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 Unified Nonlinear Controller Design for On-grid/Off-grid Wind Energy Battery-Storage System

ABSTRACT:

The objective of this paper is to explore the utilization of nonlinear control strategy to a multi-input multi yield (MIMO) nonlinear model of a breeze vitality battery stockpiling framework utilizing a changeless magnet synchronous generator (PMSG). The test is that the framework ought to work in both matrix associated and independent modes while guaranteeing a consistent progress between the two modes and an effective power circulation between the heap, the battery and the network. Our methodology is unique in relation to the regular techniques found in writing, which utilize an alternate controller for every one of the modes. Rather, in this work, a solitary bound unified nonlinear controller is proposed. The proposed unified nonlinear control framework is assessed in recreation. The outcomes demonstrated that the proposed control conspire gives high unique reactions because of network control blackout and load variety just as zero relentless state mistake.

 

BLOCK DIAGRAM:

 

Fig. 1. WECS based permanent magnet synchronous generator.

 EXPECTED SIMULATION RESULTS:

Fig. 2. Optimum Rotor Speed and Output Power.

Fig. 3. Voltage and current of the load.

Fig. 4. dc-link voltage.

Fig. 5. Wind Turbine Output Power (MW).

Fig. 6. Load Power (MW).

Fig. 7. Charge/discharge of Battery (%).

Fig. 8. Grid Power (MW).

CONCLUSION:

This paper has proposed a nonlinear MIMO controller dependent on the criticism linearization hypothesis to direct the heap voltage in both matrix associated and remain solitary mode while guaranteeing a consistent change between the two modes and an effective power dispersion between the heap, the battery and the network. Our methodology is not quite the same as the regular strategies found in writing, which utilize an alternate controller, PID based, for every method of activity. Rather, in this work, a solitary bound together nonlinear controller is proposed. The execution of the proposed controller has been tried with various breeze speeds just as in the two methods of activity with dynamic load. The recreation results demonstrate that applying nonlinear input linearization based control procedure gives a decent control execution. This execution is portrayed by quick and smooth transient reaction just as great consistent state soundness and reference following quality, even with variable breeze speed and dynamic load activity. Be that as it may, this examination expect that the framework parameters are settled. A future work will be to test the framework when parameters are obscure utilizing versatile control structure hypothesis.

Modeling, Implementation and Performance Analysis of a Grid-Connected Photovoltaic/Wind Hybrid Power System

ABSTRACT:

This paper investigates dynamic modeling, design and control strategy of a grid-connected photovoltaic (PV)/wind hybrid power system. The hybrid power system consists of PV station and wind farm that are integrated through main AC-bus to enhance the system performance. The Maximum Power Point Tracking (MPPT) technique is applied to both PV station and wind farm to extract the maximum power from hybrid power system during variation of the environmental conditions. The modeling and simulation of hybrid power system have been implemented using Matlab/Simulink software. The effectiveness of the MPPT technique and control strategy for the hybrid power system is evaluated during different environmental conditions such as the variations of solar irradiance and wind speed. The simulation results prove the effectiveness of the MPPT technique in extraction the maximum power from hybrid power system during variation of the environmental conditions. Moreover, the hybrid power system operates at unity power factor since the injected current to the electrical grid is in phase with the grid voltage. In addition, the control strategy successfully maintains the grid voltage constant irrespective of the variations of environmental conditions and the injected power from the hybrid power system.

KEYWORDS:

  1. PV
  2. Wind
  3. Hybrid system
  4. Wind turbine
  5. DFIG
  6. MPPT control

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. The system configuration of PV/wind hybrid power system.

 EXPECTED SIMULATION RESULTS:

(a) Solar Irradiance.

(b) PV array voltage.

(c) PV array current.

(d) A derivative of power with respect to voltage (dPpv/dVpv).

Fig. 2. Performance of PV array during the variation of solar irradiance.

