Maximum Power Point Tracking Using Fuzzy Logic Controller under Partial Conditions

 ABSTRACT:

This study proposes a fuzzy system for tracking the maximum power point of a PV system for solar panel. The solar panel and maximum power point tracker have been modeled using MATLAB/Simulink. A simulation model consists of PV panel, boost converter, and maximum power point tack MPPT algorithm is developed. Three different conditions are simulated: 1) Uniform irradiation; 2) Sudden changing; 3) Partial shading. Results showed that fuzzy controller successfully find MPP for all different weather conditions studied. FLC has excellent ability to track MPP in less than 0.01 second when PV is subjected to sudden changes and partial shading in irradiation.

KEYWORDS:

1.      Fuzzy Logic Controller

2.      Maximum Power Point

3.      Photovoltaic System

4.      Partial Shading

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

 

Figure 1. Schematic diagram of PV system with MPPT.

 EXPECTED SIMULATION RESULTS:

Figure 2. P-V characteristics at different irradiations.

Figure 3. P-V characteristics when partial shading from 1000 to 600 Watt/m2.

Figure 4. Output of fuzzy at1000 Watt/m2.

Figure 5. Output of fuzzy controller. (a) Full shading from 600 to 300 Watt/m2; (b) Full shading from 700 to 400

Watt/m2; (c) Full shading from 900 to 400 Watt/m2; (d) Increasing shading from 300 to 800 Watt/m2.

Figure 6. Comparison between fuzzy and P & O partial shading (partial shading 1000 to 800 Watt/m2).

CONCLUSION:

In this study, FLC has been developed to track the maximum power point of PV system. PV panel, boost converter with FLC connected to a resistive load has been simulated using Matlab/Simulink. Simulation results have been compared to nominal power values. The proposed system showed its ability to reach MMP under uniform irradiation, sudden changes of irradiation, and partial shading. Simulation results have shown that using FLC has great advantages over conventional methods. It is found that Fuzzy controller always finds the global MPP. It is found that fuzzy logic systems are easily implemented with minimal oscillations with fast convergence around the desired MP

REFERENCES:

[1] Devabhaktuni, V., Alam, M., Reddy Depuru, S.S.S., Green II, R.C., Nims, D. and Near, C. (2013) Solar Energy: Trends and Enabling Technologies. Renewable and Sustainable Energy Reviews, 19, 555-556. http://dx.doi.org/10.1016/j.rser.2012.11.024

[2] Bataineh, K.M. and Dalalah, D. (2012) Optimal Configuration for Design of Stand-Alone PV System. Smart Grid and Renewable Energy, 3, 139-147. http://dx.doi.org/10.4236/sgre.2012.32020

[3] Bataineh, K. and Dalalah, D. (2013) Assessment of Wind Energy Potential for Selected Areas in Jordan. Journal of Renewable Energy, 59, 75-81.

[4] Bataineh, K.M. and Hamzeh, A. (2014) Efficient Maximum Power Point Tracking Algorithm for PV Application under Rapid Changing Weather Condition. ISRN Renewable Energy, 2014, Article ID: 673840. http://dx.doi.org/10.1155/2014/673840

[5] International Energy Agency (2010) Trends in Photovoltaic Applications. Survey Report of Selected IEA Countries between 1992 and 2009. http://www.ieapvps.org/products/download/Trends-in Photovoltaic_2010.pdf

Dynamic voltage restorer employing multilevel cascaded H-bridge inverter

ABSTRACT:

This study presents design and analysis of a dynamic voltage restorer (DVR) which employs a cascaded multilevel inverter with capacitors as energy sources. The multilevel inverter enables the DVR to connect directly to the medium voltage networks, hence, eliminating the series injection transformer. Using zero energy compensation method, the DVR does not need active energy storage systems, such as batteries. Since the energy storage system only includes capacitors, the control system will face some additional challenges compared with other DVR systems. Controlling the voltage of capacitors around a reference voltage and keeping the balance between them, in standby and compensation period, is one of them. A control scheme is presented in this study that overcomes the challenges. Additionally, a fast three-phase estimation method is employed to minimise the delay of DVR and to mitigate the voltage sags as fast as possible. Performance of the control scheme and estimation method is assessed using several simulations in PSCAD/EMTDC and MATLAB/SIMULINK environments, and experiments on a 7-level cascaded H-bridge converter.

SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

Fig. 1 DVR strcuctures  a Conventional DVR b CHB-based DVR

EXPECTED SIMULATION RESULTS:

Fig. 2 Three-phase voltage sag

a Network voltage

b Injected voltage by the DVR

c Load-side voltage

Fig. 3 Unbalanced voltage sag (a 20% voltage sag on phase A)

a Source voltage

b Injected voltage by the DVR

c Load-side voltage

Fig. 4 Voltages of the DC link capacitors

Fig. 5 Three-phase 20% voltage sag with voltage harmonics

a Network voltage

b Injected voltage by the DVR

c Load-side voltage

CONCLUSION:

This paper presented design and performance assessment of a DVR based on the voltage sag data collected from MWPI. Using a multilevel converter, the proposed DVR was capable of direct connection to the medium voltage-level network without a series injection transformer. In addition, development of zero active power compensation technique helps to achieve voltage restoration goal just by the capacitors as energy storages. Due to internal losses of H-bridge cells and probable inaccuracies in measurements, voltage of DC link capacitors may become unequal, which prevents proper operation of the converter. A voltage control scheme, comprised of three separate controllers, was proposed in this paper for keeping voltage balance among the DC link capacitors within nominal range. A fast estimation method was also employed for calculation of phase and magnitude terms in an unbalanced three-phase system. This estimation method is able to recognise voltage sags in approximately half a cycle. Several simulations were performed in PSCAD/EMTDC environment to verify the performance of CHB-based DVR. Additionally, a laboratory-scale prototype of the proposed DVR was built and tested. Results of the experimental test also confirmed validity of the proposed control system.

 REFERENCES:

1 Chapman, D.: ‘The cost of poor power quality’ (European Copper Institute, Copper Development Association, 2001), March

2 Radmehr, M., Farhangi, S., Nasiri, A.: ‘Effects of power quality distortions on electrical drives and transformer life in paper industries’, IEEE Ind. Appl. Mag., 2007, 13, (5), pp. 38–48

3 Lamoree, J., Mueller, D., Vinett, P.: ‘Voltage sag analysis case studies’, IEEE Trans. Ind. Appl., 1994, 30, (4), pp. 1083–1089

4 Bollen, M.H.J.: ‘Understanding power quality problems: voltage sags and interruptions’ (New York, Saranarce University of Technology, 2000)

5 Ghosh, A., Ledwich, G.: ‘Power quality enhancement using custom power devices’ (Berlin, Kluwer Academic Publications, 2002)

Design and Evaluation of a Mini-Size SMES Magnet for Hybrid Energy Storage Application in a kW-Class Dynamic Voltage Restorer

ABSTRACT:

This paper presents the design and evaluation of a mini-size GdBCO magnet for hybrid energy storage (HES) application in a kW-class dynamic voltage restorer (DVR). The HES-based DVR concept integrates with one fast-response highpower superconducting magnetic energy storage (SMES) unit and one low-cost high-capacity battery energy storage (BES) unit. Structural design, fabrication process and finite-elementmodeling (FEM) simulation of a 3.25 mH/240 A SMES magnet wound by state-of-the-art GdBCO tapes in SuNAM are presented. To avoid the internal soldering junctions and enhance the critical current of the magnet simultaneously, an improved continuous disk winding (CDW) method is proposed by introducing different gaps between adjacent single-pancake coil layers inside the magnet. About 4.41% increment in critical current and about 3.42% increment in energy storage capacity are demonstrated compared to a conventional CDW method. By integrating a 40 V/100 Ah valve-regulated lead-acid (VRLA) battery, the SMES magnet is applied to form a laboratory HES device for designing the kW-class DVR. For protecting a 380 V/5 kW sensitive load from 50% voltage sag, the SMES unit in the HES based scheme is demonstrated to avoid an initial discharge time delay of about 2.5 ms and a rushing discharging current of about 149.15 A in the sole BES based scheme, and the BES unit  is more economically feasible than the sole SMES based scheme for extending the compensation time duration.

KEYWORDS:

1.      Superconducting magnetic energy storage (SMES)

2.       SMES magnet design, hybrid energy storage (HES)

3.      Battery energy storage (BES)

4.      Continuous disk winding (CDW)

5.      Dynamic voltage restorer (DVR)

6.       Voltage sag compensation

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1. Circuit topology of the HES-based DVR.

EXPECTED SIMULATION RESULTS:

Fig. 2. Transient voltage curves: (a) Load voltage before compensation; (b) Compensation voltage from the DVR; (c) Load voltage after compensation.

Fig. 3. Transient voltage curves: (a) Load voltage before compensation; (b) Compensation voltage from the DVR; (c) Load voltage after compensation.

