Fuzzy Controller for Three Phases Induction Motor Drives

ABSTRACT:

Because of the low maintenance and robustness induction motors have many applications in the industries. Most of these applications need fast and smart speed control system. This paper introduces a smart speed control system for induction motor using fuzzy logic controller. Induction motor is modeled in synchronous reference frame in terms of dq form. The speed control of induction motor is the main issue achieves maximum torque and efficiency. Two speed control techniques, Scalar Control and Indirect Field Oriented Control are used to compare the performance of the control system with fuzzy logic controller. Indirect field oriented control technique with fuzzy logic controller provides better speed control of induction motor especially with high dynamic disturbances. The model is carried out using Matlab/Simulink computer package. The simulation results show the superiority of the fuzzy logic controller in controlling three-phase induction motor with indirect field oriented control technique.

KEYWORDS:

1.      Vector control

2.      Fuzzy logic

3.      Induction motor drive

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Fig. 1. Block diagram of scalar controller for IM.

Fig. 2. Indirect Field Oriented Control of IM.

EXPECTED SIMULATION RESULTS:

Fig. 3. Speed response of scalar and vector control

Fig 4. Torque response of scalar and vector control.

 Fig. 5. Flux response of scalar control.

Fig. 6. Flux response of vector control.

CONCLUSION:

Fuzzy logic controller shows fast control response with three-phase induction motor. Two different control techniques are used with Fuzzy logic controllers which are scalar and field oriented control techniques. Fuzzy logic controller system shows better response with these two techniques. Meanwhile, the scalar controller has a sluggish response than FOC because of the inherent coupling effect in field and torque components. However, the developed fuzzy logic control with FOC shows fast response, smooth performance, and high dynamic response with speed changing and transient conditions.

REFERENCES:

[1] A. Mechernene, M. Zerikat and M. Hachblef, “Fuzzy speed regulation for induction motor associated with field-oriented control”, IJ-STA, volume 2, pp. 804-817, 2008.

[2] Leonhard, W.,” Controlled AC drives, a successful transfer from ideas to industrial practice”, CETTI, pp: 1-12, 1995.

[3] M. Tacao, “Commandes numérique de machines asynchrones par lagique floue”, thése de PHD, Université de Lava- faculté des science et de génie Québec, 1997.

[4] Fitzgerald, A.E. et al., Electric Machinery, 5th Edn, McGraw-Hill, 1990.

[5] Marino, R., S. Peresada and P. Valigi, “Adaptive input-output linearizing control of induction motors”, IEEE Trans. Autom. Cont., 1993.

Power Quality Improvement in Conventional Electronic Load Controller for an Isolated Power Generation

ABSTRACT:

This paper deals with the power quality improvement in a conventional electronic load controller (ELC) used for isolated pico-hydropower generation based on an asynchronous generator (AG). The conventional ELC is based on a six-pulse uncontrolled diode bridge rectifier with a chopper and an auxiliary load. It causes harmonic currents injection resulting distortion in the current and terminal voltage of the generator. The proposed ELC employs a 24-pulse rectifier with 14 diodes and a chopper. A polygon wound autotransformer with reduced kilovolts ampere rating for 24-pulse ac–dc converter is designed and developed for harmonic current reduction to meet the power quality requirements as prescribed by IEEE standard-519. The comparative study of two topologies, conventional ELC (six-pulse bridge-rectifier-based ELC) and proposed ELC (24-pulse bridge-rectifier-based ELC) is carried out in MATLAB using SIMULINK and Power System Block set toolboxes. Experimental validation is carried out for both ELCs for regulating the voltage and frequency of an isolated AG driven by uncontrolled pico-hydro turbine.

KEYWORDS:

1.      Electronic load controller (ELC)

2.       Isolated asynchronous generator (IAG)

3.      Pico-hydro turbine

4.      24-pulse bridge rectifier.

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Fig. 1. IAG system configuration and control strategy of a chopper switch in

a six-pulse diode bridge ELC.

 EXPECTED SIMULATION RESULTS:

Fig. 2. Simulated transient waveforms of IAG on application and removal of consumer load using six-pulse diode-bridge-rectifier-based ELC.

Fig. 3. Simulated transient waveforms on application and removal of consumer load using 24-pulse rectifier-based ELC.

Fig. 4. Waveforms and harmonic spectra of (a) conventional six-pulse ELC current (i_da ), (b) generator voltage (v_a), and (c) generator current (i_a ) under the zero consumer load conditions.

Fig. 5. Waveforms and harmonic spectra of (a) proposed 24-pulse ELC current (i_da ), (b) generator voltage (v_a ), and (c) generator current (i_a ) under the zero consumer load conditions.