(a) PV DC-link Voltage.

(b) d-q axis components of injected current from PV station.

(c) Injected active and reactive power from PV station.

(d) Grid voltage and injected current from PV station.

(e) The power factor of the inverter.

(f) Injected current from PV station.

Fig. 3. Performance of PV station during variation of the solar irradiance.

(a) Wind speed profile.

(b) The mechanical torque of wind turbine.

(c) The DC-bus voltage of DFIG.

(d) Injected active and reactive power from the wind farm.

(e) The power factor of the wind farm.

(f) Injected current from the wind farm.

Fig. 4. Performance of wind farm during variation of the wind speed.

(a) Power flow between PV station, wind farm, and hybrid power system.

(b) Injected active and reactive power from the hybrid system.

(c) PCC-bus voltage.

Fig. 5. Performance of hybrid power system at PCC-bus.

 CONCLUSION:

In this paper, a detailed dynamic modeling, design and control strategy of a grid-connected PV/wind hybrid power system has been successfully investigated. The hybrid power system consists of PV station of 1MW rating and a wind farm of 9 MW rating that are integrated through main AC-bus to inject the generated power and enhance the system performance. The incremental conductance MPPT technique is applied for the PV station to extract the maximum power during variation of the solar irradiance. On the other hand, modified MPPT technique based on mechanical power measurement is implemented to capture the maximum power from wind farm during variation of the wind speed. The effectiveness of the MPPT techniques and control strategy for the hybrid power system is evaluated during different environmental conditions such as the variations of solar irradiance and wind speed. The simulation results have proven the validity of the MPPT techniques in extraction the maximum power from hybrid power system during variation of the environmental conditions. Moreover, the hybrid power system successfully operates at unity power factor since the injected reactive power from hybrid power system is equal to zero. Furthermore, the control strategy successfully maintains the grid voltage constant regardless of the variations of environmental conditions and the injected power from the hybrid power system.

REFERENCES:

[1] H. Laabidi and A. Mami, “Grid connected Wind-Photovoltaic hybrid system,” in 2015 5th International Youth Conference on Energy (IYCE), pp. 1-8,2015.

[2] A. B. Oskouei, M. R. Banaei, and M. Sabahi, “Hybrid PV/wind system with quinary asymmetric inverter without increasing DC-link number,” Ain Shams Engineering Journal, vol. 7, pp. 579-592, 2016.

[3] R. Benadli and A. Sellami, “Sliding mode control of a photovoltaic-wind hybrid system,” in 2014 International Conference on Electrical Sciences and Technologies in Maghreb (CISTEM), pp. 1-8, 2014.

[4] A. Parida and D. Chatterjee, “Cogeneration topology for wind energy conversion system using doubly-fed induction generator,” IET Power Electronics, vol. 9, pp. 1406-1415, 2016.

[5] B. Singh, S. K. Aggarwal, and T. C. Kandpal, “Performance of wind energy conversion system using a doubly fed induction generator for maximum power point tracking,” in Industry Applications Society Annual Meeting (IAS), 2010 IEEE, 2010, pp. 1-7.

 

Single Phase Grid-Connected Photovoltaic Inverter for Residential Application with Maximum Power Point Tracking

ABSTRACT

This article proposes a topology for single-phase two stage grid connected solar photovoltaic (PV) inverter for residential applications. Our proposed grid-connected power converter consists of a switch mode DC-DC boost converter and a H-bridge inverter. The switching strategy of proposed inverter consists with a combination of sinusoidal pulse width modulation (SPWM) and square wave along with grid synchronization condition. The performance of the proposed inverter is simulated under grid connected scenario via PSIM. Furthermore, the intelligent PV module system is implemented using a simple maximum power point tracking (MPPT) method utilizing power balance is also employed in order to increase the systems efficiency.