CONCLUSION:

The structural design, fabrication process and FEM simulation of a 3.25 mH/240 A SMES magnet wound by state-of-the-art GdBCO tapes have been presented in this paper. The FEM simulation results have proved the performance enhancements in both the critical current and energy storage capacity by using the improved CDW scheme. Such a mini-size SMES magnet having relatively high power and low energy storage capacity is further applied to combine with a 40 V/100 Ah VRLA battery for developing a laboratory HES device in a kW-class DVR. In a 5 Kw sensitive load applications case, voltage sag compensation characteristics of three different DVR schemes by using a sole SMES system, a sole BES system and a SMES-BES-based HES device have been discussed and compared. With the fast-response high-power SMES, the maximum output current from the BES system is reduced from about 149.15 A in the BES-based DVR to 62.5 A in the HES-based DVR, and the drawback from the initial discharge time delay caused by the inevitable energy conversion process is offset by integrating the SMES system. With the low-cost high-capacity BES, practical compensation time duration is extended from about 32 ms in the SMES-based DVR to a longer duration determined by the BES capacity. Therefore, the proposed HES concept integrated with fast-response high-power SMES unit and low-cost high-capacity BES unit can be well expected to apply in practical large-scale DVR developments and other similar SMES applications.

REFERENCES:

[1] Mohd. H. Ali, B. Wu, and R. A. Dougal, “An overview of SMES applications in power and energy systems,” IEEE Trans. Sustainable Energy, vol. 1, no. 1, pp. 38-47, 2010.

[2] X. Y. Chen et al., “Integrated SMES technology for modern power system and future smart grid,” IEEE Trans. Appl. Supercond., vol. 24, no. 5, Oct. 2014, Art. ID 3801605.

[3] IEEE Std 1159-2009, IEEE Recommended Practice for Monitoring Electric Power Quality, 2009.

[4] X. H. Jiang et al., “A 150 kVA/0.3 MJ SMES voltage sag compensation system,” IEEE Trans. Appl. Supercond., vol. 15, no. 2, pp. 1903-1906, Jun. 2005.

[5] S. Nagaya et al., “Field test results of the 5 MVA SMES system for bridging instantaneous voltage dips,” IEEE Trans. Appl. Supercond., vol. 16, no. 2, pp. 632-635, Jun. 2006.

An Interline Dynamic Voltage Restoring and Displacement Factor Controlling Device (IVDFC)

ABSTRACT:

An interline dynamic voltage restorer (IDVR) is invariably employed in distribution systems to mitigate voltage sag/swell problems. An IDVR merely consists of several dynamic voltage restorers (DVRs) sharing a common dc link connecting independent feeders to secure electric power to critical loads. While one of the DVRs compensates for the local voltage sag in its feeder, the other DVRs replenish the common dc-link voltage. For normal voltage levels, the DVRs should be bypassed. Instead of bypassing the DVRs in normal conditions, this paper proposes operating the DVRs, if needed, to improve the displacement factor (DF) of one of the involved feeders. DF improvement can be achieved via active and reactive power exchange (PQ sharing) between different feeders. To successfully apply this concept, several constraints are addressed throughout the paper. Simulation and experimental results elucidate and substantiate the proposed concept.

KEYWORDS:

1.      Displacement factor improvement

2.      Interline dynamic voltage restorer (IDVR)

3.      Interline dynamic voltage restoring and displacement factor controlling (IVDFC)

4.      PQ sharing mode

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. Principle of IVDFC system operation during normal conditions (PQ sharing mode).

EXPECTED SIMULATION RESULTS:

Fig. 2. Per-phase PQ sharing mode simulation results: (a)–(c) for first case and (d)–(f) for the second case.

Fig. 3. Per-phase simulation results for voltage sag condition at: (a) feeder 1 and (b) feeder 2.

Fig. 4. Per-phase experimental and corresponding simulation results for DF improvement case: (a) and (b) receiving feeder; (c) and (d) sourcing feeder (time/div= 10 ms/div).

Fig. 5 Per-phase experimental results and corresponding simulation results for voltage sag case: (a) and (b) at feeder 1 and (c) and (d) at feeder 2 (time/div = 10 ms/div).

Fig. 6 Per-phase experimental results and corresponding simulation results for voltage swell case at: (a) and (b) feeder 1 and (c) and (d) at feeder 2 (time/div = 10 ms/div).

