Space Vector Pulse Width Modulation Fed Direct Torque Control Of Induction Motor Drive Using Matlab-Simulink

 ABSTRACT:

Now a day’s induction motor drives are highly demanding to design both mechanical and electrical drive system which is used widely in many industrial applications. Recent years many mathematical models for induction motor drive using Simulink models are employed. Scalar and Vector control method can be applied to induction motors in three phases symmetric as well as unsymmetrical two-phase form. The mathematical and Simulink operation of the induction motor drive can be studied and it is equivalent to a DC motor by the vector control method. With the combined performance of the numerical electronics and power electronics we are capable to smoothly control the variable speed and torque in low power industrial operations. With the help of technological achievements, several command and control techniques are developed by the technologists to control the time, flux and torque of the industrial electrical machine drives. The direct torque control (DTC) technique is one of the most advanced mechanisms in control operation of torque and speed. This technique with SVPWM gives fine regulation without rotational speed controlled feedback. The electromagnetic torque and stator flux are estimated in DTC technique only stator currents and voltage and it is independent of the parameters of the motor except for the Rs i.e. stator resistance [7].

KEYWORDS:

1.      Controller

2.      DTC

3.      IDM

4.      SVPWM and switching table.

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig.1. DTC block diagram

 EXPECTED SIMULATION RESULTS:

Fig.2. Electromagnetic torque

Fig.3. Rotor speed

Fig.4. Stator current

Fig.5. d-axis stator flux

Fig.6. q-axis stator flux

Fig.7. Electromagnetic torque

Fig.8. Rotor speed

Fig.9. Trajectory of direct axis stator and quadrature axis

flux (stationary reference frame)

Fig.10. Electromagnetic torque

Fig.11. Rotor speed

Fig.12. Direct axis stator flux

Fig.13. Quadrature axis stator flux

Fig.14. Direct axis stator current

Fig.15. Quadrature axis stator current

Fig.16. Stator flux trajectory

Fig.17. Rotor flux trajectory

CONCLUSION:

The proposed paper highlights to create a Simulink model of  DTC in induction motor drive. The DTC technique allows the decoupled control of torque and stator flux operate indipendently. The control process is simulated with the help of simpower system MATLAB Simulink block set and Sector determination with open-loop induction motor drive is obtained. In conventional DTC technique, high torque ripple is produced because the voltage space vector which are considered is applied for the whole switching period without considering the torque error value. This torque ripple can be minimized in order to achieve a smooth operation of the drive system and its performances, by changing the duty cycle ratio of the voltage vector which are selected during each switching cycle period, based on the stator flux position and torque error magnitude. This constitutes the basic of SVPWM technique. here simulate DTC scheme based on SVPWM technique and comparative study of conventional DTC-SVM scheme is derived and studied.

REFERENCES:

[1] Takahashi Isao, Noguchi Toshihiko, ,,’’A New Quick-Response IEEE Transactions on Industry Applications , Vol. IA-22No-5, Sept/Oct 1986.

Direct Torque Control of Brushless DC Drives With Reduced Torque Ripple

 ABSTRACT:

The application of direct torque control (DTC) to brushless ac drives has been investigated extensively. This paper describes its application to brushless dc drives, and highlights the essential differences in its implementation, as regards torque estimation and the representation of the inverter voltage space vectors. Simulated and experimental results are presented, and it is shown that, compared with conventional current control, DTC results in reduced torque ripple and a faster dynamic response.

KEYWORDS:

1.      Brushless dc (BLDC) drives

2.      Direct torque control (DTC)

3.      Permanent-magnet motor

 SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Fig. 1. Schematic of DTC BLDC drive.

EXPECTED SIMULATION RESULTS:

Fig. 2. Simulated results for Motor 1 (1500 r/min). (a) Phase-to-ground voltage. (b) Phase voltage. (c) Phase current. (d) Locus of stator flux linkage. (e) Electromagnetic torque.

Fig. 3. Simulated results for Motor 2 (400 r/min). (a) Phase-to-ground voltage. (b) Phase voltage. (c) Phase current. (d) Locus of stator flux linkage. (e) Electromagnetic torque.

CONCLUSION:

DTC has been applied to a BLDC drive, and its utility has been validated by simulations and measurements on two BLDC motors which have very different back-EMF waveforms. The main difference between the implementation of DTC to BLAC and BLDC drives is in the estimation of torque and the representation of the inverter voltage vectors. It has been shown that DTC is capable of instantaneous torque control and, thereby, of reducing torque pulsations.