 

KEYWORDS:

  1. Photovoltaic
  2. DC-DC Boost Converter
  3. MPPT
  4. SPWM
  5. Grid Connected
  6. Power Electronics
  7. Grid Tie Inverter(GTI)

  

CIRCUIT DIAGRAM:

Figure 1. Block diagram of two-stage grid connected PV system

 

EXPECTED SIMULATION RESULTS:

Figure 2. Output voltage of the inverter without filtering

Figure 3. Output current of the inverter

Figure 4. Output voltage after connected to grid

Figure 5. Output real power

Figure 6. Output voltage’s FFT (a) before filtering and (b) after filtering

 

CONCLUSION:

The main purpose of this paper is to establish a model for the grid-connected photovoltaic system with maximum power point tracking function for residential application. A single phase two-stage grid-connected photovoltaic inverter with a combination of SPWM and square-wave switching strategy is designed using PSIM. In the proposed design, an MPPT algorithm using a boost converter is designed to operate using (P&O) method to control the PWM signals of the boost converter, which is adapted to the maximum power tracking in our PV system. Instead of using line frequency transformer at the inverter output terminals, a DC-DC boost converter is used between solar panel and inverter that efficiently amplify the 24V PV arrays output into 312V DC, which is then transformed into line frequency (50Hz) sinusoidal ac 220V rms voltage by the inverter and thereby reducing the system losses and ensures high voltage gain and higher efficiency output. The simulation results show that the proposed grid connected photovoltaic inverter trace the maximum point of solar cell array power and then converts it to a high quality ripple free sinusoidal ac power with a voltage THD below 0.1% which is very much lower than IEEE 519 standard. The simulation also confirms the proposed photovoltaic inverter can be applied as a GTI and able to supplies the AC power to utility grid line with nearly unity power factor.

 

REFERENCES

[1] W. Xiao, F. F. Edwin, G. Spagnuolo, J. Jatsvevich, “Efficient approach for modelling and simulating photovoltaic power system” IEEE Journal of photovoltaics., vol. 3, no. 1, pp. 500-508, Jan. 2013.

[2] E. Roman, R. Alonso, P. Ibanez, S. Elorduizapatarietxe, D. Goitia, “ Intelligent PV module for grid connected PV system,” IEEE Trans. Ind. Elecron., vol. 53, no. 4, pp. 1066-1072, Aug. 2006.

[3] J. A. Santiago-Gonzalez, J. Cruz-Colon, R. otero-De-leon, V. lopez- Santiago, E.I. Ortiz-Rivera, “ Thre phase induction motor drive using flyback converter and PWM inverter fed from a single photovoltaic panel,” Proc. IEEE PES General Meeting, pp. 1-6, 2011.

[4] M. D. Goudar, B. P. Patil, and V. Kumar, “ Review of topology for maximum power point tracking based photovoltaic interface,” International Journal of Research in Engineering Science & Technology, vol.2, Issue 1, pp. 35-36, Feb 2011.

[5] S. Kjaer, J. Pedersen, and F. Blaabjerg, “A review of single-phase gridconnected inverters for photovoltaic modules,” Industry Applications, IEEE Transactions, vol. 41, no. 5, pp. 1292 – 1306, Sept. – Oct. 2005.

 

A ZVS Grid-Connected Three-Phase Inverter

ABSTRACT:

A six-switch three-phase inverter is widely used in a high-power grid-connected system. However, the anti parallel diodes in the topology operate in the hard-switching state under the traditional control method causing severe switch loss and high electromagnetic interference problems. In order to solve the problem, this paper proposes a topology of the traditional six-switch three-phase inverter but with an additional switch and gave a new space vector modulation (SVM) scheme. In this way, the inverter can realize zero-voltage switching (ZVS) operation in all switching devices and suppress the reverse recovery current in all anti parallel diodes very well. And all the switches can operate at a fixed frequency with the new SVM scheme and have the same voltage stress as the dc-link voltage. In grid-connected application, the inverter can achieve ZVS in all the switches under the load with unity power factor or less. The aforementioned theory is verified in a 30-kW inverter prototype..