CONCLUSION

This paper proposes a new operational mode for the IDVR to improve the DF of different feeders under normal operation. In this mode, theDFof one of the feeders is improved via active and reactive power exchange (PQ sharing) between feeders through the common dc link.

The same system can also be used under abnormal conditions for voltage sag/swell mitigation. The main conclusions of this work can be summarized as follows:

1) Under PQ sharing mode, the injected voltage in any feeder does not affect its load voltage/current magnitude, however, it affects the DFs of both sourcing and receiving feeders. The DF of the sourcing feeder increases while the DF of the receiving feeder decreases.

2) When applying the proposed concept, some constraints should be satisfied to maintain the DF of both sourcing and receiving feeders within acceptable limits imposed by the utility companies. These operational constraints have been identified and considered.

3) The proposed mode is highly beneficial if the active power rating of the receiving feeder is higher than the sourcing feeder. In this case, the DF of the sourcing feeder will have a notable improvement with only a slight variation in DF of the receiving feeder.

The proposed concept has been supported with simulation and experimental results.

REFERENCES:

[1] S. A. Qureshi and N. Aslam, “Efficient power factor improvement technique and energy conservation of power system,” Int. Conf. Energy Manage. Power Del., vol. 2, pp. 749–752, Nov. 21–23, 1995.

[2] J. J. Grainger and S. H. Lee, “Optimum size and location of shunt capacitors for reduction of losses on distribution feeders,” IEEE Trans. Power App. Syst., vol. PAS-100, no. 3, pp. 1105–1118, Mar. 1981.

[3] S. M. Kannan, P. Renuga, and A. R. Grace, “Application of fuzzy logic and particle swarm optimization for reactive power compensation of radial distribution systems,” J. Electr. Syst., 6-3, vol. 6, no. 3, pp. 407–425, 2010.

[4] L. Ramesh, S. P. Chowdhury, S. Chowdhury, A. A. Natarajan, and C. T. Gaunt, “Minimization of power loss in distribution networks by different techniques,” Int. J. Electr. Power Energy Syst. Eng., vol. 3, no. 9, pp. 521–527, 2009.

[5] T. P.Wagner, A. Y. Chikhani, and R. Hackam, “Feeder reconfiguration for loss reduction: An application of distribution automation,” IEEE Trans. Power Del., vol. 6, no. 4, pp. 1922–1933, Oct. 1991.

Variable speed drive with PFC front-end for three-phase induction motor

ABSTRACT:

A variable frequency drive for an induction motor is proposed. The drive uses a power factor (PF) correction bridgeless single-ended primary inductor converter-controlled rectifier operating in discontinuous inductor current mode as a front-end in order to improve the input power quality and a variation of the constant volts per hertz controller, with feedback to regulate the velocity of the motor shaft. The frequency slip is measured and compensated, since the input stage. Experiments with and without load are carried out and presented. Input power quality measurements are also presented. The proposed system is effective to regulate the velocity and achieving a close to unity PF.

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Fig. 1 Proposed AC–DC–AC converter

 EXPECTED SIMULATION RESULTS:

Fig. 2 Results from experiments I and II

Fig. 3 Input voltage and current waveforms and input current harmonics

a Input voltage and current waveforms, Channel 1 for current and Channel 2 for

voltage. Current is measured by V–I converter with 1 V:1.6 A conversion ratio

b First 39 non-fundamental current harmonics

CONCLUSION:

The proposal of an SEPIC converter as the front-end of single-phase to three-phase AC–DC–AC converter for an induction motor for improving the input power quality is presented. It is also shown a variation of the CVH controller to regulate the angular velocity of the motor shaft using the aforementioned topology. The controller compensates the frequency slip, due to mechanical load, since the rectifying stage. The experimental results show that the topology is effective for regulating the velocity and that the topology can achieve a close to unity PF and low THD. The computed spectrum can be used to design passive input filters and further improve the THD and the PF of the circuit.