 CONCLUSION:

The proposed ELC has been realized using 24-pulse converter and a chopper. A comparative study of both types of ELCs (6-pulse and 24-pulse configured ELC) has been demonstrated on the basis of simulation using standard software MATLAB and developing a hardware prototype in the laboratory environment. The proposed 24-pulse ELC has given improved performance of voltage and frequency regulation of IAG with negligible harmonic distortion in the generated voltage and current at varying consumer loads.

REFERENCES:

[1] B. Singh, “Induction generator—A prospective,” Electr. Mach. Power Syst., vol. 23, pp. 163–177, 1995.

[2] R. C. Bansal, T. S. Bhatti, and D. P. Kothari, “Bibliography on the application of induction generator in non conventional energy systems,” IEEE Trans. Energy Convers., vol. EC-18, no. 3, pp. 433–439, Sep. 2003.

[3] G. K. Singh, “Self-excited induction generator research—A survey,” Electr. Power Syst. Res., vol. 69, no. 2/3, pp. 107–114, May 2004.

[4] R. C. Bansal, “Three phase isolated asynchronous generators: An overview,” IEEE Trans. Energy Convers., vol. 20, no. 2, pp. 292–299, Jun. 2005.

[5] O. Ojo, O. Omozusi, and A. A. Jimoh, “The operation of an inverter assisted single phase induction generator,” IEEE Trans. Ind. Electron., vol. 47, no. 3, pp. 632–640, Jun. 2000.

A Control Strategy for Unified Power Quality Conditioner

ABSTRACT:

 This paper presents a control strategy for a Unified Power Quality Conditioner. This control strategy is used in three-phase three-wire systems. The UPQC device combines a shunt-active tilter together with a series-active filter in a hack to- back configuration, to simultaneously compensate the supply voltage and the load current. Previous works presented a control strategy for shunt-active filter that guarantees sinusoidal, balanced and minimized source currents even if under unbalanced and / or distorted system voltages, also known as “Sinusoidal Fryze Currents”. Then, this control strategy was extended to develop a dual control strategy for series-active filter. Now, this paper develops the integration principles of shunt current compensation and series voltages compensation, both based on instantaneous active and non-active powers, directly calculated from a-b-c phase voltages and line currents. Simulation results are presented to validate the proposed UPQC control strategy.

KEYWORDS:

1.      Active Filters

2.      Active Power Line Conditioners

3.      Instantaneous Active and Reactive Power

4.      Sinusoidal Fryze Currents

5.      Sinusoidal Fryze Voltages

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1 . General configuration of the Unified Power Quality Conditioner - UPQC.

 EXPECTED SIMULATION RESULTS:

Fig. 2: Load current. current of the shunt active filter and source current.

Fig 3 Supply voltage. compensating voltage and the compensated voltage delivered to the critical load

Fig. 4. DC link voltage signal v_DC and DC voltage regulator signal G_loss

Fig. 5. Source currents, compensated voltages  and the compensated

voltage V_aw together with the source current l

CONCLUSION:

A control strategy for Unified Power Quality Conditioner - the UPQC - is proposed. Simulation results have validated the proposed control strategy, for the use in three-phase three-wire systems. In case of using in three phase four-wire systems, there is the necessity of compensating the neutral current. In this case, three-phase four wire PWM converter is necessary.

The computational efforts to develop the proposed control strategy is reduced, if compared with pq-Theory based controllers, since the α-β-0 transformation is avoided. For three-phase three-wire systems, the performance of the proposed approach is comparable with those based on the pq Theory, without loss of robustness even if operating under distorted and unbalanced system voltage conditions.

Presently, the authors are working on the possibility of extending the proposed control strategy for the use in three phase four-wire systems.

REFERENCES:

[1] S. Fryze. "Wirk-. Blind- und Scheinleistung in elektrischen Stromkainsen mit nicht-sinusfomigen Verlauf von Strom und Spannung." ETZ-Arch. Elektrotech.. vol. 53. 1932, pp. 596-599. 625-627. 700-702.

[2] L. Malesani. L. Rosseto. P. Tenti. "Active Filter for Reactive Power and Harmonics Compensation", IEEE - PESC 1986. pp. 321-330.

[3] Luis F.C. Monteiro, M. Aredes. "A Comparative Analysis among Different Control Strategies for Shunt Active Filters." Proc. (CDROM) of the V INDUSCON - Conferencia de Aplicacoes In dustriais. Salvador. Brazil, July 2002. pp.345-350.

[4] T. Furuhashi, S . Okuma. Y. Uchikawa, "A Study on the Theory of Instantaneous Reactive Power," IEEE Trans. on Industrial Electronics. vol. 37. no. 1. pp. 86-90. Feb. 1990.

[5] L. Rossetto, P. Tenti. "Evaluation of Instantaneous Power Terms in Multi-Phase Systems: Techniques and Application to Power- Conditioning Equipments." ETEP - Eur.. Trans.elect. Po wer Eng . vol. 4. no. 6. pp. 469-475, Nov./Dec. 1994.