KEYWORDS:

  1. Grid connected
  2. soft switching
  3. space vector modulation (SVM)
  4. three-phase inverter
  5. zero-voltage switching (ZVS)

 SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

 Fig. 1. ZVS three-phase inverter.

 EXPECTED SIMULATION RESULTS:

 

 Fig. 2. Inverter output current and grid voltage (10 ms/div): (a) φu = φi , (b), φuφi = π/6, (c) φuφi = π/6.

Fig. 3. CE voltage and current of S6 (IGBT on) (5 μs/div).

Fig. 4. CE voltage and current of S6 (diode on) (2.5 μs/div).

 

 Fig. 5. CE voltage and current of S7 (25 μs/div).

Fig. 6. CE voltage and current of S7 , ibus, and iLr (10 μs/div).

 

Fig. 7. VCc and iLr (50 μs/div).

Fig. 8. Efficiency curve.

CONCLUSION:

In order to speed up the market acceptance of EVs/HEVs, the capital cost in charging infrastructure needs to lower as much as possible. This paper has presented an improved asymmetric half-bridge converter-fed SRM drive to provide both driving and on-board DC and AC charging functions so that the reliance on off-board charging stations is reduced.  The main contributions of this paper are: (i) it combines the split converter topology with central tapped SRM windings to improve the system reliability. (ii) the developed control strategy enables the vehicle to be charged by both DC and AC power subject to availability of power sources. (iii) the battery energy balance strategy is developed to handle unequal SoC scenarios. Even through a voltage imbalance of up to 20% in the battery occurs, the impact on the driving performance is rather limited. (iv) the state-of-charge of the batteries is coordinated by the hysteresis control to optimize the battery performance; the THD of the grid-side current is 3.7% with a lower switching frequency.  It needs to point out that this is a proof-of-concept study based on a 150 W SRM and low-voltage power for simulation and experiments. In the further work, the test facility will be scaled up to 50 kW.

REFERENCES:

[1] B. K. Bose, “Global energy scenario and impact of power electronics in 21st Century,” IEEE Trans. Ind. Electron., vol. 60, no. 7, pp. 2638- 2651, Jul. 2013.

[2] J. de Santiago, H. Bernhoff, B. Ekergård, S. Eriksson, S. Ferhatovic, R. Waters, and M. Leijon, “Electrical motor drivelines in commercial all-electric vehicles: a review,” IEEE Trans. Veh. Technol., vol. 61, no. 2, pp. 475-484, Feb. 2012.

[3] A. Chiba, K. Kiyota, N. Hoshi, M. Takemoto, S. Ogasawara, “Development of a rare-earth-free SR motor with high torque density for hybrid vehicles,” IEEE Trans. Energy Convers., vol. 30, no. 1, pp.175-182, Mar. 2015.

[4] K. Kiyota, and A. Chiba, “Design of switched reluctance motor competitive to 60-Kw IPMSM in third-generation hybrid electric vehicle,” IEEE Trans. Ind. Appl., vol. 48, no. 6, pp. 2303-2309, Nov./Dec. 2012.

[5] S. E. Schulz, and K. M. Rahman, “High-performance digital PI current regulator for EV switched reluctance motor drives,” IEEE Trans. Ind. Appl., vol. 39, no. 4, pp. 1118-1126, Jul./Aug. 2003.