REFERENCES:

[1] J. R. Hendershort Jr and T. J. E. Miller, Design of Brushless Permanent- Magnet Motors. Oxford, U.K.: Magana Physics/Clarendon, 1994.

[2] T. Kenjo and S. Nagamori, Permanent-Magnet and Brushless DC Motors. Oxford, U.K.: Clarendon, 1985.

[3] P. J. Sung,W. P. Han, L. H. Man, and F. Harashima, “A new approach for minimum-torque-ripple maximum-efficiency control of BLDC motor,” IEEE Trans. Ind. Electron., vol. 47, no. 1, pp. 109–114, Feb. 2000.

[4] C. French and P. Acarnley, “Direct torque control of permanent magnet drives,” IEEE Trans. Ind. Appl., vol. 32, no. 5, pp. 1080–1088, Sep./Oct. 1996.

[5] T. S. Low, K. J. Tseng, K. S. Lock, and K.W. Lim, “Instantaneous torque control,” in Proc. Fourth Int. Conf. Electrical Machines and Drives, Sep. 13–15, 1989, pp. 100–105.

b

A Novel Direct Torque Control Scheme for Induction Machines With Space Vector Modulation

ABSTRACT:

In this paper a new method for Direct Torque Control (DTC) based on load angle control is developed. The use of simple equations to obtain the control algorithm makes it easy tu understand and implement. Fixed switching frequency and low torque ripple are obtained using space vector modulation. This control strategy overcomes the must important drawbacks of classic DTC. Results shows the feasibility of the proposed method, obtaining good speed control bandwidth while overcoming classic DTC drawbacks.

KEYWORDS:

1.      Electric Drives

2.      AC Machines

3.      Direct Torque Control

4.      Space Vector Modulation

 SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

 Fig.  1. Classic DTC control block diagram

EXPECTED SIMULATION RESULTS:

Fig. 2. Comparison of dynamic response klween DTC-SVM.F ield Oriented Control and Classic DTC. (a) Field Oriented Control. (b) Classic Direct Torque Control. (e) proposed Method.

Fig. 3. Torque response comparison between DTC-SVM and classic DTC. (a) Field Onenled Control, (h) Classic Direct Torque Control, (c) Proposed Method.

Fig. 4. Size of hysteresis band and sampling frequency effects on torque

ripple for clasic DTC.

Fig. 5. Torque spectral analJsis cornpanson. (a) DTC-SVM torque spectrum,

(b) Classic DTC torque spectrum.

Fig. 6. Stator Current during speed reversal.

.CONCLUSION:

The DTC-SVM strategy proposed in this work to control flux and torque is based on few induction machine fundamental equations. Consequently, the control method is simple and easy to implement. No coordinate rotation and less PI controllers than in field oriented control are needed. 0.1 (1.2 0.3 0.4 0.5 0.6 In addition, the proposed DTC strategy is well suited for use lime Is] in conjunction with space vector modulation resulting in a powerful alternative to overcome the well known drawbacks Fig. IO. Stator Current during speed reversal. of the original DTC solution: variable switching frequency and high torque ripple.

REFERENCES:

[1] F. Blaschke. “A New Method for the Estructural Decoupling of AC Induction Machines”. Cmj Rec. IFAC, Duessektorf. Genmny, pages 1-15, Oct. 1971.

[2] 1. Takahashi, Y. Ohmori. “High-Performance Direct Torque Control of an Induction Motor?. IEEE Trons. on Indu.~rriol Applicutions, 25(2):257- 262. MarcWApril 1989.

[3] M. Depenbmk. “Direct Self-Control (DSC) of Inverter-Fed Induction Machine”. IEEE Trans. on Power Elecrronicr. 3(4):42M29, October 1988.

[4] D. Casadei. G. Sera, A. Tani. “Implementation of a Direct Torque Control Algorithm for Induction Motors Based on Discrete Space Vector Modulation”. IEEE Trans. on Power Electronics. 15(4):769-777, July 2Mm.

[5] C. Manins, X. Roboarn. T.A. Meynard. A. Carvalho. “Switching frequency lmposition and Ripple Reduction in DTC Drives by Using a Multilevel Converer”. IEEE Trans. on Power Electmnicr. 17(2):28& 297, March 2002.

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.