Implementation of a DC Power System with PV Grid-Connection and Active Power Filtering

 ABSTRACT:  

The objective of this paper is to develop a DC power supply system with photovoltaic (PV) grid-connection and active power filtering. The proposed power supply system consists of an input stage and an output stage. In the input stage, a dc/dc converter incorporated with the perturbation-and-observation method can draw the maximum power from the PV source, which can be delivered to the output stage. On the other hand, grid connection or active power filtering, depending on the power of photovoltaic; will be implemented by a dc/ac inverter in the output stage. Two microcontrollers are adopted in the proposed system, of which one is to implement the MPPT algorithm, the other is used to determine the operation modes, which can be grid connection mode, direct supply mode or active power filtering mode. Finally, the experimental results are measured to verify the proposed algorithms and feasibility of the system.

KEYWORDS:

1.      12 Pulse AClDC Converter

2.       Phase Controller

3.      Autotransformer

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1 Block diagram of the proposed DC power system

 EXPECTED SIMULATION RESULTS:

 Fig. 2 The P_in, V₁ and i₁ waveforms of the MPPT Algorithm

(V₁: 100 V/div,i₁: 2 A/div, P_in: 200 W/div, time: 10 s/div)

Fig. 3 Experimental results of the MPPT function of the boost converter operate under input voltage change (150V→200V→150V).

(V_ac: 100 V/div,i_C : 5 A/div, time: 10 ms/div)

(a)

(V_ac: 100 V/div,i_C : 5 A/div, time: 10 ms/div)

(b)

(V_ac: 100 V/div,i_C : 5 A/div, time: 10 ms/div)

Fig. 4 The AC voltage V_ac and output current i_o waveforms while output power is (a) 1kW, (b) 500W and (c) 250W.

(i_L : 5 A/div, time: 10 ms/div)

Fig. 5 The load current waveform with R_n=50Ω.

 Fig. 6 Comparison the measured harmonic amount of

grid voltage and current with Europe harmonic standard IEC 1000-3-2 Class A before compensation

Fig. 7 Comparison the measured harmonic amount of grid voltage and current with Europe harmonic standard IEC 1000-3-2 Class A after compensation

(V_ac : 200 V/div,i_S : 10 A/div, i_C : 5 A/div time: 10 ms/div)

Fig. 8 The measured results of AC voltage V_ac, AC current i_s and compensated current i_c of the system operate under the active power filtering mode.

(a)

(b)

(V_ac : 200 V/div,i_ac : 10 A/div, i_C : 5 A/div, time: 20 ms/div)

Fig. 9 The load variations of the proposed power system operates under active power filtering mode (a) heavy load → light load, and (b) light load →heavy load.

 (V_S : 100 V/div,V_C1 : 300 V/div, i₁ : 5 A/div, i_C : 2 A/div, P_in : 500 W/div )

Fig. 10 The operational mode switching of the proposed r system.

CONCLUSION:

A DC power system with PV grid-connection and active power filtering has been presented in this paper, in which a DC/DC converter is firstly used to promote the output voltage of PV array and achieve the MPP. The proposed system can automate switching among the grid connection mode, direct supply mode or active power filtering mode according to the output power of PV array. In addition, two microcontrollers are used to act as system controllers, in which can except implement complicate calculation and PWM output, it can also reduce the hardware complication and cost to improve the reliability and feasibility of system. The experimental results have verified the feasibility and flexibility of the proposed system.

REFERENCES:

[1] A. Lohner, T. Meyer and A. Nagel,“A New Panel- Integratable Inverter Concept for Grid-Connected Photovoltaic System,”IEEE International Symposium on Industrial Electronics, Vol. 2, June 1996, pp. 827-831.

[2] U. Herrmann, H. G. Langer, H. van der Broeck,“Low Cost DC to AC Converter for Photovoltaic Power Conversion in Residential Applications,”Proceedings of the IEEE PESC, June 1993, pp. 588-594.

[3] J. H. R. Enslin, M. S. Wolf, D. B. Snyman and W. Sweiges,“Integrated Photovoltaic Maximum Power Point Tracking Converter,”IEEE Trans. On Industrial Electronics, Vol. 44, No. 6, 1997, pp. 769-773.

[4] S. J. Chiang, K. T. Chang and C. Y. Yen,“Residential Photovoltaic Energy Storage System,” IEEE Trans. on Industrial Electronics, Vol. 45, No. 3, 1998, pp. 385-394.

[5] S. Sopitpan, P. Changmoang and S. Panyakeow,“PV Systems With/without Grid Back-up for Housing Applications,”Proceedings of the IEEE Photovoltaic Specialists Conference, 2000, pp. 1687-1690.