An Integrated Hybrid Power Supply for Distributed Generation Applications Fed by Nonconventional Energy Sources

ABSTRACT

A new, hybrid integrated topology, fed by photovoltaic (PV) and fuel cell (FC) sources and suitable for distributed generation applications, is proposed. It works as an uninterruptible power source that is able to feed a certain minimum amount of power into the grid under all conditions. PV is used as the primary source of power operating near maximum power point (MPP), with the FC section (block), acting as a current source, feeding only the deficit power. The unique “integrated” approach obviates the need for dedicated communication between the two sources for coordination and eliminates the use of a separate, conventional dc/dc boost converter stage required for PV power processing, resulting in a reduction of the number of devices, components, and sensors. Presence of the FC source in parallel (with the PV source) improves the quality of power fed into the grid by minimizing the voltage dips in the PV output. Another desirable feature is that even a small amount of PV power (e.g., during low insolation), can be fed into the grid. On the other hand, excess power is diverted for auxiliary functions like electrolysis, resulting in an optimal use of the energy sources. The other advantages of the proposed system include low cost, compact structure, and high reliability, which render the system suitable for modular assemblies and “plug-n-play” type applications. All the analytical, simulation results of this research are presented.

 

INDEX TERMS: Buck-boost, distributed generation, fuel cell, grid-connected, hybrid, maximum power point tracking (MPPT), photovoltaic.

 

SOFTWARE: MATLAB/SIMULINK

 

BLOCK DIAGRAM

image001   Fig. 1. Various HDGS configurations. (a) Conventional, multistage topology using two H-bridge inverters [4], [6]. (b) Modified topology with only one H-bridge inverter [4]. (c) Proposed topology. λ denotes solar insolation (Suns).

  

SIMULATION RESULTS

 image002

Fig. 2. Simulation results of the integrated hybrid configuration showing transition from mode III to mode II and then to mode I. T1 and T2 denote the transition between mode III to mode II and mode II to mode I respectively.

image003

Fig. 3. Simulation results of the integrated hybrid configuration operating in electrolysis mode (mode I to mode III and then to mode I). T1 and T2 denote the transition between mode I to mode III and mode III to mode I respectively.

image004

Fig.4. Performance comparison of the proposed HDGS system with and without an FC source in parallel with the PV source.

 

CONCLUSION

A compact topology, suitable for grid-connected applications has been proposed. Its working principle, analysis, and design procedure have been presented. The topology is fed by a hybrid combination of PV and FC sources. PV is the main source, while FC serves as an auxiliary source to compensate for the uncertainties of the PV source. The presence of FC source improves the quality of power (grid current THD, grid voltage profile, etc.) fed into the grid and decreases the time taken to reach theMPP. Table IV compares the system performance with and without the FC block in the system. A good feature of the proposed configuration is that the PV source is directly coupled with the inverter (and not through a dedicated dc–dc converter) and the FC block acts as a current source. Considering that the FC is not a stiff dc source, this facilitates PV operation at MPP over a wide range of solar insolation, leading to an optimal utilization of the energy sources. The efficiency of the proposed system in mode-1 is higher (around 85% to 90%) than mode 2 and 3 (around 80% to 85%).

 

REFERENCES

[1] J. Kabouris and G. C. Contaxis, “Optimum expansion planning of an unconventional generation system operating in parallel with a large scale network,” IEEE Trans. Energy Convers., vol. 6, no. 3, pp. 394–400, Sep. 1991.

[2] P. Chiradeja and R. Ramakumar, “An approach to quantify the technical benefits of distributed generation,” IEEE Trans. Energy Convers., vol. 19, no. 4, pp. 764–773, Dec. 2004.

[3] Y. H. Kim and S. S. Kim, “An electrical modeling and fuzzy logic control of a fuel cell generation system,” IEEE Trans. Energy Convers., vol. 14, no. 2, pp. 239–244, Jun. 1999.

[4] K. N. Reddy and V. Agarwal, “Utility interactive hybrid distributed generation scheme with compensation feature,” IEEE Trans. Energy Convers., vol. 22, no. 3, pp. 666–673, Sep. 2007.

[5] K. S. Tam and S. Rahman, “System performance improvement provided by a power conditioning subsystem for central station photovoltaic fuel cell power plant,” IEEE Trans. Energy Convers., vol. 3, no. 1, pp. 64–70.