REFERENCES:

1 Moghani, J.S., and Heidari, M.: ‘High efficient low cost induction motor drive for residential applications’. Int. Symp. Power Electronics, Electrical Drives, Automation and Motion, 2006 SPEEDAM 2006, Taormina, Italy, May 2006, pp. 1399–1402

2 Singh, S., and Singh, B.: ‘A voltage-controlled PFC Cuk converter-based PMBLDCM drive for air-conditioners’, Trans. Ind. Appl., 2012, 48, (2), pp. 832–838

3 Bist, V., and Singh, B.: ‘An adjustable-speed PFC bridgeless buck–boost converter-fed BLDC motor drive’, Trans. Ind. Electron., 2014, 61, (6), pp. 2665–2677

4 Abe, K., Haga, H., Ohishi, K., and Yokokura, Y.: ‘Fine current harmonics reduction method for electrolytic capacitor-less and inductor-less inverter based on motor torque control and fast voltage feedforward control for IPMSM’, Trans. Ind. Electron., 2017, 64, (2), pp. 1071–1080

5 APA Sabzali, A.J., Ismail, E.H., Al-Saffar, M.A., and Fardoun, A.A.: ‘New bridgeless DCM SEPIC and Cuk PFC rectifiers with low conduction losses’, Trans. Ind. Appl., 2011, 47, (2), pp. 873–881

Single-Phase Active Power Filtering Method Using Diode-Rectifier-Fed Motor Drive

ABSTRACT:

 This paper presents a single-phase high power factor motor drive system with active power filter function. Since most of electrical equipment connected to the grid must comply with regulations regarding grid current harmonics, motor drive systems are generally equipped with Power Factor Corrector (PFC) which is comprised of power switches and reactive components, e.g., inductor and capacitor. The reactive components are bulky and increase the system cost especially in low-cost applications such as electrical home appliances. In this paper, a new motor drive algorithm which is capable of both driving a permanent magnet motor and filtering the harmonic currents produced by other non-linear loads belong to the system is proposed. Since the input current of the drive system is directly controlled by manipulating not the motor current reference but the output voltage reference of the inverter, it is possible to achieve exact and immediate control of the grid current. The effectiveness of the proposed algorithms is validated by experiments with a permanent magnet motor drive system.

KEYWORDS:

1.      Active damping

2.      Constant power load

3.       Dc-link capacitor

4.       Dc-link voltage stabilization

5.      Electrolytic capacitor

6.       Power factor corrector

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

                   

Figure 1. Block diagram of the input current control and the active power filter function.

 EXPECTED SIMULATION RESULTS:

Figure 2. (a) Motor currents (a-phase current in the stationary frame and d-q axes currents in the syncronous reference frame) with the proposed input current control, and (b) grid current, dc-link voltage, speed error and estimated torque.

Figure 3. Experimental results : input current of non-linear load and motor drive, grid current, dc-link voltage of both diode-rectifier (a) with the input current control algorithm, (b) with both the input current control and the active harmonic filtering algorithms, (c) three-phase motor currents (ia, ib, ic), grid voltage and current.

Figure 4. (a) PFC operation at light motor load (15% motor load) , and (b) during load change from 15% to 100% motor load.

CONCLUSION:

In motor drive systems supplied by a single-phase grid, the problems of input harmonic currents have been mitigated by a PFC, which makes the system bulk and expensive. In this paper, a power factor correction method for motor drive systems without PFC has been proposed. In the proposed system, the dc-link capacitor is reduced for continuous conduction of diode rectifier front end. And, the input current is controlled by directly manipulating the inverter output voltage according to the motor currents and the input current reference. Since the input current can be shaped into any waveforms using the proposed input current control method, it is also possible to eliminate the harmonics in the grid current that other electric loads generate by injecting the opposite harmonics. It was validated by experiments that the input current can be controlled using the proposed algorithm and the harmonic currents from other non-linear loads can be actively suppressed.

REFERENCES:

[1] Electromagnetic Compatibility (EMC), Part 3-2: Limits-Limits for Harmonic Current Emissions (Equipment Input Current≤ 16 A Per Phase), International Standard IEC 61000-3-2, 2005, 2013.

[2] H. Endo, T. Yamashita and T. Sugiura, "A high-power-factor buck converter", in Proc. IEEE Power Electron. Spec. Conf. (PESC), pp.1071 -1076 Jun. /Jul., 1992.

[3] L. Yen-Wu and R. J. King, "High performance ripple feedback for the buck unity-power-factor rectifier", IEEE Trans. Power Electron., vol. 10, no. 2, pp.158 -163, 1995

[4] B. Chen , Y. Xie , F. Huang and J. Chen, "A novel single-phase buck PFC converter based on one-cycle control", in Proc. IEEE Power Electron. Motion Control Conf. (IPEMC), vol. 2, pp.1 -5 Aug., 2006.

[5] W. W. Weaver and P. T. Krein, "Analysis and applications of a current-sourced buck converter", in Proc. IEEE Appl. Power Electron. Conf. (APEC), pp.1664 -1670 Feb. /Mar., 2007.