pp. 2201–2208, Aug. 2007.